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Landscape pivot points and responses to water balance in national parks of the southwest US
Author(s) -
Thoma David P.,
Munson Seth M.,
Witwicki Dana L.
Publication year - 2019
Publication title -
journal of applied ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.503
H-Index - 181
eISSN - 1365-2664
pISSN - 0021-8901
DOI - 10.1111/1365-2664.13250
Subject(s) - vegetation (pathology) , environmental science , evapotranspiration , water balance , hydrology (agriculture) , water resources , precipitation , physical geography , ecology , geography , geology , medicine , geotechnical engineering , pathology , meteorology , biology
AbstractA recent drying trend that is expected to continue in the southwestern US underscores the need for site‐specific and near real‐time understanding of vegetation vulnerability so that land management actions can be implemented at the right time and place. We related the annual integrated normalized difference vegetation index ( iNDVI ), a proxy for vegetation production, to water balance across landscapes of the Colorado Plateau. We determined how changes in production per unit of water (vegetation responses) and the water balance amounts at which production shifted from above to below average values (pivot points), varied across dominant vegetation and soil types. Precipitation ( PRCP ), actual evapotranspiration ( AET ), water deficit ( D ), and soil moisture ( SM ) explained 13%–82% of variation in vegetation production. Along an increasing water availability gradient, vegetation responses to PRCP and AET increased, responses to SM decreased, and responses to D became more negative. We found trade‐offs between vegetation responses and pivot points within and across all vegetation types that were mediated by soil properties.Synthesis and applications . The water needed by native vegetation to maintain production depends on plant traits. The water available to vegetation depends on climate and soil properties that change along environmental gradients. Tracking this biologically relevant water availability in relation to water need provides an indicator of vegetation growth or stress that can help guide the time and place for management actions.