Senior Comp Projects -Scott Wissinger

Name: Colley, Ryan R.
Date: Spring 2007
Major: Environmental Science
Thesis Committee: Dr. Scott Wissinger, Dr. Milt Ostrofsky

Protection of large, high profile waterways means the protection of the cumulative network of tributary streams feeding them. To understand the health of the tributary streams, an index of biologic integrity (IBI) must be adapted to the biologic assemblages indigenous to the stream. Many studies have designed IBIs for regional streams, but often using fish as a bioindicator. In streams where fish are not present, the biological community differ enough to require the design of a new headwater IBI. The purpose of this study was to adapt and evaluate a regional IBIs to accurately assess the integrity of fishless headwater streams in northwestern Pennsylvania. Twenty streams were selected based on varying degrees of human disturbance. The human disturbance on the stream was quantified using the habitat quality assessment tools Riparian, Channel, and Environmental Inventory (RCE) and Ohio EPA Headwater Habitat Evaluation Index (HHEI). The biologic integrity of the twenty streams was quantified based on salamander and benthic macroinvertebrates assemblages.

Salamander assemblage attributes exemplified significant correlation to the habitat quality assessment. Benthic macroinvertebrate showed a significant association with the local RCE, but did not show any association with Ohio’s HHEI. One potential headwater IBI (HIBI) was build from the responsive salamander metrics alone, while a second was designed using salamander and benthic macroinvertebrate metrics. The results of the testing of both HIBI found both to have a strong correlation to the habitat quality assessment tool scores. The headwater IBI with only salamander metrics was selected as the most efficient index.

The new HIBI showed a significant and dynamic response to varying degrees of human disturbance in fishless headwater streams. It also proved as a rapid and efficient field indicator of stream health. The introduction of a tailored headwater index of biotic integrity allows for rapid biomonitoring and quantification of the overall health of a stream. The rapid assessment of the biological health allows an extensive representation of the overall integrity of a stream system.

Name: Crosser, Jinelle
Date: Spring 2007
Major: Environmental Science
Thesis Committee: Dr. Scott Wissinger, Dr. Amara Geffen

Streams in urban settings suffer from degradation due to anthropogenic causes. While there are many potential sources of this degradation, one of the most likely causes is the increase of connected impervious surfaces due to development within the watershed. As a result, hydrologic processes that normally take place in the absence of these surfaces are altered in small order streams. Recent studies on Mill Run in Meadville, Pennsylvania have shown characteristics of a degraded urban stream. The purpose of this project was to design a wetland habitat using principles of ecological art in order to enhance the stream ecosystem as well as provide an area conducive for visiting school children and the public. The design is based on recommendations and collaborations with local elementary school faculty, ecologists, engineers, and artists and includes features that facilitate an efficient learning environment that reveals underlying natural processes.

This project was supported in part by the Shanbrom Research Fund and the Henry Luce Foundation.

Name: Galletta, Sean P.
Date: Spring 2007
Major(s): Biology
Thesis Committee: Dr. Scott Wissinger, Dr. Milt Ostrofsky

Brook trout (Salvelinus fontinalis) were originally found throughout Pennsylvania. By around 1920, approximately 80% of Pennsylvania’s forests were destroyed for agriculture, lumber, and fuel resulting in the disappearance of the clean, cold streams that are required by brook trout. Stream shading, promotion of water infiltration, and bank stabilization are a few of the natural process that were once provided by the forests to maintain clean, cold streams. The forests in Pennsylvania have begun to recover, suggesting that brook could survive in areas of their original range from which they were extirpated. Nine abiotic and biotic variables were used to compare each candidate streams to brook trout streams. These variables were % forest cover, % riparian intactness, maximum summer temperature, minimum summer dissolved oxygen, % dissolved oxygen saturation, % sensitive fish, % tolerant fish, % EPTs, and benthic richness. Confidence intervals were created for each variable based on values from streams with brook trout. Candidate streams were judged based on whether their conditions fell within the confidence intervals of brook trout stream conditions. Five of the nine candidate streams were considered moderate candidates or better. Reintroducing brook trout into these streams would hopefully be source populations within their subwatershed, allowing brook trout to redistribute themselves when conditions become viable in other tributaries within the subwatershed. My data suggest that the expansion of brook trout into the eastern tributaries of the French Creek watershed is a realistic objective.

Name: Goetz, Elizabeth A.
Date: Spring 2007
Major: Environmental Science
Thesis Committee: Dr. Scott Wissinger, Dr. Jim Palmer

Fish have been widely used as an indicator group for biomonitoring studies that assess the degradation of streams. In her senior thesis, Allison Roy (1998) tailored the generic fish index of biotic integrity (IBI) (Karr 1981) to reflect the conditions in headwater streams in the French Creek watershed. Since then her revised fish IBI has been used by classes and subsequent senior projects for assessing land use impacts on 2nd and 3rd order streams in northwestern Pennsylvania. Despite the adoption of this IBI for biomonitoring projects in the region, the performance of the index has never been evaluated against a data set other than the original eight streams from which it was proposed. The purpose of my senior thesis was to compare the responsiveness of Roy’s final IBI version (Roy 2) and four other modified versions of the fish IBI to an expanded group of 23 2nd and 3rd order streams impacted by varying watershed and riparian conditions. A second goal was to evaluate the degree to which overall land use in a catchment versus the percent upstream riparian intactness is a better predictor of the results of bioassessment.

The five IBIs were evaluated against both of the land use variables using the expanded data set; by utilizing the recommended methodologies for improving IBIs (Karr and Chu 1999), I added, dropped, or modified individual metrics to increase the predictive power of the overall index. The end result was an IBI composed of six responsive metrics that had higher r2 values when regressed against the land coverage variables than did any of the previous five indices. Multiple regressions determined that watershed and percent upstream riparian intactness together give a better statistical fit to IBI metrics and to the overall IBI scores than either do alone. With the assemblage of a modified IBI, tributaries in the French Creek watershed can be rapidly assessed in order to preserve the high ecological quality of the local ecosystem.

This project was supported in part by the Class of 1939 Senior Research Fund and the Henry Luce Foundation.

Name: Gunther, Jenifer A.
Date: Spring 2007
Major(s): Biology
Thesis Committee: Dr. Scott Wissinger, Dr. Milt Ostrofsky

The short inundation period of temporary aquatic environments places time constraints on the species that complete their lifecycles in them. In response to these constraints, organisms exhibit developmental tradeoffs between the efforts put towards growth (size) and the efforts put towards development (movement through larval instars). A protein rich diet, sometimes achieved through cannibalism, has been suggested to give certain aquatic insects the ability to overcome the small size that is a consequence of the tradeoff for earlier emergence. By crossing pond permanence and food supplementation in a mesocosm experiment, I hoped to produce this tradeoff. Previous experiments on the permanent pond caddisfly, Limnephilus externus, displayed increased developmental rates under supplemented permanent, but not supplemented temporary environments. A second experiment was conducted to determine if wide temperature fluctuations experienced in temporary ponds are the reason for not observing this tradeoff. The purpose of my senior project is three-fold. First, I wanted to determine if a temporary pond species, Asynarchus nigriculus, will exhibit the same pattern as the permanent pond species L. externus; and second if food supplementation will produce a rescuing effect by increasing survival and size as adults. Thirdly, I wanted to determine the effects of temperature fluctuation on the growth and development of A. nigriculus. Overall temporary environments produced longer development times than permanent. However, when larvae received a food supplement, development times of temporary environments were shortened to times experienced in permanent ponds. Prolonged development times and reduced survival in temporary environments suggest a condition that stresses the organisms unique to these environments. Higher activity rates in temporary conditions point to physiological stress that could account for lack of rescuing effect and low survival rates in non-supplemented temporary environments. Future studies should look further into the other conditions that change in temporary environments such as ion concentrations and increased competition.

This research was supported in part by a grant from the National Science Foundation (NSF (DEB-010893)).

Name: Hamilton, Cassandra L.
Date: Spring 2007
Major(s): Biology
Thesis Committee: Dr. Scott Wissinger, Dr. Milt Ostrofsky

Many animals in nature display predator-induced phenotypic plasticity when there is an increased risk of predation. Larval amphibians are an excellent study group for investigating changes in behavior and morphology when exposed to natural predators, and most previous studies have concentrated on the effects of predators on the behavior and morphology of anuran (frog and toad) tadpoles. In this study, I quantified the separate and combined effects of dragonfly larvae (Anax junius) and largemouth bass (Micropterus salmoides) on the growth and development of spotted salamander larvae. I hypothesized that because of constraints on tail morphology in salamanders, they would not exhibit the typical anuran response to predators that has been observed in previous studies. I conducted a field experiment in cattle tanks at the Bousson Experimental Research Reserve with four treatments: i. no predators, ii. fish predators, iii. dragonfly predators, and iv. both predators, and measured the effects on a variety of salamander larvae metrics including total body length, body depth, body width, tail length, tail width, tail depth, and body mass. I found that the presence of caged fish predators significantly increased tail length, while the presence of caged dragonfly predators did not affect any of the salamander larvae metrics. Changes in morphology may require a significant tradeoff between survival and reproduction success. Future predation studies may include monitoring the changes in behavioral activity. Future studies might determine whether behavior and/or morphological change are the most important factor when it comes to avoiding predation.

Name: Angelo, Shelby J.
Date: Spring 2006
Major(s): Biology
Thesis Committee: Dr. Scott Wissinger, Dr. Catharina Coenen

Life history characteristics of wetland species depend on the hydroperiod of the habitat, quality and quantity of resources, and the ability of a juvenile to maximize adult fitness (as determined by selective forces). To determine the interactive effects of food quality and pond drying on growth, development and behavior in a vernal pond caddisfly (Asynarchus nigriculus), I manipulated habitat drying and diet. Protein supplementation shortened the larval growth time and increased the chance of survival of pupae to the adult stage. Adult fitness (dry mass) and adult body length were not affected by any of the treatments. Asynarchus was more active in drying and supplemented treatments and aggressive in drying, which may suggest a compound advantage over Limnephilus externus in vernal habitats. I concluded that late-instar Asynarchus are better able to negotiate the negative effects of pond drying than those of a permanent species, L. externus in a previous study.

