Introduction
Exotic organisms cause a great harm to the existing a balanced ecosystem in forests and grasslands. Their devastating effects on ecology have led to long periods of research. However, there has been insufficient research on the impact of invasive plants on ecological associations in native communities (Klopfer, 2009). Their effects on a new environment is that they may perform better in the new conditions and may interfere chemically with the performance of existing native plants (Stinson et al, 2006). When exotic and native species invade an area, their existence will be determined by the mutual associations of native birds, insects with soil microbes by symbiosis.
Biological invasions are commonly caused by global changes in the environment that are the result of human pollution activities (Vitousek et al, 1997). Such invasive species can have detrimental effects on the health of humans, alter stabilized ecosystems, and threaten the biological diversity of native lands. Therefore researchers are working towards changing the approach of humans towards the global environment (Tye, 2009).
The following are talks by scientists and researchers on invasive species and exotic organisms, and their detrimental effects on the environment.
First talk titled “Ecology of the Asian longhorned beetle and tools for eradicating it in urban environments” by Melody Keena
The Longhorned beetle first originated in China with other appearances in Korea, New York and Chicago. Their origin in China dates back to 50 years ago whereby, deforestation was done in many areas around the country in order to introduce trees that were first growing. The new species of trees would be used for various purposes; however, they were planted in the wrong places. The regions that they were planted in had beetles which made a huge amount of destruction and thus destroyed the trees’ original purpose. Hence, the Chinese decided to come up with the next purpose which was to make packing material from the trees which would then move around the world thus spreading the invasive species to areas that did not previously have them.
The Longhorn beetles spread through mating. The female lays eggs at the back of trees in specific spots. Some of the risks that have been posed by these insects are waste, destruction of wood and their numbers in landfills is an increased risk.
There are specific types of tree species that these beetles attack like the Maples, especially the sugar Maple. Such species are the primary susceptible hosts of the insects. Therefore, the trees that are susceptible need to be replaced by other trees like the sycamore, fig tree. This is carried out during refurbishing in urban environments and the tourism industry.
Eradication of these beetles is done by keeping more infestations out by having the soluble material coming into the United States treated using heat treatment or metal Bromide to kill the insects in the wood. This should be done by the country of origin. If it is in the United States, a systemic insecticide will be used which slows the spread by preventing insects from establishing themselves in the trees. This method is referred to as tree destructing mechanism for eradication. Any trees found infected are cut and checked.
Finding the infested trees involves carrying out a ground survey. This is done by looking around the trees (probably by climbing it) with a pair of binoculars, and searching for signs of infection. However, this method seems to be expensive, time consuming and it is not possible to do it every where that the insect can be. Another way they spread is by flying where, males have been found to fly more than females. If the wind is too high, few of the insects would fly, while if it is low, more would fly. The females lay their eggs above 15°Celcius but at high temperatures, as high as 35°Celcius, no eggs are laid since it is too hot for the hatching to take place. It has also been established that at very low temperatures the beetles live longer while in warmer temperatures the opposite happens. Thus their population reduces during summer. It is only the small larvae that are sensitive to temperature. For instance, the low temperatures in Vermont and Florida are sufficient for their development.
In order to find them, testing traps have been used in China, and the male pheromones tested. Later on traps will be placed in New York using beetle killing fungus. In order to prevent beetles form attacking other trees, they should be treated for three years in a row. The treatment moves up the tree to the leaves to areas where the beetles can be. In areas that have a lot of water the chemical is not effective therefore trap congestion method will be used.
Challenges that have been faced in eradicating this insect is that since it is not native in the US it does not come with its natural controls therefore difficult to trap. Moreover, it prefers to host Maples trees which are plenty in the United States, this makes it difficult to detect.
