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OVERVIEW Living animals and their abiotic environment are constantly interacting and changing. The biotic consumption of the plant material by animal life is known as the consumer interaction of producers (plants) being eaten by consumers (animals). This interaction of living animals and growing plants is an important system known as the ecosystem. The meer presence of man in the ecosystem brought about, at best, partially managed ecosystems which took advantage of manipulated interactions that, in many ways, satisfied man's needs. These management efforts or manipulations by man bacame a business over time and it was found that when exported energy was calculated as cultural energy it was clearly related to profit in money. Such a calculation for the management of ecosystems is known as biological efficiency. This method is based upon cultural energy expended and the amount of cultural energy exported from the system which represents profit. The role of carbohydrate reserves measured in exportable cultural energy may not sound like monetary profit but it actually calculates into real dollars and real profit. It has been demonstrated that most smaller animals like rabbits, mice, rats, etc. are more profitable in energy production in the form of exportable meat than are larger animals such as cattle, goats and sheep. This energy production is calculated as body energy or total cultural energy used. Smaller animals have shorter gestation periods, produce more individuals per litter and mature more rapidly. These facts all favor more calories produced for small female animals in an annual production cycle. As a result, the energy cost per pound of animal weight produced favors small animals in all cases.
________________________________________________________ A. Structure of Rangeland Ecosystems Here are some criteria for determining the structure of a particular range site:
It is possible to view a range site and to asses the aspect as favorable or undesirable for grazing animals. For instance, sometimes the topography is too rough or too steep for retaining natural rain water. Or there may be shallow top soils or soils with high alkaline content.
________________________________________________________ B. Rangeland Ecosystem Function Many desirable functions for rangeland uses are not present for animal grazing that fits the owner's wishes. As a result, users are obliged to make some modifications to oblige the users needs for even balanced return for possible use by domestic animals. We on earth are blessed many times over because the sun arises over the eastern horizon and shines each day as a blessing to all of us on the earth's surface. The ecosystem functions are a random relationship of the components to form functional units. The ecosystem is the level of biological organization that is suitable for application of systems analysis that reveal the true functions of the ecosystem as we know it from the thousands and thousands of interactions that are untangled from the heterotrophic ecosystems that exist in our universe. Most natural functions of the rangeland ecosystems furnish positive benefits to the natural herbivore species as well as the domestic animals grazed by man. Man is a constant manipulator by nature and is always observing his neighbor to learn what is good or bad when man is out of sync with the natural functions of the natural functioning of our rangeland ecosystems. Most ranchers in our natural western rangelands have learned through trial and error what is good or bad for his rangeland and his domestic animals. In many cases he has learned from his bank account balance. This is not necessarily bad but does depend on the rancher's evaluations in the field and does not rely on his evaluation of the family bank account. ___________________________________________________________________ C.Management of Rangeland Ecosystems In these present times of domestication, man has developed an attitude of change that will yield more financial income from the export of material from the natural or manipulated ecosystems under his management. This situation may include grazing permits from the federal govenment or rental of rangeland from the railroad. Present day management of the large rangeland areas throughout the 13 western states must address the drought situations that cause wide variations in climate from season to season. Management can involve adjusting the number of animals on a particular area from season to season in order to maintain the health of the rangeland. Selling breeding animals is not a good idea for drought years. It would be better to sell young replacements, poor producers (culls), older cows and weaner calves. Management by manipulation of the ecosystem can involve plowing the lower quality range and reseeding it with plant species that are more productive, more nutritious, more palatable and better adapted to the site. Other manipulations may include light applications of fertilizer during certain seasons and fencing to create uniformity in each pasture. Additional feed or mineral supplements for the animals can also help when range quality is poor. The use of research and statistical analysis to determine the benefits of different grazing systems provide a wealth of information for managers. |