Combining spawn egg counts,individual photo-ID and genetic fingerprinting to estimate the population size and sex ratio of an endangered amphibian  

作　　者：Marina REYNE Sarah HELYAR Aurélie AUBRY Mark EMMERSON Ferdia MARNELL Neil REID 

机构地区：[1]School of Biological Sciences,Queen’s University Belfast,Belfast,UK [2]Institute of Global Food Security(IGFS),Queen’s University Belfast,Belfast,UK [3]Agri-Food&Biosciences Institute(AFBI),Hillsborough,UK [4]National Parks&Wildlife Service(NPWS),Dublin,Ireland

出　　处：《Integrative Zoology》2021年第2期240-254,共15页整合动物学（英文版）

基　　金：This study was part of a larger monitoring and surveillance project commissioned and funded by the National Parks and Wildlife Service(NPWS);Department of Culture,Heritage and the Gaeltacht(CHG);Republic of Ireland.Natterjack toads were collected under Government license(No.C098/2016).

摘　　要：According to the International Union for Conservation of Nature Red List,41%of the world’s amphibian species are threatened with extinction,making them more threatened than any other vertebrate group nowadays.Given the global amphibian crisis,comprehensive understanding of demographics and population trends of declining and threatened species is essential for effective management and conservation strategies.Counting egg spawns is widely used to assess population abundance in pond breeding anurans.However,it is unknown how such counts translate into robust population size estimations.We monitored the breeding activity of the Natterjack toad(Epidalea calamita),combining egg string counts and individual photo-identification with Capture-Mark-Recapture population size and operational sex ratio estimation.Male Natterjack toads were identified by the pattern of natural markings with repeated ID of the same individual confirmed for 10%of the samples using genetic fingerprinting.We identified 647 unique individuals within a closed study population at Caherdaniel,Co Kerry.Population estimates derived from egg string counts estimated a breeding population of 368 females(95%CI 353–384)and Capture-Mark-Recapture estimated a breeding population of 1698 males(95%CI 1000–2397).The female:male sex ratio was conservatively estimated at 1:5(95%CI 1:3–1:6)where 62%±6%of females were assumed to spawn.These substantially departed from any priori assumption of 1:1 which could have underestimated the breeding population by up to 72%.Where amphibian absolute population size estimation is necessary,methods should include empirical survey data on operational sex ratios and not rely on assumptions or those derived from the literature which may be highly population and/or context-dependent.

关 键 词：Epidalea calamita genetic fingerprinting MARK-RECAPTURE Natterjack toad PHOTO-IDENTIFICATION 

分 类 号：Q95[生物学—动物学]