Second talk titled “Faunal invasives in New York City waterways and the exotics we can fuhgedd about” by Chris Anderson
Exotics are alien species that have been transported out of their natural environment into another by humans. Invasives are the same thing but have a detrimental effect on the species around their new environment. Plant organisms can be invasive in that they cause detrimental effects by making other plants unable to photosynthesize.
Organisms get in the waterways mostly accidentally by ship holes moving from one country to another resulting in an exchange of microorganisms. They become difficult to detect especially when they get to the new area. In fact, they may die due to lack of food, different salinity, temperature, different environment with more pollution than in areas they came from. If they live their population expands and affect the stability of the ecosystem. Sometimes plants are brought into New York because they are beautiful, but in the long run disrupt ecosystem. For instance, Water Chestnut creates huge masses of plant blankets, in beaches and become dangerous to humans. They are brought here because of their beauty and in the long run it grows quickly and takes oxygen from the water thereby posing as a danger to other organisms that require oxygen for survival. Some invasive species were also introduced through the oyster restoration projects.
The Hudson river contains many species such as the zebra mussel species. This species consumes lots of food, thus reducing oxygen drastically posing as a danger to other organisms that need oxygen. They also consume vital planktons which leads to the increase of planktonic bacteria while native planktons decrease. Organisms that feed on planktons become affected. These species also decrease turbidity of water. They do this by taking out large bacteria and plankton, making plants to photosynthesize more because they provide more light to the bottom as they consume more.
Species of crabs such as green crabs compete with the native crabs, in that they breed a lot, are aggressive, they compete for food and habitats, are versatile, and under any rock. Actually, they disrupt the biodiversity that was previously balanced. Invasive crabs compete with native crabs, by eating anything bad for the ecosystem, they even consume oyster. Butterfly fish, blue angel fish among others carry organisms living in warmer climates to colder climates thus acting as agents of invasive species. Other fauna that result from shipping are planktons, algae, snails that are exotic but present in water.
The damage caused by these invasive species is that they follow turbines, under water equipment, and water pipes in industrial companies that is used to cool down capacitors. These organisms follow the water and the only way to remove them is pull them out which is a big daunting task. Not much can be done to remove the invasive species though more has been done to monitor them. It is a tough process that needs millions of dollars to effect.
Benefits of such species is that some fish species bring money to the economy by increasing their population, provide a source of food, result in fish farming, maintains a flowing food chain, keep plankton levels at bay, are a food source for top predators, reduce unintentionally introduced species. There needs to be a call for monitoring of ships and the introduction of restrictor laws against the introduction of natives in waterways.
Third talk titled “Report from the battlefield: WildMetro Earth Tenders versus invaders in the New York Metro region” by David Burg
WildMetro, an independent metro project is in the process of working with New York City agencies to control the spread of invasive species. It is an organization that is interested in nature and people and has the aim of protecting the planet. As the human culture changes, technology and the values of people also change. The result of this is that there will be unintended changes in the environment. It becomes people versus nature even if the goal of humans was not to save nature.
Invasives are other species that invades a habitat that was kept in check by other species thereby introducing destabilization. The firsts step to discover the beauty of nature that has been invaded is by liking it and then having the need to protect it. Species that existed thousands of years ago, like the ones under glaciers no longer exist because nature was not protected. Many people have questioned the basis of protecting nature on the grounds of species that existed in the Jurassic park will not re-evolve therefore there is no basis of the struggle. Grazing animals are an example of species that have a huge impact on vegetation through grazing. People can destroy the environment by burning grasslands or trees for making charcoal, therefore damaging species
Invasive species have a competitive behavior in that they increase in population once they inhabit a new area. They also have a relationship with human development. When talking about stopping invasive species, one should think about persistent biological systems. The problem of invasive species is that they result in new species that might have died off. The examples of invasives were brought in the New York City are chestnut trees. Invasives are a threat to diversity in that they will result in extinction of other species. Therefore, natural areas should be protected, avoiding any kind of disturbance.
