We will start with the effects caused by invasive plants. The most common harm caused by invasive plants is that they have the potential to crowd out, or displace, native species. They do this by out-competing native plants for necessary resources such as sunlight, water, and nutrients. Invasive plants are always able to survive in conditions usually considered intolerable by native species- those with extreme temperatures, light conditions, soil pH, soil quality, water availability, etc., and can grow quickly. As a result, invasive plants are often found in recently disturbed areas, such as construction sites or after a forest fire. Invasive species often have special adaptations fit for competition. They almost always are prolific seeders. Often, you will see large patches of a single invasive plant, called monocultures. The abundance of a single species can lead to cross-species hybridization. For example, the invasive Oriental bittersweet (Celastrus orbiculatus) is known to hybridize with the native American bittersweet (Celastrus scandens). If this continues, we may see the American bittersweet lose its genetic identity and be wiped off of this Earth forever. Sometimes, these monocultures of invasive species will have no other plant life around. This can be due to allelopathy, or when the invasive plants release certain harmful chemicals into the soil, which prevent other plants from growing. However, there are invasive species with even more deadly poisons. Houndstongue (Cynoglossum officinale), for example, contains pyrrolizidine alkaloids, which cause photosensitization in livestock, leading to hyperactivity, loss of appetite, and eventually death. Still there are more potent poisons. Giant hogweed (Heracleum mantegazzianum) is a large plant which, if touched, causes severe burns that leave scars for years afterwards. If the poison touches the eyes, permanent blindness will ensue. However, probably the most scary effect of plant invasive species is their ability to affect the entire ecosystem- plants are the basis of terrestrial food chains, so without edible native plants around, the primary consumers will die, followed by the secondary consumers, and finally by tertiary consumers. This is how an unsuspecting plant can bring down a mighty lion.
But invasive plants do not always harm other organisms- they can harm the economy as well. Kudzu (Pueraria montana) alone causes over $500 million in damage yearly by smothering native plants, while the total estimated cost for invasive plants every year is around $34 billion, with a ‘b’. This economic damage may come from plants that harm tourism and fishing, like Brazilian waterweed (Egeria densa), which takes over lakes and rivers and may also clog irrigation pipes. It might also come from damages in forestry, like those caused by Scotch broom (Cytisus scoparius), which invades hardwood forests. However, the most economic damage is probably caused by damages in agriculture. Johnsongrass (Sorghum halepense) is particularly notorious for invading farmland, driving out cash crops like corn and wheat. In summary, the harmful effects of invasive plants are diverse.
But invasive plants do not always harm other organisms- they can harm the economy as well. Kudzu (Pueraria montana) alone causes over $500 million in damage yearly by smothering native plants, while the total estimated cost for invasive plants every year is around $34 billion, with a ‘b’. This economic damage may come from plants that harm tourism and fishing, like Brazilian waterweed (Egeria densa), which takes over lakes and rivers and may also clog irrigation pipes. It might also come from damages in forestry, like those caused by Scotch broom (Cytisus scoparius), which invades hardwood forests. However, the most economic damage is probably caused by damages in agriculture. Johnsongrass (Sorghum halepense) is particularly notorious for invading farmland, driving out cash crops like corn and wheat. In summary, the harmful effects of invasive plants are diverse.
The introduction of invasive plants is always interesting. Invasive plants can be introduced for a number of different reasons, whether intentionally or accidentally. Many invasive plant seeds have been brought to the US through ship ballast water, or through contaminated seed shipments. What is most surprising about the introduction of invasive plants is when they are introduced intentionally. Invasive plants have been introduced for medicinal purposes, as food, as an ornamental hedge, as decorative plants, and windbreaks, as aquarium plants, as landscaping plants...The list goes on and on.
Invasive plants can usually be controlled with a number of methods. These include manual (pulling and cutting the plant), mechanical (using machines), chemical (using herbicides), and biological (using the invasive species’ natural enemies). Out of these methods, biological perhaps has the most potential. However, developing a biological control is a difficult process. First, one must locate the invasive species’ natural enemies, usually insects. Then, one must carefully and specifically test these insects to make sure they will attack the invasive species and ONLY the invasive species. Many invasive species like the nutria (Myocastor coypus) were introduced as a biological control method, only to become invasive themselves. All in all, this is a painstaking process, so usually the most effective method is to use herbicides, or chemical control. Glyphosate and triclopyr are just 2 of the most commonly seen herbicides. However, some invasive plants are able to adapt so quickly that in the 30 or so years that the herbicide fluridone has been used on it, hydrilla (Hydrilla verticillata) has already developed a resistance, and can no longer be killed by fluridone. This adaptation speed rivals that of bacteria other pathogens. Invasive plants can be very deadly, from many perspectives.
Invasive plants can usually be controlled with a number of methods. These include manual (pulling and cutting the plant), mechanical (using machines), chemical (using herbicides), and biological (using the invasive species’ natural enemies). Out of these methods, biological perhaps has the most potential. However, developing a biological control is a difficult process. First, one must locate the invasive species’ natural enemies, usually insects. Then, one must carefully and specifically test these insects to make sure they will attack the invasive species and ONLY the invasive species. Many invasive species like the nutria (Myocastor coypus) were introduced as a biological control method, only to become invasive themselves. All in all, this is a painstaking process, so usually the most effective method is to use herbicides, or chemical control. Glyphosate and triclopyr are just 2 of the most commonly seen herbicides. However, some invasive plants are able to adapt so quickly that in the 30 or so years that the herbicide fluridone has been used on it, hydrilla (Hydrilla verticillata) has already developed a resistance, and can no longer be killed by fluridone. This adaptation speed rivals that of bacteria other pathogens. Invasive plants can be very deadly, from many perspectives.
Essential Question
"Could a genetically engineered invasive species potentially be used in warfare?"