Riparian systems pose unique challenges for ecologists because they are highly dynamic and complex. This complexity includes the interactive effects of topography, hydrology, soils, and vegetation. Increasingly, LiDAR measurements of riparian areas are being used to generate detailed maps of topography and vegetation structure in these systems. The detailed topographic information these data provide are used by hydrologists and fish biologists. Additionally, these data provide a unique resource for terrestrial wildlife biologists, in part because they can be easily summarized at multiple spatial scales. Capitalizing on this opportunity, we have used LiDAR imagery from the Cosumnes River in California’s Central Valley to investigate the spatial scale at which riparian birds respond to patterns of vegetation structure. Our objectives were 1) to evaluate the utility of LiDAR measurements for describing habitat associations of riparian passerine birds, and 2) to evaluate the predictive performance of vegetation measurements across spatial scales from 0.2 to 50 ha.
Results/Conclusions
Our results have provided information about the spatial scale of vegetation measurements that provide the best predictions of bird distributions. For six of the 10 bird species we investigated, models with vegetation measurements at the 0.2 to 3 ha scale had the greatest predictive power. For two species, models with measurements at the 50 ha scale performed best, but models with measurements at other spatial scales performed nearly as well. For only two species was there a clear trend toward increasing predictive performance with the broader spatial scale. This information can be used to refine the spatial scale of field measurements used to quantify bird habitat. Furthermore, these models can be applied across the LiDAR footprint, to produce a continuous surface of habitat suitability for conservation and restoration planning. Our work illustrates the potential for LiDAR to provide effective habitat measurements for multi-taxa studies where multi-scale measurements of vegetation structure are needed.
