Kéry M, Matthies D
Institut für Umweltwissenschaften, Universität Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland.
Plant Biol (Stuttg). 2004 Nov;6(6):683-8. doi: 10.1055/s-2004-830331.
Habitat destruction is the main cause for the biodiversity crisis. Surviving populations are often fragmented, i.e., small and isolated from each other. Reproduction of plants in small populations is often reduced, and this has been attributed to inbreeding depression, reduced attractiveness for pollinators, and reduced habitat quality in small populations. Here we present data on the effects of fragmentation on the rare, self-compatible perennial herb Gentianopsis ciliata (Gentianaceae), a species with very small and presumably well-dispersed seeds. We studied the relationship between population size, plant size, and the number of flowers produced in 63 populations from 1996-1998. In one of the years, leaf and flower size and the number of seeds produced per fruit was studied in a subset of 25 populations. Plant size, flower size, and the number of seeds per fruit and per plant increased with population size, whereas leaf length and the number of flowers per plant did not. The effects of population size on reproduction and on flower size remained significant if the effects were adjusted for differences in plant size, indicating that they could not be explained by differences in habitat quality. The strongly reduced reproduction in small populations may be due to pollination limitation, while the reduced flower size could indicate genetic effects.
栖息地破坏是生物多样性危机的主要原因。幸存的种群往往呈碎片化状态，即规模小且相互隔离。小种群中植物的繁殖率通常会降低，这被归因于近亲繁殖衰退、对传粉者的吸引力降低以及小种群中栖息地质量下降。在此，我们展示了关于碎片化对珍稀的、自交亲和的多年生草本植物睫毛龙胆（龙胆科）影响的数据，该物种种子非常小且推测具有良好的扩散性。我们研究了1996年至1998年63个种群中种群规模、植株大小与花朵数量之间的关系。在其中一年，对25个种群的一个子集研究了叶片和花朵大小以及每个果实产生的种子数量。植株大小、花朵大小以及每个果实和每株植物产生的种子数量随种群规模增加，而叶片长度和每株植物的花朵数量则不然。如果对植株大小差异进行调整，种群规模对繁殖和花朵大小的影响仍然显著，这表明它们无法用栖息地质量差异来解释。小种群中繁殖率大幅降低可能是由于授粉限制，而花朵变小可能表明存在遗传效应。
