CONSERVATION ELEMENTS OF AND A BIODIVERSITY MANAGEMENT FRAMEWORK FOR THE SONORAN DESERT NATIONAL MONUMENT June 2005 Photo Credit Cover photos © Dale Turner. The photos depict various scenes from the Sand Tank Mountains area of the Sonoran Desert National Monument, spring 2005. Recommended Citation Hall, J.A., S. Weinstein, N. Chambers, C.L. McIntyre, and M.D. List. 2005. Conservation Elements of and a Biodiversity Management Framework for the Sonoran Desert National Monument. The Nature Conservancy in Arizona and Sonoran Institute, Tucson. 350 + viii p. CONSERVATION ELEMENTS OF AND A BIODIVERSITY MANAGEMENT FRAMEWORK FOR THE SONORAN DESERT NATIONAL MONUMENT © 2005 by The Nature Conservancy and Sonoran Institute John A. Hall Sonoran Desert Program Manager The Nature Conservancy, Tucson, Arizona Stephanie Weinstein Conservation Planner The Nature Conservancy, Tucson, Arizona Nina Chambers Associate Director, Sonoran Desert Program Sonoran Institute, Tucson, Arizona Cheryl L. McIntyre Research Assistant Sonoran Institute, Tucson, Arizona Michael D. List Science Information Manager The Nature Conservancy, Tucson, Arizona This report was prepared under: (1) Federal Cooperative Agreement No. AAA–02–0005, Task Order AAF–02–0001 by The Nature Conservancy in Arizona for the Bureau of Land Management, Phoenix Field Office; (2) Federal Cooperative Agreement No. DACA87–02–H– 0004 by The Nature Conservancy in Arizona for the U.S. Army Corps of Engineers, Department of Defense Legacy Resource Management Program; (3) Federal Cooperative Agreement No. PAA–03–7008, Task Order AAW–03–0001 by the Sonoran Institute for the Bureau of Land Management; and (4) Federal Cooperative Agreement No. DACA87–03–H–0005 by the Sonoran Institute for the U.S. Army Corps of Engineers, Department of Defense Legacy Resource Management Program Disclaimer The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the opinions or policies of the U.S. Government. Mention of trade names or commercial products does not constitute their endorsement by the U.S. Government. EXECUTIVE SUMMARY The biological richness and ecological value of the Bureau of Land Management’s (BLM) Sonoran Desert National Monument (SDNM) and adjoining lands have been exhorted via ecoregional assessments, focused reports, and most recently through the 2001 Presidential Proclamation that established the monument. This biodiversity management framework document describes the biodiversity of the SDNM and adjoining lands by characterizing a focused set of representative conservation elements—natural communities, species, and various groupings of species—and their associated ecological processes. This information can be used by the BLM and others to guide management of this unique landscape. In addition, the framework provides both a regional ecological and socioeconomic context, the latter of which provides important clues for current and future threats to the SDNM, opportunities for their abatement, and local community perspectives. The major insight of this framework document—derived from the ecological characteristics of the conservation elements in combination and the socioeconomic factors that may affect their long-term persistence—is that the biodiversity of the SDNM exists and functions within a larger geographic context. The implications of this insight are several. First, the long-term management of the monument’s biodiversity requires attention to ecological and not just administrative boundaries. The ecological and socioeconomic data compiled in support of this framework was used to demarcate the appropriate ecological boundary (Figure ES.1). Second, long-term management success will require acceptance of a unified vision and shared sense of responsibility among several land managers, besides the BLM, and other stakeholders for the natural resources contained within this ecologically defined boundary (hereafter referred to as the Sand Tank Mountains Complex). Third, the time to act and implement this vision is now. The SDNM and adjoining lands are located in proximity to one of the most rapidly urbanizing areas in the Southwest, if not the Nation. The good news is that the landscape of the Sand Tank Mountains Complex, with some notable exceptions such as Interstate 8, is mostly unfragmented and in reasonable ecological condition. At present, land management is mostly a mix of protected areas of various types and working landscapes. The growing recognition of the value of open space, in concert with changing perceptions of the social amenity values offered by public lands, the desire by some area stakeholders to maintain a rural lifestyle, and the presence of socially valued plant communities and species such as saguaro cactus forests and desert