LB 25-216 - Using Spaceborne LiDAR to Assess Animal Demography

Ecologists have long recognized that vegetation structure plays a critical role in wildlife habitat and that species-habitat associations change with spatial scale. Remote sensing can provide spatiotemporal information about vegetation to inform habitat estimates, however these methods are often limited in availability or lack adequate resolution to capture the vegetative aspects influential to habitat. The Global Ecosystem Dynamics Investigation (GEDI) is a spaceborne light detection and ranging system (LiDAR) that has revolutionized the availability of high-quality three-dimensional vegetation measurements of the Earth’s temperate and tropical forests. However, wildlife applications of GEDI data have been limited to estimate the distribution or diversity of species. Here, we expand the use of GEDI products to a wildlife demography study by relating the abundance and survival of two small mammal species, Humboldt’s flying squirrel (Glaucomys oregonensis) and Townsend’s chipmunks (Neotamias townsendii) to GEDI-derived forest structure. Our goal was to understand how forest structure influenced these processes and whether GEDI-derived forest structures could be used to predict them. We leveraged a recently published dataset of GEDI-derived forest structures and capture-mark-recapture data from three studies in western Oregon spanning 2014-2021. We used capture histories in Huggins robust design models to estimate apparent annual survival and abundance as a derived parameter. We found support that flying squirrel apparent annual survival was related to GEDI forest structure variables, but chipmunk apparent annual survival was best explained by nuisance parameters. We used a scale optimization procedure to identify the most predictive spatial scale of GEDI-derived forest structures for each species and assessed the importance of these scaled variables in abundance estimation while also including other important spatiotemporal factors. We found strong support that both flying squirrel and chipmunk abundance was related to GEDI-derived forest structures as well as other spatiotemporal factors such as elevation and annual climatic variation. We conclude that aspects of small mammal demography can be explained by forest structure, these relationships change with the spatial scale considered, and suggest GEDI data can be applied to inventory and monitor wildlife communities.