HR: 11:50h
AN: B52B-07 INVITED     [Abstracts]
TI: Biogeochemical Linkages at Landscape Scales
AU: * Wainwright, J
EM: J.Wainwright@sheffield.ac.uk
AF: Sheffield Centre for International Drylands Research, Department of Geography, University of Sheffield, Winter Street, Sheffield, S10 2TN United Kingdom
AU: Mueller, E N
EM: enmue@uni-potsdam.de
AF: Institut fuer Geooekologie, Universitaet Potsdam, Postfach 60 15 53, Potsdam, 14415 Germany
AU: Parsons, A J
EM: ajp16@le.ac.uk
AF: Department of Geography University of Leicester, University Road, Leicester, LE1 7RH United Kingdom
AB: Investigations of plant-water interactions in drylands have typically focussed on the plant-interspace scale. While this approach has undoubtedly provided insights, especially under steady-state conditions, it often fails to represent the dynamics of changing vegetation patterns. Increasingly, ideas of connectivity between plant and interspace elements have permeated the hydrological and ecological literature. Here we argue that it is necessary to consider such linkages at the landscape scale also in order to understand the dynamics of dryland vegetation. Studies undertaken at the Jornada LTER site, New Mexico, have been carried out to characterize the biogeochemical characteristics of typical grassland and shrubland vegetation communities. Distributions of water, nutrients and sediment characteristics vary significantly and are strongly spatially autocorrelated. However, these patterns are not simply related to vegetation patterns, suggesting that fluxes operate at a range of scales to reorganize the landscape. Numerical modelling of water, sediment and nutrient fluxes has been used to demonstrate the operation of such reorganization, and have been tested using a series of instrumented catchments and arrays of spatial samplers. By focussing on ecotones, we demonstrate that certain spatial organizations of the landscape are more sensitive to flux - and thus change of local conditions - with important consequences for understanding landscape-level ecosystem dynamics. These consequences are considered in terms of concepts such as ecosystem resilience and the importance of historical contingency.
DE: 0414 Biogeochemical cycles, processes, and modeling (0412, 0793, 1615, 4805, 4912)
DE: 0439 Ecosystems, structure and dynamics (4815)
DE: 0466 Modeling
DE: 1809 Desertification
DE: 1815 Erosion
SC: Biogeosciences [B]
MN: Fall Meeting 2005