. Combining UAV remote sensing and ground sensors to model understory solar radiation and thermal habitat in a fragmented forest landscape

Abstract
Changes in the canopy structure of a fragmented forest drive habitat shifts by regulating understory solar radiation and temperature. Mapping canopy structure therefore improves both predictions of abiotic conditions within fragments and estimates of the effects of fragmentation on the distribution and abundance of ground-dwelling species. Forest fragmentation and its associated changes in canopy structure happen at large scales that are challenging to map using traditional field surveys. Remote sensing from a small unmanned aerial vehicle (UAV) provides a more efficient, data-rich method to quantify altered canopy structure. Data will be collected at the Wog Wog fragmentation experiment in southeastern Australia where native Eucalyptus forest was fragmented in 1987 and fragments were surrounded by an exotic pine tree plantation. We will take UAV-based RGB and multispectral images of the experiment and build a 3D point cloud of the canopy structure using structure-from-motion photogrammetry. Using the canopy point cloud, we will create a physically-based model of solar radiation reaching the understory and forest floor, calibrated and validated by data from ground-based solar radiation measurements. Alongside the radiation sensors, we measured soil temperature, which is important for invertebrate distributions.