Student: Gage Dayton (Ph.D. student), Texas A&M University, Dept. Wildlife and Fisheries Sciences, 210 Nagle Hall, College Station, Texas; gdayton@tamu.edu

Proposal Title:  Community Ecology and Conservation of Desert Amphibians in the Chihuahuan Desert of Southwestern Texas

Abstract:   (coming soon...)

Student: Martin Dziminski (M.S./Ph.D. student), University of Western Australia,School of Animal Biology (MO92),  35 Stirling Hwy, Crawley, WA 6009 Australia; mdzimins@cyllene.uwa.edu.au

Proposal Title:  Variable Egg Provisioning Strategy in the Quacking Frog (Crinia georgiana): Is it a Strategy for Reproduction in Unpredictable Wetland Habitats?

Abstract: Variation in egg provisioning in frogs should evolve when larvae encounter unpredictability in their aquatic freshwater environment. This reproductive strategy should suit frogs that breed in temporary or semi-permanent freshwater wetlands. Variable egg provisioning should increase parental fitness by allowing the production of an increased total number of eggs. Large eggs should survive even under harsh environmental conditions, while all eggs can survive during “good” years. This form of “bet-hedging” should maximise the lifetime reproductive success of individuals that engage in it. This project aims to investigate the evolution of variable egg provisioning in response to an unpredictable wetland environment. A survey and comparison of egg clutches of two species of frogs will be completed. The quacking frog (Crinia georgiana) breeds in temporary wetlands, whilst the bleating froglet, (C. pseudinsignifera) breeds in more permanent rockpools. Relationships between variability within and between egg clutches and the measured predictability of the breeding environment of these two species will be examined. C. georgiana is expected to have high variability in egg size within and between clutches and this is should be correlated with an expected high unpredictability of the temporary wetlands that it breeds in. A field experiment using DNA microsatellite markers to trace offspring to parents, and thus known clutch parameters, will be conducted using C. georgiana as the focal species. This will determine fitness consequences of variable egg provisioning. It is expected that variable provisioned egg clutches will have higher overall survival rates under a range of conditions that can occur in a natural temporary wetland. This experiment will confirm that variable egg provisioning in C. georgiana is in fact a strategy that has evolved to increase reproductive output in unpredictable temporary wetland environments.

Student: David J. Hoeinghaus (Masters degree student), Texas A&M University, Dept. Wildlife and Fisheries Sciences, 210 Nagle Hall, College Station, Texas  77843-2258; djhoeinghaus@tamu.edu

Proposal Title: Food-chain Length and Carbon Sources in Natural and Modified Aquatic Habitats of the Upper Rio Parana Basin, Brazil

Abstract:  A significant portion of the world’s total wetland area is comprised by tropical floodplains.  Neotropical floodplain systems are some of the most biologically diverse habitats on the planet.  Predictable seasonal flood-pulses are essential to the life-history strategies of many terrestrial and aquatic species occurring in these systems.  Modification of the natural hydrologic regime in these systems by damming eliminates or decreases the extent of seasonal flooding, and results in longitudinally and laterally disconnected systems.  Common effects of damming include: lower floodplain productivity, slower nutrient cycling, decreased inputs of detritus to aquatic habitats, lower recruitment of fisheries stocks, and blockage of fish migration routes.  The increasing rate of dam construction on tropical floodplain rivers necessitates improved understanding of anthropogenic impacts on these systems.  I will use the stable isotopes of carbon and nitrogen to address what effects dam construction has on trophic structure (i.e. food-chain length, and primary carbon sources) of aquatic communities of tropical floodplain river systems.  This study will be conducted at a large spatial scale, including the last natural stretch of the Paraná River.  My research will be an important contribution to on-going work by Brazilian ecologists studying floodplain communities and ecosystem dynamics of the upper Paraná River basin, as well as floodplain ecology in general.  This research will be conducted in collaboration with Brazilian ecologists, and will foster continued international collaboration in the future.  Results of this study will be applicable to natural resource managers, conservation professionals, and policy makers, and will promote educated decision making by these individuals.

