Jürg Stöcklin | University of Basel (original) (raw)

Papers by Jürg Stöcklin

New Phytologist, May 27, 2014

Annals of Botany, Sep 30, 2015

Alpine Botany, Sep 30, 2016

Journal of Ecology, Dec 1, 1994

1 This study explored the effects of plant size, position of fruits within inflorescences, and po... more 1 This study explored the effects of plant size, position of fruits within inflorescences, and position of seeds within fruits on the regulation of fecundity in the two outcrossing perennial herbs Epilobium dodonaei and E. fleischeri which replace each other along an altitudinal gradient. 2 Almost all reproductive components were affected by size. The largest difference between small and large individuals of both species concerned the number of mature seeds per stem, followed by the number of fruits per stem, flower buds per stem, seeds per fruit, ovules per fruit and individual seed mass. 3 The increase in the number of seeds per stem from small to large plants was not only due to the increasing number of flower buds per stem and ovules per fruit, but also a result of a decreasing abortion rate of flower buds and seeds. 4 The fruit/flower ratio was not affected by plant size, but the fruit/flower-bud ratio increased from 53% in small plants to 68% in large plants of E. fleischeri and from 22 to 62% in E. dodonaei, respectively. Early abortion of flower buds determined the abortion pattern, abortions after flowering were rare. The pattern of abortion in both species was strongly affected by the position of flower buds within the inflorescences. Buds from intermediate parts of the inflorescence had the smallest abortion frequency. 5 Seed/ovule ratio was 50% in E. fleischeri and 40% in E. dodonaei. The fate of ovules was not affected significantly by the size of plants. However, positional effects of fruits within inflorescences and of ovules within fruits on abortions were highly significant. 6 The overwhelming part of the variation in individual seed mass in both species was found within fruits and among fruits within a single inflorescence. Only in E. fleischeri was individual seed mass affected by the size of plants. 7 Our results suggest that abortion patterns in reproductive components are strongly affected by changes in resource availability during plant development, but also by morphological constraints. 8 Although the alpine E. fleischeri produced fewer fruits than E. dodonaei, a trade-off between seed number and seed mass contributed to a similar seed number per shoot in both species. We conclude that the pattern and regulation capacity in reproductive components are tightly linked to specific life-history traits of the two species.

Journal of Ecology, May 5, 2006

Molecular Ecology Notes, Dec 1, 2005

The important fodder grass Poa alpina L. occurs at several ploidy levels with common aneuploidy. ... more The important fodder grass Poa alpina L. occurs at several ploidy levels with common aneuploidy. We isolated and characterized five polymorphic microsatellite markers for the study of molecular genetic variation of this species. As first examples of the value of the developed markers for population genetic analyses, we show that plants with more chromosomes have more microsatellite bands and that isolation by distance plays a small role in shaping microsatellite diversity of P. alpina in the Swiss Alps.

Plant Ecology & Diversity, Dec 1, 2011

Background: Many arctic and alpine plant species from cold environments reproduce mainly vegetati... more Background: Many arctic and alpine plant species from cold environments reproduce mainly vegetatively and can be extremely long-lived. To understand the life history and population dynamics of such species, careful in-situ measurements of growth are essential, but reports of such measurements are still scarce.Aims: Our objectives were to compare annual horizontal growth in populations of five clonal arctic-alpine species in different geographic regions, successional stages and years, and to test how much their mean annual growth is affected by season length.Methods: We performed replicated measurements of annual size increments in 36 populations of Carex curvula, Dryas octopetala, Salix herbacea, Vaccinium uliginosum and Empetrum nigrum in three arctic-alpine regions of Europe for 2 years (2008–2010).Results: The mean annual horizontal growth was different among the species and between early and late successional stages in both years. In late successional populations, the mean growth over both years was between 0.46 mm (Carex curvula) and 13.2 mm (Empetrum nigrum), and in early successional populations, the growth was between 0.85 mm and 19.0 mm, respectively. Across geographical regions, growth rates were not different, despite a difference of as much as 50 days among season lengths.Conclusions: Our results indicate that horizontal growth in arctic-alpine clonal plants may not be strongly affected by a warmer climate in the future. As a consequence, changes in arctic-alpine late successional vegetation dominated by the clonal species studied here might be slower in the face of global warming than changes in other vegetation types.

Botanical Journal of the Linnean Society, 1992

Springer eBooks, 1996

The sedentary habit is a major constraint for plants and has important ecological consequences. R... more The sedentary habit is a major constraint for plants and has important ecological consequences. Rooted plants cannot escape their herbivorous enemies or other hazards and they interact and compete for light and other resources mostly with their close neighbors. Only clonal species have some limited possibilities to move from their natal site by creeping rhizomes, stolons, or roots. Dispersal patterns of seeds, movement of pollen, and to some limited extent clonal spread represent ways that allow migration of individuals or of genes through populations or into new populations. They represent clue events that cause not only the actual distribution of a given species but even more, on a smaller scale, they are responsible for the spatial and genetic structure of populations and subpopulations. Though dispersal patterns of plants have been of interest to naturalists for a long time, their ecological consequences in structuring populations and their role for gene flow and microevolutionary change are still poorly understood. The scope of this review is to cover recent literature that contributes to our understanding of the consequences of seed and pollen dispersal at the population and community level.