Conclusion
Our study provides empirical evidence of variation in species’ vital and
population growth rate responses to local-scale heterogeneity in abiotic
conditions and plant-plant interactions in a natural system. We
illustrate the potential for demographic trade-offs between emergence
and subsequent vital rates to counteract the effect of natural variation
in shade and soil nutrients on population growth rate. We found a
surprising lack of significant effects of neighbours on survival and
seed production among species but show the potential of weak vital rate
responses to competition to generate strong patterns for population
growth rate. We also demonstrate the importance of interactions between
different abiotic factors (shade and nutrient availability with water
availability) and between abiotic and biotic factors for vital and
population growth rates. Linking functional traits to variation in
demographic responses is the next aim of this research and will help to
generalise our understanding of the mechanisms driving
fitness-environment relationships.