Resistant high tree cover mode with increasing fire in Indonesian natural peatland ecosystems

The vulnerability of tropical ecosystems to global changes is a growing concern, with tree cover distribution patterns playing a pivotal role in their responses to changing environmental conditions. It is important to understand how natural ecosystems respond to these changes to assess the resilience of the ecosystems. While extensive research has investigated tree cover distributions in the tropics, a notable gap exists in understanding the effects of environmental variables to tree cover and the underlying mechanisms in Indonesian natural ecosystems, with its vast peatland areas. In response to this gap, we analyze the relative importance of environmental variables, specifically precipitation and fire, on shaping tree cover distributions in peatland and non-peatland ecosystems in Indonesia. We use the Global Forest Change dataset on tree cover with the spatial resolution of 30 meters. To focus on natural ecosystems, we filter out areas with human intervention. We find a consistent unimodal distribution of tree cover in the gradients of fire frequency and precipitation, marked by a distinct peak in each value range of the variables. In non-peatland, we observe a switch from high to low tree cover mode with increasing fire, which occurs at intermediate fire frequency. In contrast, peatland ecosystems show a remarkable resistance of the high tree cover mode despite increasing fire incidents. This implies that peatland could be more resistant to the same intermediate fire frequency than non-peatland. Our findings are relevant for ecosystem resistance in Indonesian peatlands and non-peatlands and their potential vulnerability to disturbances, particularly in the face of ongoing global environmental changes.