Animals and the zoogeochemistry of elemental cycling

采伐和城市化等人类活动导致了许多生态系统中动物的引入和灭绝。这种动物的引进或丧失会对生态系统和生态系统提供的许多好处产生深远的影响。例如，将驼鹿引入纽芬兰岛导致了本地香脂冷杉林的再生失败，驼鹿与车辆碰撞的事件增加，休闲狩猎和食物供应的机会增加。最近的证据表明，像驼鹿这样的大型动物可以对营养循环产生重大影响；这个过程是生命的基础，需要进一步的研究来更好地了解动物种群的变化将如何影响营养循环。我的长期目标是研究动物在生态系统养分循环中的作用，以预测人类介导的动物灭绝和引入对生态系统养分循环的影响。在未来五年内，我有两个短期目标：1)研究食草动物对陆地生态系统碳（C)和氮(N)循环的相对和综合直接和间接影响；2）研究陆地食草动物对淡水生态系统碳(C)和氮循环的影响。为了解决目标一，我建议在加拿大大西洋地区使用数学模型和实地研究。在加拿大公园和纽芬兰政府的合作下，我们将研究30个地区，这些地区已经建立了围栏，以防止驼鹿穿过加拿大大西洋的香脂冷杉主要森林。这种围栏将使我们能够研究驼鹿对北方生态系统碳和氮的影响。驼鹿可以移动很远的距离，经常在溪流和池塘附近栖息。然而，在高密度的情况下，驼鹿可以将北方森林群落转变为开阔的草原主导地区。为了解决目标二，我还建议使用数学模型和实地研究。实地研究将使用航空照片和地面采样来测量驼鹿对14条小溪附近森林的影响，并通过测量溪流营养物质和溪流动物群落来测试驼鹿对溪流的潜在影响。

Human activities such as harvesting and urbanization have led to the introduction and extinction of animals in many ecosystems. This introduction or loss of animals can have profound impacts on ecosystems and the many benefits ecosystems provide. For example, the introduction of moose to the island of Newfoundland has led to failed regeneration of native balsam fir forests, increased occurrence of moose-vehicle collisions and increased recreational hunting and food provisioning opportunities. Recent evidence suggests that large animals such as moose can have substantial impacts on nutrient cycling; a process that is fundamental to life, and further research is needed to better understand how changes in animal populations will impact nutrient cycling. My long-term objective is to investigate the role of animals in ecosystem nutrient cycling in order to predict the effects of human-mediated animal extinction and introduction on ecosystem nutrient cycling. Over the next five years I have two short-term objectives: I) investigate the relative and combined direct and indirect effects of herbivores on terrestrial ecosystem carbon (C) and nitrogen (N) cycling and II) investigate terrestrial herbivore impacts on freshwater ecosystem C and N cycling. To address Objective I, I propose to use mathematical models and field studies in Atlantic Canada. In collaboration Parks Canada and the Government of Newfoundland we will study 30 areas where fencing has been set-up to exclude moose across sections of balsam fir dominant forests of Atlantic Canada. This fencing will allow us to study the effects of moose on boreal ecosystem carbon and nitrogen. Moose can move large distances and frequently use habitat near streams and ponds. At high densities, however, moose can transform boreal forest communities to open grassland dominated areas. To address Objective II, I also propose to use mathematical models and field studies. The field studies will use aerial photographs and ground sampling to measure moose impacts on forests near 14 small streams and test for the potential impacts of moose on streams by measuring stream nutrients and stream animal communities. The proposed research over the next 5 years will accelerate our understanding of animal impacts on nutrient cycling with a broad approach using mathematical modelling and field studies. Applications of this work touch on management plans for large herbivores, restoration of degraded forest ecosystems and how to maintain benefits provided by ecosystems. It is of particular relevance to boreal regions in Atlantic Canada which are undergoing rapid changes in large animals such as moose and Atlantic salmon. The tools and evidence from the proposed research will help resource managers predict the effects of these changes which will improve management plans. Finally, the proposed research program will train 15 students in quantitative skills and knowledge that are highly sought after in diverse work environments.