The North American Breeding Bird Survey (BBS) is an ongoing effort that has collected data on bird populations and trends since 1966. The Rainwater Basin Joint Venture (RWBJV) has used this data from 2005 to 2010 to create species distribution models (SDMs) for target bird populations within Nebraska. Species targeted by this modeling include Dickcissel (DICK), Eastern Meadowlark (EAME), Grasshopper Sparrow (GRSP), and Western Meadowlark (WEME). These species were identified as high-priority Planning Species by the RWBJV Landbird Plan. The SDMs created by this analysis will be used to better inform conservation efforts throughout the state.
For this analysis we used the following variable data: Missouri Resource Assessment Partnership (MoRAP) Ecological Mapping Systems of Nebraska (MoRAP 2021), U.S. Geological Survey Digital Elevation Models (DEM, USGS 1999), and PRISM Climate Group (PRISM 2021). To quantify the amount of available habitat binary rasters were generated for each of the landscape variables. The mean of each binary raster was then summarized at various scales (800m to 3200m). This allowed us to determine which scale provides the best predictive value for each species. Using these variables, generalized linear mixed models were created using the lme4 package (Bates et al. 2021) within R (R Core Teams 2020) to produce SDMs for our target species.
This BBS modeling was done to provide guidance for the RWBJV Landbird Plan, which aims to direct and aid conservation efforts throughout the RWBJV management area. By identifying grassland bird priority areas based on model outputs, land managers throughout the RWBJV geographies can better direct funding and conservation efforts.
