Life history characteristics and genetic variation in an expanding species, Pogonatum dentatum.

Abstract

The main objective of this thesis is to get a better understanding of the processes behind species range expansions and the consequences for variation in life history characters and genetic variation. The thesis focuses on the recent expansion of the bryophyte Pogonatum dentatum, a species native in the alpine region of Fennoscandia, which has expanded its range down into the lowland area.

The specific aims are:

I. To investigate if there are differences in life history strategies between the contrasting areas in i) age and size at maturity, ii) age and stage structure of female and male patches, iii) number of spores per capsule, iv) size of spores, v) reproductive investment and vi) resource allocation.

II. To investigate if differences in life history characters are due to phenotypic plasticity or genetic diversification in i) age and size of sporophyte producing female shoots and ii) sexual reproductive investment in relation to branching, age and size.

III. To investigate genetic variation and genetic structure in the native area and the recently colonised area by using ISSR (inter-simple sequence repeats) molecular markers.