Community structure, ecosystem process, and landscape pattern: interactive effects in the distribution of southwestern savanna type ecosystems
Klopatek JM. 1997. Community structure, ecosystem process, and landscape pattern: interactive effects in the distribution of southwestern savanna type ecosystems. Bulletin of the Ecological Society of America. 78(4):19
The natural and variable forcing functions in arid and semiarid environment shave carved out a broad niche for savanna-type ecosystems in the Southwest. Historical data show that these ecosystems migrated and thrived despite broad-scale changes in climate. Savanna types now occur over a wide range of edaphic and topographic sites. Community structure of savannas reflects the combined effects of climate and past and present natural and anthropogenic disturbance regimes. While subordinate to external regulating factors, the community structure influences ecosystem processes such as resource partitioning, carbon flux and biogeochemical cycling. Ecological processes may exhibit greater differences within the savanna due to spatial heterogeneity and scale of the different patch types than in a comparison of the savanna to adjoining systems. These processes change slowly as the savanna grades into other ecosystem types across the landscape. Thus, the savanna acts as a transition zone. Only when there is an abrupt demarcation resulting from topographic-soil moisture differences will there be significant differences in rates of processes between the ecosystem types. Disturbance may rapidly affect species composition at the community scale, but a change in patch type may be slow due to the dominant'influence of the woody species at the landscape scale. A conceptual model demonstrating the internal and external regulation of processes, potential feedback mechanisms promoting or restricting ecosystem change, and the position of these ecosystem types within the landscape is presented. In particular, I discuss biogeochemical cycling and species relationships at the landscape scale in the context of global change.
- Type
- Journal Article
- Authors
- Klopatek, Jeffrey
- Units
- ORPI
- Keywords
- Community, Ecology, Ecosystem, IAR, Landscape Pattern, Other, Savanna