Related Experiment Video
Updated: May 18, 2026
10:23
A Concoction Pipeline for Generating Molecular Operational Taxonomic Units (MOTUs) Among Riparian and Aquatic Beetles
Published on: July 11, 2025
Is regional species diversity bounded or unbounded?
1Department of Environmental Science and Policy, University of California, Davis, CA 95616, USA. hvcornell@ucdavis.edu
Biological Reviews of the Cambridge Philosophical Society
|September 11, 2012
Summary
Species diversity generally increases over time but slows due to ecological constraints, not reaching upper limits. This suggests a new "damped increase hypothesis" for understanding biodiversity patterns.
Area of Science:
- Ecology
- Evolutionary Biology
- Paleontology
Background:
- Two hypotheses, unbounded and bounded, explain species diversity patterns.
- Unbounded: diversity increases indefinitely with time and rate.
- Bounded: ecological limits cap regional diversity.
Purpose of the Study:
- To evaluate existing hypotheses on species diversity.
- To propose a new hypothesis explaining diversity patterns.
- To identify factors influencing regional diversity.
Main Methods:
- Analysis of fossil records.
- Phylogenetic analysis.
- Biogeographical studies.
- Phenotypic disparity analysis.
Main Results:
- Evidence suggests diversity is ecologically constrained but rarely reaches asymptotic limits.
- Niche space is often unfilled or subdividable, with new niches created before limits are reached.
- Damped increases in diversity over time are prevalent.
Conclusions:
- A 'damped increase hypothesis' is proposed, where diversity increases but slows due to constraints.
- Distinguishing niche limitation from other factors (sampling, extinction detection, speciation dynamics) is crucial.
- Broader taxonomic scope and integrated evolutionary/ecological data are needed to explain diversity variations.
Related Concept Videos
01:19What is Biodiversity?
Biodiversity describes the variety of living things at multiple organizational levels: genetic, species and ecosystem diversity. Species diversity includes all branches of the evolutionary tree from single-celled prokaryotic organisms, bacteria, and archaea, to the eukaryotic kingdoms: plants; animals; fungi; and protists. To date, there have been about 1.75 million species identified, and new species are discovered every week.
00:54Distribution and Dispersion
To understand intra-specific interactions in populations, scientists measure the spatial arrangement of species individuals. This geographic arrangement is known as the species distribution or dispersion. Highly territorial species exhibit a uniform distribution pattern, in which individuals are spaced at relatively equal distances from one another. Species that are highly tied to particular resources, such as food or shelter, tend to concentrate around those resources, and thus exhibit a...
01:31Formation of Species
Speciation describes the formation of one or more new species from one or sometimes multiple original species. The resulting species are discrete from the parent species, and barriers to reproduction will typically exist. There are two primary mechanisms, speciation with and without geographic isolation—allopatric and sympatric speciation, respectively.
01:07Speciation Rates
Overview
01:17What is a Species?
Overview
02:31Habitat Fragmentation
Habitat fragmentation describes the division of a more extensive, continuous habitat into smaller, discontinuous areas. Human activities such as land conversion, as well as slower geological processes leading to changes in the physical environment, are the two leading causes of habitat fragmentation. The fragmentation process typically follows the same steps: perforation, dissection, fragmentation, shrinkage, and attrition.