A central focus of ecologists is to understand how ecosystem processes drive the resilience of individual species and communities. While the resilience framework has advanced in recent years, a major hurdle in progressing resilience theory further is to describe interactions among species and ecological drivers at multiple spatial and temporal scales. Light detection and ranging (lidar) is a useful tool for such purposes. We used lidar to derive scale-invariant calculations of biomass for herbaceous and woody plant species in a heavily invaded savanna ecosystem manipulated with combinations of fire and herbicide. Fire treatments of burned once, burned annually, and unburned were randomly applied to eighteen plots at the Texas A&M Agrilife Research Center located near Sonora, TX, USA. Each plot was assigned a subplot treatment of herbicide then burn, burn then herbicide, and no herbicide.
Results/Conclusions
We used estimates of biomass from field pulsed lidar to determine which treatment prompted the greatest change in plant biomass across various spatial scales. Preliminary lidar-based estimates of biomass indicated that applying herbicide in the year prior to burning resulted in the greatest reduction of woody plant biomass. As future treatment combinations are applied, field-based lidar estimates of biomass will be used to identify (1) the relative resilience of the current woodland to fire and herbicide applications and (2) the specific threshold at which the structure and processes of the woodland state transitions to a savanna stable state maintained by an alternate set of structures and processes.
