Ecosystem ServicesEcosystem Services

Ch 2.4Ch 2.4

Ecosystem ServicesEcosystem Services

Def: benefits experienced by organisms, including humans, that are provided by sustainable ecosystems– Natural result of all activities in biosphere

Cycling of nutrientsPollination of cropsBalance of growth/decompositionContribution of beauty

Let’s examine a forest…Let’s examine a forest…

How does it influence local climate?– Canopy traps humidity, keeps

cool What role do tree roots

play?– Reduce erosion

How many organisms do you see? How many are there?– Provide shelter and protection

from predation

DesertificationDesertification

Trees extract massive quantities of water from soil

On hot days, a lot of water escapes through the stomata, adding water vapour to the atmosphere– This reduces temperature, forms rain clouds

Did you know more than ½ the moisture above tropical forests comes from trees?

DesertificationDesertification

When forested areas are cleared, local precipitation drops– The climate gets hotter and drier leading to

desertification (change of non-desert land into a desert)

Can also occur from climate change, over-farming, and

excessive water use

Watersheds and ErosionWatersheds and Erosion

A watershed is an area of land over which run-off drains into a body of water

Trees benefit watersheds– How??

Watersheds and ErosionWatersheds and Erosion

Soil (without trees) cannot retain water as well as forested areas– Erosion increases

ErosionErosion Rock and soil are loosened from Earth's surface at

one location and moved to another - Natural – Wind and water break rock and soil into smaller pieces,

and loosen them from the earth's surface.

Changes landscape:– Wears down mountains– Fills in valleys– Rivers appear and disappear

Usually a slow and gradual process that occurs over thousands or millions of years. – Can be sped up by such human activities as farming and

mining.

ErosionErosion

Another ecosystem serviceAnother ecosystem service

Cross-pollination: when pollen is Cross-pollination: when pollen is transferred from one flower to a transferred from one flower to a different flowerdifferent flower

Most plants rely on animals, insects Most plants rely on animals, insects to move pollen between flowersto move pollen between flowers– Bees, beetles and bats are the busiest Bees, beetles and bats are the busiest

pollinators!pollinators!

Cross-pollinationCross-pollination

What abiotic factor could also help cross-What abiotic factor could also help cross-pollinate?pollinate?– The windThe wind

Did you know…?Did you know…?

……that cross-pollination by insects that cross-pollination by insects contributes to 1/3 of world food contributes to 1/3 of world food productionproduction– Holy cripes!Holy cripes!– $250 B per year$250 B per year

HomeworkHomework

Read “Case Study” on p 72-73 What is colony collapse disorder? What 2 parasites are named as being

potential factors in the decline of bees?

How does pesticide use affect bees? How could your cell phone affect a

poor bee?

Read section 3.1, “Measuring Biodiversity” Define these terms in the context of

ecology: – Biodiversity– Protect– Quadrat– Transect– biodiversity hotspot.

Describe how each of these methods of measuring biodiversity works:– canopy fogging– quadrat sampling– transect sampling– netting