Ecosystem

Connections:

who, what, where, when

Remember biomes?

What’s the connection?

Population = one species in a given

area and time

Community = different species

within a given area

Ecosystem = communities together

with their environment

First, some definitions:

Population = individuals of same species

who tend to mate with each other in a limited

geographic area

http://community.webshots.com

Some individuals of the same species(Canada geese, Branta canadensis) atSpring Valley Wildlife Preserve

Community = interacting populations of

different species within a given area

A few spp. in Spring Valley Wildlife Preserve

Ecosystem = communities together withtheir environment, functioning as a unit

And one more:

Biome = the world's major communities, classified

according to predominant vegetation and

characterized by adaptations of organisms to that

particular environment (Campbell)

Dr. Myers

Dr. Cummins

Some biomes we’ll consider this year … from deserts to

oceans, and temperate forests to freshwater streams …

from tropical forests to grasslands to the dirt beneath them

…

Grassland pic

Dr. Cummins

(in the mangroves!)

Dr. McCollum

So what determines where

biomes, ecosystems,

communities and

populations occur?

Geologic processes --> habitatcharacteristics

Water, dirt, rock, ice or deep sea vent?

Earth’s position in space --> solar insolationClimate, seasons, latitudinal and elevationgradients

Evolution / adaptive radiation --> speciesand their adaptations

Who got there first and what selective pressureshave they faced?

And today’s

BIG question …

how are these very

different biomes,

ecosystems,

communities and

populations connected?

First task:

Write down as many

ways as you can that

connections could exist

from one “level” to

another

Also consider different

definitions of connection

(or connectivity)

Migratory connectivity

How “in touch” are populations on their annual winter

versus summer habitats?

Landscape connectivity

How close together are habitat patches, and what

habitats lie in the matrix between them?

Fisheries connectivity ?

Where do larval fish move to, and when/where do

they return for breeding? (2 rounds of migration?)

So how many of these

did you come up with?“Process” connections - flow of:

Individuals and/or populations of individuals

Genes

Nutrients

Energy

“Geographic” connections

Moving water

Estuaries, mangroves, lagoons, etc.

Atmosphere

All kinds of “edges”!

So how many more did

you come up with???

So, let’s take a closer look

at connections

Individuals …

Migrate (seasonal)

Find new territories

Take advantage of

newly formed habitat

Spread randomly - on

the wind, with storms,

with floods, carried by

dispersers

!They carry with them

… genetic diversity

Populations, also …

Migrate (seasonal)

Find new territories

Take advantage of

newly formed habitat

Serious implications

for genetic diversity

How do populations

keep from becoming

“inbred”?

Key population ecology

concepts

Population structure

Survivorship

Reproductive rate

Genetic variability

Research questions about

individuals/populationsWhat’s the survivorship for migrating birds?

What affects them in their winter andsummer habitats?

How does their ability to find suitable habitatalong the way affect survivorship?

How do they find their way?

Are they temperate species adapted to thetropics or vice versa?

What is the age structure of the population?

How do they cope with predation?

And many more ….!!

Communities …

Most connections

are within the

community, not all

Move nutrients

among community

members

Serve as sources or

sinks for other

populationsSource = reproduction

high enough to supply

individuals

Sink = reproduction

below replacement level

Source

Sink -

poor habitat

Emigration

Sink -

invasive sp.

Key community

ecology concepts

Food chains and webs

Biodiversity

Spp. richness (#) versusspp. diversity (# plusevenness)

Genetic versus speciesdiversity

Species interactions

Predation to mutualism

Competition

Direct versus indirect

Ecological niches

Coevolution of species

Island biogeography

Research questions about

communitiesWhat is the trophic structure (food web)?

How do species within the communitypartition resources?

Is biodiversity homogeneous throughout thecommunity / habitat?

What selective pressures encouraged thedevelopment of thorns, defensive chemicals,and large, hard seeds?

And again, so many more ….!!

Ecosystems … are ALL ABOUT connections

http://www.tnstate.edu/ganter/

Movement of inorganic nutrients and other

molecules, organic energy and waste products,

water, air, and organisms themselves from one

reservoir to another is THE topic.

Key ecosystem ecology concepts

Primary productionHow much? Where? What limits?

Nutrient cyclingReservoirs and what moves in and out of them (fluxes)

Modeling

BiodiversityHabitat heterogeneity

Source/sink populations

Connectivity between patches

http://www.dickinson.edu/~wright/TeamWoodrat/TeamWoodratWeb/latchfor99/page3.html

Research questions about

ecosystems

How do organic and inorganic nutrients flow

through ecosystems?

How are humans impacting these flows?

How do inputs into a reservoir react?

Does the effect change with increasing

concentration? Duration? Consistency?

How does biodiversity change across and

between ecosystems?

And many more ….!!

And finally, what

connections could possibly

exist among biomes?

AtmosphereDust to greenhousegases

Streams and rivers

Nutrient flows

“Connector”landscapes orhabitats

Corridors

Wetlands

Elevational

gradients

Biomes are connected by …

Key biome concepts

Research questions about

and within biomes …

To be continued ….

Through the next several weeks!

A key point … many topics

cross disciplinary boundaries

Conservation

Diversity

Species interactions

Landscape ecology- patches, corridorsand “the matrix”

“the devil is in thedetails”

And my favoritequote about science….

“we stand on theshoulders of giants”

Scientists build onwhat is alreadyknown