Science Center Objects

Our science portfolio includes the study and management of mammal populations, which can require the use of methods and analysis that incorporate the difficulty in detecting them – picture how hard it is to count and identify bats at dusk or estimate the number of mountain lions in an area.

Threatened and Endangered Mammals

Key Largo woodrat (Neotoma floridana smalli - KLWR)

Key Largo woodrat (Neotoma floridana smalli - KLWR)(Public domain.)

 

Assessing Endangered Marsh Rabbit and Woodrat Habitat use and Predator Population Dynamics

 Feral and free-ranging domestic cats (Felis catus) have strong negative effects on wildlife, particularly in island ecosystems such as the Florida Keys. We deployed camera traps to study free-ranging cats in National Wildlife Refuges and state parks on Big Pine Key and Key Largo and used spatial models to estimate cat population dynamics and stable isotope analyses to examine cat diets. Top models separated cats based on movements and activity patterns and represent feral, semi-feral, and indoor/outdoor house cats. We provide evidence that cat groups within a population move different distances, exhibit different activity patterns, and that individuals consume wildlife at different rates - all of which have implications for managing this invasive predator. 

 

 

West Indian manatees, Trichechus manatus

(Public domain.)

 

Modeling, Estimation, and Adaptive Management of Florida Manatees

Florida manatees are threatened by watercraft-related mortality, the potential loss of warmwater habitat, red tide events, and other anthropogenic factors. The USFWS and the Florida Fish and Wildlife Conservation Commission have regulatory authorities under the Endangered Species Act (ESA), the Marine Mammal Protection Act (MMPA), and state statutes to recover manatees. To support management decision-making, these agencies need quantitative assessments of population status.

 

Polar Bear, Ursus maritimus

(Public domain.)

 

 

 

Adaptive Management for Threatened and Endangered Species

Threatened and endangered species have to be managed in the face of uncertainty, but traditionally, there has been reluctance to think about adaptive management of listed species. Management agencies with responsibility for threatened and endangered species need tools to help manage in the face of uncertainty, with the hope of reducing that uncertainty.

 

Survival Probability

Survival Probablity (Public domain.)

 

 

 

 

Hierarchical Models of Animal Abundance and Occurrence

Research goals of this project are to develop models, statistical methods, sampling strategies and tools for inference about animal population status from survey data. Survey data are always subject to a number of observation processes that induce bias and error. In particular, inferences are based on spatial sampling – we can only ever sample a subset of locations where species occur --and imperfect detection – species or individuals might go undetected in the sample. Principles of hierarchical modeling can be applied directly to accommodate both features of ecological data. Prior to the development of hierarchical models at PWRC, studies of unmarked populations focused on simplistic descriptions of distribution patterns and temporal trends. Hierarchical models have advanced the field of population ecology by enabling the estimation of demographic and movement parameters that previously could only be obtained using costly field methods. Ecologists can now make inferences about population dynamics at broad spatial and temporal scales using models designed specifically for this task.

 

 

 

Wildlife Management

 

White-tailed Deer, Odocoileus virginianus

(Public domain.)

 

 

Estimation of Density and Abundance of Biological Populations on National Parks and Wildlife Refuges Through Distance Sampling

Assessing the status and trends of populations of biological organisms is an important management goal and a recurrent theme in USGS research. Often, the most basic question of “how many are there?” remains elusive, thus making management decisions more difficult. This study continues a long-term commitment of technical support for the use of distance sampling for wildlife population abundance estimation in our National Parks and Wildlife Refuges.

 

 

Scientists collecting bat location data

Recorded Bat Calls: Recorded 'echolocation' calls are later evaluated by computer programs and visual inspection to ascribe bat species identities. (Public domain.)

 

 

 

 

 

Bats in Forests Managed for Wildlife

Within the Mississippi Alluvial Valley (MAV), forest managers may prescribe variable retention silvicultural treatments within bottomland hardwood forests on public lands to improve forest conditions (i.e., structural heterogeneity, species composition, and senescence) for priority wildlife species. This is referred to as wildlife-forestry silviculture. However, concerns have been voiced regarding loss of available cavities for wildlife use if hollow trees are removed or become inaccessible due to management. Of particular concern are bat species and their occurrence

and use of forests subjected to wildlife-forestry silviculture.