Habitat Composition and Connectivity Predicts Bat Presence and Activity at Foraging Sites in a Large UK Conurbation
Habitat Composition and Connectivity Predicts Bat Presence and Activity at Foraging Sites in a Large UK Conurbation
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DOI：
10.1371/journal.pone.0033300
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发表时间：
2012-03-12
期刊：
影响因子：
3.7
通讯作者：
Sadler, Jon P.
中科院分区：
文献类型：
--
作者：
Hale, James D.;Fairbrass, Alison J.;Sadler, Jon P.
背景：城市化的特点是高度封闭的土地覆盖，以及小型、几何复杂、分散的土地利用斑块。城市化土地利用的范围和密度不断增加，对栖息地质量、连通性和城市生态产生影响。人们对城市生态系统功能的致密化阈值知之甚少，而哺乳动物、夜间活动和隐秘类群的反应在这方面的研究也很少。蝙蝠（翼手目）对物种、行会和群落层面的城市形态变化很敏感，因此是分析这种性质的理想模式生物。方法/主要发现：我们调查了英国西米德兰兹大都市的城市池塘周围的蝙蝠。场地分为五个城市土地类别，代表 1 km 2 规模的建成土地覆盖梯度。利用每个池塘周围多个半径的土地覆盖和土地利用数据开发了蝙蝠存在和活动的模型。树木网络的结构连通性被用作栖息地之间功能连通性的指标。所有物种都对城市密度的测量敏感。有些还对不同空间尺度的景观组成和结构连通性敏感。这些结果代表了城市地区的新发现。 Pipistrellus pipistrellus (Schreber 1774) 的活动与建成土地覆盖面积呈非线性关系，大大减少，超过了类似于 60% 建成面积的阈值。树木网络的存在似乎减轻了城市化对该物种的负面影响。结论/意义：我们的结果表明，城市密度的增加会对研究物种产生负面影响。这对填充式开发政策、建成密度目标和紧凑城市辩论具有影响。蝙蝠对一系列空间尺度上的城市形态的组成和结构也很敏感，这对土地利用规划和管理具有影响。保护和建立树木网络可能会提高一些蝙蝠种群对城市致密化的适应能力。
Background: Urbanization is characterized by high levels of sealed land-cover, and small, geometrically complex, fragmented land-use patches. The extent and density of urbanized land-use is increasing, with implications for habitat quality, connectivity and city ecology. Little is known about densification thresholds for urban ecosystem function, and the response of mammals, nocturnal and cryptic taxa are poorly studied in this respect. Bats (Chiroptera) are sensitive to changing urban form at a species, guild and community level, so are ideal model organisms for analyses of this nature.Methodology/Principal Findings: We surveyed bats around urban ponds in the West Midlands conurbation, United Kingdom (UK). Sites were stratified between five urban land classes, representing a gradient of built land-cover at the 1 km 2 scale. Models for bat presence and activity were developed using land-cover and land-use data from multiple radii around each pond. Structural connectivity of tree networks was used as an indicator of the functional connectivity between habitats. All species were sensitive to measures of urban density. Some were also sensitive to landscape composition and structural connectivity at different spatial scales. These results represent new findings for an urban area. The activity of Pipistrellus pipistrellus (Schreber 1774) exhibited a non-linear relationship with the area of built land-cover, being much reduced beyond the threshold of similar to 60% built surface. The presence of tree networks appears to mitigate the negative effects of urbanization for this species.Conclusions/Significance: Our results suggest that increasing urban density negatively impacts the study species. This has implications for infill development policy, built density targets and the compact city debate. Bats were also sensitive to the composition and structure of the urban form at a range of spatial scales, with implications for land-use planning and management. Protecting and establishing tree networks may improve the resilience of some bat populations to urban densification.