Colloquium: Accounting for Spatio-Temporal Sampling Variation in Joint Species Distribution Models

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Dr. Erin Schliep, North Carolina State University, Department of Statistics

Accounting for Spatio-Temporal Sampling Variation in Joint Species Distribution Models

Tuesday, October 25, 11 :OOAM — 101 Carswell Hall

Estimating relative abundance is critical for informing conservation and management efforts and for making inferences about the effects of environmental change on populations. Freshwater fisheries span large geographic regions and often encompass diverse habitats and species assemblages. Monitoring schemes used to sample these diverse populations often result in populations being sampled at different times and under different environmental conditions. Varying sampling conditions can bias estimates of abundance when compared across time, location, and species. We extend the notion of preferential sampling to include varying sampling conditions due to the environment and time of sampling and develop a joint species distribution model (JSDM) that accounts for these differences when estimating relative abundance. We use the model to study relative abundance of six freshwater fish species across the state of Minnesota, USA. We discuss how gear type, water temperature, and day of the year impact catchability for each species at the lake level and throughout a year. We compare our estimates of relative abundance to those obtained from a model that assumes constant catchability to highlight important differences within and across lakes and species. Our method illustrates that assumptions relating indices of abundance to true abundance can greatly impact model inference obtained from JSDMs.