Conservation Genetics of the orange-fronted kākāriki(Cyanoramphus malherbi) (2013)
Type of ContentTheses / Dissertations
Thesis DisciplineBiological Sciences
Degree NameMaster of Science
PublisherUniversity of Canterbury. Biological Science
AuthorsAndrews, B. Janeshow all
The critically endangered orange fronted kākāriki!(Cyanoramphus malherbi)is an endemic parakeet restricted to three small breeding populations within the Hawdon, Hurunui and Poulter Valleys of North Canterbury, four translocated populations on offshore islands and a captive breeding facility in Christchurch. Seventeen polymorphic microsatellite loci were developed from next generation 454 sequencing of genomic DNA. At the commencement of this project, only birds sourced from the Hawdon and Hurunui populations had been used in the captive and translocated populations. To determine appropriate source populations for future translocation, this study used both nuclear and mitochondrial data to quantify the level of genetic diversity within, and the pattern of genetic differentiation among, the three remaining wild populations of C. malherbi. Six C. malherbi of known provenance from each of the three populations were genotyped at the 17 microsatellite loci and one microsatellite! loci previously developed for the closely related Forbe’s parakeet (C., forbesi), and sequenced at one mitochondrial (cytochrome b) and one nuclear exon (RAGT1). For each valley, the number of microsatellite alleles ranged from one to four per locus. Observed and expected heterozygosities ranged from 0.0 to 1.0 and from 0.17 to 0.74, respectively. The Poulter valley had the highest average allelic diversity (2.3) and the highest average observed and expected heterozygosities (0.40 & 0.38, respectively). Weak but significant population genetic structure was detected among valleys (FST= 0.06, F’ST=0.09,p=0.04). Pairwise FST estimates identified the Hurunui as being significantly different from both the Poulter and Hawdon Valleys (FST=0.11, p=0.01 and 0.061,p<0.01,respectively). In contrast, STRUCTURE analysis indicated that the three valleys comprise a single genetic cluster. Three cytochrome b haplotypes were identified, two of which were found in all three populations and one haplotype that was present in one Poulter valley individual only. Two RAG1 alleles were identified, both of which were shared by all three valleys. No significant population genetic structure was detected for either the cytochrome b or RAG 1 loci. These combined data suggest that the three North Canterbury valleys function as a metapopulation with some level of connectivity. The same nuclear and mitochondrial markers were used to determine the genetic distinctiveness of sympatric C. malherbi and C.auriceps North Canterbury populations and identify putative cryptic hybrids from the now extinct Hope Valley population. Based on both cytochrome b and microsatellite markers, C. malherbi and C.auriceps were found to be genetically distinct!(ϕST=p<0.01; FST=0.073,p< 0.01;K=2), and the two Hope Valley birds were confirmed to be hybrids. These findings lend support to the hypothesis that when one species is rare and the other abundant, limited hybridisation between sympatric populations of C.malherbi and C.auriceps is possible. Overall, this thesis has provided useful genetic tools and information to inform active conservation management of captive and translocated populations of C.malherbi. Based on my conclusions, I recommend the inclusion of individuals from each of the three source populations within the captive breeding and translocated populations to conserve current levels of genetic diversity. In addition, to ensure the genetic integrity of C.malherbi, I strongly recommend the use of these molecular methods to accurately identify all individuals prior to entering the captive breeding and translocation programmes. I also recommend the on going genetic monitoring and management of captive and translocated populations to guide future conservation management of this critically endangered kākāriki.