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AG Trillmich
AG Krüger
AG Bischof
AG Steinfartz
AG von Engelhardt
AG Hoffman
I am interested in the population, evolutionary and conservation genetics of natural populations. My empirical work focuses mainly on marine mammals, birds and invertebrates, with a strong Antarctic emphasis. My interests include mating system evolution and the relationship between genetic heterozygosity and fitness. Applied aspects of my work include the assessment of population connectivity in threatened species, the use of genetic tracking to construct individual life-histories and demographic reconstruction using genetic data. I am also increasingly interested in the development and application of 'next-generation' approaches to wild animal populations. My research activities can be summarised by the following 'Wordle' based on the titles of my publications (last updated in 2013).
Pinnipeds are notoriously difficult to study, being semi-aquatic, often highly agressive and breeding in remote and densely-packed colonies. However, my collaborators at the British Antarctic Survey (BAS) have constructed a scaffold walkway above a colony of Antarctic fur seals at Bird Island, South Georgia, allowing all of the animals that come ashore to be studied without disturbing the colony as a whole. Over the past 15 years, genetic samples have been collected and analysed to discover the parentage of over a thousand pups. A remarkable picture of breeding behaviour has emerged. The most successful males appear to arrive first in the colony, stay for more days per season and come ashore for more seasons in total. However, although the traditional picture is one in which males fight each other for access to females, the opposite appears to be true; males stay rooted to the spot while females appear to actively choose their partners. We have also shown that vitrually every aspect of individual fitness examined to date, ranging from territory-holiding ability, body size, reproductive success and attractiveness in males to early survival and accession to breeding in females, correlates with genetic heterozygosity. Consequently, a recent focus of this study has been to develop genomic tools with which to explore this phenomenon in more detail.
I am also involved in collaborative research on several other pinniped species, including Steller’s sea lions (Eumetopias jubatus), grey seals (Halichoerus grypus), harbour seals (Phoca vitulina) and South American fur seals (Arctocephalus australis). My genetic work on Steller’s sea lions, for example, has revealed a clear phylogenetic break within the range of this threatened 'flagship' species. This finding supports previous mitochondrial DNA studies revealing two discrete stocks, and has implications for conservation because the two stocks show opposite growth trajectories.
Mating systems and parental behaviour are among the most diverse of social behaviours, and recent work suggest that they can be influenced by the social environment. Small plovers (Charadrius spp.) exhibit diverse mating systems, ranging from monogamy to polygyny. Consequently, Oliver Krueger, Tamás Székely and I are studying populations of three species in Magagascar, using a combination of molecular genetic and demographic modeling approaches to test whether breeding systems are influenced by the social environment.
I am also interested in the application of nuclear markers including Amplified Fragment Length Polymorphisms (AFLPs) to organisms for which no genomic resources are available. Applying these techniques to poorly understood Antarctic marine invertebrates including the widespread and abundant Antarctic limpet (Nacella concinna) has revealed insights into biotic and abiotic processes that drive population structure over both coarse and fine spatial scales.
As I am currently building up a research group in Bielefeld, I would very much welcome applications from students or postdocs who would like to work with me. If you are interested in any of the research topics described above, or have your own ideas for related projects, please contact me at: joseph.hoffman (at) uni-bielefeld.de
