Inniger, Hannah (2024). Population ecology of four common and four rare alpine plant species. (Thesis). Universität Bern, Bern

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Abstract

Despite the interesting ecology of alpine plants and the fact that related rare and common species can be studied in the same or in similar habitats, there is only limited research on their population ecology. The aim of this thesis was to evaluate in field- and greenhouse studies the relative importance of different potential determinants of plant performance in eight alpine species (Androsace chamaejasme Wulfen, A. puberula Jord. & Fourr., Primulaceae; Gentiana acaulis L., G. alpina Vill., Gentianaceae; Potentilla crantzii (Crantz) Fritsch, P. nivea L., Rosaceae; Viola calcarata L., V. lutea Huds., Violaceae). As potential determinants, I studied population size, species rarity and various aspects of habitat quality inferred from vegetation records, namely abiotic conditions (species indicator values), habitat heterogeneity and plant diversity. As variables of plant performance, I investigated individual fitness, population size, within-population trait diversity and in four species also adaptation. I studied population size both as an explanatory and as a response variable, since it may be correlated to species rarity and habitat quality or to any variable of plant performance. Within habitats, abiotic conditions, habitat heterogeneity and plant diversity influenced different variables of plant performance. In habitats where abiotic conditions did not match the target species optimum, populations were smaller. Plants of the genera Potentilla and Gentiana produced seeds with lower germination rates within these habitats. A novelty of this thesis is the finding that local plant diversity and habitat heterogeneity can affect plant performance of specific target species. In particular, habitat heterogeneity was important for the performance of individuals and of populations across all study species. Additionally, this thesis showed that population size is a determinant of plant performance in the eight study species. It suggests that an extinction vortex may be ongoing in small populations of the study species. Finally, this thesis gives new input on the population ecology of species that are naturally rare. From the results across all chapters, it is concluded that the naturally rare species in this study do not suffer from reduced individual fitness but may have a low potential for further evolution. Therefore, these species could be susceptible to environmental change.

Item Type:	Thesis
Dissertation Type:	Cumulative
Date of Defense:	26 March 2024
Subjects:	500 Science > 580 Plants (Botany)
Institute / Center:	08 Faculty of Science > Department of Biology > Institute of Plant Sciences (IPS)
Depositing User:	Sarah Stalder
Date Deposited:	15 Nov 2024 11:21
Last Modified:	15 Nov 2024 12:30
URI:	https://boristheses.unibe.ch/id/eprint/5335

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