Unified neutral theory of biodiversity

Hubbell_Unified_Neutral_Theory_Cover

The Unified Neutral Theory of Biodiversity (UNTB) is a theory and model in ecology and biogeography that attempts to explain the diversity and relative abundance of species in ecological communities. It was proposed by Stephen Hubbell in 2001. The theory posits that the biodiversity of an ecosystem is the result of random processes of speciation, extinction, and dispersal.

Overview

The UNTB challenges the traditional niche theory, which suggests that species coexist by occupying different niches. Instead, the UNTB assumes that all individuals within a trophic level are ecologically equivalent, meaning that the differences between species are neutral in terms of their ability to survive and reproduce. This neutrality implies that the relative abundance of species is governed by stochastic events rather than deterministic factors.

Key Concepts

• Ecological Equivalence: The assumption that all individuals of all species are functionally equivalent in their per capita probabilities of giving birth, dying, and dispersing.
• Speciation: The process by which new species arise. In the context of UNTB, speciation is considered a random event.
• Extinction: The process by which species disappear. Extinction events are also considered random under the UNTB.
• Dispersal: The movement of individuals from one location to another. Dispersal events are random and play a crucial role in maintaining biodiversity according to the UNTB.

Mathematical Framework

The UNTB uses mathematical models to predict species abundance distributions, species-area relationships, and other patterns of biodiversity. The models often involve complex calculations and simulations to account for the random processes of birth, death, and dispersal.

Criticism and Support

The UNTB has been both supported and criticized within the scientific community. Supporters argue that it provides a simple and elegant explanation for many patterns of biodiversity. Critics, however, point out that the assumption of ecological equivalence is unrealistic and that the theory does not account for the role of natural selection and adaptation.

Applications

The UNTB has been applied to various ecosystems, including tropical forests, coral reefs, and microbial communities. It has also been used to inform conservation strategies by providing insights into the processes that maintain biodiversity.

Related Pages

• Ecology
• Biogeography
• Speciation
• Extinction
• Dispersal
• Niche theory
• Stephen Hubbell

See Also

• Species abundance distribution
• Species-area relationship
• Stochastic processes