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Four Cycles The following is an excerpt from the web site of the Allan Savory Center for Holistic Management. The four fundamental
processes that operate in any ecosystem are: water cycle, mineral cycle, solar
energy flow and community dynamics (the patterns of change and development
within communities of living organisms). Consciously modify any one of these processes, and you automatically change all of them in some way because, in reality, they are only different aspects of the same thing. It helps if you think of them as four different windows through which you can observe the same room – our ecosystem as it functions. You cannot have an effective water or mineral cycle or adequate energy flow without communities of living organisms, and vice versa. If you wanted to change the water cycle on a piece of land you would plan which tools to use and how to use them. But before going further, you would also consider how those tools would affect the mineral cycle, energy flow and community dynamics. All of us – not just
scientists, or farmers, foresters, and others
managing land – must begin to acquire a basic understanding of the
fundamental processes through which our ecosystem functions, if only to better
understand our dependence on them. You can only read these words because the
sun shone on the leaves of a plant somewhere and the leaves converted that
sunlight energy to food and oxygen. You ate the food and inhaled the oxygen,
both of which enabled you to read these words and understand them. It will
soon be unacceptable for any economist, politician, or corporate CEO to remain
environmentally illiterate, and thus ignorant of these processes and our
connection to them. 1. The water cycle An effective water cycle requires a covered and biologically active soil. When effective, most water soaks in quickly where it falls. Later, it is released slowly through plants that transpire it, or through rivers, springs and aquifers that collect, through seepage, what the plants do not take. When soil is exposed and biological activity reduced, most water runs off as floods. What little soaks in is released rapidly from evaporation which draws moisture back up through the soil surface. 2. The mineral cycle An effective mineral cycle also requires a covered and biologically active soil. When effective (left), many nutrients cycle between living plants and living soil continually. When soil is exposed and biological activity low (right), nutrients become trapped at various points in the cycle or are lost to wind and water erosion. 3. Community dynamics With few exceptions, natural communities strive to develop toward ever-greater complexity and thus stability. From unstable bare ground, where biological activity is low, stable range or forest communities develop over time. When humans reduce this complexity by planting monoculture crops or lawns, for instance, they so defy the principles of nature that they can only be maintained by unnatural means, and then only temporarily. As components within nature, humans cannot escape this principle any more than other organisms can. 4. Energy flow Almost all life requires the energy that flows daily from the sun. The basic conversion of this solar energy to usable form takes place through plant material on land and in water. That's why plants form the base of the energy pyramid depicted here. As the energy passes from plants to whatever eats them, and in turn eats the eaters of the plants, some is lost as heat, and eventually it all is. Thus, energy doesn't cycle; it flows through the ecosystem until it's used up. See Holistic Management for brief review of book by Allan Savory. Return to Top
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