In a second study conducted at Allegheny’s Bousson Reserve, I studied the life history of caddisflies that over-winter as final-instar larvae. I determined the effect of food quality on adult fitness in a community of caddisflies. In conjunction with an instar-specific dietary analysis (Mumford in progress) this project serves as an initiative to inspire further research of caddisflies with different life histories than those in Colorado. Future goals include determining the selective forces on local caddisflies and motivations behind supplementation of a primarily detrital diet with animal material.

This research was supported in part by the Class of 1939 Senior Research Fund and the Dextra Baldwin McGonagle Fund.

Large quantities of plant material fall into aquatic habitats every year. Once this detritus enters aquatic environments it becomes a usable form of energy through a complex process of breakdown. An important stage is colonization by microbes that process the detritus. Detritus breakdown has been heavily examined in many aquatic ecosystems, but not wetlands. In streams we know that a) microbes are more nutritious to invertebrate shredders then detritus itself, b) fungi are the most abundant microbial colonizer, and c) fungi proliferate best in conditions where detritus is frequently aerated. In temporary wetlands detritus is not permanently submerged and is frequently exposed to the air during dry seasons. To determine if fungi “conditions” detritus similarly in wetlands the behavioral preference of Nemotaulius hostilis was observed. N. hostilis was allowed to choose from detritus conditioned under three different wet/dry inundation schedules. It was assumed N. hostilis would select detritus based on its nutritious content. I found that caddisflies preferred detritus conditioned under semi-permanent conditions more then permanent and temporary conditions. Ergosterol was quantified to estimate fungal biomass. I found ergosterol levels to be greatest in the permanently conditioned detritus. Similarly nitrogen concentration was highest in the detritus conditioned under permanent conditions. The combined results of this study suggest that wetland caddisflies consume detritus based on other factors besides fungal biomass. Recent research in wetlands has found that bacteria are more important than fungi. Additional research is required to determine if these caddisflies were consuming detritus based on a combination of fungal and bacterial content.

The varying physical conditions along a permanence gradient in wetlands directly influence macroinvertebrate community structure by dictating the type of organisms that are able to survive in a particular environment. Permanence also impacts community structure indirectly, by restricting the type of top predator that is able to survive in a wetland, which in turn could influence macroinvertebrate populations. Due to the fact that permanence and predation covary, little research has sought to address the influence that a top predator exhibits on community structure independent of wetland permanence. Particularly, the top down effect of fish that are normally only found in permanent habitats, but at times invade temporary wetlands (i.e. riparian floodplains, beaver-created wetlands, and complex wetlands with interconnected basins) remains understudied. This experiment was designed to observe the effect that pumpkinseed sunfish (Lepomis gibbosus) had on the community structure of macroinvertebrates in a beaver-created temporary wetland. Fish were introduced into four of eight conjoined cages in a uniform and alternating pattern, and the resulting macroinvertebrate community was sampled over time. I hypothesized that fishless cages would exhibit a greater total abundance of invertebrates than cages with fish, and that large active invertebrates would be more abundant in fishless cages than in those with fish. Results did not indicate that there is a negative correlation between fish and total invertebrate numbers, or the number of large active prey. Experimental limitations such as an unusually dry fall and winter limited the credibility of results, and further research should be carried out before the importance of fish as a factor influencing community structure in temporary wetlands is disregarded.

Colonization by terrestrial invertebrates of mammalian carrion, particularly human corpses, has been well studied by forensic scientists as a means of determining post mortem interval, but little is known about invertebrate colonization of mammalian carrion in an aquatic environment. Studies have shown that aquatic invertebrates benefit from a protein supplemented diet and therefore should colonize carrion in an aquatic environment. The purpose of this study was to determine trends in colonization patterns of aquatic invertebrates on rat carrion of different treatments (clothed vs. unclothed and floating vs. submerged) in a temporary wetland. Forty-eight rats were placed in a temporary wetland over an eight-week period with biweekly collection of twelve rats from late October through early December. Colonization patterns were driven mainly by midge larvae (Diptera), which showed an increase from the first collection to the second collection but then declined in relation to temperature. Floating carrion had more colonization than submerged carrion and clothing inhibited colonization early in the experiment but acted as protection from weather later in the experiment. Future studies that repeat this experiment during a different season of the year would be valuable in comparison with my results.

Amphibians often exhibit phenotypic plasticity in morphology in response to varying environmental cues. Most research on phenotypic plasticity in response to predators has been conducted on toad and frog tadpoles that mainly eat detritus and algae. Predatory amphibians such as newts and salamanders might have a different set of trade-offs than herbivorous amphibians. Morphological changes that create an advantage of avoiding predation could result in a cost such as decreased ability to capture prey. Of the few studies on the phenotypic plasticity of salamanders, none have isolated the effects of the predator from the chemical cues from attacked conspecifics. I examined the morphological changes of larval Ambystoma opacum salamanders in response to the presence or absence of a larval dragonfly predator (Anax junius), presence or absence of a conspecific death cue, and combinations of both. In a 16-aquarium setup, four replicates were created for each treatment. The presence of a caged predator affected body length and depth, tail length, tail muscle depth and width, body mass, and condition (mass/length). Conspecific death cue affected the ratio of tail length/depth. In a second experiment, I tested survival rate when exposed to a lethal dragonfly. There was no difference in vulnerability to dragonfly predators. The larvae of this species of salamanders appear to be more responsive to chemical cues of predators than to the cues from injured/eaten conspecifics. It is possible that more frequent or concentrated conspecific death cue would have induced more evident developmental changes had the experiment been carried out through metamorphosis. Further study will be needed to determine whether predation risk is simultaneously affected by both morphological and/or behavioral traits.

This research was supported in part by the Class of 1939 Senior Research Fund and the Dextra Baldwin McGonagle Fund.

Many studies have described how increased predation risk causes tadpoles and newts to have shorter bodies and longer, deeper tails, thereby decreasing the risk of mortality. In contrast, there has been little research on predator-induced plasticity in salamanders. The purpose of this study was to determine the effects of a dragonfly predator on one species of salamander (Ambystoma maculatum) that is common in Northwestern Pennsylvania. I hypothesized that salamander larvae raised with caged dragonfly cues, salamander larvae raised with sacrificed conspecific cues and salamander larvae raised with both predator and sacrificed conspecific cues would have shorter bodies, longer tail muscles, and deeper tail fins compared to the larvae raised under predator-free conditions. Total length, tail length, body length, and mass of the salamanders all increased during the experiment. However, total length did not vary by treatment at any point during the experiment. Similarly, tail length and body length were not significant according to treatment over the course of the experiment or at the end of the experiment. Tail width did not vary according to treatment at the conclusion of the experiment. Lastly, final masses did not vary by treatment during or at the conclusion of the experiment. Any morphological changes that are made to better suit salamander in avoiding predators may also disable their ability to capture their own prey. This may be why no significant differences were found across treatments throughout or at the conclusion of the experiment for salamanders of this species.

This research was supported in part by the Class of 1939 Senior Research Fund, and the Franklin H. and Ruth L. Wells Foundation.

Many organisms can adjust their physiology and behavior depending on the conditions imposed by their environment. Such phenotypic plasticity is likely to be more important in organisms that live in fluctuating environments than those in steady environments. In amphibians, it has been shown that tadpoles are capable of sensing pond desiccation and in response, accelerate their metamorphosis. Not only do tadpoles have the ability to sense a threat to the permanence of their habitat but they also can detect cues that a predator is nearby. This presents a conflict for the optimal level of activity for survival. Increased time spent foraging should enhance growth and hence escape from drying via metamorphosis, but at the same time increase their visibility to predators. Since research has shown that both predator presence and habitat permanence have an effect on tadpole behavior, I hypothesized that temporary pond species of tadpoles, Rana clamitans, were more likely to negotiate the tradeoffs presented by drying conditions and predator vulnerability than permanent pond tadpoles, Rana catesbeiana. Tadpoles were exposed to one of four treatments; predator/permanent, predator/drying, no predator/permanent, no predator/drying. I measured treatment effects on activity levels and growth. Predator presence did not have an effect of either tadpole species activity level nor did it have an effect on total length or body length growth. The drying conditions showed significantly more tadpoles observed and moving. There was significantly less of an increase in bullfrog tadpoles’ total length and body length growth in response to drying conditions. Only the green frog tadpoles experienced a significant gain in mass for predator conditions.

This research was supported in part by the Class of 1939 Senior Research Fund and the Dextra Baldwin McGonagle Fund.

Ameiurus nebulosus (brown bullheads) have historically been important as an indicator species in Presque Isle Bay (PIB). Their tumor rates have been part of the basis for listing PIB as an Area of Concern (AOC) and for upgrading it to the first Great Lakes Area of Concern in Recovery. Recently, there has been concern that the contaminants, which presumably cause tumors, might also be affecting A. nebulosus recruitment. The purpose of this study was to determine the status of the young-of-year (YOY) population of A. nebulosus in PIB, especially in comparison to surrounding areas. Once the problem was recognized, the focus shifted to determining whether pollution was the cause. This part of the experiment was tested through exposing YOY bullheads and toxicologically similar eggs (Pimephales promelas, fathead minnows) to Bay and control sediments and food. Measurements included: survival, growth, behavior, and skin abnormalities. The results indicate no statistical significance between any of the treatments, except for average change in bullhead length during the food chain study, which could be due to a flaw in the experimental design. Overall, the results suggest pollution is not a primary cause of the recruitment failure. However, more research needs to be done, both on the effects of pollution and other possible causes of low recruitment such as changes in species interactions and hybridization.

Wetlands have decreased dramatically in total area in the United States since the late 1700s. This loss in area makes the preservation of remaining wetlands critical because of the many ecosystem services they provide. Using Geographical Information Systems (GIS), I created a model to predict wetland location and area in order to improve upon the accuracy and efficiency of wetland identification using existing datasets (National Wetlands Inventory (NWI); National Land Cover Dataset (NLCD)). These datasets have several wetland identification shortcomings that necessitate new methods for wetland predictions of location and area. The model used slope, floodplain, hydrology, and soils datasets. It was iteratively fine-tuned on the Sugar Lake division of the Erie National Wildlife Refuge to create final model iteration for modeling wetlands previously unidentified and identified by the NWI or NLCD. When run on the larger Muddy Creek watershed, the final model predicted large areas of previously unidentified wetlands and large overlap with existing wetlands datasets. While the predictions might overestimate wetland area, especially on private land, they identify tracts of unidentified wetlands that represent valuable conservation opportunities. Finally, my study demonstrates the power of GIS modeling in wetland preservation.

