3.4 Competition
Unit B
Module 3 ~ Lesson 3
Invasive Species
Competition can occur between a native species and species that have been introduced to an ecosystem. If an introduced species has no natural predators or diseases to limit their populations, they are referred to as an invasive species. These invasive species can have a serious impact on the native ecosystem, since the introduced species may have a niche similar to the niche of a native species. This will cause competition. This is an example of interspecific competition, and this competition will limit the population size of the native species. Sometimes the introduced species is a predator, and prey populations will decrease rapidly due to excess predation.
Camels were introduced to Australia between 1840 and 1907 as a way of opening up the desert outback. Camels helped build the rail and telegraph lines and also aided in supplying remote locations. Unfortunately, camels are now harming the native landscape and competing with cattle for vegetation.
Canada is not immune to the problem of exotic species. There are an estimated 800 species of exotic plants living in the wild — this is roughly 16% of all the plants in Canada. Some of the exotic species of plants and animals in Canada include purple loosestrife, knapweed, zebra mussels, sea lampreys, and starlings. The ox-eye daisy was introduced to Canada as an ornamental plant for gardens. Its taste makes it undesirable to grazers, and it spreads many seeds each year, making it a successful invasive species.
