THE GLOBAL BIOGEOGRAPHY OF ROOTS

Studies in global plant biogeography have almost exclusively analyzed re- lationships of abiotic and biotic factors with the distribution and structure of vegetation aboveground. The goal of this study was to extend such analyses to the belowground structure of vegetation by determining the biotic and abiotic factors that influence vertical root distributions in the soil, including soil, climate, and plant properties. The analysis used a database of vertical root profiles from the literature with 475 profiles from 209 geographic locations. Since most profiles were not sampled to the maximum rooting depth, several techniques were used to estimate the amount of roots at greater depths, to a maximum of 3 m in some systems. The accuracy of extrapolations was tested using a subset of deeply ( .2 m) sampled or completely sampled profiles. Vertical root distributions for each profile were characterized by the interpolated 50% and 95% rooting depths (the depths above which 50% or 95% of all roots were located). General linear models incorporating plant life-form dominance, climate, and soil var- iables explained as much as 50% of the variance in rooting depths for various biomes and life-forms. Annual potential evapotranspiration (PET) and precipitation together accounted for the largest proportion of the variance (12-16% globally and 38% in some systems). Mean 95% rooting depths increased with decreasing latitude from 808 to 308 but showed no clear trend in the tropics. Annual PET, annual precipitation, and length of the warm season were all positively correlated with rooting depths. Rooting depths in tropical veg- etation were only weakly correlated with climatic variables but were strongly correlated with sampling depths, suggesting that even after extrapolation, sampling depths there were often insufficient to characterize root profiles. Globally,.90% of all profiles had at least 50% of all roots in the upper 0.3 m of the soil profile (including organic horizons) and 95% of all roots in the upper 2 m. Deeper rooting depths were mainly found in water- limited ecosystems. Deeper 95% rooting depths were also found for shrublands compared to grasslands, in sandy soils vs. clay or loam soils, and in systems with relatively shallow

[1]  D. Nepstad,et al.  Root distribution in an Amazonian seasonal forest as derived from δ13C profiles , 1998, Plant and Soil.

[2]  H. A. Mooney,et al.  Maximum rooting depth of vegetation types at the global scale , 1996, Oecologia.

[3]  N. Buchmann,et al.  Rooting depth, water availability, and vegetation cover along an aridity gradient in Patagonia , 1996, Oecologia.

[4]  R. B. Jackson,et al.  A global analysis of root distributions for terrestrial biomes , 1996, Oecologia.

[5]  X. Roux,et al.  Spatial partitioning of the soil water resource between grass and shrub components in a West African humid savanna , 1995, Oecologia.

[6]  H. Asbjornsen,et al.  Review of root dynamics in forest ecosystems grouped by climate, climatic forest type and species , 1995, Plant and Soil.

[7]  James R. Ehleringer,et al.  Differential utilization of summer rains by desert plants , 1991, Oecologia.

[8]  R. Vandenbelt.  Rooting systems of western and southern African Faidherbia albida (Del.) A. Chev. (syn. Acacia albida Del.) —a comparative analysis with biogeographic implications , 1991, Agroforestry Systems.

[9]  O. Sala,et al.  Resource partitioning between shrubs and grasses in the Patagonian steppe , 1989, Oecologia.

[10]  Elgene O. Box,et al.  Predicting physiognomic vegetation types with climate variables , 1981, Vegetatio.

[11]  R. B. Jackson,et al.  Rooting depths, lateral root spreads and below‐ground/above‐ground allometries of plants in water‐limited ecosystems , 2002 .

[12]  Robert B. Jackson,et al.  © 2001 Kluwer Academic Publishers. Printed in the Netherlands. The distribution of soil nutrients with depth: Global patterns and the imprint of plants , 2022 .

[13]  R. B. Jackson,et al.  WATER AND TREE-UNDERSTORY INTERACTIONS: A NATURAL EXPERIMENT IN A SAVANNA WITH OAK WILT , 2001 .

