November 8, 2010

Do We Have to Exclude People to Save Frogs?

When species are listed under the Endangered Species Act, potential impacts to those species justifiably receive greater scrutiny. In our crowded world an issue that federal and state agencies frequently have to contend with is direct impacts from human visitation on habitat for a sensitive species. One of the key challenges in making such decisions is to balance the need for species protection with the need to provide the public with opportunities to see the species in question. Public support for a species and the actions necessary to ensure its survival are much more likely when the public actually has the opportunity to see the organism in its natural environment. Those interactions build empathy and fascination and a greater understanding of the threats that organisms face. Decisions to simply exclude people may provide some short-term protection but in the long-term people have to be part of the solution. 

In southern California where millions of people live within a one hour drive of several national forests, human use of those public lands is intense and conflicts with sensitive species are common. In 2002 the dwindling populations of the southern mountain yellow-legged frog (Rana muscosa) in the Transverse and Peninsular Ranges were listed as "endangered" under the federal Endangered Species Act (see In the News > ESA listing page for details). In 2005 the US Fish and Wildlife Service proposed several thousand acres of stream and riparian habitat as "critical habitat" for these R. muscosa populations. In response, in late-2005 the Angeles National Forest opted to close access to 1000 acre area along Little Rock Creek due to the presence of R. muscosa in this section of creek. This resulted in the closure of a popular climbing area, Williamson Rock, because it directly abuts Little Rock Creek. The closure also prevented access to a portion of the Pacific Crest Trail, forcing hikers to use a detour that required walking along a highway for some distance. 

The Angeles National Forest recently released a draft Environmental Assessment of the closure that proposes to keep the area closed for at least three more years while the response of the Little Rock Creek frog population to the 2009 Station fire is monitored.This potentially open-ended closure of the area has upset several user groups, in particular the climbing community (e.g., Friends of Williamson Rock). It is clear that user-created trails that access Williamson Rock and the proximity of some climbing routes to Little Rock Creek (some climbing routes actually start in the creek itself) have the potential to impact the frog population. However, many of these impacts would be relatively easy to mitigate. For example, the numerous user-created trails could be replaced by a single maintained trail and those climbing routes closest to the creek could be closed. In addition, climbers could be required to use "wag bags" for the disposal of all human waste. Discussions I recently had with a representative from the climbing community indicated that they are willing to work with the Angeles National Forest to implement these actions. It remains a big question whether the Forest will go along with this, however. 

The easiest action for agencies to take when confronted with conflicts  between human visitation and an endangered species is to simply restrict access. Although complete closures may sometimes be necessary, it is often possible to find creative solutions to conflicts that minimize impacts to sensitive species and in doing so help to build a constituency for conservation of the species. The Williamson Rock issue seems to have all the hallmarks of a situation where a suitable compromise is attainable. I hope the Angeles National Forest and Friends of Williamson Rock don't let this opportunity slip away. 

Back to The Mountain Yellow-legged Frog Site.


  1. good write up, but let's remember that US Fish and Wildife Service are the ones who mandate the US Forest Service to close areas of endangered species. I believe the USFS cannot alone make changes to the closure without consulting with F&W Service, even though the closure is on forest land.

  2. You've made a good point regarding the role of the USFWS. They do have the final say in all decisions related to the management of federally-listed endangered species. With the Williamson Rock issue I am hopeful that we can get all involved parties to take a careful look at potential mitigation measures that might resolve the current stand-off over use of the area. It won't be easy but we've got to try.