United Kingdom Butterfly Monitoring Scheme: site indices 2021

This dataset comprises individual site indices for UK butterfly species calculated from data from the UK Butterfly Monitoring Scheme (UKBMS). Site indices are a relative rather than an absolute measure of the size of a population, and have been shown to relate closely to other, more intensive, measures of population size such as mark, release, recapture (MRR) methods. The site index can be thought of as a relative measure of the population size, being a more or less constant proportion of the number of butterflies present. The proportion seen is likely to vary according to species; some butterfly species are more conspicuous and thus more easily detected, whereas others are much less easy to see. Site indices are only calculated at sites with sufficient monitoring visits throughout the season, or for targeted reduced effort surveys (timed observations, larval web counts and egg counts) where counts are generally obtained as close to the peak of the flight period as possible and are subsequently adjusted for the time of year and size of the site (area of suitable habitat type for a given species). Wider Countryside Butterfly Survey (WCBS) sites are thus excluded because they are based on very few visits from which indices of abundance are not calculated. For transect sites, a statistical model (a General Additive Model, 'GAM') is used to impute missing values and to calculate a site index. Each year most transect sites (over 90%) produce an index for at least one species and in recent years site indices have been calculated for over 2,000 sites across the UK. Site indices are subsequently collated to contribute to the overall 'Collated Index' for each species, which are relative measures of the abundance of each species across a geographical area, for example, across the whole UK or at country level for England, Scotland, Wales or Northern Ireland. Individual site indices are important in informing conservation management as not all sites show the same patterns for each species and likely reflect a combination of local climate and habitat management at the site. The UK Butterfly Monitoring Scheme is organized and funded by Butterfly Conservation (BC), the UK Centre for Ecology & Hydrology (UKCEH), the British Trust for Ornithology (BTO), and the Joint Nature Conservation Committee (JNCC). The UKBMS is indebted to all volunteers who contribute data to the scheme. This work was supported by the Natural Environment Research Council award number NE/R016429/1 as part of the UK-SCAPE programme delivering National Capability. Full details about this dataset can be found at https://doi.org/10.5285/1286b858-34a7-4ff2-84a1-a55e48d63e86

本数据集收录了源自英国蝴蝶监测方案（UKBMS）数据的英国蝴蝶物种的个体栖息地指数。栖息地指数并非对种群规模的绝对度量，而是一种相对度量，其与更密集的种群规模度量方法（如标记、释放、重捕（MRR）方法）密切相关。栖息地指数可视为种群规模的相对度量，它大致是现有蝴蝶数量的一个恒定比例。观察到的比例可能因物种而异；某些蝴蝶物种较为显眼，因此更容易被察觉，而其他物种则较为不易发现。栖息地指数仅计算在季节内进行足够监测访问的栖息地，或针对有针对性的降低努力程度的调查（定时观察、幼虫网计数和卵计数）的地点，其中计数通常在飞行高峰期尽可能接近时进行，并随后根据年份和时间以及栖息地规模（针对特定物种的适宜栖息地类型面积）进行调整。因此，更广泛的乡村蝴蝶调查（WCBS）站点被排除在外，因为它们基于非常少的访问，无法计算丰度指数。对于横断面站点，使用统计模型（一般加性模型，GAM）来插补缺失值并计算栖息地指数。每年大多数横断面站点（超过90%）至少为一种物种产生一个指数，近年来，英国已有超过2000个站点计算了栖息地指数。随后，将这些栖息地指数汇总，以贡献于每个物种的整体汇总指数，这些指数是某一地理区域内每种物种丰度的相对度量，例如，在整个英国或英格兰、苏格兰、威尔士或北爱尔兰的国家层面。个体栖息地指数对于提供信息以支持保护管理至关重要，因为并非所有站点对每种物种都显示出相同的模式，并且可能反映了当地气候和栖息地管理条件的综合影响。英国蝴蝶监测方案由蝴蝶保护组织（BC）、英国生态与水文中心（UKCEH）、英国鸟类信托基金会（BTO）和联合自然保护委员会（JNCC）组织并资助。UKBMS对为该方案提供数据的所有志愿者表示感谢。本工作得到了自然环境研究委员会（NERC）资助项目编号NE/R016429/1的支持，作为英国-SCAPE项目的一部分，该项目旨在提供国家能力。有关本数据集的详细信息，请参阅https://doi.org/10.5285/1286b858-34a7-4ff2-84a1-a55e48d63e86。