California Least Tern Monitoring and Management in San Diego County

Since 1970 when the California least tern (Sternula antillarum browni) was listed as endangered, the number of breeding pairs has gone from just 624 in 1973 to an estimated 6437-6699 in 2010 (Marschalek 2011). While the number of breeding pairs has increased substantially, fledgling success remains extremely low and appears to be declining (Schuetz 2011). In order to better understand this anomaly, a more comprehensive understanding of the ecological relationships shaping California least tern population dynamics is necessary. Although 30+ years of California least tern monitoring data exist, comprehensive, robust meta-analyses of the existing long-term dataset have not been completed.

While the CA least tern recovery plan identifies specific goals and a number of management strategies have been successfully implemented for California least tern, monitoring and management of the species has been largely site-specific and de-centralized. Led by the IEMM, this project will facilitate the implementation of a scientifically robust, statewide monitoring and management program for California least tern that is guided by recovery goals and objectives and our current understanding of California least tern ecology. Adopting a meta-analytical approach, the work in this project will improve our understanding of the factors that drive California least tern population dynamics, including survival, reproductive success, and assessment of threats and stressors. By reviewing the current monitoring and management strategies, the IEMM will evaluate the utility and efficacy of current monitoring and management protocols to track tern population status. These analyses will serve to identify knowledge gaps to guide future research needs, strengthen the draft recovery plan, provide information necessary to determine if current level of data collection is beneficial and critical for recovery of the species, and improve the ability to effectively and efficiently mitigate threats and stressors facing California least tern populations.

For more information:

Long-term Analysis of California Least Tern Data