Collaborative Research: Controls on Ecosystem Level Functions in a Lichen-Oak Woodland

林冠地衣作为关键物种，能够控制森林生态系统中养分的保存和保留，影响养分循环和初级生产的假设将得到验证。在蓝橡树林地，一个占加州6.5%的群落，林冠中地衣Ramalina menziesii的生物量可以超过700公斤/公顷。本研究旨在证明这种不固氮的冠层附生植物在整个橡树林地生态系统的净初级生产和养分循环中的重要性。一项重复因子实验将在两个地点进行，其中控制了树冠地衣和地衣凋落物，代表了加利福尼亚州蒙特利县不同程度的海洋影响。对冠层地衣生物量的控制将检验Ramalina增加大气养分输入的假设。例如，Ramalina捕获的大气气溶胶、雾水和气体可能会增加整个林地的养分输入。对作为凋落物沉积的拉玛丽娜数量的控制将检验这样一个假设，即这种地衣的分解控制着橡树的养分分解和循环。还将在试验田考察橡树的生长效率和养分利用效率。研究人员还将开发一种简单的技术，将结果外推到不同密度的橡树林地，并考虑到区域评价的尺度。研究结果对于理解特定物种在整个生态系统功能特性中的作用，以及理解栎林林冠过程对生态系统功能的其他方面具有重要意义。此外，该研究可被视为任何以地衣为主的冠层的案例研究，并将对生态系统中附生植物的一般功能产生影响。这个研究项目团队非常优秀。机构住宿条件相当好，在黑斯廷斯自然历史保护区工作的住宿条件将是足够的。

The hypothesis that canopy lichens, acting as keystone species, can control the conservation and retention of nutrients in forest ecosystems and affect nutrient cycling and primary production will be tested. In blue oak woodlands, a community that occupies 6.5% of California, biomass of the lichen, Ramalina menziesii, can exceed 700 kg/ha in the canopy. This proposed work seeks to demonstrate the importance of this non-nitrogen- fixing canopy epiphyte in net primary production and nutrient cycling throughout this oak woodland ecosystem. A replicated factorial experiment will be imposed by which canopy lichen and lichen litterfall are manipulated at two sites, representing different degrees of maritime influence in Monterey County, California. Manipulations of the canopy lichen biomass will test the hypothesis that Ramalina enhances nutrient inputs from the atmosphere. For instance, the catch of atmospheric aerosols, fog water and gases by Ramalina may enhance the input of nutrients to the entire woodland. Manipulations of the amount of Ramalina that is deposited as litterfall will test the hypothesis that the decomposition of this lichen controls the decomposition and cycling of nutrients to the oak trees. The growth efficiency and nutrient-use efficiency of the oak trees will also be examined in the experimental plots. The investigators will also develop a simple technique for extrapolating results to oak woodlands of differing density and to considerations at scales ranging to regional evaluations. The results will be significant to understanding the role of particular species in the functional properties of entire ecosystems, and to the understanding of canopy processes to other aspects of ecosystem function in oak woodlands. In addition, this study may be viewed as a case study for any lichen dominated canopy and will have implications for the function of epiphytes in general in ecosystems. The research project team is excellent. Institutional accommodations are quite good, and accommodations for the work at the Hastings Natural History Reservation will be adequate.