Biology subjects

O'Meara, D. B.

Publications and source records attributed to O'Meara, D. B..

2 recordsLinked to original sources

bioRxiv2022

Invasive genetic rescue: Dispersal following repeated culling reinforces the genetic diversity of an invasive mammal

Since its introduction from the United States in 1876 the invasive North American Eastern grey squirrel (Sciurus carolinensis) has contributed to the decline of the native Eurasian red squirrel (Sciurus vulgaris) in Britain. Consequently, grey squirrel populations are often subjected to extensive control efforts in order to reduce local abundance and prevent spread, particularly within habitats containing red squirrels. Grey squirrel removal from the island of Anglesey off the coast of north Wales began in 1998 and was completed in 2013. A parallel successful red squirrel reinforcement translocation project also took place. The narrow sea-channel, road and rail bridge connection has meant that the adjacent mainland grey squirrel population has been controlled in subsequent years to reduce the probability of re-invasion. The aim of this study was to assess the overall impact of repeated culling efforts carried out between 2011 and 2020 on the genetic diversity of the grey squirrel population in north Wales to inform future adaptive management plans. Using a combination of mitochondrial DNA (mtDNA) and microsatellite DNA analysis, we found high genetic diversity in both marker types, with six diverse mtDNA haplotypes found and relatively high levels of nuclear genetic diversity, even after repeated culling efforts. Our results suggest that ongoing culling efforts may not adequately reduce genetic diversity to a level where it contributes to a long-term population decline.

ecology↗

bioRxiv2021

Primer biases in the molecular assessment of diet in multiple insectivorous mammals

Our understanding of trophic interactions of small insectivorous mammals has been drastically improved with the advent of DNA metabarcoding. The technique has continued to be optimised over the years, with primer choice repeatedly being a vital factor for dietary inferences. However, the majority of dietary studies examining the effect of primer choice often rely on in silico analyses or comparing single-niche species. Here we apply DNA metabarcoding to empirically compare the prey detection capabilities of two widely used primer sets when assessing the diets of a flying (lesser horseshoe bat; Rhinolophus hipposideros) and two ground dwelling insectivores (greater white-toothed shrew; Crocidura russula and pygmy shrew; Sorex minutus). Although R. hipposideros primarily rely on two prey orders (Lepidoptera and Diptera), the unique taxa detected by each primer shows that a combination of primers may be the best approach to fully describe bat trophic ecology. However, random forest classifier analysis suggest that one highly degenerate primer set detected the majority of both shrews diet despite higher levels of host amplification. The wide range of prey consumed by ground-dwelling insectivores can therefore be accurately documented from using a single broad-range primer set, which can decrease cost and labour. The results presented here show that dietary inferences will differ depending on the primer or primer combination used for insectivores occupying different niches (i.e. hunting in the air or ground) and demonstrate the importance of performing empirical pilot studies for novel study systems.

ecology↗