van Breugel Michiel, Hall Jefferson S, Bailon Mario, Craven Dylan
Department of Geography, National University of Singapore, Singapore, Singapore.
Smithsonian Tropical Research Institute, Panama City, Panama.
Glob Chang Biol. 2025 Jan;31(1):e70037. doi: 10.1111/gcb.70037.
Large-scale reforestation is promoted as an important strategy to mitigate climate change and biodiversity loss. A persistent challenge for efforts to restore ecosystems at scale is how to accelerate ecological processes, particularly natural regeneration. Yet, despite being recognized as an important barrier to the recovery of diverse plant communities in tropical agricultural landscapes, the impacts of dispersal limitation on natural regeneration in secondary forests-and especially how this changes as these forests grow older-are still poorly studied. In a region where animals have been shown to be the dominant seed dispersers, we evaluate the impacts of proximity to a connected network of narrow streamside strips of forest (SSF) on recruitment in 1-40-year-old secondary forests. We used 8 years of annual census data from 45 sites with paired plots, one directly adjoining an SSF and the other further uphill (henceforth "landscape context"), and a null model approach to test the effects of proximity to SSFs and basal area, while accounting for variation in soil, topography, and distance between plots and stand structure. In general, we found that landscape context affects multiple aspects of recruitment, including species diversity and the proportion of rarer and less-widely distributed species among the recruits. Unexpectedly, this effect did not weaken over time, despite a fast increase in stand basal area and diversity. This suggests that forest development over the first decades of succession may not be sufficient to attract the animals that disperse rarer tree species. Our results provide empirical evidence to guide restoration initiatives in agricultural landscapes in tropical regions, principally prioritizing the restoration of forest corridor networks along streams, while also highlighting the knowledge gap about restoring animal dispersers in secondary forests.
大规模植树造林被视为缓解气候变化和生物多样性丧失的一项重要战略。大规模恢复生态系统面临的一个长期挑战是如何加速生态进程，尤其是自然更新。然而，尽管扩散限制被认为是热带农业景观中多样植物群落恢复的一个重要障碍，但对于次生林中自然更新的扩散限制影响——尤其是随着这些森林年龄增长这种影响如何变化——仍研究不足。在一个动物被证明是主要种子传播者的地区，我们评估了靠近狭窄的溪边带状森林（SSF）连通网络对1至40年生次生林幼苗补充的影响。我们使用了来自45个地点的8年年度普查数据，这些地点设有配对样地，一个直接毗邻SSF，另一个在更靠上坡的位置（以下简称“景观背景”），并采用零模型方法来测试靠近SSF和林分断面积的影响，同时考虑土壤、地形、样地间距离和林分结构的变化。总体而言，我们发现景观背景会影响幼苗补充的多个方面，包括物种多样性以及幼苗中较稀有和分布不广泛物种的比例。出乎意料的是，尽管林分断面积和多样性迅速增加，但这种影响并未随时间减弱。这表明在演替的头几十年里森林的发展可能不足以吸引传播稀有树种的动物。我们的研究结果提供了实证依据，以指导热带地区农业景观的恢复举措，主要是优先恢复溪流沿线的森林走廊网络，同时也凸显了次生林中恢复动物传播者方面的知识差距。
