School of Mathematics and Statistics, University of Sheffield, Sheffield, S3 7RH, UK.
Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, UK.
Oecologia. 2019 Oct;191(2):475-482. doi: 10.1007/s00442-019-04497-8. Epub 2019 Sep 4.
Natural regeneration of abandoned farmland provides an important opportunity to contribute to global reforestation targets, including the Bonn Challenge. Of particular importance are the montane tropics, where a long history of farming, frequently on marginal soils, has rendered many ecosystems highly degraded and hotspots of extinction risk. Ants play crucial roles in ecosystem functioning, and a key question is how time since abandonment and elevation (and inherent temperature gradients therein) affect patterns of ant recovery within secondary forest systems. Focusing on the Colombian Andes across a 1300 m altitudinal gradient and secondary forest (2-30 years) recovering on abandoned cattle pastures, we find that over time ant community composition and species richness recovered towards that of primary forest. However, these relationships are strongly dependent on elevation with the more open and warmer pasturelands supporting more ants than either primary or secondary forest at a particular elevation. The loss of species richness and change in species composition with elevation is less severe in pasture than forests, suggesting that conditions within pasture and its remaining scattered trees, hedgerows and forest fragments, are more favourable for some species, which are likely in or near thermal debt. Promoting and protecting natural regenerating forests over the long term in the montane tropics will likely offer significant potential for returning ant communities towards primary forest levels.
废弃农田的自然再生为实现全球重新造林目标，包括波恩挑战，提供了一个重要的机会。特别是在高山热带地区，由于长期的耕作历史，经常在边缘土壤上，许多生态系统已经高度退化，成为灭绝风险的热点地区。蚂蚁在生态系统功能中起着至关重要的作用，一个关键问题是，废弃时间和海拔（以及其中固有的温度梯度）如何影响次生林系统中蚂蚁恢复的模式。本研究聚焦于哥伦比亚安第斯山脉，跨越 1300 米的海拔梯度和在废弃牛牧场恢复的次生林（2-30 年），发现随着时间的推移，蚂蚁群落组成和物种丰富度逐渐恢复到原始森林的水平。然而，这些关系强烈依赖于海拔，较开阔和温暖的牧场比特定海拔的原始森林或次生林支持更多的蚂蚁。与森林相比，海拔导致物种丰富度和物种组成变化的程度在牧场中较小，这表明牧场及其剩余的分散树木、树篱和森林碎片内的条件对某些物种更为有利，这些物种可能处于或接近热债状态。在高山热带地区长期促进和保护自然再生森林，可能为蚂蚁群落恢复到原始森林水平提供巨大的潜力。
