Aquatic Invasive Species

The most important aspect of invasive species policy is public awareness. If the people do not support certain legislation, it will be hard to pass and remain as policy. For this reason, the goal of scientists should be to convince the public of the issues at hand, who then in turn help convince the policy makers to produce effective legislation. For example, the Burmese python could never have established itself in the everglades if the public had been properly warned of the consequences of releasing such a pet into the wild.
Lodge sees the politicians as the failures because they have not collectively acted with others outside of their state. However, politicians in areas with weaker regulations have no desire to increase regulations if they do not believe that is what their citizens want. Therefore the goal should be to convince the public that more intensive regulations are needed.

United States law currently allows for the importation of any species that is not specifically named on one of various blacklists maintained by a myriad assortment of disparate agencies. This loose regulation has allowed for the introduction of many species that pose potential harm to US ecosystems and responses to these threats are slow due to the cumbersome process of adding to these lists (i.e. Lacey Act). Ecologists demand that this essentially ‘non-regulatory’ system be scrapped for that assumes a species guilty of harm until proven innocent. This position is diametrically opposed by both transportation and pet industries. David Lodge, a researcher from Notre Dame University, believes that the solution to this debate is an approach that singles out individual species or invasion pathways for aggressive monitoring, thereby affording a greater degree of ecological protection without hampering the national economy.

Lodge’s solution is only possible due to advances in environmental modeling and transportation network mapping. By comparing a particular ecosystem’s abiotic factors to those of other ecosystem across the globe, Lodge’s team of researchers was able to identify the most likely source of invasive species for that particular ecosystem (i.e. Laurentian Great Lakes). These results were then compared with a map of shipping routes to show which ships entering the Great Lakes ports could be linked to these “hot zones” of invasive species. Lodge holds that monitoring these ships for invasive species is the most effecient preventive measure given the limited resources of most monitoring agencies.

I agree with Lodge’s assessment that the best available management option is selective screening of transportation pathways based on ecoystem comparisons and transportation network analyses. Government agencies tasked with monitoring these transportation routes are often underfunded and faced with tremendous political pressure not to slow the progress of commerce. Therefore, utilizing a strategy that focuses efforts on the most likely sources of invasion is clearly the most viable option.

One highly important aspect of invasive species management is assessing invasion vulnerability of a given region. Aquatic ecologists are often concerned with invasions of the Laurentian Great Lakes partly because of a multibillion dollar fishing industry that relies on a variety of fish that live there. However, before any action is taken to prevent invasion of the Great Lakes or any other region, the vulnerability of the area should be accurately measured. Professor David Lodge from Notre Dame outlined a measuring technique at a seminar at Duke University on March 16, 2010.
The first step in measuring the probability of invasion is determining the places that the area under inspection is connected to. Any boat that travels between two ports connects those ports, planes connect airports, etc. Indirect connections must also be considered here. Ports in the Great Lakes are indirectly connected to virtually every port in the world. With more foreign vessels entering the area is in greater risk.
Even though a boat might travel from one port directly to another, there is a good chance that these ports are in very different environments and that species from the origin area could not survive at the destination. Temperature and salinity are the main factors used to see how likely it is that a species from water A could survive in water B. Aquatic ecologists must also look where a given invasive species has established itself so far. Has that species established itself in regions that have similar characteristics to the area in question?
Lastly, the likelihood of spread via boat or canal must be assessed. If the area is directly connected to invaded watersheds, the likelihood of invasion is high. Similarly, if a water body is connected by canal to an invaded area, the likelihood of invasion is high.
This is a smart, logical way to assess the probability of an invasion. Before money is spent on the costly projects of preventing invasion, it is indispensable that the actual vulnerability of the area in question be known. Prevention may not be necessary.

There are very few positive comments to say about the current environmental policy on invasive species. Not only is it outdated, but it is also extremely inefficient. According to Dr. David Lodge, not only should new research findings about ways to control and prevent invasive species be incorporated into current policy, but there needs to be a more effective way of preventing the spread of invasive species than simply putting them on a black-list—most often times, after the said invaders have already been established in the America.

In his lecture, Dr. David Lodge described the stages of invasion process and how current research findings and methods can be used to stem invasions at each step. For example, instead of wasting resources and inspecting every ship that comes into an American port, we can allocate resources by only inspecting the ships that are most likely to carry invasive species that can become established in a particular area. For example, there are only a number of aquatic areas that have the same water temperature and salinity as the Great Lakes. Therefore, it is possible that only species that survive in areas similar to the Great Lakes will be able to become established in those areas. Simple modifications of policy such as this can greatly decrease and better allocate the amount of resources needed to prevent invasion of exotic species.

According to Dr. David M. Lodge’s lecture about science on the front lines of invasive species management and policy on March 16, 2009, at Duke University, the United States’ current system for invasive species control is not adequate and needs reform. One of the principles of Lodge’s argument involves taking a new perspective and looking at invasion potentials in probabilistic terms. Lodge claims that the invasion process can be broken up into successive steps that include, in order, the introduction of the species into a pathway, the transport and release a living specimen, the establishment of the invading population, that population’s spread, and finally concluding with ecological, human health, and economic impacts. Lodge’s new suggestion to controlling invasive species involves attention to and analysis of each individual pathway individually. He claims that the probability of a successful invasion is the combination of the probabilities of each step in the invasion process. Thus, in order to more effectively target invading species, the focus should be on the step with the highest probability, followed by combating the steps with the next highest probabilities. This way, only the most beneficial approaches will be focused on first. According to Lodge, recent scientific advances allow accuracy in specific species risk assessment up to eighty and ninety percent, so the future for this method of controlling invasive species is very promising.

To this point, the United States has had some success in invasion control using geographic modeling and environmental matching techniques. Lodge and colleagues have performed a great deal of research analyzing the temperature and salinity conditions of ports throughout the world. The results of their studies have been effective in determining the risk of invasion of aquatic species, including the zebra mussel, at various locations throughout the U.S. However, this is one of the few bright spots in U.S. control of invasive species because there are many more problems than effective solutions. First of all, there are few importations restrictions in the United States, and because of the rapid growth of globalization, there is a huge issue over control of shipping. The Lacey Act has failed to accomplish its main purpose, as it is ineffective at preventing the importation of invasive species. The few restrictions on importations that do exist are primarily motivated by the desire to protect humans (primarily from disease); also, animals are easily transported because they are considered innocent on charges of invasion ability unless already proven guilty. Furthermore, Lodge notes that policy to control both national and international trade is a long time coming. The better solutions to these outlined problems are early detection and rapid response. One technique that has been proposed by Lodge to fight the high Asian carp density in the U.S., which might be higher than its native population density, is the use of eDNA sampling. This would be an example of early detection because if the presence of an invasive species can be determined before its full-fledged invasion, the species can be more easily controlled. Rapid response is also key to eliminate the threat before it becomes too widespread.