Conservation Initiatives, Guwahati 781022, Assam, India; Centre for Wildlife Studies, Bengaluru 560042, Karnataka, India.
Conservation Initiatives, Guwahati 781022, Assam, India; Centre for Wildlife Studies, Bengaluru 560042, Karnataka, India; Wildlife Conservation Trust, Mumbai 400021, Maharashtra, India.
Sci Total Environ. 2021 Mar 1;758:144000. doi: 10.1016/j.scitotenv.2020.144000. Epub 2020 Dec 4.
With climate change, terrestrial fauna in riparian floodplain ecosystems must adapt to a predicted increase in frequency and magnitude of fluvial perturbations. Seasonal migration to seek refuge from floodwaters represents a central adaptation strategy, but may entail risky navigation of anthropogenic spaces in heterogeneous landscapes. Here, we demonstrate the opportunities and constraints large-bodied mammalian herbivores face during an adaptive response of obligatory flood-driven refuge migration, across a human-dominated environment. Our study system, centred around a productive protected area--Kaziranga National Park in Assam, Northeast India--on the floodplains of the Brahmaputra River, is home to an abundance of large herbivores that undertake seasonal migrations in response to floods. We contrast species distribution data during a major flood event with those from the dry season to illustrate season-specific movement and space use decisions of large herbivores ranging in body mass from the 3000-kg Asian elephant Elephas maximus to the 20-kg muntjac Muntiacus muntjak. In the dry season, most large herbivores--a majority of which are endangered and threatened by anthropogenic pressures--avoided areas with a strong human footprint, while preferring spaces with high land-use diversity. During the floods, such species were pushed out of inundated habitats within the protected area, and they chose to move through woodlands and areas under bamboo cover on private lands, as they migrated to forested refugia on higher ground. Our results show how seasonal environmental constraints shaped by floods determine the internal motivation of animals to risk traversing a human-dominated space to seek refuge, which contextually defines how animals view and navigate the landscape. Such insights underscore the importance of dynamic and adaptive planning, and participatory conservation efforts, to facilitate connectivity in the changing environment and climate of the present Anthropocene.
随着气候变化，河岸洪泛区生态系统中的陆生动物必须适应河流干扰频率和强度增加的预测。季节性迁徙以寻找洪水避难所是一种核心适应策略，但可能需要在异质景观中冒险穿越人为空间。在这里，我们展示了在强制性洪水驱动的避难所迁徙的适应反应中，大型草食性哺乳动物面临的机会和限制，这跨越了一个以人类为主导的环境。我们的研究系统以印度东北部阿萨姆邦的一个生产力高的保护区——卡齐兰加国家公园为中心，位于布拉马普特拉河的洪泛平原上，这里有大量的大型食草动物，它们会根据洪水情况进行季节性迁徙。我们将主要洪水事件期间的物种分布数据与旱季的数据进行对比，以说明体重从 3000 公斤的亚洲象 Elephas maximus 到 20 公斤的麂 Muntiacus muntjak 等大型食草动物的特定季节的运动和空间利用决策。在旱季，大多数大型食草动物——其中大多数受到人为压力的威胁和濒危——避免了人类足迹强烈的区域，而更喜欢土地利用多样性高的空间。在洪水期间，这些物种被赶出保护区内被淹没的栖息地，它们选择通过林地和竹林覆盖的区域在私人土地上移动，因为它们迁徙到更高海拔的森林避难所。我们的研究结果表明，洪水塑造的季节性环境限制如何决定动物内部动机冒险穿越以人类为主导的空间以寻求避难所，这从上下文定义了动物如何看待和穿越景观。这些见解强调了动态和适应性规划以及参与式保护努力的重要性，以促进在当前人类世不断变化的环境和气候中的连通性。
