Drones contributing to LTER: challenges and opportunities

Drones or UAVs are becoming widely used for uncountable scientific applications. Quick, easy and synoptic observations from the air enable to retrieve spatial explicit information on land, water or human infrastructures. Customized drone missions provide insights on targeted areas adapted to specific user requirements, such as spatial resolution, re-visiting schedule or sensor characteristics. For instance, ecological monitoring benefits from periodically replicated flights which contribute to understand ecosystem dynamics including phenology, disturbance effects or trends. Available drone hubs can implement repeated semi-autonomous flights. Ad-hoc missions allow monitoring restoration actions, recovery after disturbance or identifying invasive species and algal blooms. A diverse array of cameras and sensors have been miniaturized enough to be mounted onboard of drones. Optical cameras, including multi and hyperspectral can map vegetation and flora as well as biophysical parameters from land and wetlands. LiDAR sensors can easily map canopy heights, including understory, revealing biomass distribution in forested areas. Thermal cameras provide land surface temperature for energy-surface modeling or identify hotspots in wildlife census. Drone mapping also contribute to in situ validation of Earth Observation products, offering an intermediate scale for up-sampling procedures. Drones are not only suitable for mapping. We can also use them to collect samples in a systematic way, or to autonomously fly below tree canopies. In this talk I will provide a review on both the most frequent drone applications for LTER that can be used to measure and upscale certain eLTER Standard Observations and the upcoming opportunities based on new technologies. I will also address the main challenges to adopt drone missions as regular activities in eLTER sites and platforms, dealing with available and affordable equipment, required training and permits, mission design and processing workflows.