Ongoing changes in migration phenology and winter residency at Bracken Bat Cave

A - Papers appearing in refereed journals

Stepanian, P. M. and Wainwright, C. E. 2018. Ongoing changes in migration phenology and winter residency at Bracken Bat Cave. Global Change Biology. 24 (7), pp. 3266-3275.

AuthorsStepanian, P. M. and Wainwright, C. E.

Bats play an important role in agroecology and are effective bioindicators of environmental conditions, but little is known about their fundamental migration ecology, much less how these systems are responding to global change. Some of the world's largest bat populations occur during the summer in the south-central United States, when millions of pregnant females migrate from lower latitudes to give birth in communal maternity colonies. Despite a relatively large volume of research into these colonies, many fundamental questions regarding their abundance—including their intra- and interseasonal variability—remain unanswered, and even estimating the size of individual populations has been a long-running challenge. Overall, monitoring these bat populations at high temporal resolution (e.g., nightly) and across long time spans (e.g., decades) has been impossible. Here, we show 22 continuous years of nightly population counts at Bracken Cave, a large bat colony in south-central Texas, enabling the first climate-scale phenological analysis. Using quantitative radar monitoring, we found that spring migration and the summer reproductive cycle have advanced by approximately 2 weeks over the study period. Furthermore, we quantify the ongoing growth of a newly—established overwintering population that indicates a system-wide response to changing environmental conditions. Our observations reveal behavioral plasticity in bats’ ability to adapt to changing resource availability, and provide the first long-term quantification of their response to a changing climate. As aerial insectivores, these changes in bat phenology and propensity for overwintering indicate probable shifts in prey availability, with clear implications for pest management across wider regional agrisystems.

Year of Publication2018
JournalGlobal Change Biology
Journal citation24 (7), pp. 3266-3275
Digital Object Identifier (DOI)
Open accessPublished as non-open access
FunderMarshall Sherfield Fellowship
Publisher's version
Copyright license
Publisher copyright
Supplemental file
Copyright license
Output statusPublished
Publication dates
Online14 Feb 2018
Publication process dates
Accepted04 Jan 2018

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