Playa wetlands as possible drought refugia in a sagebrush steppe ecosystem
Abstract
Playas of the northern Great Basin, USA, are seasonal wetlands in closed basins that are important habitats for migrating shorebirds and sources of late-season forage for wildlife like sage grouse. Although playas exhibit considerable interannual variability of inundation, most typically retain shallow water from late winter through early summer. Historically, many playas were developed with "dugouts" (i.e., pits) to retain water for cattle later into the summer and fall. The hydrologic consequences of these alterations are not fully understood. Currently, some land managers are considering hydrologic restoration of playas through dugout filling. To help inform restoration planning efforts in the face of climate change, we asked: (1) What are the drivers of playa inundation? (2) Are there particular playas that provide hydrologic refugia during droughts and how are these patterns related to playa development? Using data from the Global Surface Water Explorer, we evaluated a 30-year time series (1985-2015) of inundation for 153 playas on the Sheldon-Hart Mountain National Wildlife Refuge Complex in southern Oregon and northern Nevada. Generalized Linear Mixed Effects Models indicated that playa wetness and inundated duration were positively related to the Standardized Evapotranspiration Precipitation Index (indicating greater playa inundation under wetter weather conditions), and to developed status, such that playas with dugouts had greater probabilities of wetness and longer inundated durations. Only 4% of playas were deemed drought refugia (holding water at least two months during each of the five driest years), with large and developed playas more likely to meet this designation. Given the expectation that the region will experience more frequent and severe drought, models will also be used to predict playa inundation using drought severity thresholds. Because previous land managers may have intentionally selected drought refugia sites for development, improved understanding of the factors promoting drought refugia is needed. In identifying drivers of playa inundation, playas functioning as drought refugia, and predicting playa response to future droughts, this study will help land managers make effective use of resources for ecological restoration.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.H33O2215R
- Keywords:
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- 1812 Drought;
- HYDROLOGY;
- 1817 Extreme events;
- HYDROLOGY;
- 1821 Floods;
- HYDROLOGY;
- 1855 Remote sensing;
- HYDROLOGY