Presented April 22, 2021- Presentation Slides




"Demonstration of Subsurface Passive Acoustic Monitoring (SPAM) to Survey for and Estimate Populations of Imperiled Underwater-Calling Frogsby Mr. Patrick Wolff

The management and recovery of threatened and endangered species necessarily rely upon an understanding of their occurrence, abundance and distribution. Many Department of Defense (DoD) installations spend considerable time and effort surveying for amphibians because many species have rapidly declining populations. Several imperiled frog species vocalize extensively underwater, making them difficult to detect using traditional above-surface survey methods. Passive acoustic monitoring (PAM) is an increasingly robust methodology to sample for acoustically active species that can provide a continuous, persistent record of species behavior, occurrence and abundance. As part of this project, we converted traditional PAM technology for submerged use and demonstrated that subsurface passive acoustic monitoring (SPAM) can be used to document the occurrence and relative abundance of at-risk underwater-calling frogs. With the rapidly increasing number of species being reviewed for protection under the Endangered Species Act, the DoD will need to rely upon a wide range of diverse and reliable survey technologies and approaches. SPAM is a powerful low-cost and low-effort tool that may be applied to a suite of aquatic species beyond frogs. With SPAM, land managers can obtain a better understanding of such species distributions and abundances, allowing them to develop plans to minimize impacts on these species and to reduce training restrictions.

Estimating the Density of Secretive, At-Risk Snake Species on Department of Defense Installations Using an Innovative Approach: IDEASS by Dr. Brett DeGregorio and Dr. J.D. Willson

Federal and state agencies, including the DoD, expend considerable resources managing and conserving threatened, endangered or at-risk snake species. Management of these species is often hampered by a lack of basic knowledge regarding their population size and trajectory. The low detectability of most snakes makes it difficult to determine their presence and abundance. As part of this project, we demonstrated a novel, simulation-based method, IDEASS (Innovative Density Estimation Approach for Secretive Snakes), for estimating snake density based on systematic road surveys, behavioral observations of snake movement and spatial movement (radio telemetry) data. This presentation summarized how IDEASS was used to generate meaningful density estimates for two rare and cryptic snakes of conservation concern at Fort Stewart in Georgia, the Southern Hognose and Eastern Diamondback Rattlesnake. We also applied the method to estimate density of Western Ratsnakes at Fort Hood in Texas using an existing dataset. In all three cases, traditional density estimation via visual surveys and capture-mark-recapture (CMR) failed completely despite extensive field efforts. We concluded that IDEASS is a powerful tool, and in some cases the only viable method, for estimating the density of secretive snakes that could be applied to other cryptic taxa.


Speaker Biographies
Mr. Patrick Wolff

Mr. Patrick Wolff is a research wildlife biologist at the U.S. Army Corps of Engineers, Engineer Research and Development Center, Construction Engineering Research Laboratory in Champaign, Illinois. Mr. Wolff’s work focuses on the conservation and management of wildlife on military lands with an emphasis on threatened, endangered, or at-risk species. He seeks to reconcile potential conflicts between conservation measures and military activities by using innovative technologies and techniques to better survey and evaluate animal populations. His research employs a variety of automated data collection and analytical methods, such as autonomous acoustic monitoring for amphibians and bats, automated radio telemetry to investigate the behavior of rare snakes, and artificial intelligence to automatically detect and identify wildlife species in photographs. He received his bachelor’s and master’s degrees in natural resources and environmental sciences from the University of Illinois at Urbana-Champaign.


Dr. Brett DeGregorio

Dr. Brett DeGregorio is the leader of the Fish and Wildlife Cooperative Research Unit at the U.S. Geological Survey  in Fayetteville, Arkansas, where his research focuses on wildlife conservation and behavior with a concentration on reptiles and birds. He has led and been a part of numerous investigations of snake ecology including defining their roles as predators of bird nests, understanding how some snakes can switch between diurnal and nocturnal foraging, and exploring methods of managing snake habitat for imperiled species. He has authored more than 40 peer-reviewed journal articles focusing on wildlife behavior and conservation. Dr. DeGregorio earned his bachelor’s degree in wildlife and fisheries conservation from the University of Massachusetts, his master’s degree from Purdue University, and his doctoral degree from the University of Illinois at Urbana-Champaign.


Dr. J.D. Willson

Dr. J.D. Wilson is an associate professor of biology at the University of Arkansas, Fayetteville. His research uses a combination of descriptive, experimental and modeling approaches to understand population and community dynamics of reptiles and amphibians. This is often within the context of anthropogenic stressors such as land-use change, pollution and invasive species. Dr. Wilson has a long-standing interest in developing and refining field and analytical methods for studying secretive herpetofauna. He received a bachelor’s degree from Davidson College and a doctoral degree from the University of Georgia’s Savannah River Ecology Laboratory.