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

[15]  J. Ehleringer,et al.  Intra- and interspecific variation for summer precipitation use in pinyon-juniper woodlands , 2000 .

[16]  R. B. Jackson,et al.  BELOWGROUND CONSEQUENCES OF VEGETATION CHANGE AND THEIR TREATMENT IN MODELS , 2000 .

[17]  R. B. Jackson,et al.  THE VERTICAL DISTRIBUTION OF SOIL ORGANIC CARBON AND ITS RELATION TO CLIMATE AND VEGETATION , 2000 .

[18]  R. B. Jackson,et al.  Ecosystem rooting depth determined with caves and DNA. , 1999, Proceedings of the National Academy of Sciences of the United States of America.

[19]  D. Hertel.  Das Feinwurzelsystem von Rein- und Mischbeständen der - Rotbuche: Struktur, Dynamik und interspezifische Konkurrenz , 1999 .

[20]  A. Granier,et al.  Reverse phenology and dry‐season water uptake by Faidherbia albida (Del.) A. Chev. in an agroforestry parkland of Sudanese west Africa , 1999 .

[21]  N. Fujita,et al.  Different distribution patterns of woody species on a slope in relation to vertical root distribution and dynamics of soil moisture profiles , 1999, Ecological Research.

[22]  J. Roberts,et al.  Reverse flow of sap in tree roots and downward siphoning of water by Grevillea robusta , 1999 .

[23]  Robert E. Dickinson,et al.  The role of root distribution for climate simulation over land , 1998 .

[24]  R. April,et al.  Rapid, plant-induced weathering in an aggrading experimental ecosystem , 1998 .

[25]  S. Hart,et al.  Hydraulic lift: a potentially important ecosystem process. , 1998, Trends in ecology & evolution.

[26]  Robert G. Bailey,et al.  Ecoregions: The Ecosystem Geography of the Oceans and Continents , 1998 .

[27]  Frederick R. Adler,et al.  Limitation of plant water use by rhizosphere and xylem conductance: results from a model , 1998 .

[28]  Nicolo E. DiGirolamo,et al.  A biophysical process-based estimate of global land surface evaporation using satellite and ancillary data. I. Model description and comparison with observations , 1998 .

[29]  X. Roux,et al.  Seasonal variations in soil, grass and shrub water status in a West African humid savanna , 1998, Oecologia.

[30]  K. Shepherd,et al.  Vertical Distribution of Roots and Soil Nitrate: Tree Species and Phosphorus Effects , 1998 .

[31]  M. Caldwell,et al.  Hydraulic lift: consequences of water efflux from the roots of plants , 1998, Oecologia.

[32]  R. B. Jackson,et al.  A global budget for fine root biomass, surface area, and nutrient contents. , 1997, Proceedings of the National Academy of Sciences of the United States of America.

[33]  Bhaskar J. Choudhury,et al.  Global Pattern of Potential Evaporation Calculated from the Penman-Monteith Equation Using Satellite and Assimilated Data , 1997 .

[34]  Eileen H. Helmer,et al.  Root biomass allocation in the world's upland forests , 1997, Oecologia.

[35]  I. C. Prentice,et al.  BIOME3: An equilibrium terrestrial biosphere model based on ecophysiological constraints, resource availability, and competition among plant functional types , 1996 .

[36]  Elgene O. Box,et al.  Plant functional types and climate at the global scale , 1996 .

[37]  Y. Xue,et al.  Analysis of transpiration results from the RICE and PILPS Workshop , 1996 .

[38]  R. Neilson.  A Model for Predicting Continental‐Scale Vegetation Distribution and Water Balance , 1995 .

[39]  J. Proctor,et al.  Hydrology and Biogeochemistry of Tropical Montane Cloud Forests: What Do We Really Know? , 1995 .

[40]  E. Davidson,et al.  The role of deep roots in the hydrological and carbon cycles of Amazonian forests and pastures , 1994, Nature.

[41]  Wang Bo-sun,et al.  Studies on biomass and production of the lower subtropical evergreen broad-leaved forest in Heishiding Nature Reserve, China. VI. Distribution, biomass and production of roots , 1994, Journal of Tropical Ecology.

