Fortier Riley P, Corahua-Espinoza Thalia, Swamy Varun, Feeley Kenneth J, Gallice Geoffrey R
Department of Biology University of Miami Coral Gables Florida USA.
Alliance for a Sustainable Amazon Potomac Maryland USA.
Ecol Evol. 2025 May 22;15(5):e71476. doi: 10.1002/ece3.71476. eCollection 2025 May.
The southwestern Amazon is a biodiversity hotspot home to some of the oldest permanent forest dynamics plots in the basin. Despite the region's abundance of plots, we still know relatively little about how tree diversity and composition change across the region's precipitation gradient, between habitat types, and how disturbed and managed forests compare to protected, old-growth forests since the majority of forest plots are located in protected forests. In this study, we first described a new 1-ha permanent forest dynamics plot at the confluence of agricultural land and managed Brazil nut forest. We then compared the plot to others in the region to evaluate the relationship between precipitation and plot diversity, compositional differences between floodplain and terra firme forest, and differences in forest dynamics between our disturbed forest plot and old-growth forest plots. Contrary to large-scale patterns in tree diversity, we found no relationship between precipitation and tree alpha diversity for plots in the southwestern Amazon. There were, however, clear compositional differences between floodplain and terra firme forests. Annual change in the aboveground biomass of the new plot was higher than in other plots in the region. Similarly, annual rates of mortality and recruitment were lower and higher, respectively, in the new plot compared to the other plots. The floristic and structural similarities between plots in disturbed or managed forests and plots in old-growth forests indicate a high resilience of tropical forests to low-intensity disturbances. Our findings thus provide evidence that low-intensity logging and low-impact Brazil nut harvesting in the southwest Amazon do not significantly alter forest structure and composition in the medium to long term. Our new plot bolsters the representation of disturbed and managed forests in plot databases and will be an important resource for future studies of large-scale patterns of forest diversity, structure, and dynamics.
亚马孙西南部是一个生物多样性热点地区，拥有该流域一些最古老的永久性森林动态监测样地。尽管该地区有大量的样地，但我们对树木多样性和组成如何随该地区的降水梯度、栖息地类型而变化，以及受干扰和经营的森林与受保护的原始森林相比情况如何，仍然知之甚少，因为大多数森林样地都位于受保护的森林中。在本研究中，我们首先描述了一个位于农田和经营的巴西坚果林交汇处的1公顷新的永久性森林动态监测样地。然后，我们将该样地与该地区的其他样地进行比较，以评估降水与样地多样性之间的关系、洪泛平原森林和高地森林之间的组成差异，以及我们的受干扰森林样地与原始森林样地之间的森林动态差异。与树木多样性的大规模模式相反，我们发现亚马孙西南部样地的降水与树木α多样性之间没有关系。然而，洪泛平原森林和高地森林之间存在明显的组成差异。新样地地上生物量的年变化高于该地区的其他样地。同样，与其他样地相比，新样地的年死亡率较低，而年更新率较高。受干扰或经营的森林样地与原始森林样地之间的植物区系和结构相似性表明，热带森林对低强度干扰具有较高的恢复力。因此，我们的研究结果提供了证据，表明亚马孙西南部的低强度伐木和低影响的巴西坚果采摘在中长期内不会显著改变森林结构和组成。我们的新样地增加了样地数据库中受干扰和经营森林的代表性，将成为未来大规模森林多样性、结构和动态模式研究的重要资源。
