Diverging patterns at the forest edge: Soil respiration dynamics of fragmented forests in urban and rural areas
Diverging patterns at the forest edge: Soil respiration dynamics of fragmented forests in urban and rural areas
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DOI：
10.1111/gcb.16099
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发表时间：
2022-02
影响因子：
11.6
通讯作者：
Sarah M. Garvey;P. Templer;Erin A Pierce;A. Reinmann;L. Hutyra
中科院分区：
文献类型：
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作者：
Sarah M. Garvey;P. Templer;Erin A Pierce;A. Reinmann;L. Hutyra
随着全球城市化和森林碎片化的加剧，了解这些过程如何影响土壤碳库的呼吸和碳损失是至关重要的。这项研究描述了沿城乡梯度的碎片化森林中的土壤特征，评估了土壤呼吸对森林边缘附近土壤温度和水分变化的敏感性。虽然先前的研究发现，与森林内部相比，农村地区温带森林边缘的土壤呼吸速率更高，但我们发现，城市地区森林边缘的土壤呼吸受到抑制。在城市，森林边缘的呼吸速率比内陆低25%，这可能是由于城市边缘附近的高温和干旱条件所致。虽然农村土壤继续随着气温的升高而呼吸，但城市土壤的呼吸速率随着气温的上升和土壤的干燥而接近于零。土壤温度和水分敏感性模拟表明，城市土壤的呼吸速率对温度升高的敏感性低于农村土壤。将这些结果扩展到马萨诸塞州(MA)，包括0.25 MHA的城市森林，我们发现，没有考虑到城市森林边缘附近土壤呼吸速率的下降，导致高估了生长季土壤碳通量350,000毫克C。这一差异几乎是类似比较中农村土壤的2.5倍(低估了143,000毫克C)，尽管马萨诸塞州农村森林面积是城市森林面积的4倍以上。虽然气候变化可能会刺激农村森林边缘土壤的碳损失，但城市森林可能会在森林边缘附近经历更强的土壤固碳。这些发现突出表明，在一个变暖和日益城市化的世界中，在预测土壤行为和碳循环时，需要考虑森林碎片化和土地利用背景的影响。
As urbanization and forest fragmentation increase around the globe, it is critical to understand how rates of respiration and carbon losses from soil carbon pools are affected by these processes. This study characterizes soils in fragmented forests along an urban to rural gradient, evaluating the sensitivity of soil respiration to changes in soil temperature and moisture near the forest edge. While previous studies found elevated rates of soil respiration at temperate forest edges in rural areas compared to the forest interior, we find that soil respiration is suppressed at the forest edge in urban areas. At urban sites, respiration rates are 25% lower at the forest edge relative to the interior, likely due to high temperature and aridity conditions near urban edges. While rural soils continue to respire with increasing temperatures, urban soil respiration rates asymptote as temperatures climb and soils dry. Soil temperature‐ and moisture‐sensitivity modeling shows that respiration rates in urban soils are less sensitive to rising temperatures than those in rural soils. Scaling these results to Massachusetts (MA), which encompasses 0.25 Mha of the urban forest, we find that failure to account for decreases in soil respiration rates near urban forest edges leads to an overestimate of growing‐season soil carbon fluxes of >350,000 Mg C. This difference is almost 2.5 times that for rural soils in the analogous comparison (underestimate of <143,000 Mg C), even though rural forest area is more than four times greater than urban forest area in MA. While a changing climate may stimulate carbon losses from rural forest edge soils, urban forests may experience enhanced soil carbon sequestration near the forest edge. These findings highlight the need to capture the effects of forest fragmentation and land use context when making projections about soil behavior and carbon cycling in a warming and increasingly urbanized world.