Transcript MEASURING BIODIVERSITY

GETTING THE MEASURE OF
BIODIVERSITY
How do we define ‘biodiversity’?
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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
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Species Richness
Species Evenness
Disparity
Species Rarity
Genetic Variability.
Measuring Biodiversity…
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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-taf
Measuring Biodiversity…
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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
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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
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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
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Increase of productivity in an area corresponds
with an increase in biodiversity.
Ex) tropical rain forest compared to semi-desert
or tundra
http://www.rainforest.org/projects/balamna/balamna.html
Biodiversity & Exotic Species;
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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
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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
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New Discoveries
Grouping together
Splitting apart
Phylogenies; showing past
relationships between organisms
using evolutionary lineages.
Increasing Species Worldwide
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Phylogenic Species Concept
Computer databases
Increased human exploration
Technology; electron microscope
and evidence using mDNA.
Species Richness
www.nature.com/cgi-taf
Taxonomic methods used in
relation to quantifying
biodiversity
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Phylogenic Species Concept
Biological Species Concept
Evolutionary Species Concept
Phylogenic Species Concept
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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
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Groups of organisms that can
interbreed freely under natural
conditions.
Most commonly used of the three
Evolutionary Species Concept
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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
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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
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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…
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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;
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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
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Wildland Invasive Species Team. July 2002.Vernal, UT. Retrieved on 10-26-02
http://tncweeds.ucdavis.edu/photos
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Macdonald, Glen. 2003. Biogeography; Introduction to Space, Time, and Life. New York. John
Wiley & Sons Inc.
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Sartore, Joel. 2002. National Geographic Society. Retreived
10-20-02 http://magma.nationalgeographic.com/ngm/bestwildlife/ wallpaper13.html
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Dr. Robert Rothman: Darwin’s Finches. Retrieved on 10-18-02.
http://www.rit.edu/~rhrsbi/GalapagosPages/DarwinFinch
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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/
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Happy Halloween