Unit 5 - Health of the Forest Ecosystem

Lesson 1: Agents of Change


Forest ecosystems are constantly exposed to disturbances, such as fire, insect pests, and disease.


How well a forest rebounds from such threats is closely related to its biodiversity.
Biodiversity is the variety of living organisms that live in a given region.

For example, when we refer to the biodiversity within a forest, we are referring to all the trees, plants, animals, and microorganisms that inhabit that ecosystem.

Species preservation is important to forest health. Counting caribou in a given area is a big part of fostering their conservation.
See the Oil Sands Leadership Initiative video "Mammal Counting."

If the video to the left will not play, click here to view Mammal Counting.





An ecosystem with more species is more stable and more resilient that one that has fewer species.

Habitat is the most important factor affecting biodiversity. Species need a certain amount of good quality habitat in order to thrive. This means they must have a good food source, clean water, shelter, and adequate space. Changes in forest habitat can put a species "at risk," which results in a loss of diversity. The loss of species can affect the functioning of the entire ecosystem.

In this unit, we will discuss some agents of change that affect the health of the forest: climate change, fire, insect pests, disease, and invasive weeds.

The Western Grebe, at the right,  is one of Alberta's Species at Risk. 
To learn more about Alberta's Species at Risk, click here.