Feces nitrogen release induced by different large herbivores in a dry grassland.
Feces nitrogen release induced by different large herbivores in a dry grassland.
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DOI：
10.1002/eap.1640
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发表时间：
2018
期刊：
影响因子：
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通讯作者：
Jingzhi Wang;Deli Wang;Chunqiang Li;T. Seastedt;C. Liang;Ling Wang;Wei Sun;Maowei Liang;Yu Li
中科院分区：
文献类型：
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作者：
Jingzhi Wang;Deli Wang;Chunqiang Li;T. Seastedt;C. Liang;Ling Wang;Wei Sun;Maowei Liang;Yu Li
大型食草动物对草地养分循环有显著影响。众所周知，这些生物可以改变植物生产的质量和数量，以及植物凋落物和动物废物的数量和质量。众所周知，草食动物会提高碎屑输入的相对质量，但这一过程如何受到不同大型草食动物的饮食选择加工和粪便产生的影响，在很大程度上仍未得到研究。在这里，我们测量了干燥草原上牛羊的这些差异如何影响粪便中的氮(N)矿化。我们发现，体型较大的牛倾向于选择质量较低的草大针茅作为主要食物来源。相比之下，当田间牧草不足时，小羊日粮中以亚优势草羊草（Leymus chinensis）为主，氮含量较高。这种多样化的饲粮品质导致牛粪的C:N比高于羊粪。牛粪便中较高的活性C，即较高的纤维素/半纤维素含量，促进了微生物的生长，从而加速了牛粪便的分解。一个令人惊讶的发现是，牛粪便中的氮矿化量大约是羊粪便的两倍，尽管羊粪便中的氮含量略高。从草地生产力的角度来看，增加食草动物群落中大体型物种的比例可能有利于饲料生产力和通过粪便的快速降解来循环养分。
Large herbivores have pronounced effects on nutrient cycling in grasslands. These organisms are known to alter the quality and quantity of plant production as well as the amounts and quality of plant litter and animal wastes. The generalization that the relative quality of detritus inputs is enhanced by herbivores is well known, but how this process is affected by diet selection processing and feces production of different large herbivores remains largely unstudied. Here, we measured how these differences for cattle and sheep on a dry grassland might influence nitrogen (N) mineralization from feces. We found that cattle of larger body size tended to select the low quality grass Stipa grandis as their major food source. In contrast, the subdominant grass Leymus chinensis, with relatively high N content, was a majority in the diet of smaller sheep, when palatable forbs were insufficient in the field. This diverse diet quality resulted in a C:N ratio of cattle feces that was higher than that of sheep feces. Relatively higher labile C availability in the cattle feces, namely relatively higher cellulose/hemicellulose contents, promoted microbial growth and in turn accelerated cattle feces decomposition. A surprise finding was that the feces from cattle mineralized about twice as much N as feces from sheep, despite the latter having slightly higher N content. From a grassland productivity perspective, increasing the proportion of large body-sized species in grazing herbivore assemblages perhaps is beneficial to forage productivity and nutrient recycling by the rapid degradation of feces.