Comparing reproductive success in the rare sedge Gahnia insignis and the common Gahnia clarkei in north-east New South Wales

  • Species may become vulnerable because of a reduction of habitat, leading to reduction of population sizes and an increase in geographic isolation between populations, leading to genetic drift that may result in reduced reproductive fitness. The restricted sedge Gahnia insignis S.T. Blake (family Cyperaceae), occurring in isolated pockets in north-east New South Wales and Queensland, was compared to a closely related, sympatric, common and widespread Gahnia clarkei Benl for flowering phenology and reproductive success. Flowering patterns, examination of pollen, fertilisation and embryo development and seed-ovule ratios show Gahnia clarkei has every indication of successful sexual reproduction, but that Gahnia insignis appears to reproduce mostly by vegetative means, with an occasional sexual event. This was due to the rarity of pollination opportunities, and to poor pollen viability and pollen quantity, resulting in a much lower seed-ovule ratio than Gahnia clarkei. The additional high level of vegetative reproduction in Gahnia insignis suggests it may be largely clonal in Nightcap National Park. A genetic study of the whole distribution would add knowledge of the species genetic diversity and differentiation between populations.

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Author:Margaret A. Wheeler
Parent Title (English):Cunninghamia : a journal of plant ecology for eastern Australia
Publisher:Mount Annan Botanic Garden, The Administration Officer
Place of publication:Mount Annan, NSW
Document Type:Article
Date of Publication (online):2013/03/28
Date of first Publication:2012/12/18
Publishing Institution:Universit├Ątsbibliothek Johann Christian Senckenberg
Release Date:2013/03/28
Page Number:4
First Page:385
Last Page:388
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 58 Pflanzen (Botanik) / 580 Pflanzen (Botanik)
Sammlungen:Sammlung Biologie / Sondersammelgebiets-Volltexte
Zeitschriften / Jahresberichte:Cunninghamia : A Journal of Plant Ecology for Eastern Australia / Cunninghamia : A Journal of Plant Ecology for Eastern Australia, Volume 12, Issue 4 (2012)
Licence (German):License LogoDeutsches Urheberrecht