Rapid assessment for a new invasive species threat: the case of the Gambian giant pouched rat in Florida.
Wildlife Research 33: 439–448.
The Gambian giant pouched rat (Cricetomys gambianus) is a large rodent that has established a breeding population in the Florida Keys. Should it successfully disperse to mainland Florida, it could continue spreading through much of North America where significant negative ecological and agricultural consequences could result. We rapidly developed the information for implementing an efficient and successful eradication program before dispersal to the mainland occurs. This included development of monitoring and indexing methods and their application to define the animal’s range, the development of baits attractive to Gambian giant pouched rats, efficacy testing of toxicants, and development of bait-delivery devices that exclude native animals. Gambian giant pouched rats appeared confined to the western two-thirds of Grassy Key, but have dispersed across a soil-filled causeway west to Crawl Key. We identified preferred habitat characteristics and potential dispersal pathways. We developed photographic and tracking tile methods for detecting and indexing Gambian giant pouched rats, both of which work well in the face of high densities of non-target species. We identified a commercial anticoagulant bait and we developed a zinc phosphide (an acute toxicant) bait matrix that were well accepted and effective for controlling Gambian giant pouched rats. We also developed a bait station for delivering toxic bait to Gambian giant pouched rats without risk to native species. We consider that the criteria are met for a successful eradication to commence.
Introduced Swedish Canada Geese (Branta canadensis) have low levels of genetic variation as revealed by DNA fingerprinting.
Journal of Evolutionary Biology 8(2):195-207. ISSN 1010-061X.
The Swedish, Finnish and Norwegian population of Canada geese (Branta canadensis), now amounting to some 30-50000 birds, was founded by only five individuals. We used DNA fingerprinting to assess the level of genetic variability.
Conservation genetics of native and European-introduced Chinese water deer (Hydropotes inermis).
Zoological Journal of the Linnean Society 191(4): 1181–1191.
Sufficient genetic variation is vital for the long-term survival of a population. The adaptive potential and reproductive fitness of a population is generally enhanced by greater levels of genetic diversity, while loss of genetic variation in small populations may increase extinction risk due to disease susceptibility and decreased reproductive fitness. Determining levels of genetic diversity in threatened species can, therefore, help inform conservation strategies. The Chinese water deer (Hydropotes inermis) is classified as Vulnerable in its native range on the IUCN Red List, and populations in Korea and mainland China have declined drastically in recent years. However, the species was introduced to Europe about a century ago and populations there now make up over 40% of global numbers. To infer the population genetic structure and genetic diversity of Chinese water deer both in their native China and in populations introduced to the UK and France, variation in mitochondrial DNA was investigated for over 100 individuals (92 cytochrome b and 106 control region sequences). Our results reveal lower levels of genetic diversity in the British populations, differentiation between native and introduced populations, and that the source population of British deer is likely to be extinct. Recommendations are made for the conservation of populations.
Impact of genomic leakage on the conservation of the endangered Milky Stork.
Biological Conservation 229(e1400253). DOI:10.1016/j.biocon.2018.11.009
Siehe auch Zeitungsartikel: https://www.eurekalert.org/news-releases/623399
Endangerment and extinction of threatened populations can often be accelerated by genomic contamination through infiltration with alien alleles. With a growing anthropogenic footprint, many such hybridization events are human-mediated. The Milky Stork (Mycteria cinerea) is one such species whose genomic composition is threatened by human-mediated hybridization with its sister taxon, the Painted Stork (Mycteria leucocephala). A comprehensive investigation of the stork population in Singapore using three complementary population-genomic approaches revealed a large proportion of hybrids that have undergone several generations of genomic leakage from Painted Storks and fall along a genetic cline that closely mirrors a phenotypic cline from pure Milky to pure Painted. Although originating from a limited number of introduced Painted Storks, these hybrids are now an integral part of both the wild and captive Singaporean and southern peninsular Malaysian stork population. Genetically informed conservation management including the isolation of hybrids in captivity and a strict removal of hybrids from the wild along with a release of genetically pure Milky Storks is imperative for continued survival. Similar approaches must become routine in endangered species conservation as human-mediated hybridization increases in volume.