B061-0019
Scale-dependence of remote sensing of biodiversity: A test in grasslands under different management practices
Abstract:
Most remote sensing of biodiversity studies have focused on vegetation types with large canopies such as forests. Unlike forests, relatively little work has been done to study biodiversity in grasslands using remote sensing. But from a remote sensing perspective, detecting grassland diversity is particularly challenging and interesting at the same time. First, grasslands have much smaller canopy relative to the grain size of remotely sensed data. Therefore, there is a scale mismatch between the size of grassland plants and grain size of remotely sensed data. Second, due to management practices applied to grasslands, these ecosystems have high spatial and temporal variability. However, assessing the impact of grassland management practices on remote sensing of biodiversity has been largely absent from previous studies.
We used airborne imaging spectroscopy (400 – 1000 nm; spatial resolution of 1 m) to detect plant diversity in several grasslands under different management practices including the Tallgrass Prairie Preserve – a natural grassland in northern Oklahoma – managed by fire and cattle grazing, a restored prairie in central Nebraska managed by fire, and an experimental grassland located at the Cedar Creek Ecosystem Science Reserve in Minnesota managed by regular weeding. We tested the degree to which airborne hyperspectral data predict grassland diversity. Results from the collection of our sites showed that the capability of remote sensing to detect grassland diversity varies significantly among sites. We also found strong site-specific scale-dependence of remote sensing of biodiversity. We thus posit that having multiscale biodiversity monitoring systems and considering grassland management practices are necessary to design scale-appropriate sampling approaches involving remote sensing.