Ecology: the Biology of Interactions. 3.09. Trends in Successions
In the typical case, during succession (for example in an artificial system—a microcosm—or during colonization of a new habitat in primary autotrophic succession), the following is observed: first, production and turnover rates grow rapidly...
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3.08. Successions. Basic Concepts
D. Shabanov, M. Kravchenko. Ecology: Biology of Interactions Section 3. Biogeocenology and Ecology of Communities
3.10. Nature and characteristics of communities
3.09. Trends in succession In a typical case, during succession (e.g., in an artificial system - a microcosm, or during the colonization of a new habitat in the course of primary autotrophic succession), the processes shown in Fig. 3.9.1 are observed. Initially, production increases rapidly, respiration lags behind, leading to biomass accumulation. After reaching climax, respiration catches up with production, and all system parameters stabilize. Fig. 3.9.1. Change in productivity during autotrophic succession Species diversity (or, for example, the number of species) during primary autotrophic succession usually increases, reaches a maximum when the climax community has already appeared, and the last serial community has not yet disappeared, and then slightly decreases (Fig. 3.9.2). Fig. 3.9.2. Dynamics of species diversity during succession Some of the trends observed in successions are summarized in Table 3.9.1, which concerns the 'typical' case of primary autotrophic succession. The early series described in the table (inhabiting a relatively favorable environment) differ from the low-productivity pioneer communities that settle during primary successions on inhospitable inorganic substrates. Table 3.9.1. Typical trends in autotrophic primary succession (after E. Odum, 1975)
Characteristics
Early series
Climax
P/R (ratio of gross production to respiration)
Differs from 1
Approximately 1
P/B (gross production/standing crop)
High
Low
B/E (biomass/energy flow)
Low
High
Yield
High
Low
Food chains (see section 3.11)
Linear, predominantly grazing
Branched, many detrital ones
Accumulated organic matter
Little
Many
Inorganic biogenic substances
Free
Linked
Species diversity
Low
High
Biochemical diversity
Low
High
The structuredness of the environment
Weak
Complex
Width of ecological niches (see section 4.13)
Broad
Narrow
Sizes of the organisms
Minor
Large
Life cycles
Short, simple
Complex, long
Mineral cycles
Open
Closed
Metabolic rate
High
Low
Role of detritus in biogen regeneration
Insignificant
Significant
Nature of selection (see section 4.15)
r-
K-
r-
Quantity
Quality
Internal mutualism
Undeveloped
Developed
Stability (resistance to influences)
Low
High
Entropy
High
Low
3.08. Successions. Basic Concepts
D. Shabanov, M. Kravchenko. Ecology: Biology of Interactions Section 3. Biogeocenology and Ecology of Communities
3.10. Nature and characteristics of communities