Student: Michael S. Husak (Ph.D. student), Mississippi State University, Department of Biological Sciences, Mississippi State, Mississippi 39762; msh2@msstate.edu

Proposal Title: The Effects of Various Pre-planting Treatment Methods on the Establishment of Native Trees and Shrubs in a Reed Canary Grass (Phalaris arundinacea) Monoculture

Abstract: Reed canary grass (Phalaris arundinacea) is a highly competitive invader that tends toward monocultures in wetlands and outcompetes native vegetation.  Control of this species has been moderately successful with prescribed burning, but there are limitations to the usefulness of fire.  Burning is useful only if the herbaceous community still remains suppressed under the Phalaris canopy and if the community to be restored is at least mildly fire-tolerant. On the other hand, shade has also been shown to limit the growth and germination of reed canary grass, which may aid in the restoration of Phalaris monotypes to swamp forests and other fire-intolerant communities.  The first step in such a goal is determining best methods for planting trees and shrubs in reed canary grass to ensure high survival of those species.  I will be testing twenty-five woody plants in various treatments to determine which treatments and which species are most successful for establishment in Phalaris monocultures.  My working hypothesis is that a monotypic Phalaris stand sprayed with glyphosate herbicide in the fall will be sufficiently prepared for planting.  The intact, dead vegetation will buffer against water loss in the newly planted trees and shrubs while keeping competition from other weeds to a minimum. By the time a new generation of reed canary grass has emerged, the trees and shrubs will be established and, within time, will limit the Phalaris growth by shading it out.  If successful, this research will have major implications for the restoration of areas degraded by reed canary grass to swamp forest and other fire-intolerant communities. 

Student: Randall Brian Langerhans (Ph.D. student), Texas A&M University, Department of Wildlife and Fisheries Science, 2258 TAMU, College Station, Texas 77843-2258

Proposal Title: Wetland Refugia: Survival and Diversification of Indigenous Fishes Amidst an Introduced Predator in the Lake Victoria Basin

Abstract: The introduction of non-native species represents one of the most dramatic and obvious ways that humans alter ecosystems.  Introductions of fish species (often top predators) for fishery production and recreation has been especially common.  The Lake Victoria basin in East Africa represents a catastrophic case study in the effects of species introductions.  Lake Victoria and nearby lakes were recently home to a remarkable diversity of cichlid fishes (>600 species) that radiated during the past 12,000 years.  However, the introduction of Nile perch (Lates niloticus), a large predator, into several lakes in the region during the 1950s and 1960s resulted in a massive extinction event—approximately 50% of endemic haplochromine cichlids are presumed extinct.  While many native species have disappeared, many others have survived the high densities of the introduced predator, and I propose to examine reasons why.  By better understanding the mechanisms that promote coexistence with introduced predators, we can more competently design effective conservation programs to protect native species.  Most lakes in this region are surrounded by wetlands.  The potential role of wetlands in providing a means for survival and diversification of native species in the presence of an introduced predator has not been fully explored.  Wetlands might provide protection from predators through structural complexity or reduced oxygen levels, thus harboring remnant populations of native prey fishes.  These populations may persist (or even increase) through time via evolutionary responses to environmental pressures associated with increased predation and low-oxygen environments.  I propose to document the species that have survived Nile perch invasions through use of wetland refugia.  Furthermore, I plan to evaluate whether surviving species were morphologically “pre-adapted” for life with an introduced predator and/or low-oxygen environments, rapidly evolved preferential traits, or whether both components played a role in species persistence.  If wetlands function to protect native fishes from extinction, setting the stage for evolutionary diversification, then proper conservation and management of wetlands is even more critical than previously thought.

