Tyler Wagner Ph.D.

Adjunct Associate Professor of Fisheries Ecology
Assistant Unit Leader, PA Cooperative Fish and Wildlife Research Unit

402 Forest Resources Building
University Park, PA 16802

Email: txw19@psu.edu

Work Phone: 814-865-4511

Websites

http://www.coopunits.org/Pennsylvania/

Education

B.S., University of Idaho (1999)
M.S., University of Idaho (2000)
Ph.D., Michigan State University (2006)

Academic Interests:

Fisheries ecology
Multiple spatial-scale assessment of aquatic resources
Land-water interactions
Hierarchical modeling

Courses taught:

Quantitative Methods in Ecology

Professional Affiliations:

The Ecological Society of America
American Fisheries Society
North American Lake Management Society

Recent Research/Educational Projects:

Trans-boundary management and conservation: linking large-scale dynamics to ecological monitoring and management

A central challenge to natural resource management is to understand and predict ecological responses to management and environmental change over large spatial scales. It is recognized, however, that the management and conservation of many important ecological systems and the services they provide must be addressed at spatial scales that transcend jurisdictional and political boundaries. For example Landscape Conservation Cooperatives (LCCs) recognize that managing natural resources is complex and requires landscape-scale (i.e., trans-boundary) approaches. Although trans-boundary approaches are necessary to understand large-scale phenomenon (e.g., species range), it remains unclear in many cases how best to address the inherent complexities in managing ecosystems at large (e.g., regional) spatial scales. In addition to challenges associated with performing trans-boundary research, it is often unclear how to link large-scale system dynamics with on-the-ground decision-making processes, which are often done using adaptive management principles. For example, a critical component for successfully implementing adaptive management is the development of a rigorous monitoring program, which provides a critical feedback loop for learning about system dynamics. It is unclear, however, how the interplay between components acting at different, hierarchical scales will affect the ability of natural resource managers to detect changes in important state variables (e.g., animal abundance, occupancy, etc.) at trans-boundary spatial scales. Thus, our overarching objective is to use freshwater stream fish populations as model systems to develop a framework and tools for addressing the inherent challenges in performing trans-boundary research and for linking large-scale dynamics to ecological monitoring and management.

Great Lakes Fisheries Trophic Structure Response to Climate Change

Predicting population responses to climate change requires an understanding of how population dynamics vary over space and time. Although variability has historically been viewed as an impediment to understanding population responses to ecological changes, it can provide an important signal, rather than just being viewed as noise. In this project, we will build upon recently completed analyses of fish population data in the Great Lakes basin to help predict how spatial and temporal variation in fish populations may respond to climate change and other important drivers. We suggest that shifting variance structure can be indicative of population-level responses to climate change. Our proposed research will help elucidate the extent to which quantifiable responses in spatial and temporal variability occur in different forms of fish population data.

Fish Community Assessment in the Eastern Rivers and Mountains Network and Integration with Existing Monitoring Data
The National Park Service (NPS) has initiated a long-term ecological monitoring program, known as “Vital Signs Monitoring”, to provide the minimum infrastructure to allow more than 270 national park system units to identify and implement long-term monitoring of their highest-priority measurements of resource condition. The Eastern Rivers and Mountains Network (ERMN) includes nine parks in New York, New Jersey, Pennsylvania, and West Virginia which together encompass nearly 91,000 ha of land area and more than 600 stream and river miles within the parks’ authorized boundaries. A primary objective of the ERMN monitoring program is to evaluate status and trends in the condition of tributary watersheds flowing into and through member parks. Currently, the monitoring of fish communities is not part of the monitoring program. Consequently, methodology is needed to estimate the current condition of fish communities in ERMN wadeable streams in a rigorous and repeatable manner. Estimates of the current fish community’s condition at ERMN stream sites will complement data collected on an annual basis (i.e., Vital Signs Monitoring) and enable an integrated measure of ecosystem condition that can be monitored over time. The specific objectives of this study are to: (1) characterize fish communities in selected ERMN stream reaches, and (2) combine fish community data with existing monitoring data (e.g., macroinvertebrates) to provide an integrated measure of stream ecological condition.

Managing the Nations Fish Habitat at Multiple Spatial Scales in a Rapidly Changing Climate: Successful conservation and management of aquatic habitat and fisheries will require forecasts of future environmental change to ecosystems as a result of changing climate and land use. We are working as part of a multidisciplinary team (including researchers from the University of Missouri, Michigan Department of Natural Resources, Minnesota Department of Natural Resources, Michigan State University, University of Minnesota-Duluth, University of Washington, Purdue University, and the United States Geological Survey) to develop a multi-scale assessment of the current and future status of fish habitat (and predicted biological responses) under scenarios of projected climate and land-use changes at national, regional, and local scales.

Selected Publications:

Mollenhauer, R. T. Wagner, M. V. Kepler, J. A. Sweka. Accepted. Fall and early winter movement and habitat use of wild brook trout. Transactions of the American Fisheries Society.

