Title

Improving Species Recovery: Insights From Community Occupancy Modeling

Presentation Type

Poster

Abstract

The U.S. Endangered Species Act (ESA) has been instrumental in the protection of imperiled species; however, despite the ESA’s ability to protect species and their habitats, recovery successes have been limited. The inefficiency of the ESA to recover species may be due to reliance on single-species recovery plans, which exclude considerations of community dynamics (e.g. interspecific competition). Due to the potential for variable responses of species to landscape changes that may alter community dynamics, it is critical to understand community responses to these changes as managers try to recover imperiled species. Currently, the Mexican Spotted owl (MSO) is listed under the ESA and efforts are underway to recover this species and to understand its response to stand-replacing wildfires. I collected presence/absence data for 8 owl species that are sympatric with the MSO, while conducting surveys for MSOs during a single breeding season (May-Aug 2014) in east-central Arizona. My objectives were to: 1) test the ability of MSO surveys to estimate multispecies detection and occupancy rates for 8 sympatric owl species; and 2) model the effect of burn severity on species occupancy probability, while controlling for the effects of survey date, wind, and elevation on detection probabilities. Overall, mean detection rates were low across species (p < 0.10), resulting in high uncertainty in estimates of community occupancy rates. Detection rates were highest for the Great-horned owl and these rates were comparable to the MSO, suggesting that community occupancy may be low across the study area. The very low detection rates for some species may have resulted from non-response to MSO calls, and future survey methods could use automated call boxes to increase species detection rates. Given high enough detection rates across species, these methods hold potential for application to other imperiled species projects where multispecies data is concurrently collected.

Category

Life Sciences

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Apr 17th, 3:00 PM Apr 17th, 4:00 PM

Improving Species Recovery: Insights From Community Occupancy Modeling

South UC Ballroom

The U.S. Endangered Species Act (ESA) has been instrumental in the protection of imperiled species; however, despite the ESA’s ability to protect species and their habitats, recovery successes have been limited. The inefficiency of the ESA to recover species may be due to reliance on single-species recovery plans, which exclude considerations of community dynamics (e.g. interspecific competition). Due to the potential for variable responses of species to landscape changes that may alter community dynamics, it is critical to understand community responses to these changes as managers try to recover imperiled species. Currently, the Mexican Spotted owl (MSO) is listed under the ESA and efforts are underway to recover this species and to understand its response to stand-replacing wildfires. I collected presence/absence data for 8 owl species that are sympatric with the MSO, while conducting surveys for MSOs during a single breeding season (May-Aug 2014) in east-central Arizona. My objectives were to: 1) test the ability of MSO surveys to estimate multispecies detection and occupancy rates for 8 sympatric owl species; and 2) model the effect of burn severity on species occupancy probability, while controlling for the effects of survey date, wind, and elevation on detection probabilities. Overall, mean detection rates were low across species (p < 0.10), resulting in high uncertainty in estimates of community occupancy rates. Detection rates were highest for the Great-horned owl and these rates were comparable to the MSO, suggesting that community occupancy may be low across the study area. The very low detection rates for some species may have resulted from non-response to MSO calls, and future survey methods could use automated call boxes to increase species detection rates. Given high enough detection rates across species, these methods hold potential for application to other imperiled species projects where multispecies data is concurrently collected.