Get reliable rangeland science

Rangelands across the globe are threatened by factors such as climate change, altered fire regimes, and annual grass invasion, often leading to simplified vegetation structure and reduced ecosystem function. Restoring degraded rangelands to their original state is not always possible given socially acceptable levels of financial and capacity commitment. Whether the goal is to reestablish historically occurring flora and fauna or to mitigate some of the negative impacts of a degraded system, managing and restoring these ecosystems requires knowledge of what makes rangelands multifunctional systems (e.g., grazing, wildlife habitat, recreation) and what causes declines in these ecological functions following degradation. Structural diversity metrics can be used as an indicator of ecosystem function and are now possible to continuously measure across landscapes with remote sensing. Recently, the use of structural diversity from 3-dimensional (3D) spatial datasets has been proposed as a flexible method to measure ecological functions in forested systems but has yet to be applied to rangeland management. We propose using structural diversity to monitor rangeland ecosystem function with two case studies. First, we measure structural diversity across a series of eco logical states in semiarid rangelands, from intact shrub and native bunchgrass communities to invasive annual grass-dominated sites and multiple phases of juniper (Juniperus spp.) encroachment. Second, we compare structural diversity between paired grazed and ungrazed landscapes. We found that structural diversity differs across eco logical states, demonstrating a potential way to assess ecosystem function. With the recent increase in the availability of high-resolution 3D structural data from low-cost unoccupied aerial systems (UAS), structural diversity could be used to help managers rapidly assess the ecological function of rangelands.