A survey of the hybridisation status of Cervus deer species on the island of Ireland

Abstract

Red deer (Cervus elaphus) did not recolonise Ireland after the last glaciation, but the population in Co. Kerry is descended from an ancient (c. 5000 BP) introduction and merits conservation. During the mid-19th century exotic species including North American wapiti (C. canadensis) and Japanese sika deer (C. nippon nippon) were introduced to Ireland, mainly via Powerscourt Park, Co. Wicklow. While wapiti failed to establish, sika thrived, dispersed within Co. Wicklow and were translocated to other sites throughout Ireland. Red deer and sika are known to have hybridised in Ireland, particularly in Co. Wicklow, but an extensive survey with a large, highly diagnostic marker panel is required to assess the threat hybridisation potentially poses to the Co. Kerry red deer population. Here, 374 individuals were genotyped at a panel of 22 microsatellites and at a single mtDNA marker that are highly diagnostic for red deer and Japanese sika. The microsatellites are also moderately diagnostic for red deer and wapiti. Wapiti introgression was very low [trace evidence in 2 (0.53 %) individuals]. Despite long-standing sympatry of red deer and sika in the area, no red deer-sika hybrids were detected in Co. Kerry suggesting strong assortative mating by both species in this area. However, 80/197 (41 %) of deer sampled in Co. Wicklow and 7/15 (47 %) of deer sampled in Co. Cork were red-sika hybrids. Given their proximity and that hybrids are less likely to mate assortatively than pure individuals, the Co. Cork hybrids pose a threat to the Co. Kerry red deer.

Widespread hybridization in the introduced hog deer population of Victoria, Australia, and its implications for conservation

“…The time of divergence between chital and Axis porcinus occurred during the Pliocene, approximately 2.6 Mya, and a number of mitochondrial haplotypes exclusive to each species have been detected, as seen in the haplotype network presented in this study (Gilbert et al, 2006;Gupta et al, 2018;Hassanin et al, 2012). The presence of these species-specific haplotypes suggests that incomplete lineage sorting is unlikely to be a factor in- (Smith, Carden, Coad, Birkitt, & Pemberton, 2014;Smith et al, 2018). In both cases, hybridization occurs between the female of the larger deer species (chital and red deer) and the male of the smaller deer species (hog deer and sika deer), and with males generally being the larger sex this hybridization pattern may be reflective of the phenotypic limitations that the reciprocal cross would present.…”

“…These have typically arisen from the mating of a male hog deer with a female chital, as seen in the present study with the presence of chital haplotypes in the maternally inherited mitochondrial genome. Similar unidirectional hybridization has been reported in red deer and sika deer hybrids, with genetic contributions from female red deer and male sika deer being reported a majority of the time when analyzed throughout Ireland and the UK (Smith, Carden, Coad, Birkitt, & Pemberton, ; Smith et al, ). In both cases, hybridization occurs between the female of the larger deer species (chital and red deer) and the male of the smaller deer species (hog deer and sika deer), and with males generally being the larger sex this hybridization pattern may be reflective of the phenotypic limitations that the reciprocal cross would present.…”

Human‐mediated introduction of introgressed deer across Wallace's line: Historical biogeography of Rusa unicolor and R. timorensis

“…Occurrence of such hybridization had been documented before, namely between R. timorensis individuals introduced to Borneo with the local Bornean R. unicolor (West Kalimantan, now possibly extinct, Hedges et al., ) and attained through husbandry before (Leslie, ). Hybridizations with fertile offspring have also been reported to occur between other deer species, among others between sambar and red deer Cervus elaphus (Muir et al.,) and red deer and Sika Cervus nippon (Smith, Carden, Coad, Birkitt, & Pemberton, ).…”

“…Hedges et al, 2015) and attained through husbandry before (Leslie, 2011). Hybridizations with fertile offspring have also been reported to occur between other deer species, among others between sambar and red deer Cervus elaphus (Muir et al,1997) and red deer and Sika Cervus nippon (Smith, Carden, Coad, Birkitt, & Pemberton, 2014).…”

Genomic variation across cervid species in respect to the estimation of red deer diversity

“…Through hunting, habitat degradation, domestication and translocation, humans have brought many non-native species into contact with native heterospecifi cs, leading to anthropogenically induced hybridisation that can cause signifi cant losses in the economic value of native genetic resources [5,6]. Despite the world distribution of Cervidae family half of the species are currently considered as endangered or extinct in the world [7,8].…”