Howard Thomas Odum was an American ecologist and professor at the University of Florida. He is best known for his ground-breaking work on ecosystem ecology with his brother Eugene Odum, and for the application of those same principles to energy use in society. Odum argued that society faced many of the same energetic constraints that confront other organisms and systems. He was the first to introduce the concept of energy, the amount of solar energy in the products of the biosphere and human society. His work on ecosystem ecology built important theoretical foundations for the later development of both the ecological economics and ecological engineering fields. .
The basis of Odum’s studies lie in production ecology, or the process in which the flow of energy within an ecological system from the time the energy enters the system until it is ultimately degraded to heat and is lost from the system. Ecologist use the word production to describe the “process of energy input and storage in ecosystems.” This study provides information on the energetic mutual dependence of organisms within ecological systems and measures the efficiency of energy transfer between organisms and trophic levels. Trophic levels are the different levels in a food chain, i.e. primary producers and primary consumers. Odum used a mechanism of electrical energy networks to model the energy flow pathways of ecosystems. The electron flow in Odum’s electrical model represented the flow of material in the ecosystem, and the model was scaled to the ecosystem of interest by adjusting the size of electrical component. The term ecological engineering was first coined by the Howard T. Odum. Ecological engineering, he wrote, is "those cases where the energy supplied by man is small relative to the natural sources but sufficient to produce large effects in the resulting patterns and processes.” (W.F. Humpherys)
Another field of research Odum studied in is what he referred to as self-organizing systems and how they use energy. Self-organizing systems include an ecosystem in nature or an economy in human society. The uniqueness of the field derives from its application to all complex systems when appropriately generalized. Odum proposes that growth of production is followed by growth of consumption until both factors become level in a steady state, and that the production and consumption of energy affects the development of the system itself. Odum has explained in Science that “during the trials and errors of self-organization, species and relations are being selectively reinforced as more energy becomes available to those designs that feed products back into increased production.” He believes that the long range performance of such systems are maximized by short term consumption that doesn’t interfere with production. In his analysis of self-organizing systems Odum examines why energy is categorized in such a way that "hierarchies are universal in physical and biological systems." In examining the transformation of energy, he distinguishes between low-quality and high-quality energy. Sunlight and plant matter are examples of low and high-quality energy, respectively. He has proposed the concept of "emergy" to clarify the difficulty of calculating the passage of energy through a complex system. Emergy is "the energy of one type required in transformation to generate a flow or storage." This concept can be related to carrying capacity such that the energy required to generate a flow or storage in a ecosystem could be considered part of the carrying capacity. Odum and his brother, Eugene Odum, were awarded the Crafoord Prize from the Royal Swedish Academy of Sciences in 1987. The Crafoord Prize is the equivalent of the Nobel Prize in ecological sciences. (Science), (Howard T. Odum 1,2)
The basics of ecological energetics can be most easily understood when considering the schema of energy that flows through an individual, it is equally applicable to populations, communities, and ecosystems. Of the food energy that is available, only a portion of it is put to use. Part of the consumed food is transformed but is not utilized by the body of the consumer, eventually turning into waste. The remaining energy is assimilated into the body, part of which is used to sustain the body and allow it to function properly. The remainder of the energy is used for other purposes, such as in new tissue growth. (W. F. Humpherys)
Figure 1 (W.F. Humpherys)
