在热带稀树草原生物群落中沿地理梯度的树-草生物量分布研究的最小模式的有用性
On the usefulness of a minimalistic model to study tree-grass biomass distributions along biogeographic gradients in the savanna biome
摘要：
我们提出并分析了一个模型，旨在恢复的动态结果的树木-草的相互作用的大范围的植被地貌可观察到的稀树草原生物群落沿降雨梯度在区域/大陆尺度。该模型是基于两个常微分方程（ODE），木本和草生物量。它是从文献参数化，并保留数学上的易处理性，因为我们限制它的主要过程，特别是树木草不对称的相互作用（无论是促进或竞争）和草火反馈。我们使用了一个完全定性的分析，以获得所有可能的长期动态，并表示它们在一个分叉图的关系，平均年降雨量和火灾频率。我们划定了单稳态（森林，草原，稀树草原），双稳态（例如森林草原或森林稀树草原），甚至三稳态域。值得注意的是，我们强调了两个稀树草原平衡可能是共同稳定的地区（可能除了森林或草地）。我们验证了常见的知识减少木质生物量增加火灾频率恢复所有级别的降雨，相反，以前的尝试使用类似的ODE框架。因此，这一框架似乎能够产生比通常想象的更现实和更多样化的结果。我们的模型可以帮助找出正在进行的动态大面积的热带稀树草原植被，当地的数据是稀疏或不存在的。为了探索具有不同模型参数组合的分叉图，我们开发了一个用户友好的R-Shiny应用程序，可在https://gitlab.com/cirad-apps/tree-grass上免费获得。
英文摘要：
We present and analyze a model aiming at recovering as dynamical outcomes of tree-grass interactions the wide range of vegetation physiognomies observable in the savanna biome along rainfall gradients at regional/continental scales. The model is based on two ordinary differential equations (ODE), for woody and grass biomass. It is parameterized from literature and retains mathematical tractability, since we restricted it to the main processes, notably tree-grass asym-metric interactions (either facilitative or competitive) and the grass-fire feedback. We used a fully qualitative analysis to derive all possible long term dynamics and express them in a bifur-cation diagram in relation to mean annual rainfall and fire frequency. We delineated domains of monostability (forest, grassland, savanna), of bistability (e.g. forest-grassland or forest-savanna) and even tristability. Notably, we highlighted regions in which two savanna equilibria may be jointly stable (possibly in addition to forest or grassland). We verified that common knowledge about decreasing woody biomass with increasing fire frequency is recovered for all levels of rainfall, contrary to previous attempts using analogous ODE frameworks. Thus, this framework appears able to render more realistic and diversified outcomes than often thought of. Our model can help figure out the ongoing dynamics of savanna vegetation in large territories for which local data are sparse or absent. To explore the bifurcation diagram with different combinations of the model parameters, we have developed a user-friendly R-Shiny application freely available at : https://gitlab.com/cirad-apps/tree-grass.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
