Klein Julian, Haverkamp Paul J, Lindberg Eva, Griesser Michael, Eggers Sönke
Department of Ecology Swedish University of Agricultural Sciences Uppsala Sweden.
Department of Evolutionary Ecology and Environmental Studies University of Zurich Zurich Switzerland.
Ecol Evol. 2020 Feb 5;10(4):2238-2252. doi: 10.1002/ece3.6062. eCollection 2020 Feb.
Habitat suitability models (HSM) based on remotely sensed data are useful tools in conservation work. However, they typically use species occurrence data rather than robust demographic variables, and their predictive power is rarely evaluated. These shortcomings can result in misleading guidance for conservation. Here, we develop and evaluate a HSM based on correlates of long-term breeding success of an open nest building boreal forest bird, the Siberian jay. In our study site in northern Sweden, nest failure of this permanent resident species is driven mainly by visually hunting corvids that are associated with human settlements. Parents rely on understory nesting cover as protection against these predators. Accordingly, our HSM includes a light detection and ranging (LiDAR) based metric of understory density around the nest and the distance of the nest to the closest human settlement to predict breeding success. It reveals that a high understory density 15-80 m around nests is associated with increased breeding success in territories close to settlements (<1.5 km). Farther away from human settlements breeding success is highest at nest sites with a more open understory providing a favorable warmer microclimate. We validated this HSM by comparing the predicted breeding success with landscape-wide census data on Siberian jay occurrence. The correlation between breeding success and occurrence was strong up to 40 km around the study site. However, the HSM appears to overestimate breeding success in regions with a milder climate and therefore higher corvid numbers. Our findings suggest that maintaining patches of small diameter trees may provide a cost-effective way to restore the breeding habitat for Siberian jays up to 1.5 km from human settlements. This distance is expected to increase in the warmer, southern, and coastal range of the Siberian jay where the presence of other corvids is to a lesser extent restricted to settlements.
基于遥感数据的栖息地适宜性模型（HSM）是保护工作中的有用工具。然而，它们通常使用物种出现数据而非可靠的种群统计学变量，并且其预测能力很少得到评估。这些缺点可能导致保护工作的误导性指导。在此，我们开发并评估了一种基于开阔筑巢北方森林鸟类西伯利亚松鸦长期繁殖成功率相关因素的HSM。在瑞典北部的研究地点，这种常驻物种的巢穴失败主要是由与人类住区相关的视觉捕食鸦科鸟类导致的。亲鸟依靠林下筑巢掩护来抵御这些捕食者。因此，我们的HSM包括基于光探测和测距（LiDAR）的巢穴周围林下密度指标以及巢穴到最近人类住区的距离，以预测繁殖成功率。结果表明，巢穴周围15 - 80米的林下密度高与靠近住区（<1.5公里）区域的繁殖成功率增加有关。离人类住区较远时，林下更开阔、提供有利温暖微气候的巢穴地点繁殖成功率最高。我们通过将预测的繁殖成功率与西伯利亚松鸦出现情况的全景观普查数据进行比较，验证了这个HSM。在研究地点周围40公里范围内，繁殖成功率与出现情况之间的相关性很强。然而，HSM似乎高估了气候较温和、因此鸦科鸟类数量较多地区的繁殖成功率。我们的研究结果表明，维持小直径树木斑块可能为恢复距离人类住区1.5公里以内西伯利亚松鸦的繁殖栖息地提供一种经济有效的方法。在西伯利亚松鸦分布较温暖、南部和沿海范围，预计这个距离会增加，因为其他鸦科鸟类的存在在较小程度上仅限于住区。
