Context Connectivity, which is a fundamental aspect of any landscape, has been shown to have a nonlinear relationship with the amount of natural habitat, with a marked decrease at intermediate levels of coverage. Impacts on connectivity vary according to how natural habitat is removed. We analyzed connectivity in the Brazilian Cerrado (tropical savanna), a 2 million-km 2 biodiversity hotspot. Objectives We evaluated the effects of habitat removal on connectivity, hypothesizing that a deforestation threshold exists below which connectivity is drastically reduced and that neighboring landscapes have similar patterns of connectivity. Methods We divided the Cerrado into 624 50 × 50 km cells and used the integral index of connectivity (IIC), available in Conefor software, to evaluate changes in connectivity between 2000 and 2017. We analyzed how the intra, flux, and connector components of connectivity vary with changes in percentage of remaining natural habitat. Results Between 2000 and 2017, 23.9% of the natural habitat of the Cerrado was lost (~ 254,000 km 2 ) and connectivity decreased significantly (W = 179,700, p < 0.01). The most crucial change was the removal of connector fragments or corridors, which occurred in 78.2% of the landscapes. The relationship between IIC and remaining natural area revealed a breakpoint, when native area in a landscape reached 39% in 2000 and 37% in 2017. Conclusions Regardless of the spatial arrangement of habitat fragments, landscape connectivity is lost when the remaining natural habitat falls below a certain threshold. More restrictive regulations and government permissions should be considered to avoid over-occupation of landscapes.

中文翻译：

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加热生物多样性热点：连通性比保留栖息地更重要

背景连通性是任何景观的一个基本方面，已被证明与自然栖息地的数量呈非线性关系，在中等覆盖水平时显着减少。对连通性的影响因自然栖息地的移除方式而异。我们分析了巴西塞拉多（热带稀树草原）的连通性，这是一个 200 万公里 2 的生物多样性热点。目标我们评估了栖息地移除对连通性的影响，假设存在森林砍伐阈值，低于该阈值连通性会急剧降低，并且邻近景观具有相似的连通性模式。方法 我们将 Cerrado 划分为 624 个 50 × 50 km 单元，并使用 Conefor 软件中提供的连通性积分指数 (IIC) 来评估 2000 年至 2017 年之间连通性的变化。我们分析了连接的内部、通量和连接器组件如何随着剩余自然栖息地百分比的变化而变化。结果 2000 年至 2017 年间，塞拉多 23.9% 的自然栖息地消失（~ 254,000 km 2 ），连通性显着下降（W = 179,700，p < 0.01）。最关键的变化是移除了连接器碎片或走廊，这发生在 78.2% 的景观中。IIC 与剩余自然面积之间的关系揭示了一个断点，当景观中的原生面积在 2000 年达到 39% 和 2017 年达到 37% 时。 结论 无论栖息地碎片的空间排列如何，当剩余自然栖息地低于一定的门槛。