1. Burrowing crayfish represent 15% of total crayfish species and 32% of imperiled species. Few life history studies exist for these species and more information is needed regarding their ecology, population status, distribution, and biogeography for effective conservation efforts. Challenges to gaining such information include sampling difficulty and small sample sizes. Collection efforts may be more efficient if activity patterns can be identified for species of interest. The goal of our study was to assess specific environmental indicators of burrowing crayfish activity patterns.

2. We evaluated activity patterns of two primary burrowing crayfish species, Lacunicambarus erythrodactylus Simon & Morris, 2014 and Procambarus holifieldi Schuster, Taylor & Adams, 2015 using laser-triggered digital photography for one-year periods in the Bogue Chitto Creek floodplain, Dallas County, Alabama, U.S.A. We predicted that activity would be related to time of day, season, groundwater depth, and precipitation.

3. Activity by L. erythrodactylus covaried significantly with time of day, daylength, groundwater temperature, and relative air temperature, while activity by P. holifieldi covaried with time of day, season, groundwater temperature, and relative air temperature. Additionally, burrow chimney construction by P. holifieldi covaried with daylength, groundwater temperature, relative air temperature, and precipitation.

4. Out-of-burrow activity for both species was greatest at night and during periods of relatively cool groundwater temperatures and relatively warm air temperatures, which may be linked to thermal regulation behavior. The probability of chimney construction by P. holifieldi increased with increasing daylength and decreasing precipitation and was highest during periods of cool groundwater temperatures and air temperatures. A distinct lull in activity from October through March for both species was likely the result of reproductive behaviors such as period of egg production and incubation within burrows.

5. Identifying peak out-of-burrow activity periods for burrowing crayfish will allow collection efforts to be focused on periods of greatest activity, thereby facilitating the study of burrowing crayfish behavior.

Data was collected from March 2017 to May 2019 in the field in Orrville, Alabama. It includes crayfish activity data from motion-triggered laser photography and corresponding environmental data. Generalized linear mixed models were used to determine if crayfish activity was related to time of day, daylength, season, air temperature, groundwater temperature, precipitation, and groundwater depth.