German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany.
Department of Economics, University of Leipzig, Leipzig, Germany.
Ecology. 2024 Jul;105(7):e4321. doi: 10.1002/ecy.4321. Epub 2024 May 19.
Secondary tropical forests play an increasingly important role in carbon budgets and biodiversity conservation. Understanding successional trajectories is therefore imperative for guiding forest restoration and climate change mitigation efforts. Forest succession is driven by the demographic strategies-combinations of growth, mortality and recruitment rates-of the tree species in the community. However, our understanding of demographic diversity in tropical tree species stems almost exclusively from old-growth forests. Here, we assembled demographic information from repeated forest inventories along chronosequences in two wet (Costa Rica, Panama) and two dry (Mexico) Neotropical forests to assess whether the ranges of demographic strategies present in a community shift across succession. We calculated demographic rates for >500 tree species while controlling for canopy status to compare demographic diversity (i.e., the ranges of demographic strategies) in early successional (0-30 years), late successional (30-120 years) and old-growth forests using two-dimensional hypervolumes of pairs of demographic rates. Ranges of demographic strategies largely overlapped across successional stages, and early successional stages already covered the full spectrum of demographic strategies found in old-growth forests. An exception was a group of species characterized by exceptionally high mortality rates that was confined to early successional stages in the two wet forests. The range of demographic strategies did not expand with succession. Our results suggest that studies of long-term forest monitoring plots in old-growth forests, from which most of our current understanding of demographic strategies of tropical tree species is derived, are surprisingly representative of demographic diversity in general, but do not replace the need for further studies in secondary forests.
次生热带森林在碳预算和生物多样性保护方面发挥着越来越重要的作用。因此,了解演替轨迹对于指导森林恢复和减缓气候变化的努力至关重要。森林演替是由群落中树种的生存策略(生长、死亡率和繁殖率的组合)驱动的。然而,我们对热带树种生存策略多样性的理解几乎完全来自于原始森林。在这里,我们从两个湿润(哥斯达黎加、巴拿马)和两个干燥(墨西哥)新热带森林的时间序列重复森林清查中收集了生存信息,以评估一个群落中存在的生存策略范围是否会随演替而变化。我们计算了>500 个树种的生存策略,同时控制了树冠状况,以使用二维双生存策略率超体积来比较早期演替(0-30 年)、晚期演替(30-120 年)和原始森林中生存策略多样性(即生存策略范围)。生存策略范围在演替阶段之间有很大的重叠,早期演替阶段已经涵盖了原始森林中发现的所有生存策略范围。一个例外是一组死亡率特别高的物种,它们仅局限于两个湿润森林的早期演替阶段。随着演替的进行,生存策略范围并没有扩大。我们的研究结果表明,对原始森林中长期森林监测样地的研究,尽管大多数关于热带树种生存策略的现有理解都源于此,但它们惊人地代表了一般生存策略多样性,而不能替代在次生林中进一步研究的必要性。