Summary and synthesis of 15 years of the Amphibian Vital Sign monitoring in the National Capital Region Inventory and Monitoring Network
The amphibian monitoring program, designed and conducted by the U.S. Geological Survey’s Amphibian Research and Monitoring Initiative program, is designed to estimate the status and trends of amphibian populations to assist management decisions in individual parks and across the National Capital Region Network. Detection/non-detection data for stream and wetland habitats has been collected in 2 parks annually since 2005, and recently expanded to 11 units in the network following habitat mapping efforts. Data for all parks were incorporated into an analysis of site-occupancy for each habitat type (e.g. streams, wetlands) to estimate the occupancy rates for each species. This report summarizes the monitoring efforts, changes in the program over time, and findings based on data from 2005-2018. Fifteen species or species complexes within wetland sites and 5 species of salamander in stream sites were encountered during surveys. Across the network, more than half of wetland populations (65%) are estimated to be stable, 2% are increasing, and 33% indicate a negative trend. Stream salamander populations appear to be relatively stable, with observed population fluctuations likely related to availability of surface water in a given year. Although there were among-park differences in baseline occupancy and dynamics, overall factors promoting occupancy and persistence from year to year included sites that are large, well-connected to other breeding habitats, forested, and with low conductivity.