Invasive Species Outcompeting Native Species
Invasive Species Objectives
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Provide examples of invasive species, including how they have moved into new locations.
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Describe the impacts invasive species can have on endemic species.
You may be familiar with this bird, the common starling (Sturnus vulgaris) found in many parts of the world. There are over 150 million in North America and Central America. The surprising part is that these millions came from only 60 birds released in New York City in 1890.
Although on the decline in its native European range, the common starling has flourished in the Americas, in some cases at the expense of endemic species.
Introduced species do not always do well, but in some cases, the reduction of co-evolved parasites and predators allow them to explode in number.
Barbary sheep (Ammotragus lervia) are native to the mountains of north Africa and are suited for survival in harsh climates and rocky terrain. They were introduced as game animals for hunting to North America and Spain. In Spain, the sheep compete with native ungulates, including Ibex species.
Despite our best efforts, invasive species are continually growing among the endemic species we are trying to grow. Here is a tour to give an idea of how successful invasive species can be.
Invasive beetles damage Oregon conifers and these species are an important part of the state’s economy.
We try to keep our mosquito-controlling goldfish from escaping their pond, but people have already purposely added goldfish to area lakes. These fish can outcompete native species and tolerate a wide range of water quality.
This crayfish species and two other species have already been introduced to local rivers. If you have an exotic pet that could become invasive, keep it in close containment whenever possible.
Island populations are particularly vulnerable to invasive species as population sizes of endemic species are often small and may not have been raised with a variety of parasitic or predatory threats.
Hawaiian Honeycreeper bird species are in serious decline, some like this bird are almost extinct. In the past that was largely due to uncontrolled hunting, now it relates to habitat loss and introduced species.
These are a few invasive species that threaten endemic Hawaiian species.
Wild Pigs
Pigs uproot plants and cause soil erosion.
Day Geckos
Geckos eat a wide range of endemic insects.
Blackberry
The same invasive species in our field grows rapidly in Hawaii.
Portfolio Update
Here is our final portfolio update. It may also help to watch the earlier portfolio videos or revisit the nine learning outcomes.
This could be a good time to work on this week’s “Portfolio Intro” media piece.
The next section introduces additional factors that lead a species to become endangered as well as possible solutions.
Check your knowledge. Can you:
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provide examples of invasive species, including how they have moved into new locations?
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describe the impacts invasive species can have on endemic species?
Go back to the Extinctions Page
Go forward to the Endangered Species Page
Conservation Lecture Guide Contents
The material from this guide and corresponding lecture is assessed on the weekly quiz.
Back to the Future
Module 10
This Guide
Conservation