Name: Ciofani, LeighA.
Date: Spring 2005
Major: Environmental Science
Thesis Committee: Scott Wissinger, Caryl Waggett

Wetlands are unique and independent environments that provide valuable habitat for an abundance of species. Although wetland protection has improved over the past few decades, small wetland environments continue to be underappreciated in terms of ecological importance. Destruction of small wetland ecosystems has received recent attention because small wetlands serve as breeding grounds for many amphibian species that have declined in numbers. One specific area of concern involves deforestation of wooded wetlands that are inhabited by frogs and salamanders. The effects of deforestation on macroinvertebrate populations are unknown even though macroinvertebrate shredders are proposed to be at the base of wooded wetland food webs. This study tested the effects of detritus supply on the caddisfly Nemotaulius hostilis, a shredder species found in wooded wetlands of the northeastern United States. Growth and survivorship of caddisfly larvae were measured in the presence and absence of leaf detritus (field experiment) and when reared on terrestrial (red maple) versus aquatic (smartweed) leaf litter (laboratory experiment). Caddisfly growth and survivorship were not found to be affected by the absence of leaf detritus; however, leaf dry mass was significantly lower where caddisfly larvae was present. Caddisflies were significantly larger when reared on red maple litter than on smartweed, but survivorship data were inconclusive. The combined results suggest definite effects of caddisfly larvae on increasing leaf decomposition rates but an unclear relationship between leaf detritus and caddisfly survival and growth. Although deforestation of wooded wetlands may not be detrimental to caddisfly populations, more research is needed to determine the effects of canopy removal on the remainder of wooded wetland ecosystems.

Name: Emhiser, Brianne F.
Date: Spring 2005
Major(s): Biology
Thesis Committee: Dr. Scott Wissinger, Dr. Milt Ostrofsky

Over the past thirty years, many lakes have become acidified due to fallout from acid rain. Charophytes are a group of macrophytic algae commonly found in hard-water lakes throughout North America, and should be especially vulnerable to acidification. These plants extract H+ from the water, forming alkaline patches that become heavily calcified, then extrude the protons at a different location, creating acidic patches. This assists in carbon assimilation and retention, as well as their characteristic highly stipuled, smooth appearance. I investigated the effects of carbon, calcium,a nd pH on the growth and survival of Chara vulgaris L. that grows in NW Pennsylvania. Carbon and pH had no significant main effects or interactions on dry mass at the end of the experiment. Calcium had highly significant effects at low pH for dry mass, but little significance for ash-free dry mass (AFDM) at either pH. The results indicate possible increased calcification, not biomass, in the presence of high calcium at low pH. My results suggest that once lakes become more acidified, the growth and survival rates of charophytes such as C. vulgaris will decline, eventually being replaced with more acid-tolerant species.

Name: McDowell, Mallori
Date: Spring 2005
Major: Environmental Science
Thesis Committee: Scott Wissinger, Caryl Waggett

Freshwater mussels are an abundant and diverse group of stream organisms in the United States. However, many populations are threatened by changes in stream quality connected with human activities. Approximately 72% of all the species are considered endangered, threatened, or critically imperiled. Muddy Creek in the Erie National Wildlife Refuge (ENWR), is home to two federally endangered and four Pennsylvania critically imperiled mussel species. Part of the mission of the U.S. Wildlife Refuge System is to preserve, restore, and enhance endangered and threatened species within their natural ecosystems.

This project looks at the land use threats within the wildlife refuge and outside it in the rest of the Muddy Creek watershed. While wildlife conservation is a main priority for refuge lands they are also used sometimes for other purposes including agriculture. I found that overall the watershed had relatively low impact land use; although there are two major sites where a change in land use might benefit existing mussel populations. The two main sites are currently planted in row crops, which is not a particularly compatible use with protecting the mussel beds.

Another goal of this project was to look at adjacent land outside the refuge and make land acquisition recommendations. I found three sites that are either row crops or residential land that are located near the mussel beds. A third component of this project was to look at the two watersheds in the other division of ENWR where potential translocation could be implemented. I found two main possibilities with compatible land use and appropriate in stream habitat for mussel beds. The recommendations will be forwarded to ENWR to help them to create a management plan for these important species.

Name: Sciulli, Marc R.
Date: Spring 2005
Major(s): Biology
Thesis Committee: Dr. Scott Wissinger, Dr. Lauren French

Although detritus processing in streams is well understood, much less information is known about processing in wetlands. Much of the information on detritus processing has been assumed to be appropriate for wetlands, but there are many clues hinting that they are not the same. Invertebrate shredders like caddisflies (Order:Trichoptera) consume coarse particulate organic matter (CPOM), thus playing an essential role in detritus processing. However, most studies on the importance of shredders have been conducted in streams, with few studies on the diets of wetland caddisflies. Developing a better understanding on the role of detrital processing by caddisflies depends upon the examination of the diets of these invertebrates.

This study examined the diets of three species of caddisflies (Limnephilus indivisus, Nemotaulius hostilis, and Ptilostomis ocellifera) that inhabit a semi-permanent wetland in Bousson Environmental Research Reserve of Allegheny College in Crawford County, Pennsylvania. The gut contents of the final instars of each of these species were examined, along with body mass and gut content mass. Analysis of gut contents revealed significant differences between the species. L. indivisus and N. hostilis had very similar diets that were based primarily on detritus and other plant material. However, animal material was the dominant component found in the gut contents of final instar P. ocellifera indicating they are predacious at the larval stage. These results indicate that at least some wetland caddisflies should play an important role in the transfer of detrital energy into the wetland food web. Future research should focus on 1) the transfer of detrital energy in caddisflies to higher trophic levels and 2) the degree to which caddisfly shredders can process all of the available detritus in wetlands.

Name: Shouey, Leah B.
Date: Spring 2005
Major(s): Biology
Thesis Committee: Dr. Scott Wissinger, Dr. Lee Coates

Since the dramatic results at the Mexico City Olympics, endurance athletes and their coaches have been interested in the benefits of high altitude training. The purpose of this study was to review and summarize existing knowledge from altitude studies, and compare the data to determine which altitude training regimen is best for sea-level performance. This study also identifies missing information about altitude training and proposes a new live high-train low (LH-TL) study that will include a sea-level control and will measure sea-level performance. Several altitude-training studies conducted at different altitudes (2,100- 3,090m) are discussed. There are four possible scenarios that have been developed: a.) Living at high altitude and training at high altitude (LH-TH); b.) Living at high altitude, but training at low altitude (LH-TL); c.) Living at low altitude but training at high altitude (LL-TH); d.) Living and training at low altitude (LL-TL). The first two scenarios have been found to be the most popular based on effectiveness and are the main focus of this review. Living at altitude causes multiple physiological, ventilatory, and hematological changes that could enhance endurance performance. There is some evidence that training and living at high altitude improves sea level VO₂max and thus endurance performance. However, most recently the LH-TL model has become more popular, but few studies directly compare the two methods (LH-TH and LH-TL). Thus, it is still difficult to determine which method is better for improving performance. Based on my research of the literature, I designed an experiment that will compare the LH-TH and LH-TL methods, but also include a sea level control. The study will measure post altitude performance and will take place in four phases. It is predicted that the LH-TL group will perform better in post-altitude performance tests.

Name: Shouey, Lindsey A.
Date: Spring 2005
Major(s): Biology
Thesis Committee: Dr. Scott Wissinger, Dr. Lee Coates

There has recently been considerable interest in the concept of “core-strengthening” as a part of athletic training programs. Strengthening the muscles of the abdomen, hips, and back (core) can increase the ability to balance and support the body. This in turn can decrease the frequency and severity of injuries, and even enhance athletic performance. The purpose of this study was to examine the effects of 6 weeks of core strength training with stability balls on core strength, balance, and stability in female distance runners. In this study, injury history reports were also used to determine if core strength has an effect on injury occurrence. Baseline and post-training tests included a balancing exercise, lateral bridge holds, a flexor hold, and a back extensor hold. Using baseline-testing measurements, the women were divided into two groups. The core group (n = 5) performed 6 weeks of core strength exercises using stability balls, while the peripheral group (n= 6) performed 6 weeks of exercises that focused on their peripheral musculature. Although there were no statistically significant differences ( p>0.05) between the two groups after training, the post training core-strength measures for the core group revealed a trend consistent with one of the hypotheses. This hypothesis stated that the core group would improve upon core-strength and balance after training more than those in the peripheral group. From the results, the core group on average did show improvement on the flexor hold, lateral bride holds, and the ball balance. On the other hand, the peripheral group on average declined in all three of the previously mentioned tests along with the back extensor hold. In order to determine if the trend revealed by those in the core group was statistically significant, future studies should increase sample sizes, prolong training period, reduce within group variability, and strive to increase subject motivation.

Name: Adams, Matt T.
Date: Spring 2004
Major: Environmental Science
Thesis Committee: Scott Wissinger, Terry Bensel

The purpose of this project was to design and construct an ecologically sound restoration wetlands to mitigate a jurisdictional encroachment. The Plum Creek Wetlands Mitigation Project consists of an old agricultural field in a county park that is a holding of the Medina County Park District, Medina County, Ohio. A portion of the site will be restored to satisfy mitigation requirements associated with the U.S. Corps of Engineers and Ohio EPA permits. The mitigation specifics had been negotiated with the regulatory agencies as an off-site, out-of-kind, construction/restoration. Based on the current ecological and regulatory literature and practices, I designed a conceptual plan to accomplish the requirements set forth by the regulatory agencies. This plan included: 1) goals/objectives for the type of wetlands, 2) construction design, 3) planting/seeding specifications, and 4) a five-year monitoring program. The construction plan called for 3.5 acres of shallow, seasonally inundated meadow that will eventually develop into wooded wetlands. The site currently has patches of herbaceous wetlands vegetation with adjacent existing wooded wetlands as seed source for colonization. The mitigation plan also includes a planting program of herbaceous and woody hydrophytes. A monitoring schedule was created to assess the short and long-term success of the project. Basin excavation occurred in November 2003 and planting will proceed in spring 2004. The project provides a case history of how an understanding of basic information about wetlands ecology can be used in applied restoration work.

This senior project was supported in part by the Class of 1939 Senior Research Fund.

