Sonoran Desert Rapid Ecoregional Assessment Report

James R. Strittholt, Sandra A. Bryce, Brendan C. Ward, Dominique M. Bachelet
Posted on: 7/18/2022 - Updated on: 7/18/2023

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Rapid Ecoregional Assessments (REAs) are a product of the evolution of the Bureau of Land Management (BLM) toward a landscape approach to land and resource management. Using the landscape approach, the BLM hopes to integrate available scientific data from BLM field offices, other federal and state agencies, and public stakeholders to develop collaborative management efforts across administrative boundaries. Regional scale information and assessment analyses on current and future condition will be used by the BLM and its partners to assist with land use planning, developing best-management practices, authorizing uses, and establishing conservation and restoration priorities. REAs are informational tools, not decision documents.

The regional scope of the Sonoran Desert REA and the assessment of its numerous conservation elements and their interactions with change agents produced a massive volume of results that can only be summarized within the constraints of a report of reasonable length. Major highlights of the results appear in the body of the report and appendices provide more detailed information on methods and models. Several key aspects of the REAs highlight their utility to the BLM:

Management Questions: Management questions are the foundation and catalyst for the REAs because they determine the scope of data requirements and analyses. BLM land managers and partners provided a broad range of management questions to the REA to frame regional issues and data needs (full list in Section 2.4.1). The regionally-significant management questions developed for each REA match the scale of the assessment. The 32 management questions prepared for the Sonoran Desert REA refer to native and invasive flora and fauna, disturbance factors or change agents that affect present and future resource status, and significant (designated) sites and ecological functions and services.

Assessing Current Condition: The evaluation of the current status of regionally-significant biotic elements (wildlife and plant species) and abiotic factors (e.g., soils, water resources) was a key aspect of the REA. Two characteristic vegetation communities of the Sonoran Desert represented the coarse-filter component (Table 2-2, Section 2.4.2). Fine filter elements were represented by 11 wildlife species conservation elements as well as a list of designated sites and essential ecosystem functions and services (e.g., aquatic systems, riparian areas, and soil stability).

Because of the spatial nature of the REAs, describing status for various conservation elements and resource values requires the ability to identify and map specific characteristics of that resource. As a result, REA results and the regional assessments, while valuable, must always be considered incomplete: some important elements will be absent because their effects were not visible or because data to represent them were not available.

Application to Adaptive Management: REAs are timely in supporting planning, management, and mitigation strategies for impacts anticipated from rapidly-developing issues related to traditional and renewable energy development, the spread of invasive species, changing fire regimes, and climate change. REAs provide a foundation for an adaptive management approach that will allow implementation strategies to be adjusted for new information and changing conditions. REAs represent a baseline condition from which to evaluate the results of adaptive management and to characterize potential trends in resource condition both in the near-term (2025)—as a consequence of development activities—and in the long-term (2060) as a result of climate change. Chapters 5 and 6 provide examples showing how the data and results may be arranged and manipulated using mapped and tabular results, for all land ownerships and BLM-lands only, for areas of intact habitats, resource value hotspots, and opportunities for connectivity with existing designated protected lands.


Strittholt, J.R., Bryce, S.A., Ward, B.C., Bachelet, D.M. (2012). Sonoran Desert Rapid Ecoregional Assessment Report. Prepared for the U.S. Department of the Interior, Bureau of Land Management, Denver, Colorado.

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The BLM is responsible for managing the nation's public lands and resources in a combination of ways which best serve the needs of the American people. The BLM balances recreational, commercial, scientific and cultural interests and strives for long-term protection of renewable and nonrenewable resources, including range, timber, minerals, recreation, watershed, fish and wildlife, wilderness and natural, scenic, scientific and cultural values.

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