Student: Amanda Little (Ph.D. student), University of Wisconsin - Madison, Botany Department, 430 Lincoln Drive, Madison, Wisconsin  53706; amlittle@wisc.edu

Proposal Title: Vegetation change in response to beaver inhabitation in the poor fens of Mount Desert Island, Maine, USA

Abstract: Beaver have recently become widely recognized as ecosystem engineers.  Historically, they created many of the fresh palustrine/riverine wetlands in North America.  However, few studies have explored the impacts of their inhabitation on wetland plant communities explicitly, and none in oceanic settings.  Mount Desert Island (MDI), Maine is home to beaver meadow plant communities varying in composition from poor fen sedge meadows to Sphagnum bogs.   My objectives are to 1) assess inter- and intra-wetland variation in plant community composition and diversity along environmental gradients in the poor fens of MDI, and 2) investigate the role of beaver inhabitation on the dynamics of poor fen plant communities at multiple scales.  During the summers of 2000-2002 we collected vegetation abundance and composition data at 29 sites using transects and fixed plots.  I will relate site-level vegetation data to the environmental variables of pH, conductivity, water level, and nutrient status – data which was also collected during 2000-2002.  At the intrawetland (quadrat) level, I will relate vegetation to the environmental variables of water depth, peat depth, microtopography, and woody debris cover.  This summer, I will evaluate the spatial pattern of vegetation (vascular plant density and Sphagnum cover at the species level) in 6 wetlands with varying levels of beaver inhabitation using cyclic sampling and geostatistical analyses.  At the site-level, I will compare vegetation attributes amongst sites of different age (time since beaver inhabitation and abandonment) using multivariate and multiple regression techniques.   I will also compare chronosequences between sites in historically burned and unburned regions of MDI in order to establish how beaver population dynamics influence wetland vegetation dynamics.  The end product will be a conceptual model, supported by empirical data, of the pathways of vegetation change at multiple scales in the beaver-wetland system on MDI.  The study that I propose will have consequences for the future of beaver meadows and beaver management at ANP, and will also contribute to the growing body of knowledge on wetland dynamics.

Student: John Navaratnam (Ph.D. student), Department of Biology, 5210 Life Sciences Building, 53 Campus Drive, West Virginia University, Morgantown, West Virginia 26506-6057; jnavarat@mix.wvu.edu

Proposal Title: Microbial Community Composition Associated with Phosphorus Retention and Transformation in Forested Floodplains of the Southeastern United States

Abstract: Floodplain forests are unique wetlands that are biogeochemically linked to neighboring uplands and adjacent aquatic ecosystems (rivers and streams). Floodplain forests play an important role in the retention and transformation of phosphorus (P), received from upland hydrological inputs and overbank flooding, thereby improving water quality in aquatic ecosystems downstream.  Phosphate, a common agent of cultural eutrophication in aquatic ecosystems, is likely to increase with changes in land-use as natural landscapes are transformed to culturally dominated landscapes (by agriculture and/or urban/suburban development). Phosphates can be retained within floodplain wetlands through sediment deposition, soil adsorption, plant uptake, or microbial immobilization, or transformed to organic P prior to export. Extensive field and laboratory studies have established that floodplain forests can both retain and transform P, but little is known about how these functions are accomplished. This information is critical in assessing the sustainability of these ecosystem services, as well as replicating them through wetland creation or restoration. Although the importance of microbial populations as mediators in P transformation and retention has long been recognized, little is known about the linkages between microbial community structure and these biogeochemical processes, or the relative contribution of bacteria and fungi to microbial biomass. I propose to investigate the diversity of archaeal, bacterial, and fungal populations in soils collected from ridge and swale microsites in alluvial and a blackwater floodplain, as well as spatial variation in microbial distribution at ridge vs. swale microsites, by comparing temporal variation in late winter vs. late summer populations as a function of site type (alluvial, blackwater) and microsite elevation (ridge, swale). A combination of total DNA extractions, PCR amplification, plasmid cloning, and sequence analysis with the genetic fingerprinting technique of detecting dominant microorganisms using denaturing gradient gel electrophoresis will provide an accurate description of the variation in microbial populations in floodplain soils. To correlate microbial diversity with fungal and bacterial population densities, fungal (ergosterol) vs. bacterial (muramic acid) biomass estimation will be determined between the two sites, for each date/elevation combination. 

