|ATLSS PanTrack Telemetry Visualization Tool
Louis J. Gross and E. Jane Comiskey
University of Tennessee, Knoxville, TN
ATLSS PanTrack is a visualization tool designed to display and analyze spatial movement data of panthers over georeferenced landscape maps. It has been customized for the display of radiotelemetry observations collected for the Florida panther endangered species recovery project. PanTrack was developed to help define panther behavior rules for the spatially explicit, individual-based ATLSS Deer/Panther model. The effectiveness of individual-based models depends upon the availability of detailed observations about individuals on the landscape, and on the ability to find patterns in these observations that provide insight into key animal behaviors. The availability of PanTrack, a programmable tool customized for the Florida panther data set, has facilitated the evaluation of telemetry data, and has also proved invaluable in facilitating interaction and exchange of information between the modeler and field biologists, allowing on-the-spot confirmation of field observations in the context of the full set of monitoring data and rapid visual identification of patterns in landscape/panther associations. Having a readily customizable display and analysis tool has also enabled researchers to study published panther analyses closely, evaluating whether trends reported in spatial and temporal subsets of panther data are reflected in the entire data set.
South Florida is home to the last remaining population of endangered Florida panthers (Puma concolor coryi). Panther survival is threatened by habitat loss and degradation, geographical isolation, disease, and problems associated with small population size, including inbreeding and sensitivity to stochastic events. The current verified population size is 80 adult and subadult panthers. Because the few remaining panthers have been intensively studied, a fairly detailed database is available for individuals in the population. Monitoring of Florida panthers by radiotelemetry, initiated in 1981 with the radio-collaring of two individuals, has now expanded to include 39 panthers. Over 60,000 telemetry locations are available over the monitoring period. Four Global Positioning System (GPS) collars were deployed for the first time in 2002, providing as many as 8 locations around the clock compared to the current collection schedule of 3 daytime locations per week.
Recent demographic trends in the panther population are in sharp contrast to earlier observations, necessitating a thorough reevaluation of rules and parameters in light of changes in the population. A genetic restoration project was initiated in 1995 because of low genetic variation and health and reproductive problems likely caused by inbreeding. Eight reproductive females from a closely related subspecies of Puma concolor were translocated from Texas and introduced into the South Florida population. Five of those females have mated with Florida panthers, producing a total of 17 F1 offspring over a 7-year period. F1 panthers and their offspring have been vigorous and healthy thus far, showing none of the heart and reproductive problems seen in Florida panthers. The success of genetic restoration in increasing genetic variation and producing healthy intercrossed panthers has changed the course of panther recovery, and has confounded published theories and opinions about panther ecology in South Florida.
The panther population has more than doubled since 1995, including a 5-fold increase in formerly sparsely populated areas of BCNP and ENP, thought by some researchers to be unsuitable habitat for panthers. Earlier observations and theories about habitat use, home range establishment, dispersal patterns, and rates of reproduction and kitten survival must now be reevaluated in light of new data. Pre-introgression panther habitat selection studies that focused narrowly on forest were based on the unsupported assumption that habitats associated with daytime telemetry locations are representative of total habitat use. Panther distribution patterns previously attributed to habitat suitability now appear to have resulted from dynamics associated with limited dispersal potential in a small, inbred population with low reproductive rates living in a barrier-rich environment.
Panther recovery and Everglades restoration efforts, and the modeling projects that support and guide them, depend on accurate characterizations of panther habitat use and requirements, based on all available information. With these changes in mind, the set of panther location observations (1981-1995) on which preliminary panther behavior rules for the ATLSS Deer/Panther model were originally based has been expanded to include post-introgression observations so that recent trends can be reflected in revised rules for behavior and habitat use. The PanTrack Tool is being used to display and analyze the full set of available panther telemetry data for the purpose of redefining behavior rules. The predictive capabilities of an individual-based model are closely tied to the realism of the decision rules that determine how individual animals move across the landscape, interact with one another and respond to their environment. The definition of these rules is in turn tied to the availability and interpretation of empirical observations about these behaviors and movement patterns. In this context, PanTrack has been used to study abundance and distribution; movement and dispersal patterns; seasonal effects; home range characteristics; patterns of reproduction, recruitment, and mortality; effects of gender, age, and genetic group, and patterns of habitat use.
ATLSS panther researchers have reported results of their analyses in an extensive article in the online journal Conservation Ecology. Using programming extensions to PanTrack, innovative telemetry mapping and fractal analysis techniques were used to explore panther habitat use and home range characteristics. Wildlife biologists contributed field observations indicating that habitat selection is considerably broader during active nighttime hours than during daytime. The paper provides a critical evaluation of the assumptions and limitations of the dominant forest-centered view of panther ecology, concluding that percent forest cover is a poor predictor of home range size and that forest cannot be considered a surrogate for useful panther habitat. Factors other than habitat have contributed substantially to habitat suitability, population density, and distribution.
The authors conclude that Puma concolor in Florida, as elsewhere in their range, are habitat generalists, exploiting the broad spectrum of available habitats for hunting, resting, mating, travel, denning, and dispersal. While panthers readily utilize forested habitat with understory and prey, we found no support for the view that only forested land within a habitat mosaic is potential panther habitat, or for the contention that only forested habitats are used by panthers within existing home ranges. This work suggests a more ecologically-consistent management and recovery paradigm based on maintaining the integrity of the system of overlapping home ranges that characterizes panther social structure and satisfies breeding requirements. Such a paradigm focuses on the requirements for reproductive success of a small population in a changing environment.
PanTrack currently operates on Sun workstations or on PC's with a LINUX operating system installed. Installation of PV-WAVE Version 7.50 (Visual Data Analysis Software by Visual Numerics) is required. PanTrack data and program installation require 15MB of disk space. The run-time PanTrack screen consists of a Landscape Map Window and a menu board user-interface. Zoom and animation windows may be created and dismissed during the session. Data may be subset for display by time period (day, month, year) and/or by group (e.g., individuals, age, gender, genetic lineage, cause of death).
Comiskey, E. Jane, University of Tennessee, 569 Dabney Hall,
Knoxville, TN, 37996-1610
Phone: 865-974-0224, Fax: 865-974-3067, email@example.com