Preliminary Assessment of Biodiversity Values and Management Framework Adaptation for the Expanded Kofa Complex and Yuma Resources Management Area in Southwestern Arizona

Abstract

This report presents a preliminary assessment of biodiversity values and the adaptation of a management framework for the Expanded Kofa Complex within the Bureau of Land Management (BLM) Yuma Resource Management Area in southwestern Arizona. Covering approximately 2.7 million acres of largely contiguous federal lands managed by BLM, U.S. Army Yuma Proving Ground (YPG), and U.S. Fish and Wildlife Service (Kofa National Wildlife Refuge), the study aims to guide cooperative biodiversity conservation among agencies while respecting their individual missions. Using a coarse filter–fine filter approach, 17 conservation elements—nine natural communities, five species, and three species guilds—were selected from over 160 candidates to represent the region’s biodiversity. A preliminary map of natural community distributions was developed, providing the first vegetation dataset at a scale suitable for resource management in this area. Key findings include confirmation of Mojave fringe-toed lizard populations on YPG dunes, identification of the largest unfragmented desert bighorn sheep habitat in Arizona, and documentation of rare species such as California fan palm and Kofa barberry. The report highlights major threats, including habitat fragmentation, invasive species, altered hydrology, and recreational impacts, and emphasizes the importance of maintaining ecological processes and connectivity. Recommendations focus on integrating biodiversity considerations into ongoing planning efforts, fostering interagency collaboration, and addressing data gaps through refined mapping, species monitoring, and long-term ecological research.

Citation

Weinstein, S., A. Gondor, and J.A. Hall.2004. Preliminary Assessment of Biodiversity Values and Management Framework Adaptation for the Expanded Kofa Complex and Yuma Resources Management Area in Southwestern Arizona. The Nature Conservancy, Tucson, AZ. 114 pp.