Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)




This particular study is concerned with invertebrates found on a grassland ecosystem; therefore, most of the literature reviewed was limited to studies involving insects. Since the literature on ecosystems is extensive, only the following trends as listed by Clark et al. were reviewed: physical factor ecology, production ecology, and population ecology. Smith was among the first to emphasize physical factor ecology which stressed the importance of abiotic factors in regulating animal numbers. He first used the terms density-dependent and density independent. Production ecology introduced the study of more complex life communities and considered the trophic association or food-cycles and the flow of energy within trophic levels. Since Lindeman formulated his concept of trophic dynamics, ecologists have become increasingly interested in the energy relationships of ecosystems. The application of thermodynamics and information theory to the study of energy flow through an ecosystem has progressed rapidly. Population ecology has been defined by Andrewartha as the laws governing the numbers of animals in relation to the areas that they inhabit. It takes into account the relationships of animals to their food and to other sorts of animals that eat the same sort of food, or prey on them, or are related to them in some way. Clark et al. defined population ecology as meaning the study of events and processes which determine the distribution, abundance, and persistence of specific populations. During the last thirty years, many workers have contributed differing theories to explain the abundance and distribution of species. Smith, Solomon, Nicholson, and Klomp thought that density-dependent processes play a key role in the determination of population numbers by operating as stabilizing mechanisms. Andrewartha and Birch and Andrewartha regarded such processes as being of minor importance and considered them insignificant in determining the abundance of some species. Milne sought a middle course between these views, and Birch emphasized the influence of the genetic factor in the determination of population numbers. Recently some progress has been made in dealing with the complexity of structure and interaction at the community level; however, studies of a single community and its invertebrate fauna are in the natural history stage of development. The purpose of this study is to consider and compare basic features of the invertebrate community present on a grassland ecosystem. The four basic features are: its taxonomic composition (numbers), its biomass, its trophic structure, and the seasonal patterns of more important taxa.

Library of Congress Subject Headings

Animal ecology
Cottonwood (S.D.)



Number of Pages



South Dakota State University