Navigation Links
Traditional models underestimate extinction rates

Last year, the World Conservation Union reported an unprecedented decline in biodiversity, with nearly 16,000 species facing extinction. The biggest threat to most species is loss of habitat. And as habitat loss and degradation proceed nearly unabated, the need to accurately predict the population dynamics and extinction risk of potentially endangered species has never been greater. In a new study, John Drake tests models traditionally used to estimate the likelihood of extinction and shows that because they ignore a critical parameter in projecting risk, they underestimate extinction rates.

Standard models for predicting extinction assume that population growth and decline are governed by random, or stochastic, variables. But few scientists have actually tested the accuracy of these models with empirical data. To do this, Drake first manipulated the available food sources in 281 populations of water fleas, because it's generally assumed that fluctuating environments, a given in the natural world, increase a species's chance of extinction. Drake then used half of the experimental data generated from testing the effects of environmental variability on water flea survival to select his models and estimate a range of parameters that might affect extinction, and the other half to test the models' reliability. From the estimated parameters, Drake wrote a computer program to simulate all the possible population outcomes and predict extinction rates. However, one set of simulations included a parameter for density-dependent random interactions and another did not. The idea is that if organisms interact with each other in their environments--which of course they do--then these interactions will likely affect an individual's probability of dying or reproducing, which ultimately affects species survival. Drake calls this variable density-dependent demographic stochasticity. Only when density-dependence was included did the models match the observed extinction rates in the flea experiments. When density dependence was not included, extinction rates were greatly underestimated.

Drake's results underscore the importance of bolstering extinction models with empirical validation--and of accounting for population density--to accurately evaluate risk and enhance recovery programs for at-risk populations. As threats to endangered species continue to mount, biologists will need ever more robust methods to estimate extinction risk. Unfortunately, field biologists typically can't generate the large, high-quality datasets that led to the precise predictions reported here. Conservation efforts will depend on developing methods of generating reliable predictions with the limited data available from the field.


Citation: Drake JM (2005) Density-dependent demographic variation determines extinction rate of experimental populations. PLoS Biol 3(7): e222.


Source:Public Library of Science

Related biology news :

1. Traditional Chinese medicine for diabetes has scientific backing
2. Molecular models advance the fight against malaria
3. A new way to share models of biological systems
4. Understanding biases in epidemic models important when making public health predictions
5. Gene therapy advance treats hemophilia in mouse models
6. Targeting a key enzyme with gene therapy reversed course of Alzheimers disease in mouse models
7. Elusive salamanders have role in developing new sampling models
8. Computer models aid understanding of antibody-dependent enhancement in spread of dengue fever
9. Sickle cell disease corrected in human models using stem cell-based gene therapy
10. Blocking the nerve receptor EP1 in mouse models reduces brain damage caused by stroke
11. Setting the standard for computer models of life
Post Your Comments:

(Date:6/2/2016)... , June 2, 2016   The Weather Company , ... Watson Ads, an industry-first capability in which consumers will be ... able to ask questions via voice or text and receive ... Marketers have long sought an advertising ... that can be personal, relevant and valuable; and can scale ...
(Date:5/16/2016)... YORK , May 16, 2016   EyeLock ... solutions, today announced the opening of an IoT Center ... to strengthen and expand the development of embedded iris ... an unprecedented level of convenience and security with unmatched ... authenticate one,s identity aside from DNA. EyeLock,s platform uses ...
(Date:4/28/2016)... First quarter 2016:   , Revenues amounted to ... of 2015 The gross margin was 49% (27) ... operating margin was 40% (-13) Earnings per share rose ... was SEK 249.9 M (21.2) , Outlook   ... The operating margin for 2016 is estimated to exceed ...
Breaking Biology News(10 mins):
(Date:6/27/2016)... - BIOREM Inc. (TSX-V: BRM) ("Biorem" or "the Company") announces ... Clean Technology Fund I, LP and Clean Technology Fund ... venture capital funds which together hold approximately 59% of ... as converted basis), that they have entered into an ... in Biorem to TUS Holdings Co. Ltd. ("TUS") ( ...
(Date:6/27/2016)... ... June 27, 2016 , ... Rolf K. ... the faculty of the University of North Carolina Kenan-Flagler Business School ... entrepreneurship at UNC Kenan-Flagler, with a focus on the school’s international efforts, leading ...
(Date:6/24/2016)... ... 2016 , ... While the majority of commercial spectrophotometers and fluorometers use the ... models are higher end machines that use the more unconventional z-dimension of 20mm. ... the bottom of the cuvette holder. , FireflySci has developed several Agilent flow ...
(Date:6/23/2016)... , June 23, 2016 /PRNewswire/ - FACIT ... Ontario biotechnology company, Propellon Therapeutics ... development and commercialization of a portfolio of first-in-class ... Epigenetic targets such as WDR5 represent an exciting ... significantly in precision medicine for cancer patients. Substantial ...
Breaking Biology Technology: