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Eutrophication causes speciation reversal in whitefish adaptive radiations
P Vonlanthen1, D Bittner, A G Hudson
1Division of Aquatic Ecology and Evolution, Institute of Ecology and Evolution, University of Bern, Baltzerstrasse 6, CH-3012 Bern, Switzerland.
Nature
|February 17, 2012
Summary
Species diversity loss is driven by eutrophication, causing extinctions through demographic decline and speciation reversal. Protecting ecological processes is key to conserving species and preventing further biodiversity loss.
Area of Science:
- Ecology
- Evolutionary Biology
- Conservation Science
Background:
- Species diversity is threatened by demographic decline and speciation reversal via introgressive hybridization.
- Understanding the interplay of these extinction processes is crucial for effective conservation.
Purpose of the Study:
- To investigate the relative contribution of demographic decline and speciation reversal to species loss.
- To analyze how ecological opportunity and eutrophication influence extinction processes in whitefish radiations.
Main Methods:
- Analysis of historical and contemporary data from whitefish radiations in 17 pre-alpine European lakes.
- Reconstruction of changes in genetic species differentiation over time using historical samples.
Main Results:
- Species diversity evolved in response to ecological opportunity.
- Eutrophication diminishes ecological opportunity, driving extinctions through speciation reversal and demographic decline.
- The extent of eutrophication correlates with species loss and the distinctiveness of remaining species.
Conclusions:
- Extinction by speciation reversal may be more common than previously thought.
- Conservation efforts must protect the ecological and evolutionary processes that generate and maintain species, not just existing species.
Related Concept Videos
01:07Speciation Rates
Overview
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.
02:16Genetics of Speciation
Speciation is the evolutionary process resulting in the formation of new, distinct species—groups of reproductively isolated populations.
02:29Hybrid Zones
Hybrid zones are narrow regions where two closely related species interact, mate, and produce hybrids. Relative to either parent species, hybrids may possess distinct phenotypic or genetic differences that impact their survival and reproductive success. The genetic variances introduced by hybridization influence species diversity and speciation processes within the hybrid zone.
02:04Conservation of Small Populations
Small population sizes put a species at extreme risk of extinction due to a lack of variation, and a consequent decrease in adaptability. This weakens the chances of survival under pressures such as climate change, competition from other species, or new diseases. Large populations are more likely to survive pressures such as these, as such populations are more likely to harbor individuals that have genetic variants that are adaptive under new stresses. Small populations are much less likely to...
02:39Gene Flow
Gene flow is the transfer of genes among populations, resulting from either the dispersal of gametes or from the migration of individuals.