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)

Great blue heronGreat blue heron

Animals that use Fort Collins natural areas*

• 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)

* Not all animals are found in all natural areas, and some are only occasional or rare visitors

Long-tailed weasel, summer coatLong-tailed weasel, summer coat

American bullfrogAmerican bullfrog

Western painted turtleWestern painted turtle

Common shinerCommon shiner

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• 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

Bird host

2nd Intermediate

host

Snail Intermediate

host

Trematodes, a type of parasitic worm, require two or three hosts to complete their life cycle

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, includingRibeiroia ondatrae

Gyraulus parvus 6 found

Helisoma trivolvis 55 found! IncludingRibeiroia ondatrae

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 well-studied because it is a common host for Ribeiroia ondatrae, and because it is common in some areas

* These numbers come from research across the United States, not just Colorado

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

max

1

is the Shannon Index, and

is a measure of

number of species

ln

lnn

ii

HH HJ

H S

H pn

p

heterogeneity