Refuge provides highlights of monthly biology activities
J.N. “Ding” Darling National Wildlife Refuge biological science technician Avery Renshaw recently reported on the Sanibel refuge’s following biology activities for the month of June.
Hurricane Ian disrupted a lot at the refuge, but the biology program has continued despite the challenges. One important initiative that restarted in January was monitoring of the state-designated threatened Sanibel Island Rice Rat (Oryzomys palustris sanibeli), and the refuge team is thrilled to report it has been documented at the refuge since the hurricane. Biologists found the first photographic evidence that any rice rats survived the storm after sifting through thousands of photos captured by bucket camera traps on refuge and Sanibel-Captiva Conservation Foundation lands. The teams will continue to sort through the remaining photos in hopes of finding rice rats in other locations.
Many people may not realize that this at-risk species is a unique Sanibel treasure as it is found nowhere else in the world but on Sanibel. Not to be mistaken for the non-native invasive black rat (Rattus rattus) you may find being a nuisance in human spaces, the rice rat is a secretive semi-aquatic species that only occupies the Spartina grass, interior freshwater marshes and the mangroves on the island, far from people and houses.
The rice rat already had low population estimates before Ian. After the island was inundated by over 13 feet of storm surge in some areas from the hurricane and continues to hold high salinity water inland, the species previously had not been detected at all. Through continued monitoring efforts using bucket trap cameras, evidence finally was found that the small mammal survived the storm. The rice rats use Spartina grass clumps for nesting. They move between the grass wetlands and mangroves, eating seeds, insects and crustaceans; they completely avoid developed areas. It is likely that the presence of a healthy population is an indicator of a healthy marsh system. As we learn more about the rice rats, we can use certain metrics, such as population numbers and movement patterns, to gauge the overall health of Sanibel’s freshwater marsh ecosystems. Maintaining healthy freshwater marshes through prescribed burning, invasive species removal and hydrologic restoration projects will benefit the rice rate but also many other important species, such as the roseate spoonbill, Florida box turtle and humans.
Refuge staff is partnering with the SCCF, city of Sanibel and Florida Fish and Wildlife Conservation Commission to continue research and monitoring efforts of this Sanibel resident. There is much yet to be discovered about the important species.