植被(病理学)
双稳态
磷
环境科学
水文学(农业)
生态学
土壤科学
地质学
岩土工程
材料科学
生物
光电子学
医学
病理
冶金
作者
Christiane W. Runyan,Paolo D’Odorico
标识
DOI:10.1016/j.advwatres.2012.09.004
摘要
Abstract Phosphorus (P) availability in soils can be a major factor limiting vegetation growth. Vegetation has adapted to this limitation by efficiently cycling P. Under conditions of limited P, microbes aid in mitigating P losses and enhancing P availability. Deforestation adversely impacts microbial populations. In turn, the loss of microbial biomass increases P losses and decreases P availability. This is important because P is not replenished biologically. Hence, when lost from the system, P only becomes available for uptake over geologic time scales. While vegetation clearly affects the microbial community and P cycling, it is not well-understood whether a loss of vegetation could lead to state changes in the vegetation dynamics. We develop a modeling framework and apply it to a P-limited cerrado ecosystem in Brazil with high intra-annual rainfall variability to examine whether deforestation can lead to a shift to a stable tree-less state. Following deforestation, we observed a decline in the microbial pool, a reduction in immobilization, and an increase in P losses. Although vegetation recovered from deforestation, a significant decline in the recalcitrant organic P pool occurred. A larger reduction in this pool led to a state change to the bare state from which the vegetation and microbial biomass did not recover. Results suggest that systems most susceptible to state changes may be those which have been previously deforested or those where the amount of P stored in the recalcitrant organic pool is low or becomes available very slowly.
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