Emerging mechanisms of ecosystem functioning in a warmer and drier world

Abstract

<p>Ecosystems are expected to face a significantly warmer and drier climate in the coming decades. Experiments have tried to unravel drought responses of ecosystems in mesic and humid biomes, but the structure and functioning of these systems may change when climatic regime shifts occur. Here, we summarize major mechanisms typical of drylands and indicate how these may come into play when current mesic ecosystems face tipping points in a warmer and drier world.</p><p>These dryland mechanisms of ecosystem functioning encompass (i) processes of vegetation development, such as self-organization of vegetation patchiness and formation of biological soil crust, (ii) biologically driven biogeochemical and physiological processes, such as drying-wetting cycles and hydraulic redistribution, and (iii) abiotically driven biogeochemical processes, such as photochemical degradation of organic matter and soil hydrophobicity. We present insights from published studies and original model simulations and mapping, and formulate hypotheses on thresholds and spatial locations beyond which dryland mechanisms are expected to operate in non-xeric ecosystems. Notably, for dryland mechanisms to get activated elsewhere there is no need for non-xeric biomes to become actual drylands. With a globally increasing area exposed to gradually rising temperatures, moderate decline in precipitation, and increasing frequency, duration and intensity of extreme heat and drought events, we envision that dryland mechanisms will increasingly control ecosystem functioning in many regions of the world.</p>

Six decades of warming and drought in the world’s top wheat-producing countries offset the benefits of rising CO2 to yield

“…However, extrapolating FACE results to currently dry and warm regions like Africa and the Middle East, for example, might be a challenge in the absence of prior FACE experiments in such regions. The inclusion of FACE as well as other long-term [CO 2 ] enrichment experiments in these regions that are already experiencing severe warming and drought (e.g., many parts of Africa and the Middle East) may enhance our understanding of crop response to elevated [CO 2 ] in cold and humid areas susceptible to future drier and warmer conditions and potential shift towards dryland-controlled mechanisms 42 . Studying the response of different lines bred under warm and dry conditions is also recommended to analyze crop breeding adaptation to altered environmental and climate conditions 43 .…”

The Contribution of Biotic Factors in Explaining the Global Distribution of Inorganic Carbon in Surface Soils

“…In contrast, lower values of SIC in tropical areas may be attributed to the greater rainfall, which induced the increased dissolution and leaching of carbonates and/or high soil acidity (Mi et al, 2008;Tao et al, 2022). Notably, our results suggest that there may be more SIC accumulation globally in the future, given the forecasted warmer and drier conditions in many regions on Earth due to climate change (Grunzweig et al, 2022).…”

Linking spatial self-organization to community assembly and biodiversity

“…The copyright holder for this preprint this version posted June 20, 2021. ; https://doi.org/10. 1101/2021.06.20.449156 doi: bioRxiv preprint 2005Siteur et al, 2014), such as the transition from 1 ( ) to 2 ( ) in Fig. 6 (see insets at = 4 and = 5 ).…”