Vertebrate diversity and biomass along a recovery gradient in a lowland tropical forest

Deforestation of tropical forests have resulted in extensive areas of
secondary forests with the potential to restore biodiversity to former
old-growth forest levels. The recovery of vertebrate communities is an
essential component of biodiversity and ecosystem restoration, as
vertebrates provide key ecosystem functions. However, little is known
about the recovery trajectories and habitat preferences of vertebrates in
tropical landscapes with differing land-use legacies. We used camera traps
covering three weeks to study the activity of ground-based mammals and
birds in the understory of 57 sites along a forest recovery gradient,
ranging from active agriculture, such as pastures and cacao plantations,
to naturally recovering forests and old-growth forests in the Chocó
rainforest in north-western Ecuador. Our results show that diversity and
biomass of wild vertebrates are highest in old-growth forests and late
recovery stages, while for domestic vertebrates, these indices are highest
in agricultural land. Additionally, while species-habitat networks showed
low habitat specificity for vertebrate species, an indicator species
analysis found no species to indicate old-growth forests, Dasyprocta
punctata and Tayassu pecari to indicate all forest types, and Aramides
wolfi and Pecari tajacu to indicate late regeneration forests. We suggest
that these patterns are caused by a high habitat connectivity and large
amounts of remaining old-growth forest in our study area. Our findings
indicate that secondary forests have a high potential for the recovery of
vertebrate species diversity and biomass to old-growth level in lowland
tropical forests with short regeneration times.

热带森林的滥伐导致大面积次生林形成，这些次生林具备将生物多样性恢复至原有原始林（old-growth forest）水平的潜力。脊椎动物群落的恢复是生物多样性与生态系统修复的核心组成部分，因为脊椎动物可提供关键的生态系统功能。然而，针对具有不同土地利用遗留效应的热带景观内的脊椎动物的恢复轨迹与栖息地偏好，目前尚缺乏深入认知。本研究于厄瓜多尔西北部的乔科雨林中，依托覆盖三周时长的红外触发相机（camera traps），对沿森林恢复梯度分布的57个样地林下层的地面活动哺乳动物与鸟类进行了调查。该梯度涵盖了从牧场、可可种植园等活跃农业用地，至自然恢复林与原始林的各类生境。研究结果显示，野生脊椎动物的多样性与生物量在原始林与恢复后期的生境中达到最高；而家养脊椎动物的上述两类指标则在农业用地中表现最优。此外，尽管物种-栖息地网络显示脊椎动物物种的栖息地特异性较低，但指示物种分析结果表明：暂无物种可作为原始林的指示物种；Dasyprocta punctata与Tayassu pecari可作为所有森林类型的指示物种；而Aramides wolfi与Pecari tajacu则可作为恢复后期生境的指示物种。本研究认为，上述格局的形成原因在于研究区域内较高的生境连通性，以及尚存的大面积原始林。本研究结果表明，在恢复时长较短的低地热带森林中，次生林具备将脊椎动物物种多样性与生物量恢复至原始林水平的巨大潜力。