HR: 08:20h
AN: B51A-02 INVITED     [PDF]
TI: Trees, Water, Space and Time
AU: * Archer, S
EM: sarcher@ag.arizona.edu
AF: University of Arizona, 325 Biological Sciences East, Tucson, AZ 85721-0043 United States
AB: Woody plant proliferation in grasslands and savannas over the past century has been a globally widespread phenomenon. Rates and patterns of woody community development in arid and semi-arid grasslands are often regulated by a hydrological process mediated by soils, topography and disturbance. Once established, woody plant communities have the potential to alter hydrological processes either directly or indirectly. This presentation will focus on hydrological mediation of woody plant establishment and community development. Though not widely documented, rates, patterns and dynamics of shifts from grass to woody plant domination, appear to be strongly influenced by the amount and seasonality of rainfall, operating against a backdrop of topoedaphic heterogeneity. Disturbances may override or amplify climate/soil effects. Establishment of woody seedlings is a critical first-step in woody plant encroachment. How do seedlings gain a foothold in grasslands? How important is episodic vs. continuous recruitment? How do hydrological factors affecting woody plant recruitment differ from those affecting stand development and stand dynamics at landscape levels of resolution? To what extent are woody plant communities self-regulating and subject to hydrologically mediated density dependence? These questions will be addressed in the context of vegetation inertia and lag effects which make it difficult to assign primacy to driving forces.
DE: 0400 Biogeosciences
DE: 1600 GLOBAL CHANGE (New category)
DE: 1655 Water cycles (1836)
DE: 1812 Drought
DE: 1851 Plant ecology
SC: Biogeosciences [B]
MN: 2003 Fall Meeting