Nuñez Chase L, Clark James S, Clark Connie J, Poulsen John R
University Program in Ecology, Duke University, Durham, USA.
Nicholas School of the Environment, Duke University, Durham, USA.
AoB Plants. 2018 Dec 13;11(1):ply074. doi: 10.1093/aobpla/ply074. eCollection 2019 Feb.
Hunting and logging, ubiquitous human disturbances in tropical forests, have the potential to alter the ecological processes that govern population recruitment and community composition. Hunting-induced declines in populations of seed-dispersing animals are expected to reduce dispersal of the tree species that rely on them, resulting in potentially greater distance- and density-dependent mortality. At the same time, selective logging may alter competitive interactions among tree species, releasing remaining trees from light, nutrient or space limitations. Taken together, these disturbances may alter the community composition of tropical forests, with implications for carbon storage, biodiversity conservation and ecosystem function. To evaluate the effects of hunting and logging on tree fecundity and seed dispersal, we use 3 years of seed rain data from a large-scale observational experiment in previously logged, hunted and protected forests in northern Republic of Congo (Brazzaville). We find that low-intensity logging had a meaningful long-term effect on species-specific seed dispersal distances, though the direction and magnitude varied and was not congruent within dispersal vector. Tree fecundity increased with tree diameter, but did not differ appreciably across disturbance regimes. The species-specific dispersal responses to logging in this study point towards the long-lasting toll of disturbance on ecological function and highlight the necessity of conserving intact forest.
狩猎和伐木是热带森林中普遍存在的人类干扰因素,它们有可能改变控制种群补充和群落组成的生态过程。预计狩猎导致的种子传播动物种群数量下降,将减少依赖这些动物的树种的传播,从而可能导致更大的距离和密度依赖性死亡率。与此同时,选择性伐木可能会改变树种之间的竞争相互作用,使剩余树木摆脱光照、养分或空间限制。综合来看,这些干扰可能会改变热带森林的群落组成,对碳储存、生物多样性保护和生态系统功能产生影响。为了评估狩猎和伐木对树木繁殖力和种子传播的影响,我们使用了来自刚果共和国(布拉柴维尔)北部先前已砍伐、狩猎和保护森林的大规模观测实验的3年种子雨数据。我们发现,低强度伐木对特定物种的种子传播距离有显著的长期影响,尽管其方向和幅度各不相同,且在传播媒介中也不一致。树木繁殖力随树径增加而提高,但在不同干扰状态下没有明显差异。本研究中特定物种对伐木的传播反应表明干扰对生态功能具有持久影响,并突出了保护完整森林的必要性。