British Uplands
Mountains and Moorlands. By W. H. Pearsall. (Collins' New Naturalist '' series. 2 Is.) THE uplands of Britain, which form about a third of the land, are the areas least touched by man. At any rate, here man can be regarded more as an ecological phenomenon as can the deer or the vole. This book is primarily a study "of mountains and moorlands as habitats for living organisms." In many places soil is in the fascinating processes of formation ; but, on the whole, soil condi- tions, and the flora linked with each particular condition, are characteristically unstable, and they all tend to degenerate in time into peat-covered bog. About 10,000 years ago the last Ice Age thawed out, leaving great tracts practically sterile. Since the ice covered the greater part of Britain, our flora is comparatively recent. It has developed from types largely arctic, some representa- tives of which stilt remain. It is remarkable how the character of the vegetation has changed during this period. Dense woodland first covered much of the uplands, but this by degrees has turned chiefly to peat ; climate, topography and man being the primary agents.
Owing to the high rainfall—twice as much as that on the lowlands —much of the soil is permanently waterlogged. The movement of soil particles on the sloping terrain leads to the formation of impermeable " pans " ; chemicals are rapidly leached away. The soil bacteria cannot flourish ; plants do not decay properly ; hence the development of the peat mat. In addition, low temperatures
restrict the time in which a plant can produce fertile seed, and the flora thus becomes more and more specialised. The animal poonla.
Lion, large and small, is chiefly determined by the flora. Striking
examples of this are the incapacity of some types of grassland to support grazing animals because of the lack of lime, and the
astonishing reduction of the average size of the red deer, in a com- paratively short period, because of the decreasing fertility of their pastures.
So Professor Pearsall describes the agencies at work. Part of the book is devoted to summaries of plants and animals now existing in different habitats ; and to an account of past history (not only of plant and animal populations but of climate) derived from such researches as chemical analysis and microscopic examination of pollen in samples of soil from different depths. Human activities are included, for man has undoubtedly accelerated the steady process of nature's "running down." In a final chapter on the future-the author suggests that the uplands should be exploited rather than merely retained for recreation, and stresses the importance of regeneration—of trying to reverse nature's trends. Afforestation, already well under way, is perhaps the most economical means ; but grazing need not be left out if the soil's fertility is artificially maintained. Without this, the present utilisation of uplands by grazing sheep is unsatisfactory. A third major possibility is hydro- electric power, which would help to stimulate human activity, especially in the Scottish Highlands.
Professor Pearsall is a botanist by training, but his book shows that in practice he is one of our few " all-in " naturalists—a real ecologist. Most of the material is the result of more than three decades of work in these uplands, and he has combined his multi- farious observations, where necessary with those of others, into a most carefully balanced and interlocked critical study. Beside maps, sketches and a glossary, the book contains many fine photo- graphs, over half in colour, which illustrate not only points in the text, but the diversity and beauty of Britain's scenery, and of