Natural habitat

“ What seabird cliffs, islands, lagoons, wetlands, river mouths, and other habitat features are of first importance for breeding or for maintaining the populations? Some small areas of habitat are critical for the survival of some species during periods of stress. Those habitats need official recognition. Steps are needed to ensure that the habitats are maintained.
2. What physical expressions of economic development are of little, modest, or serious impact on wildlife and its habitat? ”

“ Its habitat is in a land where plums grow with the stones outside, where aboriginal dogs have never been heard to bark, where birds are found covered with hair, and where mammals jump about like frogs! ”

“ The habitat is the sum of all the forces or factors present in a given area. It is the exact equivalent of the term environment, though the latter is commonly used in a more general sense. As an ecological concept, the habitat refers to an area much more definite in character, and more sharply limited in extent than the habitat of species as indicated in the manuals. Since the careful study of habitats has scarcely begun, it is impossible to recognize and delimit them in an absolute sense. ”

“ The Habitat.—The term habitat, in its widest sense, includes all the factors of the environment which affect a plant or a plant community, though the term is frequently used to signify only some of these factors. ”

“ The factors of a habitat are water-content, humidity, light, temperature, soil, wind, precipitation, pressure, altitude, exposure, slope, surface (cover) , and animals. To these should be added gravity and polarity, which are practically uniform for all habitats, and may, in consequence, be ignored in this treatise. Length of season, while it plays an important part in vegetation, is clearly a complex and is to be treated under its constituents. Of the factors given, all are regularly found in each habitat, though some are not constantly present. ”

“ As time went on, through the constant changes that the surface of the globe is undergoing, one variety would be isolated from another, and in such an isolation the differences would increase. And the more a species27 varied, the more fitted it might become for some habitat, from which it was completely cut off by a chain of mountains, a rapid river, or a deep sea. ”

“ A society is in entire correspondence with the physical factors of its area, and the same is true of the vegetation of a province. Nevertheless, many societies usually occur in a single habitat, and a province contains many habitats. The final test of a habitat is an efficient difference in one or more of the direct factors, water-content, humidity, and light, by virtue of which the plant covering differs in structure and in species from the areas contiguous to it. ”

“ Naturalists know well enough how indeterminate the harmonies between a fauna and its environment are. An animal may better his chances of existence in either of many ways, - growing aquatic, arboreal, or subterranean ”

“ Ecology and Physiology.—Whilst our knowledge of the nature and effect of habitat is still in a very rudimentary condition, much progress has been made in recent years in the study of plant communities, but even here the questions involved in relating the facts of the distribution of plant communities to the factors of the habitat are very imperfectly understood. ”

“ Thus the present state of the ecological resources and land-uses of any country or region are best understood in terms of:
the natural ecosystems; human economic impact; society; and the resulting human landscape.
3.4 LANDSCAPES ARE ALIVE
Ecology recognises that landscapes are alive. There is a dynamic relationship between their components, so that the landscape is always changing: not for one minute does it stay the same. Thus in ecology, landscapes are classified not just in terms of the components we have described, but in terms of life. ”

“ Methods. All field experiments in evolution are based upon a change of habitat. The latter is accomplished by the modification of the habitat itself, or by the transfer of the species to one or more different habitats, or to different areas of the same habitat. ”

“ In this way the surface of the land is divided into numerous natural regions, the flora and fauna of each of which include some distinctive species not shared by the others. The distribution of life is discussed in the various articles in this Encyclopaedia dealing with biological, botanical and zoological subjects. ”

“ The species which, by natural selection and adaptation have fitted themselves to the environment are, as a rule, the trees which will do best in that locality. That is a principle I think which ought to be thoroughly well fixed in mind. ”

“ Other provisions and adaptations in the dresses of animals, relating less to climate than to the more mechanical circumstances of life, are made with the same consummate skill that characterizes all the love work of Nature. Land, water, and air, jagged rocks, muddy ground, sand beds, forests, underbrush, grassy plains, etc., are considered in all their possible combinations while the clothing of her beautiful wildlings is preparing. ”

“ How still the woods seem from here, yet how lively a stir the hidden animals are making; digging, gnawing, biting, eyes shining, at work and play, getting food, rearing young, roving through the underbrush, climbing the rocks, wading solitary marshes, tracing the banks of the lakes and streams! Insect swarms are dancing in the sunbeams, burrowing in the ground, diving, swimming,—a cloud of witnesses telling Nature’s joy. The plants are as busy as the animals, every cell in a swirl of enjoyment, humming like a hive, singing the old new song of creation. ”

“ Around dry lakes and marshes the herbage preserves a set and orderly arrangement. Most species have well-defined areas of growth, the best index the voiceless land can give the traveler of his whereabouts. ”

“ Over the new land thus created, and surrounding these beautiful sheets of water, spread a vegetation at once so beautiful and so rich in growth that earth has now absolutely nothing with which to compare it. ”

“ Associated with these various land forms is a progression of ecosystems representing a continuum of communities from the boreal spruce forest and riparian shrub thickets in the south to the arctic tussock tundra in the north. These communities of plants and undisturbed animals offer excellent opportunities for study of natural interaction of the species. ”

“ The variety of the fauna is explained by the physical configuration of the region, where a walk of a few hours will carry one from the green sod of meadows intersected by rice-fields to the inaccessible precipices of the granitic mountains, from the sea-shore jungles of bamboo and the rich, tropical vegetation of the coasts to immense virgin forests and the stiff and dark pines of the mountain-sides. ”

“ Give these plants the least bit of fair play as regards environment—a sheltered glen, or the shores of a loch or firth, where there is sufficient moisture, plenty of sun, and good soil enriched by the water running down from the wonderful bird cliffs inhabited by hundreds of thousands if not millions of birds, or by the droppings of reindeer, musk-oxen, and other animals, and a veritable paradise of verdure is produced. ”

