Influence of soil fauna on litter decomposition

土壤动物对凋落物分解的影响

• 批准号: 203607-2006
• 负责人: Prescott, Cindy
• 金额: $ 1.41万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2006
• 资助国家: 加拿大
• 起止时间: 2006-01-01 至 2007-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=330992
• 关键词: Influence; soil; fauna; litter; decomposition

Having measured litter decomposition rates in dozens of experiments over the last 20 years, I have concluded (FEM) that 1) our expectations that changes in rates of litter decomposition explain several phenomena such as rich sites getting richer, or higher N availability in clearcut or fertilized forests are incorrect, and that we will make no further progress in measuring, modeling or understanding decomposition rates until we better understand the process itself, in particular the later stages of decomposition.  Most of our estimates of litter decomposition rates have been derived from studies in which soil macrofauna have been excluded, and thus may seriously misrepresent long-term decay rates.  Most of the litter consumed by soil fauna is passed through the gut rather than completely decomposed; thus understanding of the fate of fecal material of soil fauna is necessary before we can accurately predict and model litter decomposition. Recent development of stable isotope analysis techniques allows us to address this previously intractable problem.   In the proposed research, I will 1) characterize soil faunal communities and nutrient availability in forests across a range of site conditions and under different tree species, 2) determine relationships between soil faunal and microbial communities and nutrient availability, 3 determine whether soil faunal and microbial communities are more closely correlated to broad factors such as regional climate, or to fundamental site factors such as soil texture, soil type, slope position, aspect, or to the nature of the trees and other vegetation on the site, 4) use stable isotope analysis to determine the fate of litter carbon as it moves through the soil food web, and 5) compare rates of C, N and P mineralization in ant nests compared with surrounding forest floor to better represent nutrient cycling in dry forest ecosystems in B.C.

在过去20年里，我在几十个实验中测量了凋落物的分解速度，我得出的结论是：1)我们对凋落物分解速度的变化可以解释几个现象的预期是不正确的，例如在砍伐或施肥的森林中，丰富的场地变得更加丰富，或者N的有效性更高，而且在我们更好地了解分解过程本身，特别是分解的后期阶段之前，我们不会在测量、建模或理解分解速度方面取得进一步的进展。我们对凋落物分解速度的大部分估计都是从排除土壤大型动物的研究中得出的。因此可能严重歪曲长期腐烂率。土壤动物消耗的大部分凋落物通过肠道，而不是完全分解；因此，在我们能够准确地预测和模拟凋落物分解之前，了解土壤动物粪便物质的命运是必要的。稳定同位素分析技术的最新发展使我们能够解决这个以前难以解决的问题。在拟议的研究中，我将1)在一系列立地条件和不同树种下表征土壤动物群落和森林中的养分可获得性，2)确定土壤动物和微生物群落与养分可获得性之间的关系，3确定土壤动物和微生物群落与区域气候等广泛因素还是与土壤质地、土壤类型、坡位、坡向等基本立地因素更密切相关，还是与场地上树木和其他植被的性质有关，4)使用稳定同位素分析来确定凋落物碳在土壤食物网中移动的去向，以及5)将蚂蚁巢中的C、N和P矿化速率与周围森林地面进行比较，以更好地反映不列颠哥伦比亚省干旱森林生态系统中的养分循环。