Soil Water Balance and Ecosystem Response to Climate Change

Some essential features of the terrestrial hydrologic cycle and ecosystem response are singled out by confronting empirical observations of the soil water balance of different ecosystems with the results of a stochastic model of soil moisture dynamics. The simplified framework analytically describes how hydroclimatic variability (especially the frequency and amount of rainfall events) concurs with soil and plant characteristics in producing the soil moisture dynamics that in turn impact vegetation conditions. The results of the model extend and help interpret the classical curve of Budyko, which relates evapotranspiration losses to a dryness index, describing the partitioning of precipitation into evapotranspiration, runoff, and deep infiltration. They also provide a general classification of soil water balance of the world ecosystems based on two governing dimensionless groups summarizing the climate, soil, and vegetation conditions. The subsequent analysis of the links among soil moisture dynamics, plant water stress, and carbon assimilation offers an interpretation of recent manipulative field experiments on ecosystem response to shifts in the rainfall regime, showing that plant carbon assimilation crucially depends not only on the total rainfall during the growing season but also on the intermittency and magnitude of the rainfall events.

[1]  I. Noy-Meir,et al.  Desert Ecosystems: Environment and Producers , 1973 .

[2]  M. Budyko,et al.  Climate and life , 1975 .

[3]  Peter S. Eagleson,et al.  Climate, soil, and vegetation: 1. Introduction to water balance dynamics , 1978 .

[4]  C. Osmond,et al.  Physiological Plant Ecology I , 1981, Encyclopedia of Plant Physiology.

[5]  Werner Horsthemke,et al.  Noise-induced transitions , 1984 .

[6]  P. Wetzel,et al.  Concerning the Relationship between Evapotranspiration and Soil Moisture , 1987 .

[7]  P. Wetzel,et al.  Evapotranspiration from Nonuniform Surfaces: A First Approach for Short-Term Numerical Weather Prediction , 1988 .

[8]  N. Stephenson.  Climatic Control of Vegetation Distribution: The Role of the Water Balance , 1990, The American Naturalist.

[9]  P. Milly.  An analytic solution of the stochastic storage problem applicable to soil water , 1993 .

[10]  E. Bray.  Physiology of plants under stress: Abiotic factors , 1998 .

[11]  V. Isham,et al.  Probabilistic modelling of water balance at a point: the role of climate, soil and vegetation , 1999, Proceedings of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences.

[12]  G. Meehl,et al.  Climate extremes: observations, modeling, and impacts. , 2000, Science.

[13]  R. B. Jackson,et al.  Root water uptake and transport: using physiological processes in global predictions. , 2000, Trends in plant science.

[14]  Luca Ridolfi,et al.  Plants in water-controlled ecosystems: active role in hydrologic processes and response to water stress: III. Vegetation water stress , 2001 .

[15]  Francesco Laio,et al.  Plants in water-controlled ecosystems: active role in hydrologic processes and response to water stress: IV. Discussion of real cases , 2001 .

[16]  I. Rodríguez‐Iturbe,et al.  Intensive or extensive use of soil moisture: Plant strategies to cope with stochastic water availability , 2001 .

[17]  Luca Ridolfi,et al.  Plants in water-controlled ecosystems: active role in hydrologic processes and response to water stress: II. Probabilistic soil moisture dynamics , 2001 .

[18]  P. Milly.  A minimalist probabilistic description of root zone soil water , 2001 .

[19]  S. Carpenter,et al.  Ecological forecasts: an emerging imperative. , 2001, Science.

[20]  M. Allen,et al.  Constraints on future changes in climate and the hydrologic cycle , 2002, Nature.

[21]  I. Rodríguez‐Iturbe,et al.  Models of soil moisture dynamics in ecohydrology: A comparative study , 2002 .

[22]  Robert B. Jackson,et al.  THE GLOBAL BIOGEOGRAPHY OF ROOTS , 2002 .

[23]  D. Moorhead,et al.  Increasing risk of great floods in a changing climate , 2002, Nature.

[24]  J. Blair,et al.  Rainfall Variability, Carbon Cycling, and Plant Species Diversity in a Mesic Grassland , 2002, Science.

[25]  I. Rodríguez‐Iturbe,et al.  On the seasonal dynamics of mean soil moisture , 2002 .

[26]  R. Oren,et al.  Water deficits and hydraulic limits to leaf water supply. , 2002, Plant, cell & environment.

[27]  Wade T. Crow,et al.  Impact of Soil Moisture Aggregation on Surface Energy Flux Prediction During SGP'97 , 2002 .

[28]  Gordon B. Bonan,et al.  Ecological Climatology: Concepts and Applications , 2002 .

[29]  Balázs M. Fekete,et al.  Sensitivity of Annual Evaporation to Soil and Root Properties in Two Models of Contrasting Complexity , 2003 .

[30]  Luca Ridolfi,et al.  Soil moisture and plant stress dynamics along the Kalahari precipitation gradient , 2003 .

[31]  J. Blair,et al.  Productivity responses to altered rainfall patterns in a C4-dominated grassland , 2003, Oecologia.

[32]  I. Rodríguez‐Iturbe,et al.  Ecohydrology—a Challenging Multidisciplinary Research Perspective , 2002 .

[33]  Amilcare Porporato,et al.  Coupled Dynamics of Photosynthesis, Transpiration, and Soil Water Balance. Part II: Stochastic Analysis and Ecohydrological Significance , 2004 .

[34]  I. Rodríguez‐Iturbe,et al.  Coupled Dynamics of Photosynthesis, Transpiration, and Soil Water Balance. Part I: Upscaling from Hourly to Daily Level , 2004 .