4 public questions tagged with this topic.
Ecological succession is the gradual process of change in species composition within an ecosystem over time.
Ref: NCERT Class 12 Biology Chapter 11: Organisms and Populations Population Attributes - Birth Death Sex Ratio Age Distribution
Secondary succession occurs after disturbances like wildfires, where the soil remains intact, allowing for faster recovery.
Ref: NCERT Class 12 Biology Chapter 11: Organisms and Populations Adaptations - Morphological Physiological Behavioural
Beta diversity represents species turnover among communities, habitats, or sites. It is high when local assemblages share few species and low when they are compositionally similar. Pairwise turnover can be measured with dissimilarity coefficients such as 1 minus Jaccard or Sørensen similarity, while regional multiplicative partitioning uses β = γ/α. Alpha diversity describes diversity within one local community, and gamma diversity is the pooled diversity across the wider region. Delta diversity is sometimes applied to turnover across larger geographic gradients, but beta is the standard between-community component. Turnover should be distinguished from nestedness. Two sites may differ because one contains a subset of the other, producing richness loss without true species replacement; modern beta-diversity analyses can separate these components. Environmental filtering, dispersal limitation, geographic distance, disturbance, and historical barriers all generate turnover. For conservation, high beta diversity means that protecting a single species-rich site may fail to capture many regional species, so multiple compositionally distinct habitats are needed. The concept therefore links local assemblages to regional gamma diversity by quantifying how rapidly membership changes across space or time.
Ref: NCERT Biology Class 12, Ch. 15 Biodiversity and Conservation
Ecological succession is the directional change in community composition and structure through time, often involving gradual replacement of one group of species by another. A disturbance or newly exposed habitat creates opportunities for colonists. Those organisms alter resource availability, soil, shade, moisture, or interactions, influencing which species establish next. Replacement can proceed through facilitation, tolerance, inhibition, or combinations of these processes. Succession differs from evolution, which is heritable change in populations across generations; species composition can shift without genetic evolution. Zonation is a spatial pattern of communities along an environmental gradient, such as elevation or tidal height, rather than a temporal sequence. Competition can drive replacement but is only one mechanism within succession. “Gradual” should not be read as uniformly slow: fires, storms, invasions, and episodic recruitment can produce abrupt transitions. Nor must succession end in a single fixed climax. The core concept is temporal turnover in communities as organisms, environment, and disturbance history interact.
Ref: Ecology: Concepts and Applications, Molles, 9th Ed., Ch. 20
