Differing climate and landscape effects on regional dryland vegetation responses during wet periods allude to future patterns

Authors: PETRIE, MATTHEW - New Mexico State University; Peters, Debra; BURRUSS, N. DYLAN - New Mexico State University; JI, WENJIE - New Mexico State University; SAVOY, HEATHER - New Mexico State University

Submitted to: Global Change Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/21/2019
Publication Date: 6/10/2019
Citation: Petrie, M., Peters, D.C., Burruss, N., Ji, W., Savoy, H. 2019. Differing climate and landscape effects on regional dryland vegetation responses during wet periods allude to future patterns. Global Change Biology. 25(10):3305-3318. https://doi.org/10.1111/gcb.14724.
DOI: https://doi.org/10.1111/gcb.14724

Interpretive Summary: Dryland vegetation is influenced by Land Surface Template (LST) conditions and precipitation (PPT), such that enhanced vegetation responses to periods of high PPT may be shaped by multiple factors. High PPT stochasticity in the Chihuahuan Desert suggests that enhanced responses across broad geographic areas are improbable. Yet, multiyear wet periods may homogenize PPT patterns, interact with favorable LST conditions, and in this way produce similar responses. We tested the hypothesis that enhanced vegetation responses would be initiated by high PPT, but that LST favorability would underlie response magnitude, producing geographic differences between wet periods. We focused on two multiyear wet periods; one of above-average, regionally-distributed PPT (1990-1993) and a second with locally-distributed PPT that contained two extreme wet pulses (2006-2008). 1990-1993 had regional vegetation responses that were correlated with soil properties. 2006-2008 had higher vegetation responses over a smaller area that were correlated with PPT and secondarily to soil properties. Within the overlapping PPT area of both periods, enhanced vegetation responses occurred in similar locations. Thus, LST underlied the geographic pattern of vegetation responses, whereas PPT initiated the response and controlled the response area and maximum response magnitude.

Technical Abstract: Dryland vegetation is influenced by Land Surface Template (LST) conditions and precipitation (PPT), such that enhanced vegetation responses to periods of high PPT may be shaped by multiple factors. High PPT stochasticity in the Chihuahuan Desert suggests that enhanced responses across broad geographic areas are improbable. Yet, multiyear wet periods may homogenize PPT patterns, interact with favorable LST conditions, and in this way produce similar responses. In contrast, periods containing extreme high PPT pulses could overwhelm LST influences, suggesting a divergence in how climate change could influence vegetation by altering PPT periods. We tested the hypothesis that enhanced vegetation responses would be initiated by high PPT, but that LST favorability would underlie response magnitude, producing geographic differences between wet periods. We focused on two multiyear wet periods; one of above-average, regionally-distributed PPT (1990-1993) and a second with locally-distributed PPT that contained two extreme wet pulses (2006-2008). 1990-1993 had regional vegetation responses that were correlated with soil properties. 2006-2008 had higher vegetation responses over a smaller area that were correlated with PPT and secondarily to soil properties. Within the overlapping PPT area of both periods, enhanced vegetation responses occurred in similar locations. Thus, LST favorability underlied the geographic pattern of vegetation responses, whereas PPT initiated the response and controlled response area and maximum response magnitude. Our study suggests that future vegetation responses during wet periods will be tied to LST favorability, yet will be shaped by the pattern and magnitude of multiyear PPT events.