Биоразнообразие и его оценка. Концептуальная диверсикология - Протасов А.А.
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Диверсикология как экология в целом еще далека от создания целостной теории, многие концепции не только не дополняют друг друга, но и находятся в противоречии. Устранение этих противоречий и должно быть в центре внимания как теоретических разработок, так и прикладных исследований. Наука не должна «притворятся технологичной или мифологичной только для того, чтобы раздобыть деньги для своего существования» (Ги-ляров, 1996); рано или поздно теоретические положения становятся востребованы практикой, также как мифична полностью стерильная от практических проблем наука.
Мы далеки от мысли, что нам удалось охватить своим исследованием все экологические проблемы, связанные с биоразнообразием или даже их существенную часть. Однако если рассмотренные вопросы и их интерпре-
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Биоразнообразие и его оценка. Концептуальная диверсикология
тация вызовут интерес у читателя и желание продолжить дискуссию, цель данной работы можно считать достигнутой.
Summary
Research of biodiversity, its forming processes and reasons for its increase and decrease, takes one of the key places in the modern ecology. A section of ecology called diversicology can be designated to deal with these and related issues. The objective of this section (this section alone) is to elucidate the common trends in formation of biotic systems' diversity, its supportive mechanisms and its limitation. Biodiversity can be divided into biological — the diversity of biosystems down to the organismic level inclusive, and biotic — the diversity of systems of the above-organismic level. Environmental factor and factor of resources have their own diversity. The system connecting environmental and biotic represents the ecosystem diversity.
Biodiversity is two-component and includes two constituents — abundance of elements (for example, number of species in communities) and evenness in representation and significance of elements (for example, correlation of number of specimens in populations) (position 1.13). Many methods for the quantitative evaluation of diversity using various indexes have been introduced. Wide usage of the Shannon index for the quantitative evaluation of diversity is determined by the fact that it successfully combines consideration of both components (position 1.12).
When evaluating the diversity it should be considered that application of any index is based on assumption that all systems' elements are equivalent, and only their quantity and correlation of representation based on certain criterions are taken into consideration (position 1.20). However, it is obvious, that in real bio-systems it is far from being true. Elements of ecosystems, species in community, for example, can have higher or lower degree of importance for the functioning of the whole system and for its ability to steadiness for external disturbances. Besides, it is necessary to consider subsystem organization of biosystems: there are subsystems with elements that are more tightly connected internally than to the elements of other subsystems (position 1.22, 1.29). One of components of diversity — evenness is directly related to the degree of domination. However, formally, quantitative domination does not necessary correspond to the real role of the species in community. It is suggested to use the biocenotic MP-gradient (Mobius — Petersen gradient) principle. The dominating form of the M-pole communities really modifies conditions for other populations. Communities whose statistical dominant has no essential influence on the biotic interaction are located on the P-pole. The powerful edificator usually forms system of consortia relations and this also complicates diversity evaluation of communities based on the formal indexes (position 1.32). These peculiarities of communities structure have to be taken into account when evaluating diversity of communities. For example, decrease of the relative significance of a dominant causes not only the formal increase of diversity estimated by indexes, but also leads to disappearance
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Summary
of many consortia relations, decrease in species abundance. These inconsistent processes influence the results of diversity evaluation performed for the purposes of bio-indication, for example.
At this point it can be useful to introduce the concept of two variants of homogeneity of the relative abundance. Homogeneity of the first type is related to equal representation of all elements in the system. Homogeneity of the second type is present when community is sufficiently homogeneous due to representation of dominant species. Homogeneity of the second type is usually considered as simplification of systems. Community with high dominance and low evenness has low diversity indexes. Thus, the low diversity is associated with the simpler community structure. However, this concept can be accepted only for the P-type communities, where dominant (even with high prevalence) is formal and does not form the system with consortia relations. In general it can be concluded that complexity of communities is not always directly related to their species diversity.