Name: Dale, Dhira V.
Date: Spring 2004
Major(s): Biology
Thesis Committee: Dr. Scott Wissinger, Dr. Jim Palmer

Permanence has a major impact on community structure in lentic habitats. Patterns of species replacements along permanence gradients are well documented, but the mechanisms that underlie those replacements are poorly understood for many taxa. This research focused on three congeneric species of dragonflies that occur in ponds and wetlands across much of eastern North America. Libellula luctuosa typically occurs in permanent habitats with fish, L. lydia typically in both permanent and temporary habitats without fish, and L. pulchella in a wide range of habitats from temporary without fish to permanent with fish. In two microcosm experiments, I exposed larvae of all species to 1) drying regimes (water level maintained vs. moist soil) and 2) different predation threats (green sunfish present vs. absent). When exposed to drying conditions, more L. pulchella survived than L. luctuosa and L. lydia, whereas, L. luctuosa survival was the highest in the presence of fish. My results suggest that L. luctuosa’s vulnerability to desiccation could restrict it to permanent habitats. L. lydia appeared to be vulnerable to both fish predation and drying, and might rely on newly created habitats as a refuge from fish predation. L. pulchella was the most desiccation-tolerant species, and is probably the only species that can complete its life cycle when habitats dry. These findings suggest that the distribution of the three species along permanence gradients will depend on fundamental (desiccation tolerance) and realized niche (vulnerability to fish predation) constraints. Salamander larvae, and not fish, are often the top predators in autumnal wetlands and future studies should consider the effects of salamander predation on these dragonfly species. Future studies would be enhanced by a systematic comparative study of the distribution of Libellula dragonflies to better understand where species replacements occur along permanence gradients.

Name: Fair, Lindsay A.
Date: Spring 2004
Major: Environmental Science
Thesis Committee: Scott Wissinger, Terry Bensel

Over 50 percent of wetlands in the contiguous United States have been lost over the past two centuries. As a result of this loss, the study of the importance of wetlands for various organisms and many natural processes increased resulting in better wetland protection and restoration. In order to monitor wetland status and change, the National Wetlands Inventory (NWI) was created in the late 1970s and the first inventory was completed and published by 1981. Studies have been done since the NWI to estimate the status and trends of the nation's wetlands, but the NWI maps from 1981 are still not fully accessible to the public due to the availability of funding. I conducted a GIS analysis in order to identify changes in the areal extent of wetlands in the Erie National Wildlife Refuge and in the Pennsylvania state game lands (SGL) in Crawford County, all of which are protected areas. Since the advent of wetland protection, federal and state agencies have been encouraged to preserve and restore wetlands through policies such as President Carter's EO 11990, especially on protected lands managed by federal or state governments. Thus, I predicted that wetland area should have increased in these protected areas since the NWI of 1981. I found that there has been an increase in the percentage of wetlands in the ENWR and in the SGL. In the reevaluation of the ENWR, there was a 41.36% increase in total new wetlands, which may have been a direct result of restoration and construction efforts by the ENWR management. The reevaluated analysis, compared to the original analysis, resulted in a 2.89% decrease of "new" areal wetlands. This decrease in "new" areal wetlands could have been a consequence of misinterpretation of the data layers in the original study. The SGL, as a whole, exhibited a 63.37% increase in total new wetlands, ranging from 19.81% to 484.15%, individually. After comparing protected lands to nonprotected lands, the nonprotected lands exhibited a larger wetland increase of 43.18% than the protected lands, which displayed a 25.75% and 29.42% increase in the ENWR and in the SGL, respectively. This comparison was based solely on new NLCD wetlands. Because protected lands already have a large percentage of their area made up of wetlands, nonprotected lands might have a greater chance to experience a larger increase in new wetlands.

Name: Flaherty, Thomas M.
Date: Spring 2004
Major: Environmental Science
Thesis Committee: Scott Wissinger

Amphibians are not only an integral part of many ecosystems, but also serve as important indicator species as to the health of the ecosystem they inhabit. With the status of amphibian populations being questioned by researchers it is important to understand precisely what impacts human actions have upon these ecosystems to see if we are causing irreparable harm. One area of great concern is our woodlands, especially given that almost half of the world’s original forests no longer exist, and an additional forty million acres of woodland continue to be cleared annually. This study focused on terrestrial salamander (Plethodon cinereus) abundance in clear cut, sustainably cut, and non cut woodland stands. Soil moisture, amount of micro-habitat cover, light intensity, and soil temperature were all measured along with the number of salamanders. I found that the selectively cut woodlands had a significantly higher amount of cover and soil moisture then other types of woodlands, yielding a higher abundance of terrestrial salamanders. The ratio of salamanders found per cover did not vary significantly among forest types, and various environmental factors did not seem to play a significant role in salamander abundance. This suggests that sustainably harvested lands were qualitatively better habitat, just quantitatively more abundant in terms of micro-habitat.

Name: Kelly, James C.
Date: Spring 2004
Major(s): Marine Biochemistry (self-designed)
Thesis Committee: Dr. Scott Wissinger, Dr. Brandi Baros, Dr. Leonard Vuocolo

The erythrocytes of many fish contain functionally distinct hemoglobins that allow them to survive in varying environments associated with migratory lifestyles and to meet varied physiological needs for oxygen. The blue fish, Pomatomus saltatrix, has two distinct hemoglobin components. These components have different migratory patterns upon electrophoresis. Mass spectrophotometry of the isolated components revealed that the hemoglobin showing migration towards the cathode was made up entirely of alpha chains, having the same mass as the anodal Hb component. The anodal Hb, like most vertebrate hemoglobins, contains both alpha and beta chains and is a typical Root Effect Hb, with greatly reduced oxygen affinity at low pH and maximal cooperativity at neutral pH. The cathodal component binds oxygen non-cooperatively with high oxygen affinity that is essentially constant over the range from pH 6 to 9. Sulfhydryl groups are present on both anodal and cathodal components, with significant differences in reactivity toward the SH-specific reagent 4,4'-dithiopyridine. These structural and functional differences between the anodal and cathodal hemoglobins of the blue fish suggest that the cathodal form represents an adaptive thallasemia that allows for oxygen uptake even when the cathodal Hb is subject to low pH conditions that decrease its oxygen transport capacity.

Name: Meisner, Robert J.
Date: Spring 2004
Major(s): Biochemistry
Thesis Committee: Dr. Scott Wissinger, Dr. Brandi Baros, Dr. Leonard Vuocolo

The hemoglobin (Hb) of the Spot fish, Leiostomus xanthurus, is typical of Root effect Hbs in that oxygen binding occurs at high pH with the high affinity associated with the R-state conformation, and at low pH with the low affinity associated with the T-state conformation. Anions affect the pH-dependent conformational transition, favoring the low-affinity T-state. Studies of the rates of reaction of the sulfhydryl (SH) groups of Spot Hb with the sulfhydryl-specific reagent 4,4'-dithiodipyridine show that the SH group environment is not subject to the exaggerated pH and anion dependence characteristic of the Root effect. Remarkably, at physiological pH the SH groups of both oxygenated (R-state) and deoxygenated (T-state) Spot Hb show similar rates of reaction to those of oxygenated (Rstate) human Hb. Moreover, the SH groups of oxygenated Spot Hb and human Hb exhibit similar and unexpected pH- and anion-dependent changes in reactivity. A review of the available data suggests a conceptual model in which binding of anions and protons alter the conformational fluctuations of key residues that regulate the sulfhydryl reactivity and the binding of oxygen to Hb in both R- and T-state conformations.

Name: Mumford, Miranda L.
Date: Spring 2004
Major(s): Biology
Thesis Committee: Dr. Scott Wissinger, Dr. Ron Mumme

I studied the life history and ecology of two species of caddisflies, Limnephilus indivisis (Limnephilidae) and Ptilostomis ocellifera (Phryganeidae) in temporary wetlands. Adults emerged in spring, but egg masses did not appear until autumn, suggesting adult diapause during summer when larval habitats are dry. Field observations and substrate manipulations revealed that egg masses are always deposited within the margins of temporary basins, but not below the water line. I manipulated immersion time in the laboratory and found that survival is greater in egg masses without than with immediate immersion. I also found that larvae only emerge from egg masses after inundation. Larval habitats are vulnerable to intermittent drying and I found that larvae could tolerate desiccation for at least two weeks in experimental microcosms. Although larvae over-winter aquatically, and shallow areas of their habitat freeze into the substrate, neither species survived experimental freezing.

My results provide detailed information about the life history and physiological adaptations that allow these caddisflies to exploit temporary wetlands including 1) adult diapause when habitats are dry, 2) deposition of desiccation-tolerant eggs masses in dried basins, 3) larval emergence from egg masses upon inundation, and 4) short-term tolerance of desiccation in larvae. Future studies should focus on mechanisms that underlie observed differences in survival when eggs are deposited under as opposed to above water.

Name: Smith, Joshua M.
Date: Spring 2004
Major(s): Biology
Thesis Committee: Dr. Scott Wissinger, Dr. Ron Mumme

Dams cause alterations in flow regimes that have major biological, physical and chemical impacts on river ecosystems. In particular, dams greatly reduce movement of fish, especially migratory species. Previous studies have documented that blocked fish passage causes decreased abundance, lowered species richness, and, in some cases, extinction above dams. In this study, I compared fish population structure of two dammed and two un-dammed tributaries of French Creek. These data provided information about fish community and distribution before the removal of a low dam on one of the streams (Cussewago Creek). They also provided information on how species richness and community structure changed along the upstream to downstream gradient of each stream. I hypothesized that the presence of dams should have a major impact on fish distribution and community composition, and, in particular, migratory species, whose upstream movements should be directly hindered. I found that community structure (species richness and total abundance) did not differ between dammed and un-dammed streams. However, abundance of migratory species was affected by the presence of dams with a greater percent of migratory fish below than above dams. One cyprinid species, the common shiner (Luxilus cornutus), was more abundant at sites below than at sites above dams. The prediction that dams decrease species richness and total fish abundance did not seem to apply to Cussewago and Woodcock Creeks. It is possible that there is sufficient habitat diversity above these dams to allow migratory species to complete their life cycles. My data suggest that removal of the Cussewago Dam will increase the proportional abundance of migratory fish found in the upper reaches of Cussewago Creek.

