Anthropogenic transitions from forested to human-dominated landscapes in southern Macaronesia
Anthropogenic transitions from forested to human-dominated landscapes in southern Macaronesia
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马卡罗尼西亚南部从森林景观到人类主导景观的人为转变
DOI：
10.1073/pnas.2022215118
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发表时间：
2021
期刊：
影响因子：
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通讯作者：
Sandra Nogué
中科院分区：
文献类型：
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作者：
Alvaro Castilla‐Beltrán;L. de Nascimento;J. Fernández;R. Whittaker;K. Willis;M. Edwards;Sandra Nogué
评估人类住区的生态后果有助于保护岛屿森林及其生态系统服务，但要了解这些相互作用的遗产，需要跨越几个世纪的数据集。我们使用古生态学数据（如化石花粉）表明，前人类全新世森林是动态的气候变化的反应，人类殖民导致火灾，土壤侵蚀和放牧的影响，在加那利群岛和卡波佛得角的发病率增加。人类已经推动了卡波维德的嗜热林地区域内的成分趋同，但在加那利群岛，月桂林的残余片段仍然存在。我们的长期观点强调了过去人类影响的遗产，以及在这些生物多样性热点地区的嗜热林地中恢复和保护哪些树种。渡渡鸟等标志性物种的灭绝和复活节岛的森林砍伐象征着人类对许多海洋岛屿，特别是热带和亚热带岛屿的殖民化的变革性影响。然而，史前和殖民时代的殖民者与他们遇到的森林和森林资源的相互作用可能是复杂的，在岛屿之间存在差异，并且仍然知之甚少。长期生态记录（例如，化石花粉）提供了了解这些人类影响与自然变化和殖民化前后变异性的关系的手段。在这里，我们分析了加那利群岛和卡波佛得角的森林景观的古生态档案，第一次殖民约2,400至2,000年和490年前，分别。我们表现出对区域气候变化的敏感性之前，人类殖民，其次是不同的，但逐渐影响早期人类定居。这些与殖民时代更迅速的转变形成对比，与人类压力的显著增加有关。在加那利群岛，至少有两个本土树木类群灭绝，低地嗜热的林地大部分转化为农业用地，但残留的亚热带月桂林持续存在，外来物种的入侵有限。相反，在卡波维德，喜热的林地被耗尽，取而代之的是开阔的景观和引进的林地。这两个群岛之间的差异反映了不断变化的文化习俗和与森林的社会互动，并说明了长期数据系列在了解人类对岛屿生态系统的足迹方面的重要性，这些信息对于这两个生物多样性热点地区目前和未来的森林恢复和养护管理做法至关重要。
Significance Assessing the ecological consequences of human settlement can help preserve island forests and their ecosystem services, but to understand the legacy of these interactions requires datasets that span centuries. We used paleoecological data (e.g. fossil pollen) to show that prehuman Holocene forests were dynamic in response to climatic changes, and that human colonization led to increased incidence of fire, soil erosion, and grazing impacts in the Canary Islands and Cabo Verde. Humans have driven compositional convergence within the thermophilous woodland zone of Cabo Verde but in the Canary Islands relictual fragments of laurel forests persist. Our long-term view highlights the legacy of past human impacts and which tree species to restore and conserve in thermophilous woodlands within these biodiversity hotspots. The extinction of iconic species such as the dodo and the deforestation of Easter Island are emblematic of the transformative impact of human colonization of many oceanic islands, especially those in the tropics and subtropics. Yet, the interaction of prehistoric and colonial-era colonists with the forests and forest resources they encountered can be complex, varies between islands, and remains poorly understood. Long-term ecological records (e.g., fossil pollen) provide the means to understand these human impacts in relation to natural change and variability pre- and postcolonization. Here we analyze paleoecological archives in forested landscapes of the Canary Islands and Cabo Verde, first colonized approximately 2,400 to 2,000 and 490 y ago, respectively. We demonstrate sensitivity to regional climate change prior to human colonization, followed by divergent but gradual impacts of early human settlement. These contrast with more rapid transformation in the colonial era, associated with significant increases in anthropogenic pressures. In the Canary Islands, at least two native tree taxa became extinct and lowland thermophilous woodlands were largely converted to agricultural land, yet relictual subtropical laurel forests persisted with limited incursion of nonnative species. In Cabo Verde, in contrast, thermophilous woodlands were depleted and substituted by open landscapes and introduced woodlands. Differences between these two archipelagos reflect the changing cultural practices and societal interactions with forests and illustrate the importance of long-term data series in understanding the human footprint on island ecosystems, information that will be critically important for current and future forest restoration and conservation management practices in these two biodiversity hotspots.