Thursday, August 9, 2007 - 8:30 AMSYMP 16-3: Succession in the dynamics, management, and restoration of Central Texas plant communities
Norma Fowler and Mark T. Simmons. University of Texas, Austin
The restoration and management of central Texas plant communities requires us to work at least two different scales. At the scale of interactions among herbaceous species, our observations ‘fit’ the conceptual framework provided by models of succession. One goal is to to re-establish native herbaceous species in the face of competition from non-native grasses, altered soils, and the loss of historic disturbance regimes. The invasive Eurasian grass Bothriochloa ischaemum out-competes the related native dominant Schizachyrium scoparium, due to its rapid germination and high growth rate, but some early succession native grasses, together with the reintroduction of fire, have much better success than S. scoparium in grassland restoration. At the landscape scale, in contrast, we confront a situation that ‘fits’ neither common models of succession nor alternate stable state models. Instead, in the seemingly inexorable conversion of existing herbaceous and woody plant communities to nearly mono-specific stands of Juniperus ashei, we may be seeing a new trajectory that is shifting community composition towards an unknown, but likely novel, endpoint or endpoints. Nevertheless experience manipulating succession elsewhere may provide a source of potential management strategies to meet the challenges of maintaining or restoring species-rich native communities, both woody and herbaceous.