Biogeochemical Influence of Cutter Ants on Secondary Forests of Eastern Amazonia

摘要：在美洲热带地区，次生林是人类开垦和利用土地的副产物。大部分土地用于农业或牧场的时间有限，导致大部分土地恢复为次生林。关于这些次生林的形成和结构还有很多有待了解的地方。切叶蚁在次生林的发生率是原生林的10 ~ 100倍。它们在特定树种的落叶和土壤理化性质的改良剂中起着重要的生态作用。该项目通过在有和没有蚂蚁种群的地点描述蚁巢地点、土壤和树木生长来研究切蚁的生物地球化学影响。该研究考虑了在人类利用和遗弃后正在恢复的生态系统中优势食草动物的作用，具有重要的意义。热带生态系统土壤的地下过程是干扰后生态系统恢复的主要控制因素。切叶蚁可能在改善土壤条件，促进森林重建方面发挥关键作用。这项研究将开始解决这种潜在的相互作用，并测试这种多产的无脊椎动物在这些过渡生态系统中促进树木生长的假设。

Abstract: 9408927, PI-NEPSTAD: Secondary forests are the by-product of increased human clearing and utilization of land in the tropical regions of the Americas. The limited time duration in which much of this land can be kept in agriculture or pasture causes much of this land to revert to secondary forest. Much remains to be learned about the formation and structure of these secondary forests. Leafcutter ants are found to be incident at 10 to 100 fold higher numbers in secondary forest compared to primary forest. They play important ecological roles in defoliation of selected tree species and as modifiers of physical and chemical nature of the soils. This project investigates the biogeochemical influence of cutter ants by characterizing nest sites, soils, and tree growth at sites with and without ant populations. This research is important because it considers the role of the dominant herbivore in these ecosystems which are recovering after human utilization and abandonment. Belowground processes in the soils of tropical ecosystems are major controls on the recovery of these ecosystems after disturbance. The leafcutter ant may well play a crucial role in improving soil conditions to facilitate forest re-establishment. This research will begin to address this potential interaction, and test the hypothesis that this prolific invertebrate enhances tree growth in these transitional ecosystems.