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State of the Las Ciénegas NCA, Part II: Gila Topminnow Population Status and Trends

Report

Arizona

Publication date: July 1, 2007

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This study analyzed 15 years of data on the endangered Gila topminnow (Poeciliopsis occidentalis occidentalis) to determine the population status and trend at Las Cienegas. We also tested alternative monitoring protocol to provide managers with more timely and reliable information on topminnow populations.

Subject Tags

  • Rivers
  • Biodiversity
  • Grassland

Abstract

The Las Cienegas National Conservation Area (LCNCA) protects rare riparian, aquatic, and semidesert grassland ecosystems, supports six endangered species, and includes two eligible wild and scenic river segments. To safeguard these exceptional values, the Bureau of Land Management (BLM) adopted a science-based adaptive management program and partnered with The Nature Conservancy to evaluate resource conditions and monitoring protocols. This report, part of the project’s second phase, focuses on the endangered Gila topminnow, which persists in Cienega Creek despite regional declines and absence of invasive species. Analysis of 15 years of monitoring data reveals severe population drops in upper reaches and variable trends downstream, prompting recommendations to improve efficiency and trend detection, including expanding sampling stations, reducing uninformative measurements, and adjusting monitoring frequency. These changes aim to meet recovery plan standards, enhance management responsiveness, and inform broader conservation strategies, while further research is needed to understand causes of decline and guide adaptive actions.

Citation

Bodner, G., Simms, J. and Gori, D., 2007. State of the Las Cienegas National Conservation Area: Gila topminnow population status and trends 1989-2005. The Nature Conservancy, Tucson, AZ.

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