Chapter 2. Outlines of the study

Ecological knowledge regarding the lesser white-fronted goose has grown during the period 1996-1999 when part of the conservation work was funded by the LIFE Fund of the European Union. The primary aim of the present work has been to add a genetic perspective to the conservation plan. Genetic data offer insights not otherwise obvious.

At the species level the phylogenetic relationships of seven Anser goose species, including the lesser white-fronted goose, were studied (II). This provided a phylogenetic framework for understanding genetic diversity.

At the population level, the genetic structuring of the lesser white-fronted goose was studied (III). When this part of the project was planned, virtually nothing was known about the migratory flyways and staging/wintering areas of the lesser white-fronted goose, with the exception of some old ringing recoveries and observations (reviewed in Lorentsen et al. 1999). This information is still fragmentary, especially regarding wintering areas of the western population. The genetic study made it possible to estimate the amount of female gene flow among the breeding localities and the colonization history of the species. Additionally, this work contributes to basic knowledge of the phylogeography of Palearctic species.

For practical conservation purposes, the genetic composition of a captive lesser white-fronted goose stock was studied (IV) in light of the results from a wild population. According to the guidelines of the Re-introduction Specialist Group of the IUCN’s Species Survival Commission, reintroduction and restocking should be carried out using individuals of the same type as the original wild population. This, together with the ambiguous history of the captive population and the results from population genetic structure of the wild population (III), was the motivation for studying the genetic background of the captive lesser white-fronted goose stock.

During this project, both the characteristics and limitations in the use of mtDNA as a genetic marker became obvious. Although the discussion regarding clonal inheritance and possible recombination of mtDNA continue to be debated, other characteristics of mtDNA need to be (re)considered. These include e.g. the applicability of the molecular clock and the variation in the mutation rate among different parts of mtDNA. In addition to sequences analysed in our group, further support was obtained by using sequences from GenBank. Therefore, in I mtDNA control region and cytochrome β sequences from altogether 68 avian species fetched from the GenBank were used to characterise mtDNA as a genetic marker.