Adding space-based vegetation structure measurements to a global ecosystem model to simulate tropical forest animal communities and their role in ecosystem function

Abstract:

Animal biodiversity is currently under great threat partially because there are currently no global scale datasets available to help inform policy decisions, especially in tropical forest regions. Here we show results from a project where we use forest structure data (NASA’s GEDI) plus a General Ecosystem Model (the Madingley model) to help explain the valuable roles animals play in forest ecosystems, thus prioritizing biodiversity conservation in tropical forests. Madingley previously had no vertical structure and we have coded an arboreal layer into Madingley with cohorts described as terrestrial, scansorial or arboreal. We have studied the drivers for arboreality and body mass and fruiting are the main factors to consider. Using estimates of branch strength we can estimate the % of available NPP as fruit and leaves to an individual based on their body mass by assuming an exponential increase of availability with decreasing body mass (ie smaller individuals can access a disproportionately larger % of canopy NPP). We have integrated GEDI into the model to define total NPP in the terrestrial/arboreal layers, looking at relationships between tree height/canopy size and branch strength and for the degree of arboreal connectivity within a grid cell. These will each drive available NPP for the different cohorts. Using this framework, we can seed the model entirely randomly, and assess the emergent patterns against Tetra density animal abundance estimates from empirical studies in the form of total ecosystem biomass and body mass size distributions. We expect that the addition of an arboreal layer will improve predictions versus empirical data, thus giving us confidence to simulate future biodiversity under scenarios such as climate change, logging, and bushmeat hunting. Overall, using Madingley, we will simulate the impact of future climate variability on tropical forest biodiversity and will produce a wide range of EBV’s and ecosystem services for our partner countries (Peru, Brazil and Gabon).