How general are positive relationships between plant population size, fitness and genetic variation?

Summary Relationships between plant population size, fitness and within‐population genetic diversity are fundamental for plant ecology, evolution and conservation. We conducted meta‐analyses of studies published between 1987 and 2005 to test whether these relationships are generally positive, whether they are sensitive to methodological differences among studies, whether they differ between species of different life span, mating system or rarity and whether they depend on the size ranges of the studied populations. Mean correlations between population size, fitness and genetic variation were all significantly positive. The positive correlation between population size and female fitness tended to be stronger in…