Actual Evapotranspiration and Deficit: Biologically Meaningful Correlates of Vegetation Distribution Across Spatial Scales Export

@article{citeulike:3034778, abstract = {Correlative approaches to understanding the climatic controls of vegetation distribution have exhibited at least two important weaknesses: they have been conceptually divorced across spatial scales, and their climatic parameters have not necessarily represented aspects of climate of broad physiological importance to plants. Using examples from the literature and from the Sierra Nevada of California, I argue that two water balance parameters-actual evapotranspiration (AET) and deficit (D)-are biologically meaningful, are well correlated with the distribution of vegetation types, and exhibit these qualities over several orders of magnitude of spatial scale (continental to local). I reach four additional conclusions. (1) Some pairs of climatic parameters presently in use are functionally similar to AET and D; however, AET and D may be easier to interpret biologically. (2) Several well-known climatic parameters are biologically less meaningful or less important than AET and D, and consequently are poorer correlates of the distribution of vegetation types. Of particular interest, AET is a much better correlate of the distributions of coniferous and deciduous forests than minimum temperate. (3) The effects of evaporative demand and water availability on a site's water balance are intrinsically different. For example, the 'dry' experienced by plants on sunward slopes (high evaporative demand) is not comparable to the 'dry' experienced by plants on soils with low water-holding capacities (low water availability), and these differences are reflected in vegetation patterns. (4) Many traditional topographic moisture scalars-those that additively combine measures related to evaporative demand and water availability- are not necessarily meaningful for describing site conditions as sensed by plants; the same holds for measured soil moisture. However, using AET and D in place of moisture scalars and measured soil moisture can solve these problems.}, author = {Stephenson, Nathan L.}, citeulike-article-id = {3034778}, citeulike-linkout-0 = {http://dx.doi.org/10.2307/2846252}, citeulike-linkout-1 = {http://www.jstor.org/stable/2846252}, comment = {Presents compelling physiologically-based hypothesis that two simple climate parameters, AET and D (deficit, evaporative demand not met by available water), are best surrogates for prediction of vegetation distribution at multiple scales. My question is how do AET and D compare to other climate surrogates/indices towards prediction of ecological responses to climate change as well (fire, insect outbreaks). Carrie Enquist has already mapped trend in D for last 30 years across NM, and will do so with AET.}, doi = {10.2307/2846252}, journal = {Journal of Biogeography}, keywords = {climate-change-index, evaportranspiration, vegetation-distribution}, number = {5}, pages = {855--870}, posted-at = {2008-07-22 22:45:06}, priority = {0}, publisher = {Blackwell Publishing}, title = {Actual Evapotranspiration and Deficit: Biologically Meaningful Correlates of Vegetation Distribution Across Spatial Scales}, url = {http://dx.doi.org/10.2307/2846252}, volume = {25}, year = {1998} }

TY - JOUR ID - citeulike:3034778 L3 - citeulike-article-id:3034778 N2 - Correlative approaches to understanding the climatic controls of vegetation distribution have exhibited at least two important weaknesses: they have been conceptually divorced across spatial scales, and their climatic parameters have not necessarily represented aspects of climate of broad physiological importance to plants. Using examples from the literature and from the Sierra Nevada of California, I argue that two water balance parameters-actual evapotranspiration (AET) and deficit (D)-are biologically meaningful, are well correlated with the distribution of vegetation types, and exhibit these qualities over several orders of magnitude of spatial scale (continental to local). I reach four additional conclusions. (1) Some pairs of climatic parameters presently in use are functionally similar to AET and D; however, AET and D may be easier to interpret biologically. (2) Several well-known climatic parameters are biologically less meaningful or less important than AET and D, and consequently are poorer correlates of the distribution of vegetation types. Of particular interest, AET is a much better correlate of the distributions of coniferous and deciduous forests than minimum temperate. (3) The effects of evaporative demand and water availability on a site's water balance are intrinsically different. For example, the 'dry' experienced by plants on sunward slopes (high evaporative demand) is not comparable to the 'dry' experienced by plants on soils with low water-holding capacities (low water availability), and these differences are reflected in vegetation patterns. (4) Many traditional topographic moisture scalars-those that additively combine measures related to evaporative demand and water availability- are not necessarily meaningful for describing site conditions as sensed by plants; the same holds for measured soil moisture. However, using AET and D in place of moisture scalars and measured soil moisture can solve these problems. IS - 5 JF - Journal of Biogeography EP - 870 TI - Actual Evapotranspiration and Deficit: Biologically Meaningful Correlates of Vegetation Distribution Across Spatial Scales PB - Blackwell Publishing VL - 25 SP - 855 KW - climate-change-index KW - evaportranspiration KW - vegetation-distribution N1 - Presents compelling physiologically-based hypothesis that two simple climate parameters, AET and D (deficit, evaporative demand not met by available water), are best surrogates for prediction of vegetation distribution at multiple scales. My question is how do AET and D compare to other climate surrogates/indices towards prediction of ecological responses to climate change as well (fire, insect outbreaks). Carrie Enquist has already mapped trend in D for last 30 years across NM, and will do so with AET. AU - Stephenson, Nathan PY - 1998/// UR - http://dx.doi.org/10.2307/2846252 ER -