A little brown mouse that sleeps nine months of the year and is known for its impressive leaping ability was recently listed as an endangered species by the U.S. Fish and Wildlife Service.
On June 10 the New Mexico meadow jumping mouse gained protective status under the Endangered Species Act. The listing triggers federal conservation actions along its riparian and wetland habitats to ward off extinction.
The northern edge of the mouse's range reaches into southwest Colorado, including Montezuma, La Plata and Archuleta counties. It mostly hangs on in central New Mexico and eastern Arizona.
But 95 percent of that habitat is on federal grazing lands, prompting cattle groups in New Mexico to file a lawsuit against the listing Sept. 8.
Ranchers claim the public procedures prior to the listing were incomplete and thus illegal. They fear the endangered status will limit access to streams and water sources for livestock.
"Ranchers in these areas have had grazing allotments going back several generations," said Chad Smith, CEO of the New Mexico Farm & Livestock Bureau.
"The allotments are a private property right that the forest service is infringing upon when they fence cattle out of water sources. We had no choice to join the lawsuit to protect our members."
In Colorado, there are only two known populations identified as proposed critical habitat. One is on 184 acres along the Florida River east of Durango, and the other is on 634 acres along Sambrito Creek west of Navajo Reservoir. There are no recorded populations in Montezuma County.
Since 2005, there have been 29 documented remaining populations, down from 70 occupied areas in the early 1980s.
Habitat loss and fragmentation contributed to the significant population decline, according to the FWS. The primary sources of habitat loss include impacts from grazing, roads, and water management, along with drought and wildfires brought on by climate change.
According to FWS documents, "Isolated patches of suitable habitat are too small to support resilient populations. There is little or no opportunity for natural recolonization due to limited dispersal capacity. Therefore, the jumping mouse does not have the distribution of resilient populations needed to provide the genetic diversity required for species viability."
'Grazing can coexist'
The mouse habitat requires thick sedges and grasses reaching 24 inches high along streams and wetlands, explained David Smith, a FWS biologist studying the mice in Arizona. But saving the mouse does not mean cattle ranching has to stop.
"We firmly believe livestock grazing can coexist with the species," Smith said. "It's a matter of flexibility on allotment management."
The mouse occupies .3 percent of 22 grazing allotments located on the Apache-Sitgreaves, Sante Fe, and Lincoln National Forests.
In the coming year, each population site will be specifically surveyed for improving and protecting habitat for the mouse, he said.
Solutions may include more pasture rotations and adjusting the timing of grazing to minimize impacts during the mouse's active period.
"When they emerge in summer, it's important that their sources of food, high-calorie seed heads, are available. They need to fatten up for the next hibernation, and require good cover from predators," Smith said.
To promote stream-bed growth, range managers in New Mexico have created fenced off "cattle lanes" to control where livestock can access water. If a population is near a camping area, mitigation could take the form of stream-side fencing and mowing restrictions.
Smith said large grazing allotments lend themselves to cattle and jumping mice living together in relative peace.
"The species is concentrated in stream bottoms, so it's not a forage issue for livestock. It more of a focus on stream-side protection," Smith said.
Mouse with hops
Enlarged back feet give the jumping mouse its namesake mode of travel. It has been recorded to jump a distance of three feet when fleeing from danger. When not alarmed it moves by taking little hops of one to six inches.
The endangered fur ball hibernates nine months out of the year, the longest of any mammal in North America. During active summer months it is mostly nocturnal, and must breed, raise young, and store up sufficient fat reserves to survive next year's hibernation period.
Locally, there have not been any changes to grazing allotments due to the listing.
"It's on our radar," said Derek Padilla, Dolores district ranger for the San Juan National Forest. "Whether it affects us depends on what the recovery plan states. We're at the extreme fringes of their habitat."
A recovery plan is not expected for another year, Smith said. But a critical habitat map for the endangered mouse in Arizona, New Mexico, and Colorado is due out later this year. Activity on federal lands within habitat zones that may harm the animal will undergo a consultation process with the FWS and public land agencies to mitigate impacts.
The two Colorado populations are on private land and would require permission from the land owner to study, Smith said. However, protective actions on private land could occur if there was a federal nexus or major project, such as a Army Corps of Engineers permit to build a road or bridge, or if there is rangeland funding through the Natural Resource Conservation Service.
Protecting the mouse has far reaching environmental benefits beyond specific population sites.
"A healthy watershed is important for our water supply, irrigation districts, and recreation," Smith said. "In the long run healthier streams protect a lot of people. For those who say the mouse and grazing can't coexist, we will prove them wrong."
jmimiaga@cortezjournal.com
