PARENT SESSION
Contributed Oral Session 51: Arid Land Management, Vegetation, and Nutrient Dynamics
Tuesday, August 9, 8:00 AM - 11:30 AM, Meeting Room 522 A, Level 5, Palais des congrès de Montréal

Understanding the role of riparian boundaries within the spatial heterogeneity of a South African Savanna.

Saah, David^*,1, Benning, Tracy¹, ¹ University of San Francisco, San Francisco, CA, USA

ABSTRACT- This research explored the contribution of riparian boundaries to the spatial heterogeneity of African savanna landscapes located within Kruger National Park, South Africa. Riparian boundaries were incorporated into previous frameworks of savanna structure using a riparian-savanna object-oriented classification system. This classification system integrated information from a generalized canopy cover model adjusted for fire, floodplain hydrology, and terrain unit data with ecologically relevant indices derived from a multispectral tassel cap analysis of Landsat data. The riparian-savanna classification was then analyzed for the variety and relative abundance of patch types represented in the landscape (composition) and the arrangement, position, orientation and shape complexity of those elements within the landscape (configuration). Results from this work indicated that riparian boundaries accounted for 29% of the total study area with the majority located outside the 500 year floodplain. The inclusion of riparian habitats within the savanna mosaic increased overall patch shape complexity within the mosaic. There were several distinct structural differences found along the lateral gradients of the major rivers. The nearest-neighbor patch arrangement analysis illustrated that the average patch distance from stream centerline to uplands was longer in the basalt geology type compared to granite. The buffer area distance analysis revealed that the majority of the granite block riparian patch type was more evenly distributed across the landscape than other riparian patch types as one progresses away from the stream centerline. Lastly, the boundary between riparian and upland patch types was found to be almost three times greater on the granite geology type compared to basalt. This could imply that edge effects have a larger impact on ecosystem function located on the granite geology type compared to basalt.

Key words: Riparian, Spatial Heterogeneity, Landscape Ecology, South Africa