Suarez-Rubio Marcela, Lookingbill Todd R
Institute of Zoology, University of Natural Resources and Life Sciences , Vienna , Austria.
Department of Geography and the Environment, University of Richmond , Richmond, VA , United States.
PeerJ. 2016 May 25;4:e2039. doi: 10.7717/peerj.2039. eCollection 2016.
Housing development beyond the urban fringe (i.e., exurban development) is one of the fastest growing forms of land-use change in the United States. Exurban development's attraction to natural and recreational amenities has raised concerns for conservation and represents a potential threat to wildlife. Although forest-dependent species have been found particularly sensitive to low housing densities, it is unclear how the spatial distribution of houses affects forest birds. The aim of this study was to assess forest bird responses to changes in the spatial pattern of exurban development and also to examine species responses when forest loss and forest fragmentation were considered. We evaluated landscape composition around North American Breeding Bird Survey stops between 1986 and 2009 by developing a compactness index to assess changes in the spatial pattern of exurban development over time. Compactness was defined as a measure of how clustered exurban development was in the area surrounding each survey stop at each time period considered. We used Threshold Indicator Taxa Analysis to detect the response of forest and forest-edge species in terms of occurrence and relative abundance along the compactness gradient at two spatial scales (400-m and 1-km radius buffer). Our results showed that most forest birds and some forest-edge species were positively associated with high levels of compactness at the larger spatial scale; the proportion of forest in the surrounding landscape also had a significant effect when forest loss and forest fragmentation were accounted for. In contrast, the spatial configuration of exurban development was an important predictor of occurrence and abundance for only a few species at the smaller spatial scale. The positive response of forest birds to compactness at the larger scale could represent a systematic trajectory of decline and could be highly detrimental to bird diversity if exurban growth continues and creates more compacted development.
城市边缘以外的住房开发（即远郊开发）是美国土地利用变化中增长最快的形式之一。远郊开发对自然和休闲设施的吸引力引发了对保护的担忧，并对野生动物构成了潜在威胁。尽管已发现依赖森林的物种对低密度住房特别敏感，但尚不清楚房屋的空间分布如何影响森林鸟类。本研究的目的是评估森林鸟类对远郊开发空间格局变化的反应，并在考虑森林丧失和森林破碎化的情况下检查物种的反应。我们通过开发一个紧凑度指数来评估1986年至2009年期间北美繁殖鸟类调查站点周围的景观组成，以评估远郊开发空间格局随时间的变化。紧凑度被定义为在每个考虑的时间段内，远郊开发在每个调查站点周围区域的聚集程度的一种度量。我们使用阈值指示分类群分析来检测森林和森林边缘物种在两个空间尺度（400米和1公里半径缓冲区）上沿紧凑度梯度的出现情况和相对丰度的反应。我们的结果表明，在较大的空间尺度上，大多数森林鸟类和一些森林边缘物种与高紧凑度呈正相关；当考虑森林丧失和森林破碎化时，周围景观中的森林比例也有显著影响。相比之下，在较小的空间尺度上，远郊开发的空间配置只是少数物种出现和丰度的重要预测因子。森林鸟类在较大尺度上对紧凑度的积极反应可能代表一种系统性的衰退轨迹，如果远郊开发继续并产生更紧凑的发展，可能对鸟类多样性极为不利。
