Relationship between abundance and fecundity in the endangered grassland annual Euphrasia rostkoviana ssp. fennica

We examined 18 populations of the endangered Euphrasia rostkoviana ssp. fennica situated in managed semi-natural grasslands or gravelled road verges in ten extant localities in south-eastern Sweden. The major threat to the subspecies is the steady decrease in habitat area and quality. In each popula...

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Bibliographic Details
Published in:Annales botanici fennici 2007, Vol.44 (3), p.194-203
Main Authors: Schmalholz, M, Kiviniemi, K
Format: Article
Language:English
Subjects:
Euphrasia
Fecundity
Fruits
Habitat fragmentation
Habitats
Natural grasslands
Plants
Population density
Population growth
Population size
Seeds
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Summary:We examined 18 populations of the endangered Euphrasia rostkoviana ssp. fennica situated in managed semi-natural grasslands or gravelled road verges in ten extant localities in south-eastern Sweden. The major threat to the subspecies is the steady decrease in habitat area and quality. In each population, abundance and fecundity of individuals were examined. Local factors (soil pH, litter-layer depth and vascular species richness) and isolation were also measured. We specifically wanted to examine if there was a positive relationship between abundance (population size and density) and fecundity in the investigated taxon. Larger populations of E. rostkoviana ssp. fennica were found to be denser. Population size and density were both significantly positively related to fecundity. A higher variability in seed production was also detected for individuals in sparse populations. An Allee effect, i.e. a reduced fecundity in small and sparse populations, could thus be demonstrated for the already strongly threatened subspecies.
ISSN:0003-3847
1797-2442