[42]  R. Dickinson,et al.  Biosphere-Atmosphere Transfer Scheme (BATS) version le as coupled to the NCAR community climate model. Technical note. [NCAR (National Center for Atmospheric Research)] , 1993 .

[43]  Ann Henderson-Sellers,et al.  Biosphere-atmosphere transfer scheme(BATS) version 1e as coupled to the NCAR community climate model , 1993 .

[44]  Michelle R. Leishman,et al.  Classifying plants into groups on the basis of associations of individual traits: evidence from Australian semi-arid woodlands , 1992 .

[45]  Osvaldo E. Sala,et al.  Long‐Term Soil Water Dynamics in the Shortgrass Steppe , 1992 .

[46]  L. Carter,et al.  Infiltration Rate of a Sandy Loam Soil: Effects of Traffic, Tillage, and Plant Roots , 1992 .

[47]  W. Cramer,et al.  A global biome model based on plant physiology and dominance, soil properties and climate , 1992 .

[48]  E. Lucot,et al.  Organisation du système racinaire du chêne pédonculé (Quercus robur) développé en conditions édaphiques non contraignantes (sol brun lessivé colluvial) , 1992 .

[49]  E. L. Stone,et al.  On the maximum extent of tree roots , 1991 .

[50]  N. Roulet,et al.  NUTRIENT FLUX AND RETENTION IN A TROPICAL SAND-DUNE SUCCESSION , 1990 .

[51]  N. Zverev,et al.  Underground mass of shrub and subshrub plants of the Karakum. , 1990 .

[52]  D. Freckman,et al.  Plant-Feeding Nematodes in Deep-Rooting Desert Ecosystems , 1989 .

[53]  D. F. Grigal,et al.  Vertical root distributions of northern tree species in relation to successional status , 1987 .

[54]  B. W. Wilgen,et al.  Root systems of selected plant species in mesic mountain fynbos in the Jonkershoek Valley, south-western Cape Province , 1987 .

[55]  C. Cerri,et al.  Carbon content in a yellow latosol of central Amazon rain forest , 1987 .

[56]  F. Woodward.  Climate and plant distribution , 1987 .

[57]  R. Neilson,et al.  High-Resolution Climatic Analysis and Southwest Biogeography , 1986, Science.

[58]  N. T. Nechaeva.  Description of plants used for vegetative range improvement , 1985 .

[59]  T. Weaver.  Root Distribution and Soil Water Regimes in Nine Habitat Types of the Northern Rocky Mountains , 1982 .

[60]  B. Carbon,et al.  The distribution of root length, and the limits to flow of soil water to roots in a dry sclerophyll forest. , 1980 .

[61]  W. Lauenroth,et al.  The structure and function of ten Western North American grasslands: I. Abiotic and vegetational characteristics , 1978 .

[62]  D. Mueller‐Dombois,et al.  Ecology of Tropical and Subtropical Vegetation. , 1972 .

[63]  R. Coupland,et al.  Rooting Characteristics of Native Grassland Species in Saskatchewan , 1965 .

[64]  P. Hosegood.  The Root Distribution of Kikuyu Grass and Wattle Trees , 1963 .

[65]  J. E. Weaver.  Summary and Interpretation of Underground Development in Natural Grassland Communities , 1958 .

[66]  J. E. Weaver,et al.  Soil‐Root Relationships of Certain Native Grasses in Various Soil Types , 1949, Agronomy Journal.

[67]  J. E. Weaver,et al.  North American Prairie , 1955 .

[68]  J. E. Weaver,et al.  Resurvey of Grasses, Forbs, and Underground Plant Parts at the End of the Great Drought , 1943 .

[69]  W. A. Cannon.  THE ECOLOGICAL RELATIONS OF ROOTS. , 1920, Science.

[70]  Frederic E. Clements.  Pflanzengeographie auf Physiologischer Grundlage , 1899 .