Big Cypress fox squirrel ( Sciurus niger avicennia ) ecology and habitat use in a cypress dome swamp-pine forest mosaic

Abstract

Forested wetlands are in decline, as are many species that are obligate residents. Big Cypress fox squirrels (BCFS; Sciurus niger avicennia) are a threatened endemic to wet pine and cypress forests in southwestern Florida. The region is characterized by development resulting in habitat loss, habitat fragmentation, and hydrological change that influence the quality of these wet forests. Through radiotelemetry and field observations, we examined the ecology and habitat use of BCFS in a natural cypress dome-pine forest mosaic. BCFS selected cypress domes for food and nests throughout the year. Cypress dome habitats were the only habitat type to be used more than available; however, the availability of nearby pine forest was also important. Home ranges were large relative to other tree squirrels, with male home ranges exceeding female ranges. Males overlapped more females than males, while sharing similar food preferences and use patterns with females, suggesting that the sexual dimorphism in home range size is related to mate searching. Roads and oil extraction pads were used less frequently than expected and were incorporated into home ranges less than randomly generated features. The importance of cypress domes within the wet forests and grasslands of Big Cypress National Preserve demonstrates the value of maintaining this delicate mosaic.

Multiscale effects of habitat loss and degradation on occurrence and landscape connectivity of a threatened subspecies

“…All sampled locations were at least 500 m apart and buffered at least 50 m from OHV trails and roads. We chose 500 m as a buffer size between sample locations to represent the approximate size of the home range of BCFS and to reduce the possibility that the same individual was detected at more than one location (Kellam et al, 2016). We used Bushnell Natureview Essential HD wildlife cameras (Bushnell Natureview Essential HD, Overland Park, KS 66214) to survey squirrels on approximately 75% of plots established throughout the study, chosen at random.…”

“…Additionally, some data from satellite imagery were only available at specific spatial resolutions. Similarly, variables we chose to measure were selected based on previous support for their influence on occupancy of BCFS or other closely related subspecies of fox squirrels (Eisenberg, Noss, Waterman, & Main, 2011;Kellam et al, 2016;Maehr, 1993;Sovie et al, 2020). We measured plot-level features of vegetation structure and composition on each 20-m radius plot location.…”

“…We assessed home-range-level features within 500-m buffers surrounding each sample location, including summer land-surface temperature and percent of tree canopy cover. Prior studies indicate that BCFS primarily inhabit upland pine/cypress mosaic communities, which can vary widely in temperature and tree canopy cover (Kellam et al, 2016). In comparison to plot-level assessment of temperature as a determinant of occupancy, we wanted to assess whether occupancy in such mosaic communities would be influenced by land surface temperature on a home-range-level.…”

“…These features included Euclidean distance to three types of roads based on traffic intensity (high: road corridor contains at least four lanes, is separated by a median and has a maximum speed of at least 45 mph, moderate: road corridor includes at least two lanes that may or may not be separated by a median and with a maximum speed of at least 40 mph, and low: two lanes or fewer, not separated by a median, and maximum speed lower than 40 mph), distance to three levels of residential development (urban, suburban, and rural), and distance to five potentially important vegetation communities (cypress strand, isolated freshwater wetland, hydric pine flatwoods, and mesic pine flatwoods). These five vegetation communities provide unique food sources and shelter found to be important to BCFS occurrence (Kellam et al, 2016).…”

“…Once a game species (Duever et al, 1986), the Big Cypress fox squirrel is now a Species of Greatest Conservation Concern in Florida's Wildlife Legacy Initiative Wildlife Action Plan (2012). Remaining intact freshwater forested communities important for BCFS occur predominantly within conservation areas (Ditgen, 1999;Kellam et al, 2016;Martin, 2002). Ecological function and habitat quality vary greatly among these conservation areas, however, due to current and historic patterns of land use (Brandt & Ewel, 1989;Carter et al, 1973).…”