Topic 6 Succession and Changes in Ecosystems

Succession Changes are constantly occurring in an ecosystem. A landslide can quickly destroy an ecosystem Other changes are slow: wind moves seeds, which cause grass to grow in a parking lot If strong enough certain plants can establish themselves and replace old plants that were already growing. Succession- is the gradual process by which some species replace other species in an ecosystem.

Succession Primary Succession- is the gradual growth of organisms in an area that was previously bare, such as on bare rocks. As they become established and grow they change the landscape of the area they are in.

Succession Secondary Succession- Is like primary succession but it is the change of an already existing ecosystem where life had existed.

Adapting to Change – by people Humans have a drastic effect on the environment around them Forestry technologies Industrial Processes Transportation Farming technologies Urban sprawl (cities) Construction When humans change an environment the ecosystem responds – some organisms succeed while others cannot

Adapting to Change The clearing of land for farming has led to the decline of songbirds, the warbler and vireos. The brown-headed cowbird spread and took over song bird nests The cowbird babies quickly take over the smaller birds

Adapting to Change The brown-headed cow bird is very well adapted to the prairies and competes with song birds The coyote can survive in cities, but the wolf cannot (scavenger) The wolf is being forced into smaller and smaller habitats.

What do you think? Where do you think these foxes are adapted to survive

Pest Control – Pesticides A side effect of using pesticides like DDT is it can kill beneficial organisms for farmers. The right shows the Lygus bug. It kills alfalfa and canola crops. The spraying for Lygus bugs kills bees. Why do you think this is a problem farmers?

Pest Control – Biological Controls Biological Controls are a natural way to kill of pests by using natural predators. The leafy spurge is a weed that infests land and cattle will not eat it The black dot spurge beetle will feed on it returning the land back to its normal state.

Pest Control – Biological Controls Biological control can be risky especially if a species that is not native to an area is introduced. If it has no natural predators then it can be become a pest itself.

Introduced Species Species introduced to an area can be a huge risk if they are not normally found there. Without predators, some species populations can get so large they cannot be controlled. They can take over an entire ecosystem Purple Loosestrife Black margined loosestrife beetle

Invasive Species Great Lake Asain Carp Mussels in the Great Lakes Snakehead Fish

Species In Danger Many species in Alberta and worldwide are endangered. The loss of habitat is the number one reason why species are at risk of going extinct. Other reasons include: Competition with non native species Over use and overhunting Pollution and Climate Change The Polar Bear

Species in Danger – Extinct Cdns Great Auk Sea Mink Dawson’s Caribou Blue Walleye

Species in Danger Many species are at risk of going extinct. They are called Endangered Species Canadian Species at Risk

Eastern Cougar

Piping Plover

Grizzly Bear

Whooping Crane

Sea Otter

Burrowing Owl Burrowing Owl