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Abstract
The ecological roles and ecosystem services that bats provide have been increasingly recognized and valued in recent years. However, despite their diversity and prevalence throughout temperate North America, spatiotemporal patterns in abundance and assemblage composition of bats remain poorly understood at multiple spatial scales. To address this, and to establish a baseline from which the ecosystem services of bats (e.g., to agriculture) may be better characterized, we conducted a year-long systematic acoustic survey of bats along a typical riparian corridor in California’s Central Valley. Because Putah Creek is both actively managed and a highly altered riparian ecosystem, flanked by agricultural lands and intercepted by dams for water storage and diversion, it provides a good representation of Central Valley waterways. We collected full-spectrum acoustic recordings for one week each month over the course of a year at eight sites along 48 km of the creek. These efforts yielded 157,762 identifiable calls and highlighted a rich bat assemblage, comprising 15 species from eight genera and two families. We categorized seven species as year-round residents, six as seasonal migrants, and two as incidental visitors. Spatial patterns suggest highly individualistic distributions that presumably reflect species-specific habitat preferences, while temporal patterns highlight a marked decline in activity during winter and an unexpected dip in activity in late spring and early summer. The late spring decline likely reflects emergence of seasonal hibernators or movement of migratory species using this riparian corridor. Generalized linear models conducted on three species with sufficient observations underscore the individualistic nature of spatiotemporal activity patterns.
