Time

1. Succession is the gradual process of community development. It involves species in one stage being replaced by different species. The time involved in succession is on a scale of tens, hundreds and thousands of years. Time

2. Abiotic factors such as windstorms, droughts and fire can cause change in a community of plants and animals.

3. Biotic Factors also change communities over time. Insect epidemics can kill trees or grass. Overgrazing can selectively remove species of plants from a field. Grubs are killing the grass Overgrazing Scales on maple tree

4. Environmental disturbances have natural and man-made causes. Trees dying and falling in a rainforest Clearing land for mining or housing developments

6. This picture was taken after the fire.What plant life will emerge? What plants will succeedafter this environmental change? Forest fires are a natural part of the life cycle of the community.

7. After a major change in an environment mosses and lichens begin to colonize. It is the first step in the process of succession.

8. The first species to colonize or grow in an area are called pioneer species. Only pioneer species are able to grow after a major disturbance in a community due to the lack of soil or nutrients. Examples: lichens and mosses

9. Soil has been established. Grasses and small shrubs start to inhabit the area. Animals begin to inhabit the area. Usually, insects appear first, then rodents and larger mammals are the last to appear.

10. Opportunistic species take advantage of the work done by the pioneer species. Pioneers modify the environment in such a way that it becomes less suitable for their growth but more suitable for other species. Opportunists eventually replace pioneer species. Examples: grasses & weeds Over time, the decay of pioneer species, grasses and shrubs adds nutrients to the forest floor allowing more complex species to grow.

11. The biodiversity of a community continues to increase as it ages. A variety of plants and animals will inhabit the area.

12. Succession takes hundreds of years before completion. Species replacement continues until the community is dominated by competitively superior species. Once the community reaches a stable state of maturity it is called a climax community.

14. Primary succession- a change in an environment where soil never existed before. Examples include recently formed volcanic lava and rock revealed when glaciers melt. Lichens and mosses first grow on the rock then soil forms from decayed mosses. Eventually, shrubs and trees follow. Eventually mosses start to grow on bare rock Land after volcanic eruption

15. Secondary succession- a change in an environment where soil already exists. Examples include areas destroyed by forest fire, clear-cutting, or insect epidemics.

16. Secondary succession also occurs on smaller scales. When one giant emergent tree falls, sunlight reaches the forest floor. This brings many changes to this section of the rainforest. After a large tree falls, other plant species are able to grow. Can you identify any other signs of succession in this picture?

17. More roads are being built in undeveloped areas. Farmers clear land for crops and easier access to the main road. What type of succession do new roads cause? How would it affect the plants and animals?

18. This is an old development. What type of succession is happening?