Effects of prescribed fire on Yuma Clapper Rails and California Black Rails on the lower Colorado River

The Yuma clapper rail (Rallus longirostris yumanensis) is a federally endangered species and 90% of the U.S. population exists in only 2 wetlands. California Black Rails (Laterallus jamaicensis coturniculus) are state endangered in Arizona and state threatened in California. To ensure long-term persistence of these two species, we need to have effective management and mitigation activities that improve habitat quality and restore populations. One possible management activity that has been proposed to benefit both species is prescribed burning in areas with decadent emergent vegetation. Historically, marsh habitats along the Lower Colorado River were highly ephemeral with periodic flooding and natural fires eliminating decadent stands of emergent vegetation. Years of flood control and fire suppression has resulted in substantial areas of decadent emergent marsh h habitat, but very little early successional emergent marsh along the Lower Colorado River. Prescribed fire may be the best technique for creating early-successional emergent marsh habitat required to enhance populations of these 2 species. This project evaluates the usefulness of prescribed fire as a potential conservation measure for both Yuma Clapper Rails and California Black Rails in southern Arizona and southern California. Call-broadcast surveys before and after burning in both burned and unburned areas (2 adjacent to each burned area) will allow us to examine the effects of fire on rail abundance. We worked with a variety of federal and state cooperators to identify study plots that did not have populations of breeding rails, but are near existing breeding areas for both species and dominated by dense emergent vegetation. If rail populations respond positively to prescribed fires, the project will provide a proven method for restoring rail populations and rail habitat along the entire Lower Colorado River. The immediate goal of the proposed project is to provide a tested and proven technique for creating/restoring optimal habitat for both Yuma Clapper Rails and California Black Rails.

Our results demonstrated that fire increased the number of Yuma clapper rails detected and did not affect the number of black rails detected. Marsh vegetation grew back rather quickly after fires, and was typically tall enough to attract rails within 1-3 months. The species composition of the vegetation did not change as a result of the burns, but the amount of decadent vegetation was reduced. These results suggest that prescribed fire can be used to set back plant succession in freshwater emergent marsh and thereby benefit recovery of the endangered Yuma clapper rail.

We saw some evidence that the positive effects of fire diminished as time since fire increased. We also monitored crayfish abundance (an important prey item for Yuma clapper rails) and examined the rate at which decadent vegetation accumulated on a subset of plots. We are currently analyzing data to determine the effects of fire on crayfish abundance and determine how accumulation of decadent vegetation affects rail abundance. These data will help us provide detailed recommendations on the fire frequency needed to maintain optimal rail habitat.

• Conway, C. J., C. P. Nadeau, and L. Piest.  2010.  Fire helps restore natural disturbance regime to benefit rare and endangered marsh birds endemic to Colorado River.   Ecological Applications  20:2024-2035.

• Conway, C. J., C. P. Nadeau, and L. Piest. 2006. Fire effects on Yuma Clapper Rails and California Black Rails on the Lower Colorado River. Arizona Cooperative Fish and Wildlife Research Unit, Wildlife Research Report Number 2006-07, Tucson, Arizona.

• Conway, C. J., and C. P. Nadeau. 2005. Effects of Fire on Yuma Clapper Rails and California Black Rails, 2004 Annual Report. Wildlife Research Report Number 2005-01. Arizona Cooperative Fish and Wildlife Research Unit, Tucson, Arizona .

• Nadeau, C. P., and C. J. Conway. 2010. Marsh bird research at Imperial National Wildlife Refuge. Colorado River Terrestrial and Riparian (CRTR) Conference, Laughlin, NV, 3 Feb 2010.

• Conway, C. J., C. P. Nadeau, and L. Piest.  2008. Using prescribed fire as a management tool for the Yuma clapper rail and California black rail.  Lower Colorado River Science and Management Symposium, Scottsdale, AZ, 19 November 2008.

• Conway, C. J., C. P. Nadeau, and L. A. Piest.  2007.  Effectiveness of prescribed fire as a management tool to improve habitat quality of endangered Yuma clapper rails and California black rails along the Lower Colorado River.  40th Joint Annual Meeting of the Arizona/New Mexico Chapters of The Wildlife Society and American Fisheries Society.  Albuquerque, NM, 8 February 2007.

• Nadeau, C., and C. J. Conway. 2005. "Fire Effects on Yuma Clapper Rails and California Black Rails on the Lower Colorado River. Joint Fire Science Program, Principle Investigator Conference." San Diego, CA.

• Conway, C. J.  2004.  Using prescribed fire to recover the federally endangered Yuma Clapper Rail on the Lower Colorado River National Wildlife Refuges.  U.S. Fish and Wildlife Service Region 2 Fire Management Conference.  Tucson, AZ.  7 December 2004.