Student: Beth Ravit, Rutgers University, Environmental Science Department, Cook College, 14 College Farm Road, New Brunswick, New Jersey 08901-8551; bravit@eden.rutgers.edu

Proposal Title: Salt Marsh Sediment Catabolic Response Profiles under Natural Conditions and after SHort- and Long-term Mitigation

Abstract: Loss of coastal wetlands resulting from development projects or pollutant impacts is being offset by regulated restoration and/or mitigation projects. Determinants of project success typically include measurements of system structural components. However, there is currently a lack of knowledge with respect to the correlation between structural attributes, functional wetland sediment processes and time. Although it is critically important to include sediment biogeochemical function as part of salt marsh restoration criteria, very little is known about the effects of restoration activities on sediment microbial communities that provide these functions. In an effort to preserve and improve degraded wetlands, a number of restoration projects have occurred within the Hackensack Meadowlands District over a time period spanning the last 16 years. Spartina alterniflora and Phragmites australis are the two most abundant plant species found in the Meadowlands salt marshes, and Spartina is typically used to replace Phragmites during site restoration. These plants exhibit large differences in root morphology, depth, biomass, and physiology. My preliminary data supports the hypothesis that biogeochemical functions in Spartina sediments are different from those in Phragmites sediments in natural salt marsh systems. I propose to adapt a method that was developed in upland soils. This method will be used to characterize sediment catabolic response profiles (CRPs) at different time points after restoration activity has occurred. Through the measurement of CO₂ production in response to 25-30 different carbon compounds, the CRP method uses multivariate statistical analysis to characterize the ability of a sediment community to degrade simple carbon substrates, thus creating a profile of microbial catabolic functional diversity. I have received funding to characterize non-disturbed estuarine sediments using the CRP method and will expand this work by conducting assays of Spartina and Phragmites sediments from three restoration/mitigation sites in the Meadowlands. The additional study will characterize variability in CRP response at different points in time after restoration activity has occurred, and will compare CRP variance between restored and natural sites. Since currently there is little known about the long-term impact of restoration activity on sediment biogeochemical functions, this work has important applications in salt marsh restoration and mitigation projects.

Student: Carrie Reinhardt, University of Minnesota, 290 Alderman Hall, 1970 Folwell Avenue, St, Paul, Minnesota  55108; rein0050@umn.edu

Proposal Title: Invasive Phalaris arundinacea (L.): Control Techniques and Implications for Wetland Restoration

Abstract: Wetland restoration projects in Minnesota (and across temperate North America) often fail to establish native vegetation communities as a result of Phalaris arundinacea (reed canary grass) invasion. Phalaris is a strongly clonal, cool-season perennial grass that has been bred for over 200 years for many traits including vigor. Phalaris is dominant on many pre-restoration sites, and even after site hydrology is restored, Phalaris continues as the dominant species. For other species to establish on a wetland restoration site, effective site preparation strategies are needed to control Phalaris prior to restoring site hydrology. This research seeks to develop a predictive understanding of Phalaris dominance in prairie pothole wetland restorations. There are two objectives: 1) to identify phenologic factors that contribute to the effectiveness of control techniques for reducing existing stands of Phalaris, and 2) to determine how soil seed bank composition affects transition to the post-restoration community of native prairie pothole species. Focusing on objective 1, a large-scale field experiment looks at Phalaris response to burning and several herbicide application timings. A companion study seeks to determine the optimal timing for herbicide efficacy by examining seasonal fluctuations in carbohydrate storage to determine when the population is most vulnerable to herbicide efforts. To compliment the carbohydrate study, a phenology study estimates seasonal above/below ground biomass production rates on an individual plant basis. Focusing on objective 2, one study looks at the effect of control techniques (herbicide application and burning) on remnant seed bank density and composition through periodic seed bank assays. Another experiment, using experimental wetland mesocosms, seeks to determine what level of Phalaris in the seed bank can be outcompeted by a restoration seed mix. Artificial Phalaris seed banks are created, restoration seed mix is added, and competitive interactions are assessed in terms of above/below ground biomass production. Preliminary results from this research suggest that the knowledge gained from these experiments will do much to increase the control effectiveness for Phalaris in wetland restorations, thereby increasing the potential for ecosystem recovery in these systems. Strategies identified as successful by this research are already steering Phalaris management by regional agencies.

