A laboratory approach to ecological studies of the grasses : Arrhenatherum elatius (L.) Beav. ex J. and C. Presl Agrostis tenuis Sibth. and Festuca ovina L.

An attempt has been made to recognise laboratory characteristics which allow features of the ecology of three common British grasses, Arrhenatherum elatius (L.) Beauv. ex J. and C. Presl, Agrostis tenuis Sibth and Festuca ovina L. to be predicted. Experimental work was carried out in controlled and semicontrolled environments and involved a consideration of plant morphology, measurements of responses in germination and growth to light and temperature, and measurement of responses to nutrient stress, metal toxicity, and defoliation. In some experiments, additional species, Deschampsia flexuosa and Zerna erecta, were included in order to provide a wider basis for comparison. Predictions of the field ecology, were evaluated by reference to published accounts of the ecology of the species and predictions of competitive ability were tested by carrying out competition experiments. Attributes which when used singly or in combination appear to have a predictive value include seed weight, seed dormancy, response of germination and vegetative growth to temperature, relative growth rate under productive conditions, dry matter production in seedlings subjected to mineral nutrient stress or manganese toxicity, root growth of plants exposed to soluble aluminium, leaf extension growth in shade, light intensity compensation point and tiller production -under continuous clipping. The ecological significance of the differences between the species with respect to these attributes is explored in the Discussion. The data on which predictions have been based were derived from investigations carried out on a single field population of each species. Evidence of the need to/account of intraspecific variation was obtained in the present study; it was necessary to carry out additional experiments to take account of morphological variation in Arrhenatherum elatius. It is concluded, however, that whilst genetic variation within the species may have an important influence, the laboratory characteristics of plants drawn from a single field population frequently reveal attributes which control the broad ecology of the species.