Bischoff, Mascha , Lord, Janice M .
Beggars canít be choosers? Assuring reproductive success in a New Zealand alpine plant community.
The New Zealand alpine flora is thought to be of relatively recent origin and appears to have evolved rapidly under highly changeable conditions. Much of the alpine habitat in New Zealand arose during the Kaikoura Orogeny, 2-3million years ago and all of it has been repeatedly and profoundly altered by extensive glaciation in the Pleistocene. These extremely challenging environmental conditions seem to have provided unusual opportunities for plant evolution in response to a novel, isolated, and always changing environment. The story of New Zealand alpine plants is a story of success due to processes of adaptive radiation, interspecific hybridisation and recombination, and despecialisation of pollination systems. But it has historically been assumed that pollinator services in alpine New Zealand are too imprecise for plants to rely on and therefore self-pollination was thought to be the rule. We examined breeding systems in an alpine plant community to assess the role that insect pollination may play for New Zealand alpine plants. Given the value of outcrossing in maintaining genetic diversity in unstable conditions, we expected strict autogamy to be much rarer than outcrossing or mixed mating systems. Our results from P:O ratio data and pollinator exclusion experiments suggest that a considerable proportion of the plant species examined have greater success in seed set when outcrossing than autonomously selfing. Furthermore insect visitation is not at all random and visitation rates as well as the subset of flower visitors varied according to plant species. Thus in a relatively young system with unstable conditions a mixed mating system may be the key for plants to have it both ways: reproductive assurance as well as genetically variable offspring according to the circumstances in a given season.
Log in to add this item to your schedule
1 - University of Otago/ HIP Heidelberg, Botany Department, PO Box 56, Dunedin, New Zealand
2 - University of Otago, Botany Department, PO Box 56, Dunedin, New Zealand
alpine New Zealand.
Presentation Type: Oral Paper:Papers for Topics
Location: Lake Ontario/Hilton
Date: Tuesday, July 10th, 2007
Time: 9:00 AM