Name: Mattie, Sara E.
Date: Spring 2003
Major(s): Environmental Science
Thesis Committee: Dr. Scott Wissinger, Dr. Ron Mumme

Larval caddisflies potentially face tradeoffs related to the allocation of energy to case building vs. growth and development depending on the relative importance of predation and time constraints relative to pond drying. I reared newly re-cased Limnephilus externus caddisflies under different predation threats (salamanders present, absent) and drying regimes (level maintained vs. natural evaporation) in laboratory microcosms, and measured case size and mass, body mass, and instar development. I found that caddisfly body mass was greater in permanent than drying treatments, regardless of salamander presence. Case mass did not differ among treatments; therefore, the case mass / body mass ratio was significantly greater in drying than permanent microcosms. These results imply energy allocation to L. externus case building is primarily affected by time constraints and energy availability and not by predator threat. Previous studies showed similar outcomes where larval behavior and not case morphologies determined vulnerability to predation. In this experiment, drying was a more prominent threat to survival to metamorphosis. In comparison to the natural population of L. externus, body mass was similar or greater relative to treatment. My results suggest energy allocation towards a certain minimum growth (body mass) is necessary. Body mass energy allocation could directly relate to fecundity which is consistent with previous studies in which number of offspring correlates to body size.

Name: Miwa, Christopher T.
Date: Spring 2003
Major(s): Environmental Science
Thesis Committee: Dr. Scott Wissinger, Dr. Rich Bowden

Nitrogen deposition in northeastern United States is an important component of acid rain. To evaluate the long-term effects of N fertilization, three control and three fertilized plots were established at Bousson Environmental Research Reserve (BERR) in northwestern Pennsylvania. In 2002 soil respiration rates and total fine-root biomass were measured after eight years of N amendments in the form of 100 kg NH₄NO₃ ha^-1 yr^-1. Soil respiration decreased as a result of fertilization. Overall respiration was 11 % lower at the fertilized plots compared to the ambient plots; average respiration from May to December was 150 and 168 mg C m^-2 h^-1 respectively. Total fine-root biomass at the fertilized plots was 5.87 Mg ha^-1 and 6.61 Mg ha^-1 at the ambient plots. Differences in total fine-root biomass were not significant, suggesting that the reduction in total soil respiration at the fertilized plots was due to decreases in microbial activities.

Name: Quinn, Kathleen B.
Date: Spring 2003
Major(s): Biology
Thesis Committee: Dr. Scott Wissinger, Dr. Lee Coates

Blood chemistry analyses are used to monitor health levels of many different organisms, since levels of certain compounds vary according to factors such as stress. The objective of this study was to investigate the health of commercially sold lobsters in context of ambient and agonistic situations. Haemolymph (blood) of the American lobster, Homarus americanus, was sampled and analyzed in order to establish ambient blood chemistry levels of specimens bought from grocery stores as live seafood items. Also, lobsters were paired in dominance fights to simulate the fights that establish social hierarchies, which occur when lobsters are held in captive groups, in order to investigate post-capture and transport stressors. When blood chemistry levels from the fight trials were compared to ambient levels from before, creatinine was found to significantly increase after fighting, suggesting significant use of phosphocreatine as an energy source for muscles used in conspecific fights and possibly decreased efficiency in creatinine elimination. Also, blood glucose levels were found to be lower in lobsters that had their second antennae removed, which could suggest the second antennae are the second site for release of crustacean hyperglycemic hormone (CHH) theorized by a previous study.

Name: Streble, Laurie A.
Date: Spring 2003
Major(s): Biology
Thesis Committee: Dr. Scott Wissinger, Dr. Milt Ostrofsky

Research has shown that some invertebrate larvae are damaged by exposure to natural sunlight. To date, however, few taxa have been tested and it is unknown how general the effects are. Survival of larvae is very critical to the survival of a species because it determines the size of the adult population, thus it is important that we learn how the survival of individuals in this stage can be extended to adulthood. In this study, I examined the effects of sunlight on larvae from several invertebrate groups in the Puget Sound, Washington. I isolated the PAR, UVA, and UVB portions of the light spectrum and exposed larvae to these treatments to determine mortality and sublethal effects. To examine whether laboratory results modeled natural effects, I also tested sand dollar larvae at different depths in the field. Several species of brachyuran crab larvae, rhizocephalan barnacle larvae, ascidian larvae, brachiopod larvae, nudibranch larvae, tubeworm larvae, and sand dollar larvae had dramatically different sensitivities to sunlight. Sand dollar larvae also showed significant sublethal effects (determined by measurements of arm lengths). Sand dollar larvae in the field showed significant light damage to a depth of nearly one meter. The effects of sunlight on invertebrate larvae from different taxa were highly variable. Invertebrate species in different taxa vary in their vulnerability to sunlight damage and may have different protective mechanisms. Therefore it is unlikely that there is one model organism that will predict the effects of light on the larvae of other unstudied species.

Name: Ver Hague, Joshua P.
Date: Spring 2003
Major(s): Environmental Science
Thesis Committee: Dr. Scott Wissinger, Dr. Milt Ostrofsky

The Erie National Wildlife Refuge (ENWR) in northwestern Pennsylvania, manages wetland habitats for waterfowl and other types of wildlife. Constructed wetlands called Moist-Soil Units (MSU) are one type of waterfowl habitat that has been used by ENWR. MSU construction is designed in increase both production and taxonomic diversity in plant and invertebrate communities. The purpose of this study was to compare the plant and invertebrate communities of three MSUs at ENWR to two other types of constructed wetlands - ephemeral depressions (McFadden Cattail, Middle, and Back) and permanent wetlands (Henslow Northeast, Northwest, South). I predicted that seed and invertebrate biomass would be higher in the MSUs than in the other types of habitats. I measured seed biomass in quadrats in each wetland, and estimated the abundance and diversity of invertebrates using semi-quantitative sweeps and cores in the benthos. Mean seed biomass, invertebrate biomass, and invertebrate diversity did not differ among the three wetland types. Although the MSU habitats are visually more diverse and have a higher vegetation cover, the within-group variation and low sample sizes (N=3 for wetland type) prevented a statistical verification of this apparent difference in vegetation. Management protocols for MSU habitats recommend mowing, discing, or burning technique every three to five years in MSU’s. This type of disturbance reduces dominance and perpetuates an early successional state that is conducive for high productive and diversity. The absence of a difference in invertebrate biomass among habitats could be related to the presence of fish in the MSUs that colonize from the intake stream. Fish reduce invertebrate biomass and are considered competitors with invertebrate-feeding waterfowl. The MSUs have control structures and annual drying should eliminate fish and increase seed production from annual plants.

Name: Vikara, Derek M.
Date: Spring 2003
Major: Environmental Science
Thesis Committee: Dr. Scott Wissinger, Dr. Milt Ostrofsky

Eastern hemlock (Tsuga canadensis) is a common conifer in the northeastern United States and is estimated to occur on 7.6 million hectares of timberland. This species is threatened by the Hemlock Wooly Adelgid (Adelges tsugae)(HWA), an introduced aphid pest from Asia. The HWA feeds on the needles of hemlocks resulting in tree mortality and is characterized by the presence of white, cottony sacs. Infestation could ultimately lead to the annihilation of hemlocks leading to forest composition changes, resulting in an understory response and community reorganization. Forest floor vertebrates within hemlock stands are poorly studied and the effects of hemlock decline on these vertebrates is unknown. In this study, I compared the abundance of terrestrial salamanders in stands of high, medium and low hemlock abundance. Forest stands with high and low hemlock concentrations had significantly more salamanders found/objects turned than medium stands. In addition, the abundance of salamanders to hemlock was positively correlated with relative importance of hemlock. The infestation of the HWA could reduce the amount of hemlocks in forests by 95%, dramatically reducing the relative importance of hemlocks in forest stands and potentially terrestrial salamander abundance within those stands. However, HWA infestation will allow for surpluses of organic debris from hemlock carcasses, thus providing increased shelters and habitats.

Name: Brian M. Dillemuth
Date: Spring, 2001
Major: Environmental Science
Thesis Committee: Scott Wissinger, Terrence Bensel

Conservation of stream ecosystems requires the identification of indicator species that can be used to quickly assess the cumulative and multiple impacts of land use on stream health. In this study I chose brook trout (Salvelinus fontinalis) as a quick and reliable indicator of watershed health. Brook trout, the Pennsylvania State fish, are top predators in pristine headwater streams. I predicted that brook trout would be found in streams that had greater percentages of forest cover and riparian zone intactness than streams containing introduced brown trout (Salmo trutta), which would in turn have greater percentages of these characteristics than stream containing no trout.

Electro-fishing was conducted on headwater streams to locate brook trout, brown trout, and no trout streams, in which quantitative analysis was performed. ArcView GIS 3.2 was used to quantify stream and land use characteristics including, percent forest cover, riparian zone intactness, watershed area, and stream order. I found that streams containing brook trout had significantly smaller watersheds than streams containing brown and no trout, and were smaller in order than streams containing no trout. Brook trout were significantly more abundant in highly forested watersheds than brown trout, however there was no significant difference when looking at riparian zone intactness. I concluded that brook trout are indeed good indicators of pristine water quality. However, the establishment of non-native salmonids has complicated using them as bioindicators because these non-natives can exclude them from habitats in which they would have otherwise been found. Future studies should be conducted during summer to establish how landscape affects oxygen levels, hence brook trout distribution.

Numerous studies have shown relationships between chemical stream water quality and either watershed land use or riparian zone intactness. However, few studies have attempted to isolate the relative importance of basin wide land use vs. riparian zone intactness for predicting water quality of streams. Successful separation of these landscape variables would allow for directly focused non-point source pollution control and conservation efforts on the most important land use variable for stream water quality.

This study examined the practicality of isolating the effects of watershed land use from those of intact riparian zones on stream water quality. In order to investigate these relationships, I studied twelve headwater streams (ranging from 1.95 km² to 2.93 km²) in the French Creek watershed. ArcView version 3.2 GIS software was used to accurately determine the percent of the watershed forested and the percent of the riparian zone intact. Each stream was sampled at various flow conditions, ranging from base flow to high flow, for six water quality parameters: total nitrogen, total phosphorus, total suspended solids, total dissolved solids, pH and temperature.

