Will predicted positive effects of climate change be enough to reverse declines of the regionally Endangered Natterjack toad in Ireland?

Abstract

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Landscape genetics identifies barriers to Natterjack toad metapopulation dispersal

“…This was confirmed by landscape genetic analysis, where resistance distances based on habitat explained Natterjack toad genetic structure and gene flow better than Euclidian distance alone. None of the climate variables were selected in the final models suggesting that restrictions to gene flow imposed by differences in climatic conditions may operate on a larger scale than those related to land cover and anthropogenic pressure (Reyne 2021a). Analysis suggested spatial genetic structuring with three main clusters separated by distance and unfavourable habitat: (i) Magharees, Castlegregory Golf Course (CGC) and Lough Gill; (ii) Killeen and Roscullen; (iii) Inch, Dooks, Dooks Golf Club (DGC), Nambrackdarrig, Yganavan, Quarry and Glenbeigh.…”

“…This study aimed to investigate the role of geographic distance, climate, habitat, geographical features, and anthropogenic pressure in determining the spatial genetic structure of a species of conservation concern in Ireland, the Natterjack toad (Epidalea calamita (King et al 2011). The species is widely distributed over much of southwest and central Europe, inhabiting environments with a wide range of climatic and habitat conditions including human-modified landscapes like agricultural land and quarries (Reyne et al 2021a). However, the species is often associated with open habitats on sandy substrates with shallow, ephemeral ponds for breeding (Beebee 1979).…”

“…To halt the Natterjack toad decline, the National Parks and Wildlife Service (NPWS) initiated a 'Pond Creation Scheme' in 2008 installing over 100 artificial ponds on agricultural grasslands throughout the Natterjack toad range. Only artificial ponds in close proximity to natural breeding pools had been colonised by 2018 (Reyne et al 2019(Reyne et al , 2021a. Consequently, the NPWS initiated a Natterjack toad 'Head-start and Reintroduction Programme' in 2016 by collecting egg strings/tadpoles annually to raise toadlets in captivity before release back into the wild as part of assisted migration and translocation to newly created ponds.…”

Population genetic structure of the Natterjack toad (Epidalea calamita) in Ireland: implications for conservation management

“…Hence, shifts towards genome-wide single nucleotide polymorphisms (SNPs) or a combined approach can Pond breeding amphibians are predisposed to lower levels of genetic variation compared to other taxa resulting from high amplitude fluctuations in population size (Alford and Richards 1999;Newman and Squire 2001). For example, the Natterjack toad typically breeds in ephemeral ponds where breeding success can depend on stochastic climatic (Beebee and Griffiths 2000;Baker et al 2011;Smith and Skelcher 2019;Reyne et al 2021b). However, small, declining amphibian populations have been shown to retain high genetic diversity, for example, the black toad (Bufo exsul, Wang 2009), the critically endangered Montseny brook newt (Calotrina arnoli, Valbuena-Ureña et al 2017) and the Hula painted frog (Latonia nigriventer, Perl et al 2018), considered to be one of the world's rarest amphibians.…”

Conservation efforts fail to halt the decline of the regionally endangered Natterjack toad (Epidalea calamita) in Ireland

“…Other methods like eDNA (Reyne et al 2021) could be used to monitor artificial pond colonisation rate by detecting species presence before field signs of colonisation (breeding) are observed.…”