Conservation Ecology and Zoonosis Research Group, University of Brighton, Brighton, United Kingdom.
School of Animal, Rural and Environmental Sciences, Nottingham Trent University, Brackenhurst Campus, Southwell, United Kingdom.
PLoS One. 2018 May 22;13(5):e0197445. doi: 10.1371/journal.pone.0197445. eCollection 2018.
Globally there are many examples of synanthropic carnivores exploiting growth in urbanisation. As carnivores can come into conflict with humans and are potential vectors of zoonotic disease, assessing densities in suburban areas and identifying factors that influence them are necessary to aid management and mitigation. However, fragmented, privately owned land restricts the use of conventional carnivore surveying techniques in these areas, requiring development of novel methods. We present a method that combines questionnaire distribution to residents with field surveys and GIS, to determine relative density of two urban carnivores in England, Great Britain. We determined the density of: red fox (Vulpes vulpes) social groups in 14, approximately 1km2 suburban areas in 8 different towns and cities; and Eurasian badger (Meles meles) social groups in three suburban areas of one city. Average relative fox group density (FGD) was 3.72 km-2, which was double the estimates for cities with resident foxes in the 1980's. Density was comparable to an alternative estimate derived from trapping and GPS-tracking, indicating the validity of the method. However, FGD did not correlate with a national dataset based on fox sightings, indicating unreliability of the national data to determine actual densities or to extrapolate a national population estimate. Using species-specific clustering units that reflect social organisation, the method was additionally applied to suburban badgers to derive relative badger group density (BGD) for one city (Brighton, 2.41 km-2). We demonstrate that citizen science approaches can effectively obtain data to assess suburban carnivore density, however publicly derived national data sets need to be locally validated before extrapolations can be undertaken. The method we present for assessing densities of foxes and badgers in British towns and cities is also adaptable to other urban carnivores elsewhere. However this transferability is contingent on species traits meeting particular criteria, and on resident responsiveness.
全球有许多例子表明，在城市化进程中，城市共生的肉食动物在不断增加。由于肉食动物可能与人类发生冲突，并且是潜在的人畜共患病媒介，因此评估郊区的密度并确定影响其密度的因素对于帮助管理和缓解这些问题是必要的。然而，分散的、私人拥有的土地限制了在这些地区使用传统的肉食动物调查技术，因此需要开发新的方法。我们提出了一种结合了向居民分发问卷、实地调查和 GIS 的方法，以确定英格兰、英国两个城市肉食动物的相对密度。我们确定了：14 个约 1 平方公里的郊区中红狐（Vulpes vulpes）社会群体的密度；以及一个城市的三个郊区中欧亚獾（Meles meles）社会群体的密度。平均相对狐群密度（FGD）为 3.72 公里-2，是 20 世纪 80 年代有居民狐狸的城市估计值的两倍。密度与另一种基于陷阱和 GPS 跟踪的替代估计值相当，表明该方法的有效性。然而，FGD 与基于狐狸目击的全国性数据集没有相关性，这表明全国性数据不可靠，无法确定实际密度或推断全国人口估计值。使用反映社会组织的特定物种聚类单元，该方法还被应用于郊区獾，以获得一个城市（布莱顿，2.41 公里-2）的相对獾群密度（BGD）。我们证明，公民科学方法可以有效地获取数据来评估郊区肉食动物的密度，但是在进行推断之前，需要对公众获取的全国性数据集进行本地验证。我们提出的用于评估英国城镇和城市狐狸和獾密度的方法也适用于其他地方的其他城市肉食动物。然而，这种可转移性取决于物种特征是否符合特定标准，以及居民的响应能力。