Significant differences were found for four of the six water quality parameters measured with respect to the % watershed forested, the % riparian zone intact, stream discharge or some combination thereof. The % riparian zone intact was correlated with the % watershed forested. Thus, it was not easy to separate each factor's impact on chemical water quality indicators. Despite this draw back, ArcView GIs software was determined to have been a valuable tool. The efficiency and feasibility of determining small scale watershed land use and riparian zone intactness was vital to approaching an investigation of this nature.

The loss of natural wetlands is a concern of ecologists, regulators and conservationists. The USFWS, Partners for Wildlife (PFW), has taken part in an effort to restore wetlands once destroyed by development or agriculture. Wetland depth and permanence has been a concern for wetland restorations because of the impact on presence or absence of fish and hence, abundance of macroinvertebrates. Many studies have shown that fish can influence macroinvertebrate community composition in a variety of aquatic habitats, but less is known about the influence of fish on macroinvertebrates in reconstructed wetlands. The purpose of this study was to compare the macroinvertebrate communities in fish-containing and fishless PFW restoration wetlands. This comparison assessed invertebrate species richness, density, biomass and changes in species composition along a predator permanence gradient.

Mean invertebrate species richness and density were similar for both types of habitats, perhaps a result of the potential for species replacements along a predator permanence gradient.The richness and density data from fishless wetlands were comparable to data from a former experiment that compared richness and density in natural vs. constructed wetlands.Mean biomass was also similar in both types of habitat. The timing of the sampling (late fall - early winter) may have biased the results, as most invertebrates do not reach their maximum size until spring. Surprisingly, there was no difference in the number of top invertebrate predators with and without fish. There was also no difference in the biomass ratio of large invertebrates to total biomass. Coleoptera biomass was greater in fishless wetlands than in those containing fish and average number and biomass of Ephemeroptera were lower in wetlands that contained fish as opposed to those that did not. Community similarity (Jaccard Index) was not significantly different in the two habitats. The results provide little evidence that fish have an effect on macroinvertebrate composition in reconstructed wetlands. Maintaining diversity should be a primary goal when rebuilding wetlands both for biodiversity and waterfowl management. Congruent results with past research for species richness and density support PFW's success in reconstructing wetlands as close as possible to their original state.

Terrestrial salamanders of the family Plethodontidae are the top predators of soil invertebrates in forest ecosystems. They are very plentiful and their numbers stay stable over time only being disturbed by habitat loss. The purpose of this study was to explore the effects of logging on the abundance of terrestrial salamanders in forests logged with and without management plans. The abundance of salamanders was determined in Bousson Experimental Forest, an annex plot to the Cornplanter State Forest (CSF) (logged in a sustainable manner), and Kiser Hill (logged). This was done by searching under likely logs in 2500m² quadrants for thirty minutes, keeping track of the number of logs turned over, and the number of salamanders found. There were significantly more salamander in the unlogged sections of the CSF than the sustainably logged sections of the CSF (31.6 and 20.7 respectively). There were also significantly more salamanders in the unlogged sections of Kiser Hill than in the logged sections (13.9 and 4.2 respectively). In addition, there were significantly more salamanders in the sustainably logged sections of the State Forest than the logged sections of Kiser Hill (20.7 and 4.2 respectively). Sustainable forestry does seem to have less of a detrimental effect on Plethodontidae numbers than traditional forestry practices.

Stream ecosystems continue to be altered and degraded throughout the United States. Human modifications of the landscapes within watersheds are affecting our ability to achieve the goal of chemical, physical, and biological integrity in our Nation's waters stated in the Clean Water Act of 1972 (CWA). Outdated regulations that focus on chemical and physical criteria do not take into account the multiple impacts of land use on stream ecosystems and do not reflect their combined effects of non-point source pollution on the biological integrity of streams. In this study, I modified Karr's (1981) Index of Biotic Integrity (IBI) to assess the stream ecosystem health of low-order cold headwater streams in Northwestern Pennsylvania. The fish communities of 13 headwater streams in the French Creek and Oil Creek watersheds was examined using a backpack electroshocker during the autumn of 2000 and winter and spring of 2001. Appropriate fish community metrics were selected to create a fish community IBI. The presence of remnant native Brook trout species (Salvelinus fontinalis) was used as an indicator species in the reference site selection. The brook trout streams had significantly higher forest cover then streams with no salmonidae. The modified fish IBI was able to differentiate between different land-uses, where IBI scores correlated with percent watershed forested and riparian zone intactness. The modified fish IBI scores were significantly different p<0.001 between brook trout streams and streams with no salmonidae. Two species abundances, Semotilus atromaculatas and Rhinichthys atratulus, were particularly relevant with increasing stream degradation. Due to the amount of variability within stream ecosystems it is necessary to continue exploring cold headwater streams using a biologic approach. Very few studies have been conducted on low-order cold headwater streams in Northwestern Pennsylvania. More studies need to be done in this geographic area with continued development and modification of a fish IBI for use on cold headwater streams at a regional level. Future studies should combine both fish metrics and macroinvertebrate metrics to give a more holistic and robust approach in measuring stream ecosystem health.

The beaver (Castor canadensis) is considered a 'keystone species' because of the profound effect it has on 2nd to 4th order streams. Beavers build dams that create ponds or wetlands that in turn affect the hydrology, geomorphology, and ecology of the surrounding riparian zone. The hydrologic changes include: 1) effects on the annual stream discharge, 2) slowed current velocity, 3) expanded area of flooded soils, and 4) increased retention of sediment and organic matter. In spite the hydraulic importance of beaver wetlands, surprisingly little is known about the hydrology of beaver dams on headwater streams.

The purpose of this study was to conduct a hydrologic investigation of Kiser Marsh, a beaver maintained wetland at Allegheny's Bousson Environmental Reserve in northwestern Pennsylvania. Surface water input was measured using 90^o V-notch weirs on the five small input streams and the one larger output stream. Changes in groundwater level and hydraulic gradient were measured with three shallow peizometers installed along a transect to the north of the beaver pond. Groundwater elevation and hydraulic gradient were compared during high flow and low flow events to understand how the hydrology of Kiser Marsh changes.

I predicted that the beaver wetland would retain storm water during high flow events and maintain low flow conditions during periods of base flow. The beaver pond did retain water during the first high flow event, but discharged water during the other two high flow events. One hypothesis for this reversal is related to seasonal variations in water table level. Base flow was maintained during all the low flow events providing further evidence that the hydrology of Kiser Marsh is seasonally dependent. One of the other major findings of the study was that the geomorphic setting of Kiser Marsh is a groundwater dominated hydrologic system. Future studies should focus on comparing beaver wetlands in other geomorphic contexts to determine the degree to which all beaver wetlands are dominated by groundwater dynamics. This could allow for the hydrologic values of beaver wetlands to be more clearly identified for a functional assessment model for beaver wetlands.

Factors such as water depth, temperature, shelter, and resource availability have been examined while studying habitat selection in many fish species. The component of habitat selection focused on in this study was potential spawning site preference in the female convict cichlid (Cichlasoma nigrofasciatum). In this study I conducted three experiments to test hypotheses related to cave size and structure in relation to habitat selection. Choices of small and large nesting sites, with or without structure, in various combinations were presented to females of this species. While selecting a potential nesting site the cichlid must consider the safety and security it will provide for its fry. Previous experiments have shown that both cave size and structure are important to convict cichlids; however, which (if either) variable is more important had not been previously determined. Results of the three related experiments revealed that large cave sites and structure were more important to female convict cichlids than small caves and lack of structure. Cichlids chose the small cave site with structure more often than the large cave site without structure in the final experiment. This might be representative of a tradeoff the cichlids are making between two desirable variables. However, the most desirable habitat overall was a large cave site surrounded by structure.

Burning and disking are intended to have direct effects on a wetland plant community, but little is known as to the effects on the invertebrate community. This study examines the effects of burning and disking on invertebrates important to waterfowl. Burned, burned & disked, and disked treatments were performed in the spring of 1999 within a constructed wetland located in the Mosquito Creek Wildlife Management Area. This was followed by the construction of 3 silt fence plots (5m x 5m) within each treatment. That fall, the resulting total invertebrate densities and diversities and order densities were tested for differences between the treatments using an appropriate ANOVA. My results show that burning enhanced density and diversity of invertebrate substrate & aerial recruitment, total colonization, and floodwater recruitment more than any other treatment, followed by burning & disking, and finally disking. Total invertebrate colonization densities were greater in the burned treatment than disked treatment (F_{1084.875, 22}=5.401, P=0.0298) and the control (F_{1219.550, 31}=5.884, P=0.0213). Total genera were greater in the burned treatment than burned & disked (F_{5.439, 22}=8.855, P=0.0070), disked (F_{4.576, 22}=24.623, P=<0.0001), and control (F_{4.782,
31}=8.518, P=0.0065). These findings support managing wetlands by burning and disking to increase invertebrate densities and diversity that will enhance waterfowl foraging habitat.

Bufo americanus (American toad) tadpoles use chemosensation to detect predators and respond to alarm pheromones from conspecifics. Chemosensory recognition of chemical cues is an innate behavior, but the extent to which tadpoles can be conditioned is unknown. I addressed this issue by combining a non-predator chemical cue with conspecific alarm pheromones to see if B. americanus would react to a non-predator with anti-predator response during repeated exposure. Tadpoles were exposed to a predator (Anax junius), a non-predator (Notophthalmus viridescens), or a control (plain water) and all were combined with a conspecifc alarm pheromones. Anti-predator behavior was measured using three behaviors: aggregation, shelter use, and center line crosses. Compared to the other measures of anti-predator behavior, center line crosses proved to be the best measure for this combination of chemical cues. The control group was found to decrease their number of line crosses with repeated exposure and within trials when conspecific alarm pheromones were added. However, no evidence was found for the conditioning of tadpoles to a non-predator cue. I concluded that B. americanus can not be conditioned to elicit anti-predator behavior response to a non-predator chemical cue, but that B. americanus can be conditioned to reduce activity with repeated exposure to conspecific alarm pheromones.

