The impact of invasive species has emerged as a high-priority issue in planning the restoration and conservation of the Greater Everglades Ecosystem. Resource managers in Florida are particularly interested in one of the most direct impacts of the invasive Burmese python population: what are they eating, and has it changed over time? Burmese pythons may prey on threatened or endangered species, and they may exhibit spatial, temporal, and/or size-related shifts in their prey species composition. We identified prey species from the digestive tract contents of 350 pythons collected from 2010 to 2016 using a morphological approach (i.e., using hair, feather, and scale morphology). We used python location data to subdivide the samples into regions that reflect the expansion of the range from the southern Everglades, north to Water Conservation Area 3A, and west to Collier County.
Results/Conclusions
We found that shifts are occurring over time in diet composition for pythons collected from within Everglades National Park (ENP) boundaries, with birds becoming more prevalent in the diet as compared to data collected before 2008 (p<0.001). These trends were driven mostly by pythons within the 2.4-3.0 m SVL size class. The percentage of birds found in the python diet north and west of ENP remained near previously reported numbers (~25%). The mammalian component of the diet for pythons collected within the ENP boundaries consisted of primarily rodents (85%). The mammalian component north and west of ENP was more diverse, and rodents were only 45% of the diet. These results suggest spatial and temporal shifts in prey species composition for pythons throughout their range, which supports previous studies showing declining trends for some mammal species throughout the ENP. Dietary shifts in this common invasive species may have implications for ecosystem stability, as well as Everglades restoration.