CRB: Research Toward Sustainable Land Use and Biodiversity in Mosaic of Agriculture and Tropical Forest

9424606海恩斯这项研究将分三个阶段进行。这三个阶段的长期目标是确定不同土壤质量和地形的热带地区各种自然或半自然土地利用的可持续性。可持续性被定义为养分和土壤质量流失率低于养分投入和土壤形成速率的土地利用。这一点很重要，因为在整个气候变化过程中，物种丰富的森林越来越多地被转化为农田。在许多热带地区，农业通常是短暂的，然后田地就会被遗弃。废弃农田和热带湿润森林分别具有负和正的净土壤质量和养分平衡。因此，在景观尺度上，森林可以抵消邻近田地的损失。因此，景观尺度的可持续性需要天然林植被的恢复和更新。该项目的近期目标是记录废弃牧场的演替模式，并确定可能限制森林更新速度的因素。为此，将量化不同土壤类型和条件下的演替速率，并测量种子雨、种子库、种子萌发、幼苗建立和幼树生长。这些因素将结合在一起，以了解恢复热带森林群落对物种殖民和生长的限制。鉴于许多热带地区森林砍伐率和人口增长速度的迅速增加，迅速恢复废弃农田植被的能力变得越来越重要。这项研究将在景观尺度上提供有价值的人口水平数据，以指导热带地区大规模恢复废弃农地的实验方法。

9424606 Haines This research will be conducted in three phases. The long-term goal for the three phases is to determine the sustainability of various natural or semi-natural land uses on tropical sites of differing soil quality and topography. Sustainability is defined as land use in which rates of nutrient and soil mass loss are less than rates of nutrient input and soil formation. This is important because of increasing conversion of species rich forests to agricultural land throughout the tpopics. in many tropical areas, agriculture is typically short-lived, and fields are then abandoned. Abandoned fields and tropical moist forest tend to have negative and positive net soil mass and nutrient balances, respectively. Thus, at the landscape scale, forests can offset losses from adjacent fields. Therefore, landscape scale sustainability requires restoration and regeneration of natural forest vegetation. The near-term goal of this project is to document patterns of abandoned pasture succession, and identify factors potentially limiting the rate of forest regeneration. To do so, rates of succession on different soil types and conditions will be quantified, and seed rain, seed bank, seed germination, seedling establishment and sapling growth will be measured. These factors will be combined to understand limitations to colonization and growth of species for the restoration of tropical forest communities. Given the rapidly increasing rates of deforestation and population growth in many tropical areas, the ability to rapidly restore vegetation to abandoned cropland becomes increasingly important. This study will provide valuable population-level data at the landscape scale to guide experimental approaches to large-scale restoration of abandoned agricultural land in the tropics.