Members of the superorder Ostariophysi, such as fathead minnows (Pimephales promelas), possess a distinct alarm substance, or Schreckstoff, that is released when the epidermal club cells are damaged. This alarm substance, when detected by conspecifics, serves as a warning that there is a predator nearby, and results in antipredator behavior. Because the condition of many aquatic habitats can vary quite frequently, turbidity has been found to place obvious constraints on predator-prey interactions. I hypothesized that minnows would rely more heavily on chemical detection of predators in high turbidity, but different levels of turbidity would alter the employment of antipredator behavior. Fatheads were exposed to chemical cues from predators, which contained digested Schreckstoff, at 3 turbidity levels, and changes in antipredator behavior were observed. The minnows displayed significantly more dashing and freezing upon the addition of a chemical stimulus from a predator; however, this change did not vary as a function of turbidity. The minnows displayed no significant changes in shelter-usage at high and intermediate turbidities. At the lowest turbidity, minnows decreased shelter-usage upon addition of the chemical stimulus. Based on all results, it appears as though turbidity has no effect on chemical detection of predators in fathead minnows.

The interaction between predators and prey is one of the most fundamental in nature. Therefore, prey species have evolved tactics with which to combat against predation. Such tactics include changes in body morpholoy and/or behavioral adaptations. However, despite the best of these behavioral mechanisms, direct encounters between predator and prey typically lead to the capture and death of the prey species. Thus, it becomes evolutionarily advantageous for prey species to develop a mechanism by which they can detect a predator without coming into direct contact. Indeed, many prey species have evolved the ability to detect the chemical cues of predators within their environment. The most recent hypotheses suggest diet plays a key role in the chemical labeling of a species as a predator. While this hypothesis has been tested for a variety of aquatic species, the area remains largely unexamined for terrestrial vertebrates. Therefore, I examined the behavioral response (avoidance) of the streamside salamander, Desmognathus fuscus, to chemical cues from garter snakes, Thamnophis sirtalis, fed either conspecific salamanders or earthworms. Salamanders did not exhibit stronger avoidance behavior in response to cues from a salamander-fed snake as compared to the cues from a minnow-fed snake. Rather, D. fuscus significantly preferred those substrates conditioned with cues from injured and/or eaten conspecific salamanders. In addition, salamanders significantly selected substrates conditioned with cues from minnow-fed snakes as compared to the control substrate (distilled water). The results of this study suggest that D. fuscus salamanders have not evolved the capability to chemically detect a predator, regardless of diet. However, it appears that they do possess highly specialized olfaction capabilities that can be used for the location of food as well as the relocation of their natal streambed.

Trichoptera is a diverse order of invertebrates and abundant in a variety of aquatic habitats throughout the world. Relatively little is known about the life history and dietary habits of the larvae of these species. There is evidence to suggest that Ptilostomis ocellifera is a predacious species in late instars, but may feed on algae during earlier instars. These findings do not adequately describe the diet and ecological role that these larvae serve in the aquatic environments they inhabit. Since P. ocellifera is one of the most prolific species of Trichoptera in northwestern Pennsylvania, developing a better understanding of the trophic role that these larvae play in the aquatic systems they inhabit depends upon the determination of the life history and diet of this species.

This study examined the life history and diet of P. ocellifera in a temporary autumnal pool. Larvae were sampled weekly from November through December and bi-monthly from January through March as the development of these larvae slowed and permanent ice cover made sampling more difficult. Instars were determined by measuring the head width and dry weight of larvae. P. ocellifera appears to follow a life history pattern similar to that described for other species inhabiting temporary autumnal pools, including spring emergence, adult diapause, the appearance of larvae shortly after autumn filling, and rapid larval growth. Analysis of the gut contents of six larvae from each instar indicates that there are significant differences between the dietary habits of different instars. Animal material was the dominant in the guts of every instar and cannibalism was observed in final instar larvae. Third instar larvae consumed a significantly greater amount of algae than other instars. This study also provides evidence that the diet of early instar P. ocellifera is not restricted to flocculent detritus and particulate organic matter as previously reported.

Larvae of the salamanders Ambystoma macrodactylum and Ambystoma tigrinum express an alternate trophic phenotype in response to crowding and consumption of large prey. These salamanders have a discrete cannibal morph while other ambystomatids, including A. maculatum, are occasionally cannibalistic but do not have specialized trophic features. The goal of this experiment was to investigate the potential for trophic plasticity in A. maculatum. I attempted to induce a cannibal morph A. maculatum by rearing larvae under conditions ideal for the manifestation of that phenotype; that is, high density, high intraspecific size variation, and large prey availability. I found a behavioral tendency for cannibalism among A. maculatum larvae that increased with greater conspecific body size variation and that ‘risky’ cannibalism (consumption of similarly-sized conspecifics) was more frequent in crowded conditions. ‘Non-risky’ cannibalism (large on small conspecifics) was dependent on encounter rate. However, these larvae showed no indication of morphological changes characteristic of the discrete cannibal morph. Thus, although cannibalism might be an important alternate feeding strategy among A. maculatum larvae under crowded and/or highly variable intraspecific size conditions, there was no suggestion of a discrete cannibal morph. Cannibalism within natural populations of A. maculatum should have important ecological consequences and could serve as a density-dependent mechanism for population control.

The purpose of this study was to determine the relative importance of canopy cover and its effects on substrate drying and wetland invertebrate colonization. I rehydrated substrate samples taken during the dry phase of the hydroperiod in wooded and non-wooded wetlands to determine the number of invertebrates that recolonize from one or more drought-tolerant stages (e.g. egg, larvae, pupae, adult) in the substrate. I also collected physical data (e.g. substrate moisture and temperature, maximum radiance) to help define the role of the canopy in shaping wetland ecology. Additionally, I qualitatively sampled all field sites following inundation to determine the importance of other routes of colonization. I found that wetlands shaded by the forest canopy had higher substrate moistures during the dry phase and subsequently had higher density and diversity of invertebrates recolonizing from desiccation-tolerant stages. My results indicate that wetland conditions determine which routes of colonization can succeed and, therefore, are largely responsible for the structure of invertebrate assemblages. In particular, I found that colonization from desiccation tolerant stages in the substrate is more important in woodland pools where moist conditions allow high densities and diversities of invertebrates to survive the dry phase. In contrast, aerial colonization is more important in non-wooded marshes where harsh substrates make drought tolerance difficult. Therefore, because factors such as canopy cover and hydroperiod have such a profound influence on wetland conditions, it is essential that they be included in all wetland conservation, management, and mitigation efforts. Taking this into consideration, deforestation should drastically alter the community composition of wooded wetlands.

Wetlands are unique habitats with unique assemblages of plants and animals. Because the physical, chemical, and biological conditions in wetlands differ from those in aquatic habitats such as lakes, I proposed that the invertebrate communities should also differ between wetlands and the littoral zone of lakes. I compared the invertebrate communities of five freshwater marshes to the communities in three nearby lakes in Crawford County, PA. Qualitative samples were collected at all sites. Data were summarized using cluster analysis to group communities or sites most similar to each other, and Analysis of Variance (ANOVA). Jaccard coefficient of community similarity values were calculated between all wetland and lake sites. The cluster analysis divided the sites into three major clusters or groupings; a lake cluster, a wetland cluster, and a wetland cluster distinct from the other two groups. The ANOVA revealed that the mean Jaccard similarity values between wetland and lake communities were significantly different from the mean values for wetland-wetland and lake-lake community comparisions. The results also showed that in general wetland communities were more similar to each other than to lake communities regardless of geographic proximity to lakes. The results of this study suggest that wetlands host a unique assemblage of macroinvertebrates and lends further support to the argument for wetlands conservation. By destroying our wetlands, we are destroying the fauna that depends upon these unique habitats for survival.

A complete understanding of the effects of beaver (Castor canadensis) on stream ecosystems is critical to the development of beaver management. Beavers are considered a keystone species which, through habitat alterations and nontrophic interactions, have a disproportionately large impact on an ecosystem relative to their abundance. Through the modification of nutrient cycles and decomposition processes, creation and maintenance of wetlands, and retention of organic matter, beavers influence the composition and diversity of stream ecosystems.

In this study, the impacts of beavers on fish abundance and diversity in three low gradient streams were examined. Sites were sampled by catch-per-effort surveys during the fall of 1998 using a backpack electrofisher. Abundance, species diversity (Shannon-Weiner), species richness and species composition (Jaccard coefficient) were compared between beaver influenced and unmodified reaches, pools and riffles, and four habitats (pools resulting from beaver dams, reaches immediately below dams, riffles and pools in undammed reaches).

Beavers did not significantly impact overall fish abundance, species richness, diversity or composition. Since the French Creek tributaries are low gradient streams with pools common in unmodified reaches, substantial differences in habitat characteristics and fish communities between beaver influenced and unmodified reaches were not apparent. The impact of beavers on overall game fish abundance was unable to be determined due to differences in catching effort. Smallmouth and rock bass abundances were greatest in pools created by dams. This trend can be attributed to the ecological requirements of bass which are predominantly found in rocky pools of moderate gradient streams. In contrast, abundances of rainbow and greenside darters, who inhabit fast, rocky riffles, were significantly greater in riffle than pool habitats. To determine the maximum effect beavers can have on fish communities, experiments testing both high and low gradient streams should be conducted.

Laboratory experiments were conducted to examine the effects of shredding caddisflies (Fabria inornata) on the biological breakdown of detritus (Acer rubrum and Sparganium spp.). Experimental conditions were designed to mimic the natural environment of a wetland during the winter. There was no effect of caddisflies on the overall decay rate of detritus but there was a significant difference in decay rate between the two plant treatments. However, I found a significant effect of caddisflies on the increase of course particulate organic matter (CPOM) and fine particulate organic matter (FPOM). The high variance within treatments obscured the interpretation of the effects of treatment on the growth rates of caddisflies. The results suggest that shredding caddisflies could have an effect on the processing of detritus in wetlands. However, high mortality rate among the caddisflies reduced the opportunity for testing the hypothesis completely. Improvements in the methods may give more definite results.

Understanding how interspecific interactions affect distribution and abundance is a cornerstone of community ecology. The feeding niches of organisms often overlap, which potentially leads to interspecific competition for food resources. Data from a previous study indicate that two types of benthic, insectivorous stream fishes, darters (Etheostoma caeruleum and E. blenniodes) and sculpin (Cottus bairdi), coexist in some reaches of the tributaries of French Creek, and are isolated in other reaches. Specifically, the sculpin were present in the headwaters, both darters and sculpin present in the intermediate reaches, and only the darters present in the mouths of the tributaries at French Creek. I studied the diets of the darters and sculpin at three sites corresponding to darter presence only, sculpin presence only, and coexistence of the species, in three tributaries of French Creek: Woodcock Creek, Little Sugar Creek and Gravel Run. The invertebrate communities at each of the sites were also were also sampled and the electivities of the darters and sculpin for food items in the diet was calculated. Using electivity, the darter and sculpin diets were compared in the presence and absence of each other. Using the proportions of food items in the diets, niche overlap was calculated. The niche of the sculpin was compared to each darter when coexisting and apart.

