Landscape‐level effects on aboveground biomass of tropical forests: A conceptual framework
Landscape‐level effects on aboveground biomass of tropical forests: A conceptual framework
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景观水平对热带森林地上生物量的影响：概念框架
DOI：
10.1111/gcb.13970
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发表时间：
2018
影响因子：
11.6
通讯作者：
A. D. de Oliveira
中科院分区：
文献类型：
--
作者：
Melina Melito;J. Metzger;A. D. de Oliveira
尽管人们普遍认识到，碎片化可以通过边缘效应减少森林生物量，但对文献的系统回顾并未揭示边缘在调节生物量损失中的明确作用。此外，边缘效应似乎受到基质类型的限制，这表明景观组成对生物量有影响。缺乏经验证据表明，整个热带森林普遍存在与边缘有关的生物量损失，这突出表明，有必要建立一个将景观结构与地上生物量联系起来的一般框架。在这里，我们提出了一个概念模型，在该模型中，景观组成和配置中介了林地斑块之间的边缘效应和种子通量的大小，最终影响了生物量。我们的模型假设，生物量的迅速减少可能发生在森林复盖损失的门槛以下。就在这个阈值以下，我们预测，景观配置的变化会强烈影响斑块的隔离，从而增加生物量损失。此外，我们期待景观组成和斑块属性之间的协同作用，其中基质类型中介边缘对物种衰退的影响，特别是对于耐荫物种。为了测试我们的概念框架，我们提出了一个抽样协议，其中可以集体和单独评估边缘、森林数量、森林隔离、碎片大小和基质类型对生物质储量的影响。所提出的模型将景观和斑块结构对生物量的综合影响统一到一个框架中，提供了一套新的人类修改景观中生物量损失的主要驱动因素。我们认为，碳交易议程(例如，REDD+)和碳保护倡议必须超越森林丧失和边缘对生物量的影响，考虑到与景观组成和配置变化相关的对生物量的一整套影响。
Despite the general recognition that fragmentation can reduce forest biomass through edge effects, a systematic review of the literature does not reveal a clear role of edges in modulating biomass loss. Additionally, the edge effects appear to be constrained by matrix type, suggesting that landscape composition has an influence on biomass stocks. The lack of empirical evidence of pervasive edge‐related biomass losses across tropical forests highlights the necessity for a general framework linking landscape structure with aboveground biomass. Here, we propose a conceptual model in which landscape composition and configuration mediate the magnitude of edge effects and seed‐flux among forest patches, which ultimately has an influence on biomass. Our model hypothesizes that a rapid reduction of biomass can occur below a threshold of forest cover loss. Just below this threshold, we predict that changes in landscape configuration can strongly influence the patch's isolation, thus enhancing biomass loss. Moreover, we expect a synergism between landscape composition and patch attributes, where matrix type mediates the effects of edges on species decline, particularly for shade‐tolerant species. To test our conceptual framework, we propose a sampling protocol where the effects of edges, forest amount, forest isolation, fragment size, and matrix type on biomass stocks can be assessed both collectively and individually. The proposed model unifies the combined effects of landscape and patch structure on biomass into a single framework, providing a new set of main drivers of biomass loss in human‐modified landscapes. We argue that carbon trading agendas (e.g., REDD+) and carbon‐conservation initiatives must go beyond the effects of forest loss and edges on biomass, considering the whole set of effects on biomass related to changes in landscape composition and configuration.