ABSTRACT
Of the original pattern of plant communities described in the previous two chapters, only vestiges remain. In places it has been replaced by an orderly, well-tended patchwork of cultivated crops, in others by an exploited and depleted vegetative cover; in a few areas, nothing remains but the bare rock. Man has been an element in the fauna of the British Isles throughout the whole of post-glacial times but for thousands of years, as a hunter and food collector, he modified the vegetation and soils but little. It was only with the arrival of people of the Neolithic Culture, shortly before 2000 B.C., that mankind began to modify the landscape for his own ends. Fire and the axe were used to clear scrub and forest in order to use the land for growing crops [10]; a great deal more forest was prevented from regenerating by the grazing of flocks and herds. For these two reasons, little forest remained by the end of mediaeval times [27]. The effect of these changes on the actual flora must have been profound. Many herbaceous plants are adapted to live either in open sunlight or in the shade of trees and shrubs. Consequently, large numbers of forest plants must have been much reduced in range and in numbers when the thick forests were thinned or removed. The changes were by no means all on the debit side however; a variety of cereals and fruit trees were introduced purposefully to provide food, and along with these came many weeds o cultivation, actually introduced involuntarily from abroad with the seed grain. Native plants which heretofore had been quite rare elements in the flora, having a foothold only on cliffs, screes, foreshores and other disturbed areas, were now able to compete with the crop plants on the deforested arable lands. It is also interesting to reflect that the familiar daisies (Bellis perennis), dandelions (Taraxacum officinale) and buttercups (Ranunculus spp.) of our fields and waysides could not have been anything but rarities in the original primeval forests. Similarly, many other conspicuous flowering plants of the pastures and meadows which are thought of today as being typical of the British landscape, cannot have been common originally. One would be quite surprised today if one came upon a patch of clover (Trifolium spp.) or a clump of ox-eye daisies 176(Chrysanthemum leucanthemum) when walking through an oakwood; how much more unlikely it would be for them to have occurred beneath closed-canopy primeval oak forest! One must not go so far as to overstress this point however. The exact nature of the primeval forest will never be known, but it must not be forgotten that the natural fauna contained animals such as wild cattle (Bos primigenius) and wild deer (Cervus spp., which must have had some effect on forest regeneration. When a large tree died of old age or was brought down by strong winds, light would stream on to the forest floor and stimulate the growth of herbaceous plants. It may well be that grazing animals would congregate in such areas and even enlarge them by preventing tree regeneration. Pasture grasses and other light-loving plants may have persisted for some time in such places so that, at any one time, a scattering of 'natural glades' may have existed within the forest. Though palaeo-botanical evidence indicates that such 'glades' cannot have been of great extent, their possible existence must not be overlooked.
