Soil fertility underlies the positive relationship between island area and litter decomposition in a fragmented subtropical forest landscape
Soil fertility underlies the positive relationship between island area and litter decomposition in a fragmented subtropical forest landscape
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DOI：
10.1016/j.catena.2021.105414
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发表时间：
2021-09
期刊：
影响因子：
6.2
通讯作者：
Xian Yang;Yating Wang;Qianna Xu;Weixing Liu;Lingli Liu;Yujia Wu;Lin Jiang;Jianbo Lu
中科院分区：
文献类型：
--
作者：
Xian Yang;Yating Wang;Qianna Xu;Weixing Liu;Lingli Liu;Yujia Wu;Lin Jiang;Jianbo Lu
生境碎片化将许多曾经相连的生境变成了大小不一的较小斑块，特别是在森林生态系统中。然而，虽然生境片断化对生物多样性和生态系统功能(例如生产力)的影响已被广泛记录在案，但我们对生境片断化如何影响凋落物分解--生物地球化学循环的一个关键组成部分--知之甚少。在亚热带中国千岛湖的一组陆桥岛屿上进行了凋落物试验，研究了森林破碎度对凋落物分解的影响。我们还通过评估自下而上(通过土壤养分)和自上而下(通过土壤动物)对凋落物分解的影响，探索了凋落物分解-岛屿地区关系的机制。我们发现，在较大的岛屿上，6种不同凋落物质量的常见植物，包括甜锥、湖北黄檀、枫香、马尾松、栎树和木荷，其凋落物的分解速度一致较快，那里的土壤肥力较高，有利于分解。土壤动物多样性也促进了凋落物的分解，但其影响主要与凋落物质量有关，不受岛屿大小的影响。我们的研究证明了生境破碎化对凋落物分解的有害影响，以及土壤肥力自下而上调节在调节生境破碎化对生物地球化学过程的影响方面的重要性。
Habitat fragmentation has transformed many once contiguous habitats into smaller patches varying in size, especially in forest ecosystems. However, while the consequences of habitat fragmentation for biodiversity and ecosystem functioning (e.g., productivity) have been widely documented, we know much less about how habitat fragmentation affects litter decomposition, a key component of biogeochemical cycling. Here we investigated the effect of forest fragment size on leaf litter decomposition by conducting a litterbag experiment on a group of land-bridge islands in the Thousand Island Lake in subtropical China. We also explored the mechanisms underlying litter decomposition-island area relationship by assessing the bottom-up (via soil nutrients) and top-down (via soil fauna) effects on litter decomposition. We found that the leaf litter of six common plant species with different litter quality, includingCastanopsis sclerophylla,Dalbergia hupeana,Liquidambar formosana,Pinus massoniana,Quercus fabri,and Schima superba, consistently decomposed faster on larger islands, where greater soil fertility facilitated decomposition. Soil faunal diversity also enhanced litter decomposition, but its effect was mainly associated with litter quality and unaffected by island size. Our study demonstrates the deleterious effect of habitat fragmentation on litter decomposition, as well as the importance of bottom-up regulation by soil fertility in modulating habitat fragmentation effect on biogeochemical processes.