I hypothesized that the fish would feed on similar food items when apart and eat different food items when together in avoidance of the other fish. Secondly, I hypothesized that the niches of the darters and sculpin would be similar when alone, but differ in the presence of another. Neither hypothesis was supported – the fishes seemed to feed on the same food items in the presence and absence of the other and there were no significant differences in niche overlap when together as opposed to apart. Based on my results and observations, I hypothesized that: either 1) food was not limiting enough to result in competition due to low abundance of sculpin and darters or adequate abundance of aquatic invertebrate prey; 2) the sample sizes of the fish diets and/or aquatic invertebrates were not large enough to provide accurate results of electivity and niche overlap analyses; and/or 3) pressures other than competition for food resources may dominate the interactions between darters and sculpin.

Beaver dams can dramatically change a stream's habitat and nutrient availability. By slowing the water velocity, increasing pool depth, and providing more snags as substrate, beaver dams can provide totally different habitats. The dams also entrain particulate organic matter which contain nutrients needed by plants as well as invertebrates living within the stream. These two changes in the stream continuum should change the type of macroinvertebrate community that live within the watershed.

This study assessed the changes in the number of species from non-beaver influenced habitat which is located upstream to beaver influenced habitat located within and just below the impoundment. The study areas compared the differences between three high gradient streams in northcentral Pennsylvania to three low gradient streams in northwest Pennsylvania. Further quantitative sampling took place on the three high gradient streams comparing the riffles upstream of the impoundment to those found directly below the impoundment.

The study showed that there were no significant changes in the number of species between beaver influenced and non-influenced habitat. However, snag habitats overall were found to contain higher numbers of different species than pool-bottom habitats in low gradient streams. In the high gradient streams, invertebrates were significantly more abundant and dense in upstream riffles than downstream riffles. Of particular emphasis, there were significantly higher numbers of scrapers, Chironomidae and Ephemeropterans, mainly STENONEMA in upstream riffles. There were also trends that suggest Plecoptera and Trichoptera were more abundant in the upstream riffles. Finally, there was a trend that suggests that Megalopterans were more abundant in downstream riffle sites. The differences are suggested to be caused by unmeasured data.

Following the post-WWII era, the U.S. Army Corps of Engineers initiated a program of constructing flood control impoundments throughout the United States. The rapid increase in dam construction provided scientists with a perfect opportunity to study artificial impacts on natural systems. Since the mid 1900s numerous studies on a wide range of scales and topics have been conducted on dams. A central theme that appears time and again is that impoundments have a widespread and dynamic impact on lotic ecosystems. A small percentage of studies, however, have related their findings to central concepts of stream ecology.

The purpose of this study was to compare macroinvertebrates between upstream and downstream sites on a regulated stream and then to relate these patterns back to trends described by the River Continuum Concept (RCC). The study was conducted on Woodcock Creek, a fourth order tributary to French Creek in Northwestern Pennsylvania. Macroinvertebrate and food resource samples were quantitatively collected during the fall of 1998. Invertebrates were identified, classified into their respective functional feeding group, and compared among above and below dam sites. I found that shredders, gatherers, and predators were significantly more abundant upstream versus downstream whereas scrapers were significantly lower upstream. There was no significant difference between above and below dam densities of filter feeders. However, the first sampling site immediately downstream of Woodcock Dam had an invertebrate community composed of approximately ninety nine percent filter feeders. This community was primarily composed of two groups, filter feeding caddisflies, Hydropsychidae, and blackfly larvae, Simuliidae. Site four also had the highest overall density of invertebrates. The only pattern observable between energy sources and invertebrates was the correlation between increased filter feeder densities with increased fine particulate organic matter (FPOM) levels. I concluded that the downstream changes imposed by Woodcock Dam were very localized as invertebrate communities reverted to those characteristic of mid order streams within 1.5 kilometers of the dam outflow.

Name: Susan R. Bolden
Date: Spring 1998
Major(s): Biology
Thesis Committee: Scott A. Wissinger, Bret Tobalske

Very little is known as to how well constructed wetlands function as replacements for the natural wetlands that they are restoring or replacing. Twelve constructed wetlands and twelve natural wetlands were surveyed for Mollusc and Odonate species in the fall of 1997. The constructed wetlands were divided into three age classes and an equal number of permanent and temporary habitats were sampled. It was hypothesized that mollusc species richness should be higher in natural wetlands than constructed, while Odonate species richness should be the same throughout, based on their colonization methods. Molluscs were found two years after wetland construction while Odonates were present less than a year after construction. Because Molluscs are passive colonizers, their colonization of newly constructed habitats was slower than the aerial colonizing Odonates. Molluscan species richness was significantly greater in natural habitats than constructed habitats, but Odonate species richness was not affected, as hypothesized. Thus, the wetlands surveyed in this study were functioning as good replacements for natural habitats in terms of Odonate richness, but not in molluscan richness. It is important to use a conservative estimate, such as molluscs or any other passive dispersers, to determine the success of a constructed wetland. Because molluscs are important to waterfowl diets, they should not be overlooked when considering a wetland's potential as productive waterfowl habitat.

Results of previous studies differ in whether the addition or removal of a top predator in freshwater ecosystems causes a cascading effect throughout lower trophic levels. The purpose of this study was to first test for the presence of a trophic cascade in response to the removal of fish from a headwater stream using exclusion cages. Results from the field study showed that algae in cages devoid of fish grew at a greater rate during the latter stages of the experiment. I hypothesized that predatory invertebrates (e.g. stoneflies) might have compensated for excluded fish predators, thereby suppressing grazing invertebrates. In a second experiment conducted in laboratory stream tanks, I examined specific trophic interactions between the mottled sculpin (Cottus bairdi), the grazing mayfly, Stenacron, and periphyton grown on benthic tiles. Data and photographs showed that periphyton assemblages grew more dense and at a greater rate in the presence of sculpin. I found evidence for heavy Stenacron grazing in tanks without sculpin and no grazing in tanks with sculpin. Results and observations suggested that the Stenacron-periphyton trophic link in a headwater stream environment would be heavily impacted by the addition or removal of sculpin. I hypothesize that trophic cascades can potentially exist in headwater streams, especially where human interaction has caused the addition or removal of a top predator.

Agriculture and development have eliminated many wetland areas since European settlement. Recently, many state, federal and non-government organizations have begun to create artificial wetlands to replace those destroyed by human development. However, the biological quality of constructed wetlands remains to be tested. Recently, a Wetlands Index of Biological Integrity (WIBI) was developed in order to determine the quality of wetlands based on their biotic content. The WIBI provides criteria for determining the biological integrity of a wetland area based on the macroinvertebrate fauna contained within the wetland.

This study applied the metrics of the proposed WIBI to wetland age in order to determine the quality of wetlands in different age groups. Specifically, this study was used to determine whether recently constructed wetlands are of comparable biological quality or are approaching the biological quality of natural wetlands in the Crawford County area.

Twelve sites were sampled, four that were less than two years old, four that were two to six years old, and four natural sites. Macroinvertebrates were quantitatively and qualitatively sampled and identified to the taxonomic level specified by each WIBI metric. These data were then scored on the WIBI metrics to determine the biological integrity of each site.

Newly constructed wetlands (less than two years old) scored the lowest on the WIBI while two to six year old sites and natural sites scored considerably higher. Newly constructed wetlands were dominated by high densities of rapidly colonizing opportunistic invertebrates such as chironomids. Invertebrate communities in these sites had low diversities and did not score highly on the WIBI. Two to six year old sites contained both rapidly colonizing and slowly colonizing invertebrates. These sites supported relatively high diversities of invertebrates and scored the highest of all three study groups. Natural sites were dominated by slowly colonizing k-selected invertebrates and were slightly less diverse than two to six year old wetlands. According to this study, invertebrate communities take only about three years to develop into a nearly natural state in constructed wetlands.

The use of biomonitoring techniques such as the WIBI can show which construction techniques are the most efficient and effective to ensure the creation of diverse and productive wetland habitats.

Several Studies over the past few years have focused on determining a Benthic Index of Biotic Integrity (B-IBI) for French Creek and its tributaries. However, many streams and stretches of streams in the French Creek Watershed are low-gradient and are not suited for standard analysis. Most secondary production in these sections of streams appears to occur on woody debris (snags) instead of on the unstable, muddy substrate.

The purpose of this study was to determine how benthic macroinvertebrates assemble in the low-gradient tributaries and sections of French Creek. Additional goals were to report that standard approaches for sampling macroinvertebrates are not going to be applicable, and to offer important information toward the overall goal of establishing a Benthic Index of Biotic Integrity for the French Creek Watershed. Three tributaries, Cussewago Creek, Muddy Creek, and Woodcock Creek, were sampled and compared with relation to each other and the mud and snag habitats present within them.

Three sampling methods were used to collect macroinvertebrates from the streams. The snag habitats were analyzed using a DHT sampler, while the mud habitats were analyzed using an Ekman dredge. Additionally, Hester-Dendy Multiple Plate Artificial Substrate Samplers (MPASS) were used to gather organisms from both habitats.

The results showed that, in fact, there was no significant difference between the mud and the snag habitats with regards to total numbers of individuals, as well as total diversity of organisms. Likewise, the streams did not significantly differ from each other in these two categories. Functional group percent composition showed few similarities present among the three streams. Also, significant differences were nearly absent in comparing the functional group percent composition between the mud and snag habitats.

The most viable reason for the similarities in the total number of individuals and the total diversity of organisms between the mud and snag habitats was due to introducing a stable, artificial substrate onto the mud habitat. The dissimilarities in functional group percent composition among streams could best be attributed to their differences in size, thus supporting the River Continuum Concept. Comparing functional group percent composition between habitats resulted in collectors-gathers being found significantly more abundant on the mud habitat than the snag habitat due to the increased amounts of fine particulate organic matter found on the mud substrate.