Do Now

• In what ways have humans altered landscapes locally?

• Is this harmful or helpful to the natural ecosystem?

• How have humans tried to reclaim ecosystems locally?

WHAT THE STORK SAYS

CHAPTER 8 COMMUNITY ECOLOGY

A bird species in the Everglades reveals the intricacies of a threatened ecosystem

What is Community Ecology?

Community ecology is the study of how a

given ecosystem functions.

Ecosystem function includes:

How space is structured

Why certain species thrive

How species interact

Community ecology also includes understanding how

species contribute to ecosystem services like

pollination, water purification, and nutrient

cycling.

Wetlands like the Florida Everglades provide important water management services, the most important of which

is flood control.

Wetlands capture and store precipitation and runoff, then

release them downstream slowly, reducing peak flood levels during

major rain events.

The Florida Everglades wetlands are extremely important because they: A.capture and store large amounts of participation.B.recharge groundwater.C.capture contaminants and excess nutrients, converting them to safer forms.D.All of the above.

Clicker Question

Community ecology also includes

understanding how humans have altered

ecosystems.

In the Everglades, humans have altered the landscape

with roads and canals.

Pollutants have upended the balance of reactions

that make the Everglades function.

Do Now

• What is an indicator species?• How do scientists use this as a way

to examine ecosystems?• How are species related to one

another when you compare using a trophic pyramid?

The Wood Stork is an indicatorspecies for the Everglades. It is

particularly vulnerable to changes in the ecosystem and can warn ecologists of

problems early on.

The Everglades were once ideal for Wood Storks. In the 1930s, an estimated 15,000–

20,000 pairs nested throughout the

southeastern United States.

But in 1948, Congress authorized a plan to drain the Everglades. As water levels changed, the

wading bird population dropped 90 percent from 1930s–1990s.

Ecologists would soon discover the loss of even one species can disrupt an entire ecosystem—

from the health of giant wading birds down to the movement of

matter and energy.

Do Now

• What did the scientists determine as the culprit for the decline of Stellar Sea Lion population in the North Pacific?

• How was this determined?• What lessons can be learned from

this and applied to the issue with the Florida Everglades?

Do Now

• How could you design an experiment to test how the diet of the Stellar Sea Lions would impact their population abundance?

• Would this be an observational study or an experimental study?

Do Now

• How did dirt form on Earth?• How is this important for

understanding ecological succession?• List the ways an invasive species

disrupts an ecosystem? Be specific.• What types of invasive species do we

have locally?

Asian Longhorned Beetle

ALB Tree Damage

ALB Tree Damage

Worcester Street Before

Worcester Street After

Bittersweet Vine

Bittersweet Vine

Though the Everglade changes have been extreme, changes to

ecological communities are the norm – nature is

not static.

Wetlands and other communities go through ecological succession: the progressive

replacement of plant and animal species due to changing conditions the plants create.

As conditions change, other species better

adapted to those conditions move in and

displace previous residents.

Energy is the foundation of every ecosystem. It’s captured through photosynthesis and

passed to organisms through the food chain.

An ecosystem may have dozens of food chains. Linked together, they create a food

web that shows the connections in the community.

Food chains and webs help ecologists track energy and

matter through a given community.

A food web is:

A.a collection of food chains linked together.B.a simple linear path that shows what eats what.C.a graphic that shows how animals are related to each other.D.None of the above.

Clicker Question

As humans altered water cycles in South Florida, there

were fewer fish for Wood Storks to feed on.

As human development expanded, Wood Storks had to fly farther from

their nesting grounds to forage.

Wood Storks were not the only species

affected. Each species has its own niche, or

unique role, in an ecosystem.

Dams, dikes and bridges caused the Everglades to stay too wet or dry for too

long, killing off worms, grass shrimps, and microbial

communities.

This led to the decline of snakes, fish, alligators, turtles, and

wading birds that fed on them.

Agriculture has introduced synthetic nutrients that have

caused algae blooms, choking off plant and

animal life.

Oceanfront forests have replaced mangrove forests – a keystone species, one that impacts its community more than its abundance would

predict.

Alligators are also keystone species. “Gator holes” hold water during

dry season, providing refuge for fish,

invertebrates, and aquatic plants.

Competition – the vying between organisms for limited resources – is another way that species interact.

Restoration ecology is the science that deals

with the repair of damaged or disturbed

ecosystems.

In 2000, Congress enacted the Comprehensive Everglades Restoration Plan (CERP) to address declining water

quality.

The Wood Stork population has rebounded – possibly because they have moved away from South Florida to Central and North Florida,

Georgia, and North Carolina.