Impact of human activity on species diversity, spatial genetic structure, and genetic diversity of P. alba in P.alba-communities
Abstract
Species in nature do not live separated. They rather live in communities, which are tightly linked with the abiotic environment forming an ecosystem. Human activities such as exotic species introductions, river modifications, and clear-cuts are widespread and might influence the natural community/ecosystem composition, structure, function and thus their further evolution. Trees represent foundation species of forest communities, which “drive” the structure of communities by creating locally stable conditions for other species. They have developed two different reproductive strategies, sexual and asexual allowing them to resist to human and natural disturbances. Asexual reproduction allows safe colonisation of new habitats as well as fast regeneration after disturbances. Sexual reproduction compensates for the loss in genetic diversity brought upon by asexual reproduction and natural selection. Species hybridization followed by introgression is another phenomenon, which increases intraspecific genetic diversity. The plasticity of the reproductive strategy, the ability to hybridize and the tight connections between species within a community make some tree species highly dynamic in ecosystems. This project focuses on Populus alba L. (white poplar) and P. alba communities in the Danube river valley. The following characteristics make this species ideal to study interaction between human activity, the hybridization and the reproductive strategy: (1) P. alba is under strong selection of two forces; the river and human activity, (2) it possesses both reproductive strategies, (3) it is dioecious, (4) it hybridizes easily and its natural hybrid P. × canescens lives in sympatry with P. alba, (5) it has favourable genetic characteristics, and (6) both managed and unmanaged types of P. alba communities have been identified in the Danube river valley. The primary aim of the proposed work is to study structure and composition (species diversity and genetic diversity of P. alba) of three managed and three unmanaged P. alba communities and look for (composition, structure and diversity)-trends within each community type. This will allow us to estimate the status of P. alba within the communities and to recognize in which way the human activity might affected the P. alba communities. The secondary aim is to study the relationship between genomic composition of P. alba and P. x canescens and environmental variables and thus estimate ecological amplitudes of both taxa. We believe that detailed investigations of P. alba as planned in this study scaled up from the population to the community level using molecular, and non-molecular methods will provide important insights into plant population- and community dynamics in general, in particular on the relationship of disturbance (management) to hybridization, and different reproductive strategies. In addition our work will allow us to address one extremely timely topic in plant evolutionary genetics: the role of hybridization in exploitation of new habitats.
keywords Populus sex species and genetic diversity clonality and introgression ecological amplitudes
Publikationen
Project staff
Hubert Hasenauer
Univ.Prof. Dipl.-Ing. Dr.nat.techn. DDr.h.c. Hubert Hasenauer
hubert.hasenauer@boku.ac.at
Tel: +43 1 47654-91301, 91311
Project Staff
01.11.2009 - 31.10.2012
BOKU partners
External partners
University of Fribourg
Ass.Prof. Ch. Lexer
partner
Bundesforschungs- und Ausbildungszentrum für Wald, Naturgefahren und Landschaft (BFW)
Dr. Dipl.-Ing. Berthold Heinze
partner
University of Wienna, Institute of Botany
Ass.Prof.Dr. Luise Ehrendorfer-Schratt
partner