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What is biodiversity, how to measure biodiversity..and classification
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THE MEASURE OF BIODIVERSITY
How do we define ‘biodiversity’?
The sum of all biotic variation from the level of genes to ecosystems.
The number, variety, and variability of living organisms in a quantified area.
Methods to Measure Biodiversity
Species Richness Species Evenness Disparity Species Rarity Genetic Variability.
Measuring Biodiversity…
Species Richness; the total number of given species in a quantified area.
Species Evenness; the degree to which the number of individual organisms are evenly divided between different species of the community.
www.nature.com/cgi-tafwww.nature.com/cgi-taf
Measuring Biodiversity…
Disparity; measures the phenotypic differences among species resulting from the differences genes within a population.
Species Rarity; the rarity of individual organisms within a quantified area.
http://www.rit.edu/~rhrsbi/GalapagosPages/DarwinFinch.html
Biodiversity & Genetics
Genetic Variability: each population of a species contributes to additional biodiversity due to variations between genes.
http://magma.nationalgeographic.com/ngm/bestwildlife/wallpaper13.html
Biodiversity and the Relationship to Ecosystem Functions Diverse communities are typically more stable
and function more efficiently. Loss of a umbrella species leads to a unoccupied
niche, in turn potentially affecting ecosystem processes.
Extinction events are commonly followed by high rates of diversification. Ex) Species turnover
Productivity
Increase of productivity in an area corresponds with an increase in biodiversity.
Ex) tropical rain forest compared to semi-desert or tundra
Biodiversity & Exotic Species;
Ecosystems with high measures of biodiversity are more resistant to invader species.
Ex) Cheatgrass & Tamarisk
http://tncweeds.ucdavis.edu/ http://tncweeds.ucdavis.edu/photos
Keystone & Umbrella Species
Species whose presence or resource requirements affect ecosystem functions.
Health of an umbrella species is a way to monitor the health of an ecosystem.
Ex) Northern Spotted Owl & Grizzly Bears
Taxonomy
New Discoveries
Grouping together
Splitting apart
Phylogenies; showing past relationships between organisms using evolutionary lineages.
Increasing Species Worldwide
Phylogenic Species Concept
Computer databases
Increased human exploration
Technology; electron microscope and evidence using mDNA.
Species Richness
www.nature.com/cgi-tafwww.nature.com/cgi-taf
Taxonomic methods used in relation to quantifying biodiversity
Phylogenic Species Concept
Biological Species Concept
Evolutionary Species Concept
Phylogenic Species Concept
taxa are separate species if they can be diagnosed as distinct either by phenotypic or genotypic information.
Leads to an increase in the number of species.
Does not allow for natural variations within populations to be listed as separate species.
Biological Species Concept
Groups of organisms that can interbreed freely under natural conditions.
Most commonly used of the three
Evolutionary Species Concept
Groups organisms together using an ancestral/descendant relationship that is traceable in the fossil record
Focuses on studying the morphological features of closely related organisms.
Problems in General
Measuring biodiversity is ultimately a complex process involving many facets.
Various applications of species concepts either divide and/or group organisms together.
Biodiversity can’t be reduced to a single number.
Studying biodiversity using all ecosystem processes at all scales.
In attempting to preserve biodiversity we often are ‘speciesists’ ;favoring the cute and popular species.
Conclusions
Generally, areas of higher productivity correlate with increases in biodiversity.
Biodiversity is also measured using the genetic variability of different populations of a single species.
Biodiversity can’t be reduced to a single number, thus creating complications when comparing biodiversity in different ecosystems.
The importance of biodiversity is accepted by some and disregarded by many others.
QUESTIONS…
How do different taxonomic methods create potential problems in measuring biodiversity?
How do difficulties in measuring biodiversity create complications for policy makers and administrative regulations?
Can we study all processes at all scales?
Why should anyone care
about‘biodiversity’ ?
REFERENCES;
Purvis, Andy. Hector, Andy. May 2000. Getting the Measure of Biodiversity. Nature Magazine. Vol.405 pgs 212-219. Berkshire, United Kingdom.www.nature.com/cgi-taf
Wildland Invasive Species Team. July 2002.Vernal, UT. Retrieved on 10-26-02
http://tncweeds.ucdavis.edu/photos Macdonald, Glen. 2003. Biogeography; Introduction to Space, Time, and Life. New York.
John Wiley & Sons Inc. Sartore, Joel. 2002. National Geographic Society. Retreived 10-20-02 http://magma.nationalgeographic.com/ngm/bestwildlife/ wallpaper13.html Dr. Robert Rothman: Darwin’s Finches. Retrieved on 10-18-02.
http://www.rit.edu/~rhrsbi/GalapagosPages/DarwinFinch
Paul Walker. Balam Na Project. Rainforest Preserve. 8-28-02 http://www.rainforest.org/projects/balamna/balamna.html
Paul Williams, 2002 ”Biodiversity: Measuring the variety of nature and selecting the priority areas for conservation.” London, 10/23/02, http://www.nhm.ac.uk/science/projects/worldmap/
Bryant, Peter J., 2001, “Biodiversity and Conservation: A Hypertext book”. Irvine, 10/23/02, http://darwin.bio.uci.edu/~sustain/bio65/Titlpage.htm#Table%20of%20contents
Dooley, Laura Lee S., 1982-2002, “Biodiversity and Protected Areas”, Washington D.C., 10/23/03, http://www.wri.org/biodiv/