Student: Nina Wurzburger, Warnell School of Forest Resources, University of Georgia, Athens, Georgia 30602; wurzburg@uga.edu

Proposal Title: The Effects of Nitrogen Deposition on Mycorrhizal Fungal Communities in Ombrotrophic Bogs

Abstract: Elevated atmospheric nitrogen (N) inputs have affected nutrient cycling, productivity and species composition in many terrestrial ecosystems. Plant species composition changes in particular indicate substantial and long-term impacts, but the complex nature of the N cycle makes quantifying the subtle or early effects of N inputs difficult in most ecosystems. Ombrotrophic (or raised) bogs, however, are uniquely suited for studying N deposition effects, especially below ground. First, their only external N source is atmospheric, facilitating the detection of subtle, and perhaps early, N deposition effects. Second, ombrotrophic bogs support both ectomycorrhizal (ECM) and ericoid mycorrhizal (ERM) fungal communities that exhibit a number of unique N acquisition mechanisms. Lastly, bog-adapted plants and fungi evolved in nutrient-poor conditions, and are likely to be especially sensitive to increases in nutrient availability. My proposed research in ombrotrophic bogs involves examining the effects of a regional N deposition gradient on ECM and ERM fungal community structure. There is a well-documented N deposition gradient in the Lake States region, along which N deposition rates range from 21 kg N ha^-1 yr^-1 in central Michigan down to 8 kg N ha^-1 yr^-1 in northern Minnesota. I intend to study the below ground response of ombrotrophic bog mycorrhizal fungal communities to long-term elevated N inputs along this regional gradient. Mycorrhizal fungi mediate plant nutrient acquisition, and studies in other ecosystems suggest that mycorrhizal community structure is influenced by N availability. I will use molecular characterization to identify ECM and ERM fungi in both roots and in soil. To my knowledge, no one has examined the ECM fungal community response to N deposition in bogs, and no one has examined the ERM fungal community response to N deposition in any ecosystem. This study will improve our understanding of the long-term effects of N deposition and breaks new ground by characterizing the previously unexplored response of bog mycorrhizas to elevated N. Results will have implications for both our understanding of ecosystem function and anthropogenic effects on fungal biodiversity.

Student: Carrie L. Yoder (Ph.D. student), Louisiana State University, Department of Biology, 107 Life Sciences Building, Baton Rouge, Louisiana 70803

Proposal Title: Disturbance Interactions in Marsh and Forest Ecotones, Weeks Bay National Estuarine Research Reserve, Alabama

Abstract:  Large-scale disturbances that occur in close association may produce effects different from those of isolated disturbances.  Further, if effects on important species are novel and unexpected, there may be long-term community alterations.  Multiple disturbances may have their greatest effects on ecotones, the transitions between communities.  The compounded effects of multiple disturbances may be augmented by environmental stresses already present in ecotones.  We propose to simulate multiple large-scale disturbances experimentally and measure the effects on two coastal ecotones at Weeks Bay National Estuarine Research Reserve, Alabama.  A fringing and interior estuarine marsh ecotone will be used to test the interaction of flooding induced by sea level rise and fire.  The ecotone between the interior marsh and bottomland hardwood forest will be used to test the interaction of fire and hurricane canopy disturbance.  We hypothesize that the interaction of fire and flooding in the marsh ecotone should limit species composition to species that can germinate and establish in flooded conditions, thereby reducing species diversity.  Further, the interaction of fire and canopy removal in the marsh-forest ecotone should reduce woody species composition and seedling establishment as a result of increased graminoid species dominance from rapid regrowth and reduced competition from woody species.  We will additionally measure fire temperatures to determine the intensity of the fire and correlation of intensity to fire effects.  The marsh interaction experiment will clarify how species composition may respond to global climate change and natural or managed fires.  The forest multiple disturbance experiment will clarify how Acer, the dominant woody species, might respond to natural disturbances and natural area management.  Species composition changes within the ecotone can lead to shifts in the ecotone boundaries, which may have broader significance as an indicator of large-scale change.