Background

Studies on the spatial ecology of invasive species provide critical information for conservation managers such as habitat preferences and identification of native species at risk of predation. To understand the spatial ecology of non-native Burmese pythons (Python molurus bivittatus), now well-established in Everglades National Park and much of South Florida USA, we radio-tracked 19 wild-caught adult pythons, 16 with VHF tags during 2006 through 2009 and 3 by GPS tags between 2010 and 2011. Our goal was to identify individual core-use areas and quantify home ranges, as well as to explore correlations of python movements with environmental parameters such as the presence of surface water.

Results

Radio-tracking periods ranged from 87 to 697 days for snakes with VHF tags, with a total of 5,119 tracking days (mean ± 1 SD = 319.9 ± 184.3 days); GPS tracking periods ranged from 12 to 93 days, with a total of 146 tracking days (mean ± 1 SD = 48.7 ± 40.7 days). We observed mean individual radio-tracked python home ranges of 22.5 km² (2250 ha) with overall low site fidelity; all home ranges were within the park boundary. Python core-use areas included slough and coastal habitat types, and we delineated 18 common-use areas (that is, areas where individual core-use areas spatially overlapped). Tree islands were a principal feature of common-use areas, even if they were not the predominant habitat type. Multiple common-use areas were in proximity to roads. The longest movements of individual pythons correlated well with presence of surface water, and occurred during both wet and dry seasons.

Conclusions

High-use areas determined from python habitat-use and movement data may be optimal locations for targeted control efforts and further studies on impacts to native fauna.