Can plant palatability trials be used to predict the effect of rabbit grazing on the flora of ex-arable land?

Surplus food production has led to increased interest in taking land out of arable farming, notably under set-aside regulations, and converting it into grasslands that resemble semi-natural plant communities. Despite the value of being able to predict the long-term success of such habitat creation projects, there is little ecological data available on which to base such predictions. This study tests whether plant palatability trials can be a useful method to predict the effect of grazing by rabbits on the success of individual species growing in grasslands. The palatability of 22 common, grassland species was tested by offering wild rabbits pot-grown plants of each species in a variety of grassland vegetation backgrounds in NE Scotland, Plants were inserted into plots consisting of a regular grid of holes cut into rabbit-grazed grasslands. The palatability of each species was tested in 10 such plots, on 20 occasions each. Plots varied in their vegetation composition and were each grazed by rabbits from a different warren. Plant species were found to differ greatly in their palatability to rabbits. Palatability was found to be unaffected by the composition of the surrounding vegetation. A survey was also carried out to determine the floristic composition of ungrazed and rabbit grazed swards of 8-year old set-aside. A strong relationship was found between the palatability of most plant species and their comparative abundance in ungrazed and grazed swards. Possible reasons for the few exceptions are discussed. In general, these finding indicate that palatability trials can be a useful and robust method of predicting the effect of rabbits on the success of individual plant species growing in grasslands. A method such as this, that allows the impact of rabbits on floristic composition to be predicted, can be used to inform grassland recreation and management decisions. (C)2000 Published by Elsevier Science B.V. All rights reserved.