United Kingdom Butterfly Monitoring Scheme: site indices 2022

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.

本数据集包含英国蝴蝶物种的单个站点指数，这些指数由英国蝴蝶监测计划（UK Butterfly Monitoring Scheme，UKBMS）的数据计算得出。站点指数是种群规模的相对度量而非绝对度量，且已被证明与其他更密集的种群规模度量（如标记-释放-重捕（mark, release, recapture，MRR）方法）密切相关。站点指数可视为种群规模的相对度量，大致为存在的蝴蝶数量的恒定比例。观测到的比例可能因物种而异；有些蝴蝶物种更显眼，因此更容易被发现，而另一些则难以观测。
站点指数仅在整个季节有足够监测访问的站点计算，或针对针对性低投入调查（定时观测、幼虫网计数和卵计数）计算，这些调查的计数通常尽可能接近飞行期峰值获取，并随后根据年度时间和站点规模（特定物种的适宜栖息地面积）进行调整。广义乡村蝴蝶调查（Wider Countryside Butterfly Survey，WCBS）的站点因此被排除，因为它们基于极少的访问，无法计算丰度指数。对于样带站点，使用统计模型（广义相加模型（General Additive Model，GAM））来插补缺失值并计算站点指数。每年，大多数样带站点（超过90%）会生成至少一个物种的指数，近年来英国全国已有超过2000个站点计算了站点指数。
站点指数随后被汇总，以形成每个物种的整体“汇总指数（Collated Index）”，该指数是每个物种在地理区域（例如全英国或英格兰、苏格兰、威尔士或北爱尔兰的国家层面）丰度的相对度量。单个站点指数对指导保护管理至关重要，因为并非所有站点对每个物种都呈现相同模式，且可能反映了站点局部气候与栖息地管理的综合影响。
英国蝴蝶监测计划由蝴蝶保护组织（Butterfly Conservation，BC）、英国生态与水文中心（UK Centre for Ecology & Hydrology，UKCEH）、英国鸟类学信托基金（British Trust for Ornithology，BTO）和联合自然保护委员会（Joint Nature Conservation Committee，JNCC）组织并资助。UKMS感谢所有为该计划贡献数据的志愿者。
本研究由自然环境研究委员会（Natural Environment Research Council）资助，项目编号NE/R016429/1，是英国环境科学能力计划（UK-SCAPE）的一部分，旨在提供国家层面的环境评估能力。