Research begins on Sanibel rice rats
A study of Sanibel rice rats has begun at J.N. “Ding” Darling National Wildlife Refuge by researchers from the University of Florida to gather more information about the species that only resides on Sanibel.
“This study is important to the refuge because we have caught very few Sanibel rice rats during our survey and monitoring efforts and we don’t know much about this subspecies that is exclusive to Sanibel,” Deputy Refuge Manager Joyce Palmer said in a prepared statement. “We are indebted to the various agencies that support this study at a time when federal budget cuts have severely slashed our staff from 20 in 2011 to 12 today. We are fortunate to have partners who are able to help us achieve our research needs.”
University of Florida Assistant Professor of Wildlife Ecology Conservation Robert McCleery said the three year study, which will survey every sampling possible of the Sanibel Rice Rats, resulted from a call from FWC to do a proposal for the research. He said restoration is also an important component of the study.
The samplings will be done during the wet season and dry season because the rice rat population fluctuates drastically, according to McCleery.
“My goal is to do publishable research,” he said of “three years of intense monitoring.”
Three University of Florida researchers, McCleery, intern Daniel Filho and PhD student Wesley Boone, began working on the study in mid-June. Two full-time researchers are staying onsite at “Ding” Darling during the research, due to financial support from the refuge, U.S. Fish & Wildlife Services and the “Ding” Darling Wildlife Society-Friends of the Refuge.
So far no rice rats have been trapped in the freshwater marshes, mangrove and transitional zones since the last week of June.
McCleery said the research will focus on what is limiting the rice rats and what can be done to change the outcome.
The research is being funded by the Florida Fish & Wildlife Conservation Commission. The $89,000 study will also include an estimated $351,000 restoration, which is a research driven component. Signage and a possible observation tower at Bailey Tract on Tarpon Bay Road is also included in the study with matching funds from the refuge and DDWS.
FWC Biologist Alyssa Jordan said they will do some studies before the restoration takes place to have an idea of what is there. Once the restoration is done another study will be conducted to see what changed.
She said woody brush and invading buttonwood will be among some of the vegetation that will be eliminated. The restoration, Jordan said will restore the hydrology at Bailey Tract, as well as restore the flow and hydrology in marshes. The restoration, she hopes will benefit the rats and wading birds.
Jordan said if the marshes are doing well, it’s a good indicator that the rice rat species are also doing well.
The rice rat has been identified as a state threatened species due to habitat loss and fragmentation, as well as feral house cat predation and competition against the nonnative Black Rat.
The Sanibel Rice Rat helps in shaping the rodent community, which is why this species is important to the island. The rice rat eats seeds and snails, and also provides such predators as hawks and bobcats with food.
Small mammal surveys have been conducted by the J.N. “Ding” Darling National Wildlife Refuge biology staff and interns each spring and fall for the rice rats.
In the spring, staff and interns captured two rice rats at the Legion Curve site on the refuge. A male rat, baring the number 193, was captured on March 11 and weighed 80 grams and measured 11.5 centimeters from its nose to tail tip. On April 17, another male was captured and tagged with number 187. It weighed 150 grams and measured 14 centimeters.
According to biology intern Hanna Joergens both of the males had tan backs and white undersides. Its tail, she said, was half-brown, half-white skin coloration.
In order to obtain data regarding the rice rats population location, size and habitat requirements, the biology staff and interns use live traps, general body size metrics and tagging methods to study the rice rats.
After the rice rat is tagged with a small number on its ear it is safely released back into its habitat.