The paradox of invasion: R eeves' muntjac deer invade the B ritish I sles from a limited number of founding females

A centenary tale: population genetic insights into the introduction history of the oriental fire-bellied toad (Bombina orientalis) in Beijing

Background

The successful establishment of a species population following a single introduction of a few individuals to a non-native area has been limited. Nevertheless, the oriental fire-bellied toad (Bombina orientalis) population in Beijing is purportedly descended from a single introduction of about 200 individuals translocated from Yantai, Shandong Province, China, in 1927.

Results

To resolve the introduction process and to understand the genetic consequences since that introduction approximately 90 years ago, we investigated the population’s genetic diversity and structure using 261 toads from Beijing and two native Shandong populations and inferred the species’ introduction history using simulation-based approaches. Analysis of mitochondrial DNA (mtDNA) sequences showed the two haplotypes found in Beijing nested within Yantai haplotypes, thus corroborating the historical record of the translocation source. The mtDNA and 11 nuclear microsatellite markers revealed both considerably lower genetic diversity in Beijing than in the source population and strong genetic differentiation between them. Although the current census population in Beijing may be in the range of a few thousand, the effective population size was estimated at only 20–57. Simulations also suggest that this population may have descended from 40–60 founders.

Conclusions

The Beijing population’s genetic patterns were consistent with the consequences of a severe bottleneck during introduction followed by genetic drift. The introduction trajectory constructed for this B. orientalis population reveals the genetic footprints of a small population sustained in isolation for nearly a century. Our results provide an intriguing example of establishment success from limited founders and may inform ex situ conservation efforts as well as the management of biological invasions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12862-022-02072-z.

Reeves’ muntjac populations continue to grow and spread across Great Britain and are invading continental Europe

The appropriate response for controlling an invasive non-native species depends on the extent to which its invasion has progressed, which can be revealed by information on its distribution and abundance. Reeves’ muntjac is a native deer to China and Taiwan, but has been introduced and become well-established in Great Britain. Moreover, in recent years, reports and verified records in the wild from other European countries have become more frequent. We reviewed the status of Reeves’ muntjac in Britain and evaluated its national range expansion from 2002 to 2016. While the British population appears to have tripled in size since 1995, the rate at which it has expanded its range seems to have peaked at approximately 12% per year between 2002 and 2005 and has since declined. We also consolidated observations on its international distribution, including a conservative evaluation of its presence in zoological collections. We predict that this species could expand its range to include every European country, although the availability of suitable landcover and climate is likely to vary substantially between countries. To prevent the significant impacts to conservation interests that have been observed in Great Britain from extending across Europe, national administrations should consider eradicating Reeves’ muntjac while that is still feasible.

Detection of a novel gammaherpesvirus (genus Rhadinovirus) in wild muntjac deer in Northern Ireland

This study represents the initial part of an investigation into the potential for non-native, wild, free-living muntjac deer (Muntiacus reevesi) to carry viruses that could be a threat to livestock. A degenerate PCR assay was used to screen a range of tissues from muntjac deer culled in Northern Ireland for the presence of herpesviral nucleic acids. This was followed by sequencing of PCR amplicons and phylogenetic analysis. We report the detection of a novel gammaherpesvirus most closely related to a type 2 ruminant rhadinovirus from mule deer. It remains to be determined if this new virus is pathogenic to deer or presents a risk to food security through the susceptibility of domestic livestock.