“ The physiographic factors of a definite habitat are altitude, exposure, slope, and surface. In addition, topography is a general though less tangible factor of regions, while the dynamic forces of weathering, 81erosion and sedimentation play a fundamental role in the change of habitats. ”

“ Forests flourishing on all but naked rock, greenest prairies on a soil but an inch or two deep, earth-pillars, threads of water on every mountain side, and a glancing stream in every valley, oblige you to think of the relation of oceans, clouds, winds, the varying capacity of the atmosphere for retaining moisture, and of rain, to the vegetable and animal life of the land. ”

“ Before the advent of man this selection of types was made by the environment or by Nature, as the environment used to be called. Hence the expression, natural selection, is used to describe the process by which Nature or environment selects certain types for survival at the expense of the rest; the process by which animals that live in the desert gradually adapt themselves to endure great heat; and those that live near the Poles gradually adapt themselves to endure great cold. ”

“ Modification of habitat. As the final factors in ecesis and competition, water, light, and temperature control the grouping of plants into vegetation. An efficient change in one of these, or in all of them, brings about a visible adjustment in the structure of the plant group concerned. Modifications 308of water-content and light are readily produced in the field by drainage, irrigation, shading, clearing, etc. In fact, all the changes of habitat indicated under experimental evolution serve equally well to initiate experiments in experimental vegetation ”

“ Throughout every state, on every shore-line, in all the millions of fresh water lakes, ponds and rivers, on every mountain range, in every forest, and even on every desert, the wild flocks and herds held sway. ”

“ This necessarily presupposes a certain preliminary acquaintance with the habitat to be investigated, as it is imperative that the station for making readings be located well within the formation, in order to avoid transition conditions. In vegetation, there are as many habitats as formations, and in addition a large number of new and denuded habitats upon which successions have not yet started; a knowledge of each formation or succession must rest ultimately upon the factors of its particular habitat. ”

“ A short reconnoissance through the forest revealed a veritable zoological wonderland. I was consequently very glad that we were delayed, as this gave me an opportunity to study the fauna of a zoologically unknown region, and to work on some of the problems of nature with which we are constantly confronted, but of which so little is known. One of the facts that no field-naturalist can fail to have thrust upon his notice is the exact precision and nicety with which the balance in nature is preserved. ”

“ The Conservation of our Natural Resources.—Still another reason why we should study biology is that we may work understandingly for the conservation of our natural resources, especially of our forests. The forest, aside from its beauty and its health-giving properties, holds water in the earth. ”

“ Such are the elements of the scenery, but it is a hopeless attempt to paint the general effect. Learned naturalists describe these scenes of the tropics by naming a multitude of objects, and mentioning some characteristic feature of each. To a learned traveller this possibly may communicate some definite ideas: but who else from seeing a plant in an herbarium can imagine its appearance when growing in its native soil? Who from seeing choice plants in a hothouse, can magnify some into the dimensions of forest trees, and crowd others into an entangled jungle? ”

“ At this time, somewhere in the warm temperate zone, in an oasis or island of fertility, appeared a new thing on the earth, a man and woman walking erect in the forest glades, bathing in the waters, gathering and tasting every edible fruit, watching with curious and inquiring eyes the various animals around them, and giving them names which might eventually serve not merely to designate their kinds, but to express actions and emotions as well. ”

“ Let us consider, in the first place, the chances for the preservation of remains of the present fauna and flora of a country. The surface of the land may be densely clothed with forest and abundantly peopled with animal life. But the trees die and moulder into soil. The animals, too, disappear, generation after generation, and leave few or no perceptible traces of their existence. ”

“ Yet we cannot refuse to admit that in the disposition of land and sea, in the form and trend of coast-lines, in the grouping of mountains, valleys, and plains, in the disposition and flow of rivers, in the arrangement of climates, and in the distribution of vegetation and animals, a series of influences must be recognized which have unquestionably played a large part in the successive stages of human development. ”

“ But where is that favoured land?—It is in that great continent to whose distant shores Europe has sent forth her adventurous sons, to wrest for themselves a habitation from the wild inhabitants of the forest, and to convert the neglected soil into fields of exuberant fertility. ”

“ And then, what is to be said for the multitude of species to be found in the same localities, the same forests, the same jungles, the same lakes, the same streamlets, where there is literally no room for any difference in the environments at all? ”

“ An oak growing in the ocean and a seaweed on the top of a hill, are incredible combinations of ideas. We find that each kind of animal is limited to a certain range of climate; each kind of plant to certain zones of latitude and elevation. Of the marine flora and fauna, each species is found only between such and such depths. Some blind creatures flourish in dark caves ”

“ Apart from botany, the physical side of ecology is largely a question of soil physics, and of physiography. On the other hand, vegetation is coming more and more to be regarded as a fundamental factor in zoogeography and in sociology. Furthermore, with respect to the latter, it will be pointed out below that the principles of association which have been determined for plants, viz., invasion, succession, zonation, and alternation, apply with almost equal force to man. ”

“ Of course the land strips are not inhabited by human beings, but vegetation is abundant, similar to that found in our tropical regions. Many kinds of fruit, growing on the land, are sought after by the masters of the water. ”

“ What is said of the dissemination of fish, shells, and reptiles may be consistently said of vegetation.
The earth is filled with the seed of every plant and tree and shrub that ever sprang into life in any place, clime or time. Dig to whatever depth [76] you will, the substance you throw out, whether earth or stone, when exposed to the air, will produce some growth of vegetation. Frequently something entirely new and different from the surrounding vegetation. ”