Georgia Project: Characterization of spatial and temporal variability in fishes in response to climate change

Georgia Project

Characterization of spatial and temporal variability in fishes in response to climate change

September 2012 - August 2017

Personnel

Participating Agencies

Northeast Climate Science Center

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.

Research Publications

Research Publications	Publication Date
Vidal, T. E., B. J. Irwin, T. Wagner, L. G. Rudstam, J. R. Jackson, and J. R. Bence. 2017. Using Variance Structure to Quantify Responses to Perturbation in Fish Catches. Transactions of the American Fisheries Society 146:584-593. [Featured Article] \| Abstract	April 2017	Unexpected shifts in the state-space conditions of an ecosystem can result in unintended and undesirable conditions, jeopardizing conservation efforts and efficacy of natural resource management. Previous research has identified general statistical behaviors associated with major ecological shifts, yet reliable prediction of these events remains limited. Development of statistical indicators to detect and forecast large-scale change (i.e., regime shifts) in ecological systems could prove valuable for better understanding population dynamics, continuing effective monitoring of fisheries resources, and allowing for timely management actions. Changes in mean and variance have been previously associated with large-scale shifts in ecosystems; here we provide evidence that source components contributing to total variability may also be responsive to large-scale shifts and therefore have potential as new statistical indicators of ecological response to a changing environment. We present a case study from Oneida Lake in NY that evaluates walleye catch rates over time in response to changes to tropho-dynamics and an exotic species invasion. Our results indicate that variance structure provides insight into how an ecosystem changes across space and through time, and also may serve as an indicator of instability and transition into an alternate stable state.
Wagner, T., S.R. Midway, T. Vidal, B.J. Irwin, and J.R. Jackson. 2016. Detecting unusual temporal patterns in fisheries time series data. Transactions of the American Fisheries Society 145:786-794. \| Abstract \| Download	June 2016	Fishery-independent surveys are an important source of information for making inferences about the temporal dynamics of ecologically and recreationally important fisheries. For example, time-series of catch per effort data are often examined for the presence of long-term trends. However, it is also of interest to know if certain sampled locations are exhibiting temporal patterns that deviate from the overall pattern exhibited across all sampled locations. These ‘unusual’ sites may be the result of site-specific abiotic (e.g., habitat) or biotic (e.g., the presence of an invasive species) factors that cause them to respond differently to natural or anthropogenic drivers of population dynamics or to management actions. We present a Bayesian model selection approach that allows for detection of ‘unique’ sites—locations that display temporal patterns with documentable inconsistencies from the overall global average temporal pattern. We apply this modeling approach to long-term gillnet data for yellow perch in Oneida Lake, but the approach is also relevant to shorter time-series data. We used this approach to identify six unique temporal patterns among 15 sampled locations, and describe the magnitude of difference between these patterns and the lake-wide average. Detection of unique sites may be informative to management decisions related to prioritization of rehabilitation or restoration efforts, stocking decisions, determination of fishable areas, and to further understanding changes to ecosystem dynamics.
Irwin, B., T Wagner, and J. R. Bence. 2018. Characterization of Spatial and Temporal Variability in Fishes in Response to Climate Change. Project completion report [extended abstract], Northeast Climate Science Center.	January 2018
Vidal, T., B. J. Irwin, C. P. Madenjian, and S. J. Wenger. 2019. Age truncation of alewife in Lake Michigan. Journal of Great Lakes Research. https://doi.org/10.1016/j.jglr.2019.06.006	July 2019

Presentations

Presentations	Presentation Date
Vidal, T. E., B. J. Irwin, and C. P. Madenjian. 2016. Disentangling exogenous drivers of Alewife population dynamics in Lake Michigan. Georgia Chapter Meeting of the American Fisheries Society. Columbus, GA.	February 2016
Vidal, T. E., B. J. Irwin, and C. P. Madenjian. 2017. Demographic structure influences how environmental forcing affects Alewife recruitment in Lake Michigan. Meeting of the Southern Division of the American Fisheries Society, Oklahoma City, OK.	February 2017
Vidal, T., B. J. Irwin, T. Wagner, L. G. Rudstam, J. R. Bence, and J. R. Jackson. Using variance structure to quantify perturbation induced ecological reorganization. Warnell Graduate Student Symposium, University of Georgia, Athens, GA.	February 2015
Vidal, T., C. Jansch, B. J. Irwin, T. Wagner, J. R. Bence, J. R. Jackson, L. G. Rudstam, and W. W. Fetzer. 2014. Using variance structure as statistical indicators of large scale ecological change. Annual meeting of the American Fisheries Society, Québec City, Québec, Canada.	August 2014
Irwin, B., T. Vidal, B. Crawford, T. Gancos Crawford, and C. Moore. 2016. Quantitative Consideration of Uncertainty and Variability in Decision Analysis for Conservation and Management of Ecological Systems. Annual meeting of the Ecological Society of America, 7-12 August, 2016, Fort Lauderdale, FL.	August 2016
Irwin, B. J. 2017. Spatial and temporal variability in fish populations. Northeast Climate Science Center Regional Science Meeting, Amherst, MA. [Invited (no abstract)]	May 2017
Staudinger, M. D., E. Grant, B. Irwin, R. Kraus, D. Krueger, and J. Stewart. 2014. Climate impacts on fish and fish habitats: Case studies from the Northeast Climate Science Center. Annual Meeting of the American Fisheries Society,	August 2014
Irwin, B. J., T. Vidal, T. Wagner, J. R. Bence, J. R. Jackson, L. G. Rudstam, and W. W. Fetzer. 2014. Shifting variance structure as an indicator of large-scale ecological change. Annual meeting of the Ecological Society of America, Sacramento, CA.	August 2014

Cooperative Fish and Wildlife Research Units Program: Georgia Education, Research and Technical Assistance for Managing Our Natural Resources

Georgia Project

Characterization of spatial and temporal variability in fishes in response to climate change

September 2012 - August 2017

Personnel

Participating Agencies

Cooperative Fish and Wildlife Research Units Program: Georgia
Education, Research and Technical Assistance for Managing Our Natural Resources