Case Studies in US Forest Ecosystems

America's forest ecosystems are threatened by invasions of exotic species of insects, disease pathogens, and plants. Invasives introduced from Europe and Asia have damaged 70% of the 165 million acres of forest in the northeast and midwest United States. Exotic weeds infest a total area as large as Texas; they are damaging half our national parks and 60% of preserves managed by The Nature Conservancy. (3)

Some of the most devastating forest ecosystem invasions have been of herbivorous insects and plant pathogens that were apparently benign in their native habitats. Examples include the European and Asian gypsy moths, chestnut blight fungus, Dutch elm disease, and white pine blister rust. Each of these species has exhibited a greater impact on tree species in its invaded habitat than on trees of the same genus in its native habitat. These invaders would not have been predicted to become serious pests based on their interactions with co-evolved hosts in their native surroundings. However, once in contact with new species without adapted behaviors, and in surroundings perhaps devoid of predators, they become major problems. Significant environmental change may result from forest invasions, including loss of species, changes in ecosystem structure and other irreversible occurrences. (8)

As a forestry and resource ecology student, I am interested in how invasive species will change the future landscape and ecosystem composition of our country’s and the world’s forests. I researched two major invasive species of United States forest ecosystems within each of the following categories: insects or pests, plants (“weeds”), and pathogens or diseases. Please click on the links to read more about balsam woolly adelgid, gypsy moths, tree of heaven, kudzu, chestnut blight, and Dutch elm disease. These case studies are representative of the invasive problems present on a larger scale both in this nation and worldwide.



	Case Studies in US Forest Ecosystems

Home Overview of Invasives Case studies in US forest ecosystems Insects BWA Gypsy moth Plants Tree of heaven Kudzu Pathogens Chestnut blight Dutch elm disease Long-term effects on forests Conclusions References Useful links	America's forest ecosystems are threatened by invasions of exotic species of insects, disease pathogens, and plants. Invasives introduced from Europe and Asia have damaged 70% of the 165 million acres of forest in the northeast and midwest United States. Exotic weeds infest a total area as large as Texas; they are damaging half our national parks and 60% of preserves managed by The Nature Conservancy. (3) Some of the most devastating forest ecosystem invasions have been of herbivorous insects and plant pathogens that were apparently benign in their native habitats. Examples include the European and Asian gypsy moths, chestnut blight fungus, Dutch elm disease, and white pine blister rust. Each of these species has exhibited a greater impact on tree species in its invaded habitat than on trees of the same genus in its native habitat. These invaders would not have been predicted to become serious pests based on their interactions with co-evolved hosts in their native surroundings. However, once in contact with new species without adapted behaviors, and in surroundings perhaps devoid of predators, they become major problems. Significant environmental change may result from forest invasions, including loss of species, changes in ecosystem structure and other irreversible occurrences. (8) As a forestry and resource ecology student, I am interested in how invasive species will change the future landscape and ecosystem composition of our country’s and the world’s forests. I researched two major invasive species of United States forest ecosystems within each of the following categories: insects or pests, plants (“weeds”), and pathogens or diseases. Please click on the links to read more about balsam woolly adelgid, gypsy moths, tree of heaven, kudzu, chestnut blight, and Dutch elm disease. These case studies are representative of the invasive problems present on a larger scale both in this nation and worldwide.