Wagner, T. B. J. Irwin, J. R. Bence, and D. B. Hayes. Accepted. Detecting temporal trends in freshwater fisheries surveys: statistical power and the important linkages between management questions and monitoring objectives. Fisheries.

Wagner, T. , J. T. Deweber, J. Detar, and J. A. Sweka. 2013. Landscape-scale evaluation of asymmetric interactions between brown trout and brook trout using two-species occupancy models. Transactions of the American Fisheries Society 142:353-361.

Irwin, B. J., T. Wagner, J. R. Bence, M. V. Kepler, W. Liu, and D. B. Hayes. 2013. Estimating spatial and temporal components of variation for fisheries count data using negative binomial mixed models. Transactions of the American Fisheries Society 142:171-183.

Sweka, J. A., T. Wagner, J. Detar, and D. Kristine. 2012. Combining Field Data with Computer Simulations to Determine a Representative Reach for Brook Trout Assessment. Journal of Fish and Wildlife Management 3:209-222.

Rennie, M.D., Ebener, M.P., Wagner, T. Can migration mitigate the effects of ecosystem change? Patterns of dispersal, energy acquisition and allocation in Great Lakes lake whitefish (Coregonus clupeaformis). 2012. Proceedings of the 10th Annual Coregonid Symposium. Advances in Limnology 63:455-476.

Wagner, T., D. R. Diefenbach, A. S. Norton, and S. A. Christensen. 2011. Using multilevel models to quantify heterogeneity in resource selection. Journal of Wildlife Management 75:1788-1796.

Wagner, T., Soranno, P.A., Webster K.E., and Spence Cheruvelil K. 2011. Landscape drivers of regional variation in the relationship between total phosphorus and chlorophyll in lakes. Freshwater Biology 56:1811-1824. doi:10.1111/j.1365-2427.2011.02621.x

Soranno, P.A., Wagner, T. Martin, S., McLean, L., Novitski, L., Provence, C., and Rober, A. 2011. Quantifying regional reference conditions for freshwater ecosystem management: A comparison of approaches and future research needs. Lake and Reservoir Management 27:138-148.

Wagner, T. and Sweka, J.A. 2011.Evaluation of hypotheses for describing temporal trends in Atlantic salmon parr densities in Northeast U.S. Rivers. North American Journal of Fisheries Management 31:340–351.

Soranno, P. A., Spence Cheruvelil, K., Webster, K. E., Bremigan, M. T., Wagner, T., Stow, C. A. 2010. Freshwater Ecosystem Classification for Landscape-scale Management. BioScience 60:440-454.

Wagner, T. and 7 coauthors. 2010. Spatial and temporal dynamics of lake whitefish (Coregonus clupeaformis) health measures: linking individual-based indicators to a management-relevant endpoint. Journal of Great Lakes Research 36:121-134.

Wagner, T., Vandergoot, C. S., and Tyson, J. 2009. Evaluating the Power to Detect Temporal Trends in Fishery-Independent Surveys: A Case Study Based on Gillnets Set in the Ohio Waters of Lake Erie for Walleye. North American Journal of Fisheries Management 29:805-816.

Wagner, T. W., Benbow M.E., Brenden, T. O., Qi, J., and Johnson R. C. 2008. Buruli ulcer disease prevalence in Benin, West Africa: associations with land use/cover and the identification of disease clusters. International Journal of Health Geographics 7:25.

Wagner, T., P.A. Soranno, K. Spence Cheruvelil, B. Renwick, K. Webster, P. Vaux, and R. Abbitt. 2008. Quantifying sample biases of inland lake sampling programs in relation to lake surface area and land use/cover. Environmental Monitoring and Assessment 131-147.

Wagner, T., Bence, J. R., Bremigan, M. T., Hayes, D. B., and Wilberg, M. J. 2007. Regional trends in fish mean length at age: components of variance and the power to detect trends. Canadian Journal of Fisheries and Aquatic Sciences 64:968-978.

Wagner, T., Bremigan, M. T., Spence Cheruvelil, K., Soranno, P. A., Nate, N. N., and Breck, J. E. 2007. A multilevel modeling approach to assessing regional and local landscape features for lake classification and assessment of fish growth rates. Environmental Monitoring and Assessment 130:437-454.

Wagner, T. Jubar, A. K., and Bremigan, M. T. 2006. Can habitat alteration and spring angling explain black bass nest distribution and success? Transactions of the American Fisheries Society 135:843-852.

Wagner, T., Hayes, D. B., and Bremigan, M. T. 2006. Accounting for multilevel data structures in fisheries data using mixed models. Fisheries 31:180-187.

Research Interests

Fish & Wildlife Biology & Ecology Faculty
Land Use Impacts on Water & Forests Faculty
Climate Change Ecology Faculty
PA Cooperative Fish and Wildlife Research Unit

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