Arbuscular mycorrhizal (AM) fungi are well-known contributors to soil aggregation and nutrient cycling functions, but we still know little about their capacity to resist or recover from persistent disturbance. Rangeland management may deteriorate these functions by affecting the activity of soil biota, including AM fungi, among other consequences. If affected, some soil properties show recovery when management stops and natural regeneration is allowed. We conducted an experiment to evaluate if the functions related to soil aggregation and promotion of exocellular enzymatic activities associated with AM fungal communities had been affected by rangeland management and, if they had, whether they recovered with successional time when management stopped. AM fungal communities from ten sites with different successional ages in a tropical dry forest region were inoculated to the same host growing in pots divided by mesh into a plant compartment and an AM mycelium compartment. We examined soil stable aggregates fractions and enzymatic activities produced or promoted by AM fungi. Soil aggregation changed significantly only after the study had run for 3 years, was higher in the hyphosphere than in the root compartment, and showed a low but positive relation with the successional age of the communities. The activity of phosphatase, but not casein-protease and beta-glucosidase, increased with successional age. Therefore, soil aggregation and enzyme activities associated with AM fungal communities seemed resilient because casein-protease and beta-glucosidase were unchanged, and aggregation and phosphatase were reduced by rangeland management but recovered with successional time.

中文翻译：

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在热带干旱森林中，土壤微生物的团聚能力和与丛枝菌根真菌群落相关的胞外酶功能的梯度变化

丛枝菌根（AM）真菌是土壤聚集和养分循环功能的众所周知的贡献者，但我们对其抗药性或从持久性干扰中恢复的能力仍然知之甚少。牧场管理可能会通过影响包括AM真菌在内的土壤生物区系的活动而破坏这些功能，并带来其他后果。如果受到影响，当停止管理并允许自然再生时，某些土壤性质会恢复。我们进行了一项实验，以评估牧场管理对与土壤聚集和与AM真菌群落相关的胞外酶活性的促进有关的功能是否受到牧场管理的影响，如果有的话，它们是否会在管理停止时连续恢复。将来自热带干旱森林地区十个具有不同演替年龄的地点的AM真菌群落接种到生长在花盆中的同一宿主上，该花盆通过网眼分为植物室和AM菌丝体室。我们检查了AM真菌产生或促进的土壤稳定聚集体组分和酶活性。仅进行了3年的研究后，土壤团聚发生了显着变化，在土壤层的疏水性高于在根系中，并且与群落的演替年龄呈低但正相关。磷酸酶的活性随年龄的增长而增加，但酪蛋白蛋白酶和β-葡萄糖苷酶则不增加。因此，与AM真菌群落相关的土壤聚集和酶活性似乎具有弹性，因为酪蛋白蛋白酶和β-葡萄糖苷酶没有变化，