Ground Beetle Sampling Ground beetle diversity sampling is used to help understand how the distribution of ground beetles changes in different habitats and ecosystems over time. Ground beetle species are found in each of the NEON domains, are easy to sample, and changes in their numbers can indicate significant changes in the local ecological community. Biweekly sampling for ground beetles takes place at SRER over the course of the growing season (roughly March – October). Specimens are collected at the outer edges of a subset of Distributed Plots (n = 10) using pitfall traps (four traps per plot) containing a dilution of propylene glycol, buried flush in the ground and shaded by flat covers to keep out sun, rain, and vertebrates. Each beetle sampling bout occurs for 14 consecutive days and requires a pair of field technicians to access plots on foot. A subset of all the ground beetles collected at SRER is submitted for DNA barcoding each year. DNA barcoding is a taxonomic method that uses a short genetic marker (mitochondrial gene, COI) to identify species. NEON is using DNA barcoding to establish a library of ground beetles at our sites to aid in specimen identification. Along with expert morphological identifications, this will ensure consistency of identifications across many technicians at different sites for 30 years of data collection.