Invasive Species Damaging the Ecosystem Restoration Project

The San Antonio River Authority (SARA) is contracting with wildlife management specialists over the next few weeks to control the non-native Nutria-rat population within the Eagleland and Mission Reach segments of the San Antonio River Walk.  There will be 60 visible trapping mechanisms placed off the trails along the banks of the San Antonio River, and the community is cautioned not to come in contact with these traps for their safety. 


Nutria-rats are large, brown, stocky rodents that are similar in size to beavers.  Instead of the beaver’s famous broad flat tail, Nutria-rats have long round scaly tails with bristles.  Breeding up to two times a year with up to nine offspring per litter, Nutria can increase in population at an alarming rate.  These semi-aquatic rodents prefer to live in marshes and riverbanks, where they forage on 2.5-3.5 pounds of vegetation daily.  They were introduced in North America in the 1930s as a fur-bearing species, and since then they have spread to cover the eastern two-thirds of Texas as well as many other states.  

Nutria-rats have already damaged banks and destroyed significant portions of the restored native emergent plants within the Eagleland and Mission Reach river segments, and their removal will protect these restored ecosystems from further damage.  Nutria-rats kill vegetation by eating the soft, succulent parts near the base of plants and the roots.  Besides their destructive appetite, Nutria-rats also damage the environment by burrowing into the soft soil in the banks of the River, triggering excess erosion to those banks and causing them to collapse and fail. 

The wildlife management specialist contract to remove these rodents is for 45 days and is in accordance with the guidelines of the United States Department of Agriculture’s Wildlife Services. Contact Kirk Moravits, SARA’s Natural Resource Management Specialist, at (210) 302-3249 with questions.

- Lee Marlowe, Sustainable Landscape Ecologist
San Antonio River Authority