Soil nematode assemblages respond to interacting environmental changes
Soil nematode assemblages respond to interacting environmental changes
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DOI：
10.1007/s00442-023-05412-y
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发表时间：
2023-06
期刊：
影响因子：
2.7
通讯作者：
Laura Martinez;Shuqi Wu;Lauren E. Baur;Mariah T Patton;Paul C Owen-Smith;S. Collins;Jennifer A. Rudgers
中科院分区：
文献类型：
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作者：
Laura Martinez;Shuqi Wu;Lauren E. Baur;Mariah T Patton;Paul C Owen-Smith;S. Collins;Jennifer A. Rudgers
多因素实验表明，环境变化之间的相互作用通常会影响生物多样性和群落组成。然而，大多数田间试验只操纵单一因素。土壤食物网对生态系统健康至关重要，可能对包括土壤变暖、富营养化和降水变化在内的环境变化之间的相互作用特别敏感。在这里，我们询问了环境变化如何相互作用来改变奇瓦瓦沙漠北部草原上的土壤线虫群落。对氮、冬季降雨量和夜间变暖的因子处理与区域环境变化的预测相匹配。变暖使线虫多样性降低25%，属水平丰富度降低32%，但随着冬季降雨的增加，这种下降逐渐消失，这表明变暖效应是通过干燥来实现的。降水和氮素之间的相互作用也改变了线虫群落组成，但对线虫总丰度的影响很小，表明大多数变化涉及物种丰度的重新排序。具体地说，在常温降水条件下，氮肥使食菌动物减少68%，食草动物减少73%，但对食真菌动物没有影响。相比之下，在冬雨增加的情况下，氮肥使食菌体增加了95%，对食草动物没有影响，食菌体丰度增加了一倍。雨水会降低土壤氮素的有效性，增加微生物循环中的周转，潜在地促进被氮素富营养化淹没的线虫种群的恢复。线虫群落与植物群落组成不是紧密相连的，而是可能跟踪微生物，包括生物结壳或分解者。我们的结果强调了环境变化应激源之间的相互作用对于塑造旱地土壤食物网的组成和功能的重要性。
Multi-factor experiments suggest that interactions among environmental changes commonly influence biodiversity and community composition. However, most field experiments manipulate only single factors. Soil food webs are critical to ecosystem health and may be particularly sensitive to interactions among environmental changes that include soil warming, eutrophication, and altered precipitation. Here, we asked how environmental changes interacted to alter soil nematode communities in a northern Chihuahuan Desert grassland. Factorial manipulations of nitrogen, winter rainfall, and nighttime warming matched predictions for regional environmental change. Warming reduced nematode diversity by 25% and genus-level richness by 32%, but declines dissipated with additional winter rain, suggesting that warming effects occurred via drying. Interactions between precipitation and nitrogen also altered nematode community composition, but only weakly affected total nematode abundance, indicating that most change involved reordering of species abundances. Specifically, under ambient precipitation, nitrogen fertilizer reduced bacterivores by 68% and herbivores by 73%, but did not affect fungivores. In contrast, under winter rain addition, nitrogen fertilization increased bacterivores by 95%, did not affect herbivores, and doubled fungivore abundance. Rain can reduce soil nitrogen availability and increase turnover in the microbial loop, potentially promoting the recovery of nematode populations overwhelmed by nitrogen eutrophication. Nematode communities were not tightly coupled to plant community composition and may instead track microbes, including biocrusts or decomposers. Our results highlight the importance of interactions among environmental change stressors for shaping the composition and function of soil food webs in drylands.