Bat inventory for Sequoia and Kings Canyon National Parks and Devils Postpile National Monument

Pierson, Elizabeth; Rainey, William

The Sierra Nevada Network (SIEN) Inventory & Monitoring Program identified a bat inventory as a high priority biological inventory for Sequoia and Kings Canyon National Parks and Devils Postpile National Monument (National Park Service 2001). A review of existing literature and museum records revealed that very few bat records existed for these parks, while Yosemite had more historic as well as recent bat surveys and research The goals of this inventory were to fill information gaps on bat distribution and relative abundance and assist park personnel in assessing the potential impacts of management actions on bat populations using park lands. This project had four primary objectives: 1. Characterize the distribution and relative abundance of bat species along elevation gradients of major watersheds in Sequoia and Kings Canyon National Parks (Kern, Kaweah, South Fork Kings, Middle Fork Kings, and South Fork San Joaquin) and in Devils Postpile National Monument (Middle Fork San Joaquin). 2. Characterize gross habitats, identify the bats found and document their specific uses of those habitats (foraging, day roosting and rearing young). Through literature review and/or field data, identify preferred habitats by species for these activities. 3. Identify species sensitive to disturbance (visitor impacts and management actions) through literature review and/or field data. 4. Make recommendations for long-term monitoring of bat species in Sierra Nevada parks. This study maximized the probability of documenting bat species by targeting habitats where bat foraging and roosting activities were expected to be prevalent. Sample sites were not randomly selected thus the results of this inventory cannot be extrapolated to the larger park landscapes. The main purpose of this inventory was to document species present in the parks and their associated habitats. While the study suggests habitat and elevation associations for bat species, there is not a study design that allows inference to areas not sampled. This study was conducted between 2001 and 2006 and documented a total of seventeen species of bats in the three parks: ten in Devils Postpile National Monument, sixteen in Kings Canyon National Park, and sixteen in Sequoia National Park. We used literature reviews, museum searches, and existing wildlife observations to document bat records for these parks and identify species expected to occur. Our field sampling targeted bat foraging and roosting habitats and documented bats through a combination of acoustic and mist-net sampling methods. To gain a better understanding of habitat use for various species, we categorized sampling stations in five general categories: 1) roost sites; and foraging areas associated with 2) forest; 3) meadow/scrub; 4) water; or 5) rock habitats. Acoustic methods using an Anabat system enabled us to identify a subset of bat species based on the call frequency, pattern, and duration; seven Sierra Nevada bat species are readily identified acoustically. Using mist-netting, we captured bats and collected data on age, sex, and reproductive status for 15 species. We conducted statistical analyses to determine how strongly numbers of bats captured in mist nets were associated with the five habitat categories. We captured 655 bats in 68 mist-netting sessions conducted at 64 sites. This assemblage included 15 of the 17 species known to occur in the parks. The spotted bat (Euderma maculatum) and the western mastiff bat (Eumops perotis) were detected only acoustically. Two species, Eptesicus fuscus and Myotis yumanensis, account for 50% of all captures. Taken together, the five most frequently captured species accounted for nearly 80% of all captures. We describe bat diversity, abundance, and distribution for each major river drainage, evaluate bat conservation issues, and make monitoring recommendations.

Bat inventory for Sequoia and Kings Canyon National Parks and Devils Postpile National Monument

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