Inferring resilience of forest ecosystems from satellite data

Background/Question/Methods Predicting ecosystem resilience to climate and disturbance events is one of the most urgent and challenging problems in ecology today. We used the MODIS remotely-sensed estimations of tree cover (%) at 1 km2 to explore the patterns of tree cover distribution in tropical regions of South America, Africa, and Australia, and their relationship with climate. We used the tree-cover frequency distributions to infer ecological resilience and to map the potential vulnerability of tropical ecosystems in the three continents. Results/Conclusions We found striking tri-modal distributions corresponding to treeless (< 5 %), savanna (20 %), and forest (> 60 %) states which are strongly associated to mean annual precipitation. The transitional conditions between treeless-savanna (5-10 % tree cover) and between savanna-forest (55-60 % tree cover) occur at very low frequencies, which we interpret as an indication of transient unstable conditions. We found that not o...