Burmese pythons help mice invade Florida

The Burmese python is invasive, killing many of the rat's natural predators and creating conditions for them to thrive and invade the Everglades.

Burmese python and cotton mouse. Photo: Rhona Wise/Danita Delimont — Burmese python and cotton mouse. Photo: *Rhona Wise/Danita Delimont*

Burmese pythons are helping rats dominate many areas of Florida's Everglades by wiping out many of their traditional predators, according to research published in the journal Mammalogy. The increase in rat numbers could disrupt an already fragile ecosystem and increase the risk of disease transmission to humans, Live Science reported on June 5th.

The Burmese python ( Python bivittatus ) was discovered in Everglades National Park in 1979. Its population skyrocketed in the 1980s and 1990s. Today, tens of thousands of pythons live in the Everglades. Over the past 40 years, they have decimated many native animal populations, including bobcats, rabbits, and foxes.

However, smaller mammals appear to be unaffected by the presence of the Burmese python, including the cotton mouse ( Sigmodon hispidus ). To investigate the impact of the Burmese python on this species, researchers captured 115 mice and fitted them with tracking devices, 34 in areas with few pythons and 81 in areas with many pythons. They monitored the mice every two days and recorded the predators involved whenever any mice died. In cases where the carcasses were likely ingested, the research team analyzed the mouse DNA in the feces and excreted carcasses.

The research team's findings showed similar mouse mortality rates in both areas. While the pythons killed six cotton mice wearing the devices, their impact on the overall mouse population was minimal. However, because pythons severely affect populations of large mammals like bobcats and foxes, this creates an ecological gap for the mice to invade. As a result, in areas with high python populations, cotton mice are invading communities, according to study author Robert A. McCleery, associate professor of wildlife ecology and conservation at the University of Florida.

The collapse of large and medium-sized mammal populations in the Everglades affects crucial ecological processes such as nutrient and scavenging cycles. Rats cannot replace the role of these disappearing mammals. Their dominance also has the potential to spread disease to humans. Cotton rats are reservoirs of viruses that can be transmitted to humans, such as Everglades virus (EVEV) and hantavirus.

An Khang (According to Live Science )

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