Understanding forest regeneration in bracken-dominated areas of tropical montane forest: a trait-based approach

热带山地森林是世界上最重要的生物多样性热点地区之一。然而，由于土地利用的变化，特别是人为引起的火灾，许多森林地区已经变得高度破碎。残存的森林遗迹被以蕨类植物（蕨类植物）为主的强烈扰动生境所包围。由于蕨类植物通常在长时间和大面积上占主导地位，破坏了森林演替和生态系统服务，因此迫切需要以科学为基础的加速森林更新的战略。我们将在玻利维亚安第斯山脉以热带蕨类植物为主的山地群落中进行观察和实验研究，以便：a)确定在森林更新期间解释物种共存和表现的主要非生物和生物过滤器；B)确定能与蕨类植物共存的树种的功能特征。我们的项目分为四个工作包（WP）：在WP1中，我们将研究火灾以来不同年龄地区树种的自然更新，以预测可能的时间模式，并使用时间序列方法（空间替代时间）描述环境条件和社区功能特征的变化。为了验证我们的假设，即在蕨类植物为主的地区，种子限制（而不是种群限制）是延迟森林恢复的最重要过滤器，我们将通过实验评估与更新相关的植物-植物相互作用（WP2：竞争、促进）和植物-动物相互作用（WP3：种子传播）。在WP2中，我们将评估不同功能性状的本地树种在不同的实验蕨菜处理下的表现，并测试蕨菜对普通园林植物发育的潜在化感作用。在WP3中，我们将评估鸟类和蝙蝠的种子传播效果，以及栖木和蝙蝠栖息地在增加种子传播和幼苗招募方面的潜在价值。在WP4中，我们将使用结构方程模型，通过考虑非生物和生物变量在其生命周期不同阶段的直接和间接影响，研究热带山地树种的主要招募瓶颈。最后，在综合方法中，我们的数据将结合形成基于生态特征的模型，预测物种丰度，并根据蕨类植物的存在和气候变化预测测试替代的群落路径。我们的项目将大大提高我们对热带山地森林更新动态的理解，并将为加速在蕨类植物为主的地区的森林恢复提供必要的信息，这在整个热带地区都很常见。

Tropical montane forests are among the most important biodiversity hotspots of the world. However, many forest areas have become highly fragmented due to land-use change, especially caused by human-induced fires. The remaining forest remnants are surrounded by strongly disturbed habitats dominated by bracken fern (Pteridium spp.). Since bracken usually dominates the vegetation for long periods and across large areas, disrupting forest succession and ecosystem services, science-based strategies to accelerate forest regeneration are urgently needed. We will combine observational and experimental studies in tropical bracken-dominated montane communities of the Bolivian Andes in order to: a) identify the major abiotic and biotic filters that explain species coexistence and performance during forest regeneration; b) determine the functional traits of the tree species that can coexist with bracken. Our project is structured in four work packages (WP): In WP1, we will study the natural regeneration of tree species in areas with different ages since fire to predict the likely temporal pattern, as well as characterize the changes in environmental conditions and functional traits of the community, using a chronosequence approach (space-for-time substitution). To test our hypothesis that seed limitation, rather than establishment limitation, is the most important filter delaying forest recovery in bracken-dominated areas, we will experimentally assess regeneration-related plant-plant interactions (WP2: competition, facilitation) and plant-animal interactions (WP3: seed dispersal). In WP2, we will evaluate the performance of native tree species with different functional traits under different experimental bracken treatments and test the potential allelopathic effects of bracken on plant development in a common garden. In WP3, we will assess seed dispersal effectiveness of birds and bats, and the potential value of perches and bat roosts to increase seed dispersal and seedling recruitment. In WP4, we will study the main bottlenecks for the recruitment of tropical montane tree species by considering direct and indirect effects of abiotic and biotic variables on different stages in their life cycles, using structural equation models. Finally, in an integrative approach, our data will be combined to form ecological trait-based models that predict species abundances and test alternative community pathways according to bracken presence and climate change predictions. Our project will substantially enhance our understanding of the dynamics of tropical montane forest regeneration, and will provide essential information for accelerating forest restoration in bracken-dominated areas, which are common throughout tropical regions.