The Interacting Effects of Genetic Variation, Habitat Quality and Population Size on Performance of Succisa pratensis

• Published in: The Journal of ecology Vol. 91; no. 1; pp. 18 - 26
• Main Authors: Vergeer, Philippine, Rengelink, Ramses, Copal, Annemieke, Ouborg, N. Joop
• Format: Journal Article
• Language: English
• Published: Oxford, UK British Ecological Society 01.02.2003; Blackwell Science Ltd; Blackwell Science; Blackwell Publishing Ltd
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Biological and medical sciences; Botany; Conservation; Conservation biology; Demecology; Depopulation; Ecological genetics; fitness; Fundamental and applied biological sciences. Psychology; Genetic variation; Genetics of eukaryotes. Biological and molecular evolution; Habitat conservation; Inbreeding; path analysis; Plant growth; Plant reproduction; Plants; Plants and fungi; Population ecology; Population genetics; Population genetics, reproduction patterns; Population size; Pteridophyta, spermatophyta; small populations; Soil quality; Vegetals; Netherlands; Europe; Genetic variability; Perennial plant; Population number; Plant conservation; Edaphic factor; Dipsacaceae; Dicotyledones; Angiospermae; Inbreeding; Spermatophyta; Habitat; Performance; Environment quality
• ISSN: 0022-0477; 1365-2745
• DOI: 10.1046/j.1365-2745.2003.00736.x

1 We studied the performance of 17 Dutch populations of the perennial Succisa pratensis, in relation to population size, genetic variation and habitat quality. We used a path-analytical model to analyse the possible relationships between these variables and performance. 2 Plants in smaller populations produced fewer seeds per flower head. Their seeds had lower germination rates and higher seedling mortality, and more seeds were dormant or non-viable. 3 Population size was also correlated with genetic measures. Small populations had higher inbreeding coefficients than large populations and observed heterozygosity was positively correlated with population size. The mean genetic diversity (expected heterozygosity) was relatively high ($\text{H}_{\text{exp}}$= 0.42), but not correlated with population size. 4 Less eutrophic habitats appeared to support larger populations. High concentrations of NH4and NO3in the soil were significantly negatively correlated with population size. 5 Path-analysis showed that Succisa pratensis is vulnerable to habitat deterioration (eutrophication). Population size was strongly influenced by habitat quality. Reduced performance, however, was better explained by direct genetic effects and by habitat deterioration rather than by effects of population size per se. Both habitat quality and genetic effects are thus important for population persistence, even in the short term. The results suggest that there will be a continuing decline of the small populations, due to deteriorating habitat conditions, decreased genetic variation and a reduced reproductive capacity.