Calculation of collated indices of abundance of butterflies based on monitored sites
Calculation of collated indices of abundance of butterflies based on monitored sites
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根据监测点计算蝴蝶丰度整理指数
DOI：
10.1111/j.1365-2311.1993.tb01083.x
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发表时间：
1993
影响因子：
2.2
通讯作者：
E. Pollard
中科院分区：
文献类型：
--
作者：
D. Moss;E. Pollard
抽象的。1蝴蝶监测计划利用固定地点的定期样带计数来确定联合王国蝴蝶物种丰度的年度指数。到目前为止，每一物种的整理指数的年度变化都是以所有参与地点的总数之和的简单比率计算的。2.提出了一种计算整理指数的修正方法，该方法对立地值进行对数变换，以降低物种数最多的立地对指数的影响。零计数与非零值一起处理。另一种方法，使用几何平均值的比率也检查。3将对数变换法计算的指数与传统方法计算的指数进行了比较。两个内部测试的依赖性整理指数的网站上最高丰度。另一项评价采用回归分析，分析温度和降雨量对蝴蝶数量整理指数的影响。[4]第一次内部检验表明，对数变换降低了27个物种中25个物种的整理指数对最高丰度地点的依赖性;而第二次检验显示，42个物种中26个物种的指数降低，一个物种的指数增加。温度变量的显着回归的数量增加，使用对数转换从11%到13%的测试，从10%到11%的降雨量。5几何平均比率法在处理零值时引入了相当大的偏差，对此没有补救办法。6尽管使用对数变换计算的修订后的整理指数与传统计算值大致相当，但对种群最丰富的地点的依赖性的减少使修订后的指数更少受到当地“噪音”的干扰，因此更适合研究影响蝴蝶丰度的因素。
Abstract. 1 The Butterfly Monitoring Scheme uses regular transect counts on fixed sites to establish annual indices of abundance of butterfly species in the United Kingdom. The annual change in collated index for each species has hitherto been calculated as a simple ratio between total counts summed over all participating sites. 2 A revised method for calculation of collated indices is proposed, which applies a logarithmic transformation to site values so as to downweight the influence on the index of the sites with greatest numbers of a species. Zero counts are handled comparably with non‐zero values. An alternative method using geometric mean ratios is also examined. 3 Indices calculated using the logarithmic transformation are compared with those calculated using the traditional method. Two internal tests of dependency of collated indices on the sites with highest abundance are made. Another evaluation uses regression analysis for the effects of temperature and rainfall on collated indices of butterfly abundance. 4 The first internal test shows that logarithmic transformation reduces the dependence of the collated index on the sites of highest abundance for twenty‐five out of twenty‐seven species examined; while a second test shows a reduction for twenty‐six out of forty‐two species, and an increase for one species. The number of significant regressions on temperature variables increases with the use of the logarithmic transformation from 11% to 13% of tests made, and on rainfall from 10% to 11%. 5 The geometric mean ratio method introduces considerable biases in its treatment of zero values, for which a remedy is not available. 6 Although the revised collated indices calculated using logarithmic transformation are broadly comparable with traditionally calculated values, the reductions in dependency on sites with the most abundant populations render the revised indices less subject to perturbation due to local ‘noise’, and so more suitable for research on factors influencing butterfly abundance.