In January 1995, fourteen wolves from many separate packs were captured in Canada and transported into Yellowstone Park where they have sense forth resided and been watched and tracked. In this case, the wolves were considered as “experimental, [and] non-essential”. This categorization gave government officials greater flexibility in dealing with problem wolves, which catalyzed a series of compromises made with concerned local ranchers. Local environmental groups battled for years over the Yellowstone wolf reintroduction effort. The wolf reintroduction into Yellowstone is an example of modeling an ecosystems carrying capacity because the case exemplified the theories and studies previously made by Howard Odum. The wolfs were set in a foreign area and were expected to live off the resources of that specific area. After a few deaths, mostly due to accidents rather than because of the resources of the area, the carrying capacity of the wolves in the Yellowstone environment was found. (Yellowstone Wolves), (Yellowstone Wolf Reintroduction)
The Isle Royale case is similar to the reintroduction of wolves to Yellowstone National Park, though the extreme remoteness of Isle Royale leads to it having fewer visitors in one year than Yellowstone National Park has in just one day. Isle Royale is a national park that is made up of several islands, and is in the northwest portion of Lake Superior. It is about fifty miles from Michigan’s shore, and twenty-two miles from the Canadian shore. The main island is forty-five miles long, and about nine miles wide, with an area of 205 square miles. There are no roads, and no motorized vehicles are allowed on the island. Because there are no roads, nor any residential area, ninety-nine percent of the land on the island is wilderness. The wilderness of Isle Royale and its surrounding islands harbors a relationship between wolves and moose that is unlike any other area in the world. Because Isle Royale is an isolated island, the two species are able to be studied with virtually no factor of human interaction, as the island is protected by its national park status. The unique single predator-single prey relationship, where wolves are the only predator of moose, and moose are almost exclusively the only prey for wolves, lends incomparable research to the study of predator-prey relationships, and the cause of the fluctuation of the two populations. Because this research is so valuable to the understanding of the interaction of predator-prey relationships, it should be recognized and valued as such. (Isle Royale), (Isle Royale National Park), (Isle Royale Wolves)
Both the Yellowstone and the Isle Royale case modeled Howard Odum’s theories. In the Yellowstone case, the wolves used the energy they gained when consuming other animals, that originally derived from the sun, to survive. In the Isle Royale case the moose and wolves lived off of each other and the other producers and consumers in the environment. The moose of Isle Royale consumed both plants and other animals, receiving a portion of all of their energy to use as their own. The wolves main prey was the moose. Also, both cases could be categorized by their status as a self-organizing system. The level of production in the Yellowstone and Isle Royale ecosystem is dependant upon the growth of consumption in both environments. When the levels of consumption and henceforth production are high and close to equilibrium, the development of the system takes place more rapidly and more efficiently. Odum’s concept of emergy also applies to both cases. The energy required to sustain life within the two ecosystems is considered that specific ecosystem’s emergy. The amount of life that is sustained with this amount of emergy is the ecosystem’s carrying capacity.
These two specific examples, Yellowstone and Isle Royale, exemplify Howard Odum’s theories of ecosystem ecology and self-organizing systems. Both theories lead to an understanding of carrying capacities of different environments, and how they can be manipulated and modeled.
References
Carrying Capacity. http://www.ace.mmu.ac.uk/esd/Principles/Carrying_Capacity.html
Ecological Model. http://en.wikipedia.org/wiki/Ecological_model
"Howard T. Odum." Notable Scientists: From 1900 to the Present. Gale Group, 2001.
Reproduced in Biography Resource Center. Farmington Hills, Mich.: Thomson Gale. 2007. http://galenet.galegroup.com/servlet/BioRC
Howard T. Odum. (1). http://www.eoearth.org/article/Odum,_Howard_T.
Howard T. Odum. (2) http://en.wikipedia.org/wiki/Howard_T._Odum
Isle Royale. http://www.nps.gov/isro
Isle Royale National Park. http://www.isle.royale.national-park.com/info.htm#moose
Isle Royale Wolves. http://www.isleroyalewolf.org/wolfhome/home.html
Science, Self-Organization, Transformity, and Information, November 25, 1988, pp. 1132-1139.
W. F. Humphreys, "Ecological energetics", in AccessScience@McGraw-Hill, http://www.accessscience.com, DOI 10.1036/1097-8542.212150
Wolves and Moose on Isle Royale. http://en.wikipedia.org/wiki/Wolves_and_Moose
_on_Isle_Royale
Yellowstone Wolves. http://www.yellowstone-bearman.com/wolves.html
Yellowstone Wolf Reintroduction http://en.wikipedia.org/wiki/Wolf_reintroduction#
Yellowstone_National_Park_and_Idaho