Udell, B.J., Straw, B.R, Cheng, T., Enns, K.D., Winfred, F., Gotthold, B.S, Irvine, K.M., Lausen, C., Loeb, S., Reichard, J., Rodhouse, T., Smith, D.A., Stratton, C., Thogmartin, W.E., Wiens, A.M., and Reichert, B.E., 2022, Status and Trends of North American Bats Summer Occupancy Analysis 2010-2019 Data Release: U.S. Geological Survey data release, https://doi.org/10.5066/P92JGACB.
NABat status and trend information is intended to inform conservation decision making, leading to the long-term viability of bat populations across the continent. These data were provided to allow for more detailed investigation of the results from 'Status and Trends of North American Bats Summer Occupancy Analysis 2010-2019' report. Bat occupancy probability is a key measure of species distributions and their space use in the summer, and comparing these occupancy probabilities across space and time can provide key insights into important areas in space use, and how they are changing over time. Some potential uses of these data include: visualizing grid cell level predictions of species occupancy probabilities for each bat species and year, visualizing the changes in species’ grid cell level occupancy over time, and visualizing aggregate measures of status and trends for larger spatial regions (e.g., across modeled species ranges, or states/provinces/territories). These data also provide the exact values of the status and trends results for each species at all scales, which can be used to assist and inform continental, regional, and local conservation management efforts. Data for grid cell level occupancy covariates used in these analyses are provided in the geospatial data layer, which can also be used for visualization or analytical purposes. These data will also be used to construct interactive dashboards and summary materials. As noted in the accompanying report, the methods used in these analyses were determined to be insufficient for modeling the occupancy distributions of 3 species: Eptesicus fuscus (EPFU), Lasiurus cinereus (LACI), Lasionycteris noctivagans (LANO). This was due to several factors including: i) limitations of the monitoring data (i.e., misclassification rates, large data sets, temporal and geographic biases), ii) computational and analytical limitations when fitting the models (i.e., convergence issues for some parameters despite long model runs), iii) weak and uncertain covariate effects for the occupancy process and observation processes. Finally, because many species of North American bats have complex life cycles and seasonal migration behavior, the status and trends of summer occupancy distributions are just one of several lines of information (e.g, analysis of winter colony counts, summer roost counts, summer mobile transect monitoring for relative abundance, bat activity modeling) that may be used to gain a full understanding the status and trends of a bat populations.
