Climate change shifts the distribution of vegetation types in South Brazilian hotspots

摘要

Research on the dynamics of vegetation distribution in relation to past climate can provide valuable insights into terrestrial ecosystems' response to climate change. However, paleoenvironmental data sources are often scarce. The integration of ecological niche modeling and paleoecological data can fill in this knowledge gap. In order to elucidate the potential impacts of past and future climate change on the distribution of multiple vegetation types, we used 433 occurrence points of 100 species to build distribution models of five vegetation types occurring in southern Brazil, based on past, current, and future scenarios. Past models indicated the existence of a steppe domain during the Last Glacial Maximum, with forest expansion during the Mid-Holocene, which is consistent with paleoenvironmental data. The current distribution model identified a large area that was climatically suitable for ecotones in an important protection area threatened by agribusiness. The optimistic projections for 2070 predicted an expansion of mixed ombrophilous and seasonal semi-deciduous forests to a higher altitude and latitude, respectively. The pessimistic projections predicted a catastrophic scenario, with the extinction of the steppe and the savanna and a major increase of areas unsuitable for all vegetation types. The ombrophilous dense forest remained stable in all time scenarios, even in the pessimistic future projection. The results of the present study reinforce the need for the implementation of policies that will reduce greenhouse gas emissions that drive global climate change, which may lead to the extinction not only of species but also of landscapes as we know them today.