DECAY RATES, NITROGEN FLUXES, AND DECOMPOSER COMMUNITIES OF SINGLE- AND MIXED-SPECIES
DECAY RATES, NITROGEN FLUXES, AND DECOMPOSER COMMUNITIES OF SINGLE- AND MIXED-SPECIES
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DOI：
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发表时间：
1990
期刊：
影响因子：
2.4
通讯作者：
J. Blair;R. Parmelee;M. Beare
中科院分区：
文献类型：
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作者：
J. Blair;R. Parmelee;M. Beare
分解率，N通量，和分解有机体的丰度进行了量化的混合物种的垃圾袋（含有以下树种的两个或三个：红槭，Cornusflorida，和栎属prinus）和含有单一物种的树叶的垃圾袋。从单一物种的垃圾袋的数据被用来产生预测的衰减率，N通量，和分解生物的丰度混合物种的垃圾袋，对观察值进行比较，以确定是否发生显着的相互作用的影响时，不同物种的垃圾，不同的资源质量，混合。在1年的研究中，混合物种的垃圾袋的腐烂率没有显着不同的预测从个别组成物种的腐烂率。然而，有显着的交互作用的N通量和分解生物的丰度。在C.佛罗里达-A. rubrum和C.佛罗里达-A.红栎属prinus凋落物组合中，有显着更大的初始释放N和较低的后续N固定比预测。明天早上红栎属prinus和C.佛罗里达-A.红栎属在Prinus凋落物组合中，真菌菌丝的长度在至少一半的收集日期显著小于预测。混合窝仔组合中的细菌数量通常也低于预测值。线虫丰度，特别是食真菌动物，一般大于预测的混合物种垃圾袋，直到最后一个采样日期。在所有日期内观察到的线虫平均丰度比预测值高20-30%。微型节肢动物丰度更多变，但往往低于预测。我们的研究结果表明，在单一物种的凋落物袋中的N通量的测量可能无法反映实际的N通量在现场，几个树种的叶子混合在一起。单一和混合物种的凋落物袋之间的N通量的差异，可以影响生态系统水平的估计分解凋落物中的N释放或积累。例如，在我们的现场生态系统水平的N通量的估计，从单一物种的垃圾袋的数据的基础上，导致在一个64%低估的N释放的第75天和183%高估的N积累在凋落物中的第375天，相对于估计的基础上从混合物种的垃圾袋的数据。我们建议，观察到的N通量在混合物种的垃圾袋从那些预测使用单一物种的垃圾袋的偏差是在分解者社区的差异，如较低的微生物和微型节肢动物密度和较高的线虫密度，导致不同的资源质量的垃圾混合在一起。将需要长期的研究，以确定观察到的和预测的混合物种凋落物组合的分解者社区之间的差异是否会影响后期的分解，其中无脊椎动物-微生物的相互作用可能会有更大的影响腐烂率和养分释放。
Decomposition rates, N fluxes, and abundances of decomposer organisms were quantified in mixed-species litterbags (containing leaves of two or three of the following tree species: Acer rubrum, Cornusflorida, and Quercus prinus) and in litterbags containing leaves of a single species. Data from single-species litterbags were used to generate predicted decay rates, N fluxes, and abundances of decomposer organisms for mixed-species litter- bags, against which observed values could be compared to determine if significant inter- action effects occurred when litter of different species, and different resource quality, was mixed. Decay rates of mixed-species litterbags during the 1-yr study were not significantly different than predicted from decay rates of individual component species. However, there were significant interaction effects on N fluxes and abundances of decomposer organisms. In the C. florida-A. rubrum and C. florida-A. rubrum-Q. prinus litter combinations there were significantly greater initial releases of N and lower subsequent N immobilization than predicted. In the A. rubrum-Q. prinus and C. florida-A. rubrum-Q. prinus litter combi- nations, lengths of fungal hyphae were significantly less than predicted on at least half the collection dates. Bacterial numbers in the mixed-litter combinations were also generally less than predicted. Nematode abundances, especially fungivores, were generally greater than predicted in mixed-species litterbags until the last sample date. Observed mean abun- dances of nematodes over all dates were 20-30% greater than predicted. Microarthropod abundances were more variable, but tended to be lower than predicted. Our results indicate that measurement of N flux in single-species litterbags may not reflect actual N flux in the field, where leaves of several tree species are mixed together. The differences in N flux between single- and mixed-species litterbags can affect ecosystem-level estimates of N release or accumulation in decomposing litter. For example, estimates of ecosystem-level N fluxes at our field site, based on data from single-species litterbags, resulted in a 64% underestimate of N released by day 75 and a 183% overestimate of N accumulated in the litter by day 375, relative to estimates based on data from mixed-species litterbags. We suggest that the deviation of observed N fluxes in mixed-species litterbags from those predicted using single-species litterbags are the result of differences in the decomposer community, such as lower microbial and microarthropod densities and higher nematode densities, resulting when litter of varied resource quality is mixed together. Longer term studies will be needed to determine if the differences between observed and predicted decomposer communities in mixed-species litter combinations influence the latter stages of decomposition where invertebrate-microbial interactions may have a greater effect on decay rates and nutrient release.