Ecology: the Biology of Interactions. 3.01. Ecosystems and Biogeocoenoses
Chapter 3. Biogeocoenology and Community Ecology. Ecology studies different levels of biosystems, from the organismal (or even lower) to the biospheric. Yet the level most characteristic for the biological science of interactions is the ecosystem/community level...
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2.17. (addendum) Anthropogenic Paradox
D. Shabanov, M. Kravchenko. Ecology: Biology of Interactions Section 3. Biogeocenology and Ecology of Communities
3.02. Ecosystem Components
Section 3. Biogeocenology and Community Ecology 3.01. Ecosystems and Biogeocenoses Within ecology, various levels of biosystems are studied—from the organismal (or even lower) to the biosphere. However, the most characteristic level for the biological science of interactions is, of course, the ecosystem level. We have already discussed (see point 2.02) that life on Earth likely originated as separate ecosystems. It is within ecosystems that the cycling of matter and the transformation of energy entering our planet occur; it is ecosystems that create the totality of ecological niches to which organisms adapt. Finally, despite all its specificity, the biosphere is also an ecosystem, just a very large one, encompassing all the surface layers of our planet. The first thing to do when starting a discussion about ecosystems is to clarify the terminology. Unfortunately, this area of ecology also suffers from a certain terminological confusion due to the existence of two closely related terms: "ecosystem" and "biogeocenosis" (Fig. 3.1.1). The former term is older; it was introduced in 1935 by the American ecologist Arthur Tansley. An ecosystem is "a unit that includes all of the living organisms (biotic components) in an area as well as the nonliving physical environment (abiotic components) of that area" (A. Tansley). Fig. 3.1.1. Comparison of the composition of a biogeocenosis and an ecosystem Developing Tansley's approach, we can say that an ecosystem is a combination of living organisms and their environment, within which matter cycles and energy flow are transformed. An ecosystem consists of a community (living components) and a habitat (or biotope, the non-living part). The term "biogeocenosis" was introduced by the prominent Soviet botanist, ecologist, and forester Volodymyr Mykolaiovych Sukachov. Sukachov had specific reasons for introducing the new term. On the one hand, the concept of biogeocenosis stemmed from research on plant communities, which possess a certain extent and integrity. On the other hand, there was a struggle in Soviet biology against "foreign influences," which included American ecology. Sukachov utilized the term "biocenosis," proposed for describing interconnected communities of living organisms back in the 19th century, and developed the concept of biogeocenosis. "A biogeocenosis is a combination, over a certain extent, of uniform natural phenomena (atmosphere, rock, vegetation, animal world and microorganism world, soil, and hydrological conditions), possessing its own specific interaction of these constituent components and a certain type of matter and energy exchange among themselves and with other natural phenomena, and representing an internally contradictory unity that is in constant motion and development" (V. M. Sukachov, 1964). Analyzing Sukachov's definition, one can see the reflection of the prevailing ideology of his time—dialectical materialism, manifested in the discussion of "contradictory unity." However, it is evident that, unlike Tansley's approach, Sukachov pays special attention to the interdependence and relative uniformity of the components of a biogeocenosis. A biogeocenosis consists of a biocenosis and a geocenosis. A biocenosis, according to Sukachov, consists of a phytocenosis, a zoocenosis, and a microbocenosis, while a geocenosis consists of an edaphotope (components related to soil and underlying rocks) and a climatotope (components related to the atmosphere and hydrosphere). There are two viewpoints on the relationship between the terms "ecosystem" and "biogeocenosis." Sometimes they are considered identical or very similar (Fig. 3.1.1). However, it is more accurate to consider the concept of an ecosystem as more general and scale-independent, and to refer to biogeocenoses as ecosystems of a specific scale. An important idea attributed to Sukachov and his scientific school is that the integrating element of a biogeocenosis is its vegetation—the phytocenosis. If this is the case, the boundaries of biogeocenoses should be drawn along the boundaries of phytocenoses. "A biogeocenosis is an ecosystem within the boundaries of a phytocenosis" (Ye. M. Lavrenko, N. V. Dylis, 1968). Is it worth paying so much attention to discussing these terms? In our opinion, yes. To study an object or phenomenon, one must grasp its integrity and distinguish it from the chaos of random interrelationships. A well-chosen term allows this task to be accomplished. The branch of ecology that studies ecosystems is best called biogeocenology, and the part of it that studies the living components of ecosystems themselves (biocenoses, communities) is called community ecology.
2.17. (addendum) Anthropogenic Paradox
D. Shabanov, M. Kravchenko. Ecology: Biology of Interactions Section 3. Biogeocenology and Ecology of Communities
3.02. Ecosystem Components