van Aardt, J.A.; Wu, J.; McGlinchy, J.; Sarrazin, D.; Kelbe, D.; Erasmus, B.F.; Mathieu, R.; Wessels, K.; Asner, G.P.; Knapp, D.; Kennedy-Bowdoin, T., Towards a Species-specific Description of Detailed Savanna Woody structure at Various Scales Using Imaging Spectroscopy and Waveform Lidar Sensing. , ISRSE, 34th International Symposium for Remote Sensing of the Environment, April 10-15, 2011, Sydney, NSW, Australia, April (2011) [BibTeX]
Keywords: waveform lidar ecology
terrestrial ecosystems. Although such biomass can be assessed remotely using both passive and active sensing, characterization of detailed structure, important to conservation of structural biodiversity, remains elusive. Novel technologies, such as imaging spectroscopy and waveform light detection and ranging, have emerged as candidates for such assessment. We evaluated whether species-specific assessment of woody and foliar biomass, crown structure, and woody cover can be mapped at various scales using these remote sensing technologies in a set of related research efforts. Data were acquired via the Carnegie Airborne Observatory across a degraded-to-conserved landuse gradient in the savannas in and around the Kruger National Park, South Africa. A robust processing approach for waveform lidar data was first developed and included smoothing, deconvolution, and angle correction for off-nadir pulses. This was followed by a data fusion approach to species classification and waveform-based quantification of woody biomass and structure at the tree- to landscape scales. Classification results (53-74% overall accuracies) varied according to species and were constrained by phenological variation, while structural quantification was dependent on the management regime that dominated in either the conservation or rural subsistence farming regions. We were able to develop tree-, landuse-, and landscape-level models that described the structural variation in the system. More importantly, the detailed structural metrics can be used to steer management policy in these areas towards sustainable "natural thresholds" and subsistence farming, respectively. Results at various scales will be presented.
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