Szangolies Leonna, Gallagher Cara A, Jeltsch Florian
Plant Ecology and Nature Conservation, Potsdam University, Potsdam, Germany.
Ecoscience, Aarhus University, Roskilde, Denmark.
Glob Chang Biol. 2025 May;31(5):e70224. doi: 10.1111/gcb.70224.
Biodiversity is threatened by land-use and climate change. Although these processes are known to influence species survival and diversity, predicting their combined effects on communities remains challenging. We here aim to disentangle the combined effects of drought-induced resource shortage and habitat fragmentation on species coexistence. To understand how both fragmentation and droughts affect individual movement and physiology, and ultimately influence population and community dynamics, we use an individual-based metabolic modelling approach to simulate a community of small mammals. Individuals forage in the landscape to ingest energy, which they then allocate to basal maintenance, digestion, locomotion, growth, reproduction, and storage. If individuals of several species are able to balance their energy intake and needs, and additionally store energy as fat reserves, they may overcome stress periods and coexist. We find that species recover best after a drought when they live in moderately fragmented landscapes compared to those with low or high fragmentation. In low fragmented landscapes, high local competition during resource shortages is problematic, while in highly fragmented landscapes, low energy balance and storage often lead to high mortality during drought. Intermediately fragmented landscapes balance these effects and show the least impact of droughts on species richness, a pattern that holds also when integrating observed drought time series from monitoring data in the model simulations. Due to the interacting negative impacts, we suggest that with ongoing global change, it is increasingly important to understand stressors simultaneously to identify measures that support species coexistence and biodiversity. Including individual energy dynamics allowed us to conflate the different global change effects through energy storage and energy allocation to different processes. Our presented community model, which integrates metabolic and behavioural reactions of individuals to different stressors and scales them to the community level, offers valuable insights with great potential to support nature conservation.
生物多样性受到土地利用和气候变化的威胁。尽管已知这些过程会影响物种的生存和多样性，但预测它们对群落的综合影响仍然具有挑战性。我们的目标是厘清干旱引发的资源短缺和栖息地破碎化对物种共存的综合影响。为了理解破碎化和干旱如何影响个体的移动和生理机能，并最终影响种群和群落动态，我们采用基于个体的代谢建模方法来模拟小型哺乳动物群落。个体在景观中觅食以摄取能量，然后将能量分配到基础维持、消化、运动、生长、繁殖和储存等方面。如果几个物种的个体能够平衡能量摄入和需求，并额外储存能量作为脂肪储备，它们可能会度过压力期并实现共存。我们发现，与低破碎化或高破碎化景观中的物种相比，生活在中度破碎化景观中的物种在干旱后恢复得最好。在低破碎化景观中，资源短缺期间的高强度局部竞争是个问题，而在高破碎化景观中，低能量平衡和储存往往导致干旱期间的高死亡率。中度破碎化景观平衡了这些影响，并且干旱对物种丰富度的影响最小，在模型模拟中纳入监测数据中的观测干旱时间序列时，这种模式同样成立。由于相互作用的负面影响，我们建议，随着全球变化的持续，同时理解各种压力源对于确定支持物种共存和生物多样性的措施变得越来越重要。纳入个体能量动态使我们能够通过能量储存和对不同过程的能量分配来合并不同的全球变化影响。我们提出的群落模型整合了个体对不同压力源的代谢和行为反应，并将其扩展到群落水平，为支持自然保护提供了具有巨大潜力的宝贵见解。
