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Show CHAPTER III PLANT AND ANIMAL LIFE RECREATIONAL VALUE OF PLANTS AND ANIMALS Plants.- Regions devoid of plant life are among the most uninhabitable wastelands in the world. The rains or melting snows, unchecked by an absorbent mantle of forest or grassland, sweep over the bare slopes in torrents, carving out gullies that grow with the years until they become great barren valleys. Then, with the passing of each unchecked flood, the watercourses shrink to a trickle or vanish entirely. Without plants there can be no cool, clear trout streams; no shady camping spots; no fertile, humus- bearing soil; no food for other forms of life. Even in desert lands there is usually a thin mantle of plant cover which, though sparse, helps hold the soil in place and permits a foothold for higher forms of life. Recreational enjoyment of plants ranges from subconscious appreciation of their beauty and shade to active interest and wonderment at the marvelous diversity of plant forms which results from their adaptation to the earth's extremes of climate and environment. Unity of plants and animals.- Plants and animals are dependent upon one another in a manner so complex and far reaching that they cannot be fully enjoyed, or protected, separately. As an example of this interdependence, in mountain regions acorns roll downhill when they fall from the trees. Therefore, in the course of centuries the forests would travel downward from the high country and eventually would disappear if their reproduction were not assisted by other members of the plant- animal community. However, jays, woodpeckers, squirrels and other small animals that eat acorns assist the forest through their habit of carrying off and storing the surplus crop of nuts. Often these creatures fly or run up hill with the seeds, and not infrequently they fail to find them or are caught by some natural enemy before the storehouse can be used. Seeds which sprout from these abandoned supplies become the trees which maintain the forest in the high places. 1 Figure 28.- Abert squirrel of the Transition Zone. In a like manner, many species of desert yucca are wholly dependent for their pollination upon a single kind of moth. This insect thrusts its eggs into the plant tissues surrounding the future seed, where the larvae will be safe from most enemies, and at the same time collects and applies the yucca pollen by means of mouth parts that are specially shaped for this work. 2 A commonplace, though very important and often forgotten, example of plant- animal dependence is the plowing and cultivation of the soil by billions of insects, earthworms, field mice, pocket gophers, moles, and other small burrowing animals. The vegetable matter that they drag underground to line their nests, or to eat, is transformed into 1 Grinnel, 1936, p. 82. 2 Holland, 1920, p. 441. 56 |