|Abundance and flowering succes patterns in a short-term grazed grassland: early evidence of facilitation|In: Journal of Ecology. British Ecological Society: Oxford. ISSN 0022-0477, more
associational resistance; competition; grazing avoidance; herbivory; relative palatability
|Authors|| || Top |
- Bossuyt, B., more
- De Fré, B.
- Hoffmann, M., more
Associational resistance is a grazing avoidance mechanism resulting from herbivores being less inclined to eat palatable plant species when these species grow in association with unpalatable species. Such facilitative interactions between plant species may have important consequences for patterns of relative abundance and reproduction in plant communities.
We studied the relationship between abundance and flowering success of palatable species and the cover of three unpalatable species (Senecio jacobaea, Iris pseudacorus and Lysimachia vulgaris) in a grassland where moderately intense grazing (0.17–0.42 grazers ha-1) had been ongoing for 3 years. Plots were selected so that there were no systematic differences in microenvironmental conditions associated with the level of cover of unpalatable species.
Several palatable species had a higher frequency, cover and/or flowering success when they grew in the neighbourhood of an unpalatable species.
Several species (both palatable and unpalatable) were significantly taller in the vicinity of a large unpalatable species, probably due to the combined effects of grazing avoidance and increased light competition.
These facilitative effects, however, have not yet resulted in a higher local species richness or plant community evenness. It is nevertheless likely that more pronounced effects will be seen if grazing is continued, because facilitative interactions between plant species induced by grazing have already led to a shift in patterns of abundance and flowering success.