Fourth talk titled “Invasive plants of New York City forests” by Timothy Wenskus
Invasive plants problems are bigger than imagined.
There are about 50 invasive plants in the New York City such as vines, trees and shrubs. Invasive vines have berries that germinate when they hit the ground, strangle the tree next to it, by twining it since it does not have strong enough width to support itself; and then chokes off the flow of water from the roots and nutrients from the leaves necessary for the growth of the tree; and later the tree dies. The vines can be cut off at the base by killing the roots to save the tree. Maples, being the number one selling tree in America, are examples of invasive trees that form canopies such that plants growing underneath are deprived of light. It is known to be a very competitive type of invasive plant. Invasive herbaceous plants disrupt the balance of plants while invasive shrubs produce berries that have carbohydrates or sugar in them but provide lesser quality of food. Their shoot elongation offers them a competitive advantage over other plants. The locally invasive plants grow on certain properties and spread.
Prevention of invasive plants can be done by using biological control methods, and cutting trees, which is a reliable way of stopping its spread. Satellite populations should also be captured since they can reinfest an area that has been cleared. Mechanical removal can be used whereby only native plants are left. However, there are invasive plants that have been treated but they do not go away, due to the satellite populations that have not been captured. To control the spread of invasive species there have been restrictions of selling maples in the United States.
Fifth talk titled ” Opportunities and constraints of large-scale ecological restoration in Phragmites-dominated sites” by Mike Feller
Phragmites are tall grasses that are bushy and cover hundreds of acres. They can appear even in shorelines and are hypercompetitive. A monoculture is referred to as a community of phragmites and are familiar with fresh water islands. Due to its height and competitive nature, nothing grows underneath phragmites. Ecosystems have certain self-organizing abilities and species exist in dynamic equilibrium, coevolving with one another, each having its niche. What invasive species do to these ecosystems is that they destabilize the ecosystem, by giving negative feedback mechanisms.
Specific restoration projects have been used to get rid of these invasive species. Landscapes and parks dominated by phragmites have been filled with garbage and sand to control their spread. Herbicides have also been sprayed on phragmites, by running through the phragmites, and behind them, using direct application right on to the phragmites and not other plants. Some plants which may not be invasives such as other types of berries are nitrogen fixers and support the growth of invasive species.
Sand resists invasion by nonnative plants and phragmites do not grow well, it is nutrient limited and moisture limited. Fire is not a good way to manage phragmites dominated communities but they can be mowed if they occupy a small area.
Conclusion
Therefore, the overall theme of these talks being the detrimental effects of invasive species and exotic organisms on the native species, there seems to be a need to eliminate these species from the environment by all means. They destroy the existing equilibrium of the native species by depriving them of the essential requirements of plants to grow such as sunlight, water and nutrients. Thus, more research needs to be done on how to control their spread or eliminate them from the environment in order to maintain a balanced ecosystem.
Reference List
Jager, H., Kowarik, I., Tye, A. (2009). Destruction Without Extinction: Long Term Effects of an Invasive Tree Species on Galapagos Highland Vegetation. The Journal of Ecology, 97 (6), 12-52. Web.
Klopfer, E., Scheintaub, H., Huang, W., & Wendel, D. (2009). Constructing Learning: How will the Ecology of Silver Lake Change If An Invasive Species is Introduced? Learning and Leading With Technology, 37 (5), 26. Web.
Stinson, K.A., Stuart, A.C., Powell, J.R., Wolfe, B.E., Callaway, R.M., Thelen, G.C., et al. ( 2006). Invasive plant suppresses the growth of native tree seedlings by disrupting belowground mutualisms. PloS Biology 4, 1-3.
Vitousek, P.M., D’Antonio, C.M., Loope, L.L., Rejmanek, M., & Wetbrooks, R. (1997). Introduced Species: A Significant Component Of Human-Caused Global Change. New Zealand Journal of Ecology, 21(1), 1-16. Web.