Abstrakt
Aim Niche differentiation along the temporal axis has often been suggested as a potential mechanism of species coexistence. Species may co-occur by shifting timing of growth, or by changing their growth rate to avoid competition for resources, namely light.
However, due to the lack of data on growth phenology of a large set of species, we do not know how common each phenomenon is and whether the phenology of coexisting species shows a non-random distribution, which would be indicative of either niche differentiation or resource competition. Location Czech Republic.
Methods We recorded growth phenological data of 381 perennial herbaceous species in plant collections in the Botanical Garden of Charles University in Prague, allowing frequent recordings on a large number of species that grow in conditions close to their natural habitats. We used the measurements to derive the day of peak growth and two types of growth rates.
We then used co-occurrence data of these species from the Czech National Phytosociological Database and examined whether co-occurring species show non-random patterns of these parameters in 11 individual habitats, which were identified by the European Nature Information System. Results We found large differences among habitat types, partly due to differences in habitat productivity, indicated by the mean height and summed cover of all species in the habitats.
Unexpectedly, we did not find temporal niche differentiation in woodlands, indicating the day of peak growth of species was essentially random. Growth rates in forests were strongly over-dispersed.
This pattern contrasted with grasslands where the distribution of all parameters showed synchronization, which is likely because plants need to succeed in asymmetric competition for light. Conclusion These data provide the first quantitative assessment of differences in growth dynamics across communities and show one of the first unequivocal demonstrations of trait overdispersion in plant communities.