A protocol for monitoring bats at cave roosts in the Cumberland Piedmont Network: Version 2.0

Thomas, Steven; Ingersoll, Tom; Jernigan, Johnathan; Moore, Bill

This monitoring protocol is focused on monitoring a subset of eight species of cave-dwelling bats that regularly inhabit selected caves within the four CUPN parks. The approach to determine abundance of summer cave-roosting bats (objective 1) centers around evening bat exit counts with multiple independent observer methods using night vision and thermal infrared equipment at cave entrances. Fourteen caves will be monitored at least twice every year, while another group (26 caves) will follow a four-year rotation where either six or seven caves are surveyed each year—each cave receiving at least two visits during the sampling year. Thus, 20 or 21 caves total will be monitored, at least twice each cave, every summer (between May 15 and July 31) at all four parks. Winter in-cave counts primarily using direct visual or photographic techniques will be used to assess abundance (objective 2) each year between 1 January and 28 February. Fifteen bat hibernacula will be censused in years ending with an odd number (e.g., 2017, 2019) at CUGA and MACA, and another 14 hibernacula will be monitored in years ending with an even number (e.g., 2016, 2018) at CHCH, MACA and RUCA. Cave air temperature and relative humidity (objective 3) will be collected using two methods. First, opportunistic grab sampling uses handheld sensors to measure cave air/rock temperature and relative humidity next to concentrations of bats during winter censuses at 29 selected hibernacula. Second, continuous sampling uses automated data loggers to continuously collect cave air temperature and relative humidity measurements in all 50 summer and winter bat roost caves. The use of multiple visits and multiple independent observer methods to obtain “multiple-measures” data will allow the use of hierarchical models and estimation of detectability to obtain abundance estimates of summer cave-roosting bats. The total number of bats counted by species will be used for winter abundance status and time series trend analysis using additive models to produce population trajectories. Issues related to cave atmospheric conditions (temperature and relative humidity) under which bats use caves will be addressed using a combination of summary and descriptive statistics, graphic analysis, and additive models for trend analysis. Data handling procedures will be in place to ensure data collected under this protocol are of an acceptable quality and are available for current and future data users. Data recorded in the field onto data forms will be entered and stored in the CUPN’s Cave Bat database, developed in Microsoft Access. Data verification and validation will be conducted before electronic data sets are archived. Queries and reports in the database will be used to retrieve data for analysis and to generate Annual Summary Reports and eight-year Trend Analysis Reports for park management. This protocol details the why, where, how, and when of the CUPN cave bats monitoring project. As recommended by Oakley et al. (2003), it consists of a protocol narrative and a set of standard operating procedures (SOPs) which detail the steps required to collect, manage, and disseminate the data representing the status and trend of summer and winter cave-roosting bats and associated habitat parameters in the four network parks. The protocol is a living document in the sense that it is continually updated as new information acquired through monitoring and evaluation leads to the refinement of program objectives and methodologies. Changes to the protocol are carefully documented in a revision history log. The intent of the protocol is to ensure that a scientifically credible story about the ecological condition of cave-roosting bats and their responses to exotic disease, park management actions, land use changes, and other stressors can be told to park visitors and managers alike.

A protocol for monitoring bats at cave roosts in the Cumberland Piedmont Network: Version 2.0

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