An invasive species is any living thing that is put into a different ecosystem and causes harm. In Southern Florida, the Everglades is a huge area grassy wetlands. Burmese pythons were first sighted in Everglades National Park in the 1980s, they were not seen as a reproducing population until 2000.
Since then, the number of pythons has grown a lot and we now believe there are between 30,000 and 300,000. One of the main sources of food for these snakes, and all other predators, are Marsh rabbits.
An aerial view of a mangrove forest in the Everglades. These forests give organisms a unique environment of wetlands, which many of the living things that live there have adapted to over millions of years.
In a University of Florida study, they released marsh rabbits in several different areas. In the places where pythons live, they saw that 77% of the rabbits they released were eaten by pythons. In areas where there were no deaths by pythons, 71% of the rabbits were eaten by other mammals, such as bobcats and coyotes.
In the Mammal Sightings graph below, we see the change in mammal sightings between the years 1996-1997 and 2003-2011. This shows how many hundreds of each mammal were sighted during the first time period in green. In red, it shows how many hundreds of each mammal were sighted during the second time period.
In the bottom graph, Areas with Mammals, we see the places where animals were seen. The number of mammals found in areas with pythons is in Red. The number of animals found in areas near where pythons live is in Orange. The number of animals found outside where pythons live is in Yellow.
References:
Dorcas, M. E., J. D. Willson, R. N. Reed, R. W. Snow, M. R. Rochford, M. A. Miller, W. E. Mehsaka, Jr., P. T. Andreadis, F. J. Mazzotti, C. M. Romagosa, and K. M. Hart. 2012. Severe mammal declines coincide with proliferation of invasive Burmese pythons in Everglades National Park. Proceedings of the National Academy of Sciences 109:2418-2422.