Encyclopedia of Global Resources part 108 provides a wide variety of perspectives on both traditional and more recent views of Earth's resources. It serves as a bridge connecting the domains of resource exploitation, environmentalism, geology, and biology, and it explains their interrelationships in terms that students and other nonspecialists can understand. The articles in this set are extremely diverse, with articles covering soil, fisheries, forests, aluminum, the Industrial Revolution, the . Department of the Interior, the hydrologic cycle, glass, and placer mineral deposits. . | 998 Rangeland Global Resources ter the 1970 s when fuel costs increased and environmental concerns over pesticide use increased brush control practices were reduced considerably. Modern environmental concerns include rangeland degradation from livestock grazing especially on riparian vegetation along streams endangered animal and plant species. These issues have become controversial in the United States. Rangelands as Ecosystems Rangelands constitute natural ecosystems with nonliving environmental factors such as soil and climatic factors primar y producers grasses forbs and shrubs herbivores livestock big game animals such as deer bison pronghorn antelope and many rodents and insects carnivores and omnivores coyotes bears weasels eagles spiders and cougars and decomposers that break down organic matter into elements that can be utilized by plants. Plants convert carbon dioxide and water into complex carbohydrates fats and proteins that can be utilized by animals feeding on the plants. Individual chemical elements are circulated throughout the various components. Many of these elements are present in the parent material of the soil for example phosphorus magnesium potassium and sulfur . Nitrogen on the other hand is present in large amounts in the atmosphere but must be converted fixed into forms that can be utilized by plants before it can be cycled. When chemicals are taken up by plant roots from the soil solution they are available to a wide group of herbivores from small microbes to large ungulates. Eventually nutrients are passed on to higher trophic groups omnivores and carnivores . Both plant and animal litter is eventually broken down by decomposers bacteria fungi and other small soil organisms and returned to the soil or in the case of nitrogen given off to the atmosphere. Energy is fixed through the process of photosynthesis and transformed to forms useful for the plants themselves and animals that feed on the plants. However energy is degraded at each .
