Hysteresis of tropical forests in the 21st century

Abstract

Tropical forests modify the conditions they depend on through feedbacks at different spatial scales. These feedbacks shape the hysteresis (history-dependence) of tropical forests, thus controlling their resilience to deforestation and response to climate change. Here, we determine the emergent hysteresis from local-scale tipping points and regional-scale forest-rainfall feedbacks across the tropics under the recent climate and a severe climate-change scenario. By integrating remote sensing, a global hydrological model, and detailed atmospheric moisture tracking simulations, we find that forest-rainfall feedback expands the geographic range of possible forest distributions, especially in the Amazon. The Amazon forest could partially recover from complete deforestation, but may lose that resilience later this century. The Congo forest currently lacks resilience, but is predicted to gain it under climate change, whereas forests in Australasia are resilient under both current and future climates. Our results show how tropical forests shape their own distributions and create the climatic conditions that enable them.

Irrigation of biomass plantations may globally increase water stress more than climate change

“…effects of moisture recycling or sea level rise), and potentially even include complex process couplings which could explain global tipping points 71 . Resilience to complete deforestation, for example, depends on the region and also on the timing of the forest loss 72 . Including such processes would eventually also allow for even more detailed water stress analyses.…”

The mid-Miocene Zhangpu biota reveals an outstandingly rich rainforest biome in East Asia

“…Our findings confirm that a megathermal biota existed in the middle Miocene Zhangpu area and extend the biological and physical homogenization of Asian tropical forests to most areas of South China. The middle Miocene expansion of Asian tropical rainforests, with potential alterations of local food webs, biogeochemical cycles, and climatic conditions ( 24 ), is consistent with the concurrent diversification of various plants and animals ( 25 – 27 ) and probably laid the foundation for today’s East Asian terrestrial biota. In conclusion, the MMCO probably strongly shaped the East Asian biota via the northern expansion of the megathermal rainforest biome, which favored both increasing diversity and had a homogenizing effect on the composition and distribution of plant and animal communities.…”

Vegetation‐Climate Feedbacks Enhance Spatial Heterogeneity of Pan‐Amazonian Ecosystem States Under Climate Change

“…The fate of the Amazonian ecosystem is important not only due to the massive part tropical rainforests play within the global carbon cycle but also warrants attention for the ecological management of the Amazon (Scheffer et al., 2001). Numerous studies have explored the critical influence of the hydroclimate regime on the transition of ecosystem states between moist forest, dry savanna, and shrubland across the Amazon Basin, suggesting the importance of local feedback processes in sustaining Amazonian ecosystem resilience (Ciemer et al., 2019; Hirota et al., 2011; Holmgren et al., 2013; Spracklen et al., 2012; Staal et al, 2018, 2020; Staver et al., 2011; Zemp et al., 2017), such as the effects of cascading feedback process in air passage on redistributing hydroclimate conditions over rainforest (Spracklen et al., 2012; Staal et al., 2018; Zemp et al., 2017), the effects of long‐term rainfall variability (Ciemer et al., 2019; Holmgren et al., 2013), and the effects of timing and amplitude of seasonal hydrological conditions as well as their interactions with other climatic drivers (Restrepo‐Coupe et al., 2017) on shaping the resilience of tropical forest and savannah. However, the strong reciprocal vegetation‐climate couplings in the nexus of multiple drivers usually induce nonlinear impacts on vegetation states, which challenge the assessment of the vulnerability of Amazonian ecosystems to future climate change.…”