Transcript Biodiversity

Biodiversity
Something catchy here
• The outstanding scientific discovery of the twentieth
century is not television, or radio, but rather the
complexity of the land organism. Only those who know
the most about it can appreciate how little we know
about it. The last word in ignorance is the man who
says of an animal or plant: "What good is it?" If the
land mechanism as a whole is good, then every part is
good, whether we understand it or not. If the biota, in
the course of aeons, has built something we like but
do not understand, then who but a fool would discard
seemingly useless parts? To keep every cog and wheel
is the first precaution of intelligent tinkering.
Aldo Leopold, A Sand County Almanac, and Sketches
Here and There, 1948
What is Biodiversity?
• Biodiversity can be expressed or measured in four
different ways:
– Genetic variability within a species
– Diversity of populations of a species.
– Diversity of species within a natural community.
– A wide array of natural communities and ecosystems
We will focus on diversity of species
– Diversity of species within a natural community
• Examples:
– Fish species in a lake
– Bird species in a forest
– Snail species in a pond or stream
– Parasite species in a host
So, How Do We Measure Biodiversity?
• Count species in a pond, river, city, county,
state, etc.
• How many species per unit (e.g., pond, river)
• How many of each species in an area
• Richness, abundance, etc
• Indicator taxa
Fort Collins Natural Areas
• Many cities invest much time
and money creating and
preserving wildlife habitat
• The city of Fort Collins
manages over 36,000 acres of
natural areas in and around
the city
• 37 natural areas
(as of early 2008)
Animals that use Fort Collins natural areas*
Long-tailed weasel, summer coat
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Marsupials (1)
Insectivores (4)
Rabbits and allies (5)
Carnivores (14)
Even-toed ungulates (3)
Bats (8)
Rodents (32)
Amphibians (6)
Snakes (15)
Lizards (5)
Turtles (3)
Fish (32)
Birds (297)
American bullfrog
Western painted turtle
Common shiner
Great blue heron
* Not all animals are found in all natural areas, and some are only occasional or rare visitors
297 bird species use Fort Collins natural areas!
• About 75 of these rely on aquatic habitats
(streams, ponds, lakes)
* Not all birds are found in all natural areas, and some are only occasional or rare visitors
How do we figure out if the natural
areas provide good bird habitat?
• Count bird species
– Problem: Not all species present all the time
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Year round residents
Migrants (just passing through, but rely on habitat)
Seasonal
Uncommon
Rare
Is there another way to figure this out?
• Find some “surrogate” for measuring bird diversity
•  PARASITES! Some examples from the literature
– Huspeni and Lafferty (2004) Using larval trematodes that
parasitize snails to evaluate a saltmarsh restoration project.
Ecological Applications 14:795-804
– Hechinger and Lafferty (2005) Host diversity begets parasite
diversity: bird final hosts and trematodes in snail intermediate
hosts. Proceedings of the Royal Society (B) Biological Sciences
272:1059-1066
– Hechinger et al (2007) Can parasites be indicators of free-living
diversity? Relationships between the abundance of larval
trematodes and of local benthos and fishes. Oecologia 151:82-92
Trematodes, a
type of parasitic
worm, require
two or three
hosts to complete
their life cycle
Bird host
Snail
Intermediate
host
2nd
Intermediate
host
Wait! I don’t understand!
• How can we use parasites we find in snails as a
“surrogate” for bird diversity?
– The parasites we are considering (trematodes)
REQUIRE a bird and a snail to complete their life cycle
– If the parasite is present in the snail, the bird MUST
be present at some point
• Are there any problems with this method?
– Yes…
Using trematodes as a surrogate for
bird diversity…
• Problems:
– Relationships between trematodes and their snail and
bird hosts are not always known
– Parasites often difficult to identify to species
• But there are advantages…
– Snails are easy to collect
– Snails don’t migrate to other parts of the world, and
so are present all year
• Conclusion: using trematodes as a surrogate for
bird diversity appears reasonable…
Snails and Trematodes in Larimer County
Snail species
# of trematode taxa
Lymnaea bulimoides
Unknown
Lymnaea obrussa
Unknown
Physa anatina
Unknown
Physa elliptica
Unknown
Lymnaea elodes
7 found
Physa integra
3 found, including
Ribeiroia ondatrae
Gyraulus parvus
6 found
Helisoma trivolvis
55 found! Including
Ribeiroia ondatrae
* These numbers come from research across
the United States, not just Colorado
The number of any species
that we know about
depends on the amount of
research that has been done
People are interested in
Ribeiroia ondatrae because
it causes frog deformities
Helisoma trivolvis is wellstudied because it is a
common host for Ribeiroia
ondatrae, and because it is
common in some areas
The Activity
• It would be great to use real snails and real
trematodes for this activity…
• That would require specialized training in
parasitology, and many hours out in the field
• Instead, we will use plastic eggs and jelly beans as
surrogates for snails and trematodes
• The idea and the statistics are exactly the same as
they would be if we were to use real snails and
real trematodes, but it is less messy and a whole
lot easier!
The Activity
• Everybody will receive one plastic egg
• Each egg will contain variable numbers and
colors of jelly beans
• The eggs represent snails
• The jelly beans represent trematodes, but it’s
okay to eat them when you’re done 
In Class
• Fill out the ‘species’ information forms in class
• Hand in your forms before you leave
• A tally of the ‘species’ will be posted on
RamCT – these are the numbers you will use
in your analyses
Outside of Class
• Collaborate with a partner to calculate
measures of biodiversity using the equations
provided on the handout
• After completing your calculations, follow the
instructions on the module website to
complete your written report
Equations
• Species richness = S = total number of species
• Abundance = total # trematodes / total # snails
= total # jelly beans / total # plastic eggs
• Evenness = J’ = variability in species abundances
H
H
H  is the Shannon Index, and
J

H max ln S
is a measure of heterogeneity
n
H     p  ln pi 
i 1
n  number of species