bighorn sheep, respectively, also offer a social context in which a comprehensive conservation vision can be pursued. The bad news is that projected growth in the area and its associated impacts threaten this landscape. Species such as desert bighorn sheep are sensitive to continued fragmentation of their habitat. The boundary of the Sand Tank Mountain Complex is defined in part by the habitat and movement needs of this species. Although appropriate management and retention by BLM of existing public lands within the Sand Tank Mountains Complex is key, appropriate management of non-BLM land also is critical for several conservation elements. This document, along with its supporting documents, provides a blueprint and information base that all stakeholders concerned with the ecological and social values of the Sand Tank Mountains Complex can use to help guide the long-term management of the area. Background and Scope The Nature Conservancy (Conservancy) and Sonoran Institute (Institute) prepared the SDNM biodiversity management framework as a project under the Sonoran Desert Ecosystem Initiative. The Initiative is a partnership between the Department of Defense, BLM, Conservancy, and Institute. One of its primary ES.1 Biodiversity Management Framework FIGURE ES.1 Sand Tank Mountains Complex Functional Conservation Landscape ES.2 Executive Summary thrust areas is to improve the prospects for the management of biodiversity in the Sonoran Desert by assisting federal land managers with conservation planning. With the recent designation of the SDNM and its associated requirement for a resource management plan, as well as its close ecological ties with the eastern portion of the Barry M. Goldwater Range (BMGR), the SDNM was a logical place to partner on conservation planning in the region. Subsequently, the SDNM also became identified as a pilot demonstration area for integrating the Conservancy’s approach to conservation planning with the BLM’s planning process. The biological aspects of the framework are based on the Conservancy’s approach to site conservation planning that has been adapted to a federal land management context. This approach was applied previously to the BMGR and adheres to contemporary principles of conservation planning. For the SDNM, the focus here is on the selection of conservation elements that can represent the biodiversity of the SDNM and their ecological characterization within regional and monument-scale contexts. Ecological characterization includes an analysis of stresses and their sources by conservation element. In addition, the framework includes, under the direction of the Institute, a significant contribution from the social sciences. In this regard this framework is relatively unique as a biological resource management strategy in its integration of social science considerations. Land managers need to consider both biological and social data, and the linkages between them, when making resource management decisions. To enhance its relevance this document also identifies correspondences between the framework and the (1) principles of ecosystem management and (2) steps in the BLM planning process. Findings A total of 26 natural communities/guilds/species are proposed to serve as a focal set of conservation elements for the SDNM. Besides desert bighorn sheep and saguaro, these elements include desert tortoise, Tucson shovel-nosed snake, rufous-winged sparrow, Desert Grassland, and Mountain Upland, the last of which is a natural community that is found only within high-elevation mountain ranges of the Sonoran Desert. The elements selected are the outcome of a coarse filter-fine filter approach meant to capture and represent the biodiversity of the SDNM and adjacent portions of the BMGR and Tohono O’odham Nation for management planning purposes under the BLM’s resource management plan for the monument. Detailed ecological characterization information is provided for each element. A fairly broad and strong correspondence exists between the conservation elements recommended for the SDNM as part of the biodiversity management framework and the biological objects identified in the monument proclamation. The areas where overlap does not occur reflect in part situations in which new information since the proclamation was issued has come to light concerning the rarity of certain species and the opportunities afforded by the SDNM for their conservation. The proposed set of conservation elements is based on our knowledge to date of the natural resources occurring on the SDNM and vicinity. Additional species were suggested by our information gathering or by experts for consideration as conservation elements; however, in many cases we lacked the requisite information