Linking arthropod biodiversity and food webs with changes in surface and below-ground detritus

生物多样性与生态系统功能之间的关系在生态学中继续获得相关性。增加多样性被认为通过选择[也称为‘采样’效应]和互补效应来影响生态系统功能，这种效应将表现更好的物种的影响与协同物种混合的影响区分开来。重要的生态系统功能，如北方森林中碎屑生物量的分解，进一步受到地上和地下群落之间相互作用的调节。我将通过1)混交木和黑云杉占主导地位的时间序列和2)通过森林采伐实验改变CWM蓄积量的管理杰克松林，比较地表和埋藏的CWM的腐氧节肢动物和真菌的多样性。然后，我将进行一系列对照实验，在三个营养水平(木材腐烂真菌、食真菌和捕食者)按顺序增加物种和官能团多样性，并测量对木材分解速度的总体影响。这些实验将由一个额外的实验来补充，该实验旨在分离每个营养水平上的选择和互补效应。综上所述，这些研究将清楚地了解物种多样性与地上和地下食物网如何相互作用，以控制北方土壤中碎屑生物量的积累。了解地下碎屑动力学很重要，因为在碳平衡模型中，地下碎屑C的储量往往被忽略，而且可能比地上发现的更多。通过比较一系列林分年龄和管理活动中多样性和组成的变化，我将能够进一步概括出森林管理何时对生态系统功能产生最大影响。通过划分选择和互补效应，我还将能够确定何时需要额外的精细过滤保护策略[如相对较强的选择效应所示]，以维持受管理森林的生态系统功能。

Relating between biodiversity to ecosystem function continues to gain relevance in ecology. Increasing diversity is thought to affect ecosystem functions through both selection [also termed 'sampling' effects] and complementarity effects which partition the effects of species with superior performance from those of synergistic species mixtures. Critical ecosystem functions such as decomposition of detrital biomass in boreal forests are further regulated by interactions between above- and below-ground communities. I will compare diversity of saproxylic arthropods and fungi between surface and buried CWM across 1) mixedwood and black-spruce dominated chronosequences [spanning >300 years] and 2) managed jack-pine stands where CWM volume has been experimentally altered through forest harvesting. I will then perform a series of controlled experiments where species and functional group diversity is increased sequentially at three trophic levels [wood decaying fungi, fungivores and predators] and overall effects on wood decomposition rate are measured. These experiments will be complemented by an additional experiment designed to separate selection and complementarity effects at each trophic level. Taken together these studies will provide clear understanding of how species diversity and above- and below-ground food webs interact to control the accumulation of detrital biomass in boreal soils. Understanding below-ground detrital dynamics is important as below-ground stocks of detrital C are often neglected in carbon balance models and can be greater than those found above-ground. By comparing changes in diversity and composition across a range of stand ages and management activities I will be able to further generalize when forest management will have greatest effects on ecosystem functions. By partitioning selection and complementarity effects, I will also be able determine when additional fine filter conservation strategies [as indicated by relatively strong selection effects] will be required to maintain ecosystem functions in managed forests.