Plant populations in a community can change over time. This is also known as Evolution or Succession. Communities of plants are established and then change over time as the external environment in which they live changes. The external environment can change in the following ways: 1. Climate changes: e.g. drought conditions, floods and global warming. 2. Increase or decrease in animal and human population e.g. some plants are eaten by herbivorous animals and people. 3. Ecological Disasters affect the growth of plants in a community. For example, the Wild Flower population in the Western Cape region of South Africa regenerates itself through fire. If wildfires do not occur, the wildflower population dies out. On the other hand fire also destroys large forested areas and the plants take a while to regrow, if ever. This is just a small sample of how plant populations change over time.