Hydrologic refugia, plants, and climate change.
Climate, physical landscapes, and biota interact to generate heterogeneous hydrologic conditions in space and over time, which are reflected in spatial patterns of species distributions. As these species distributions respond to rapid climate change, microrefugia may support local species persistence in the face of deteriorating climatic suitability. Recent focus on temperature as a determinant of microrefugia insufficiently accounts for the importance of hydrologic processes and changing water availability with changing climate. Where water scarcity is a major limitation now or under future climates, hydrologic microrefugia are likely to prove essential for species persistence, particularly for sessile species and plants. Zones of high relative water availability - mesic microenvironments - are generated by a wide array of hydrologic processes, and may be loosely coupled to climatic processes and therefore buffered from climate change. Here, we review the mechanisms that generate mesic microenvironments and their likely robustness in the face of climate change. We argue that mesic microenvironments will act as species-specific refugia only if the nature and space/time variability in water availability are compatible with the ecological requirements of a target species. We illustrate this argument with case studies drawn from California oak woodland ecosystems. We posit that identification of hydrologic refugia could form a cornerstone of climate-cognizant conservation strategies, but that this would require improved understanding of climate change effects on key hydrologic processes, including frequently cryptic processes such as groundwater flow.
Department of Natural Resources and Society, University of Idaho, Moscow, ID, USA.
Blair C
BC
McLaughlin
Department of Integrative Biology, University of California, Berkeley, Berkeley, CA, USA.
David D
DD
Ackerly
Department of Environmental Science, University of Idaho, Moscow, ID, USA.
P Zion
PZ
Klos
Department of Landscape Architecture and Environmental Planning, University of California, Berkeley, Berkeley, CA, USA.
Jennifer
J
Natali
Departments of Integrative Biology and Environmental Science, Policy & Management, University of California, Berkeley, Berkeley, CA, USA.
Todd E
TE
Dawson
Department of Civil and Environmental Engineering, University of California, Berkeley, Berkeley, CA, USA.
Sally E
0000-0003-4618-5066
SE
Thompson
D002140:California; D002980:Climate; D057231:Climate Change; D017753:Ecosystem; D062070:Hydrology; D010944:Plants; D000068236:Refugium
climate change; conservation; fog; groundwater; hydrologic niche; hydrologic refugia; microrefugia; refugia