Giant salvinia is an aquatic fern that has invaded 13 states because of its ability to form mats across water bodies and outcompete native plants. Ballard proposes to study a known method of control, the herbicide glyphosate, and test the effects of cold temperatures on its efficacy related to the winter conditions of the Toledo Bend Reservoir. Ballard anticipates that the results of the study will be useful to water resource managers to determine an optimal method of control.
G. calmariensis and G. puscilla are biological control weevils used to control the invasive purple loosestrife, which limits the growth of native vegetation such as the winged lythrum. Gaskins proposes to explore the effects of these weevils on the native winged lythrum to understand whether or not this control method is the most appropriate.
The water hycinath has proven itself to be in aquatic invasive species. It has spread all over the world and E. crassipes has migrated to over 50 countries on 5 continents, but is mainly found in southeast Asia, the southern United States, central America and western, central, and southern Africa. Dickey proposes an experiment to show how Diquat, 2, 4-D amine can restrict the growth rate of water hyacinth such that biological agents can effectively reduce water hyacinth populations.
Diaz proposes an experiment geared towards the prevention and reduction of the Didymo, an aquatic invasive algae in North America. Thus far the efforts to combat this species have involved raising public awareness and preventing further spread of the algae. Knowing that particular base-flow indexes of streams may affect Didymo grwoth, this proposal suggests using hydrological control of model streams with Didymo populations to see whether nuisance blooms could be prevented and whether existing Didymo mats could be washed out. The author believes that if their experiment shows successful reduction and prevention of Didymo populations, they will have identified a mechanism for permanently control Didymo.
We recommend soliciting a full proposal from Diaz’s experiment. The presence of Didymo is clearly a significant issue, and the author presents the concern in a concise, yet sufficient, manner. The methodology is very clear. The process for this experiment is realistic and thorough. Also, the application and findings from this experiment would be an important discovery to help understand the characteristics of Didymo and control this species in an ideal way.
Our suggestions for Diaz are limited but significant. Firstly, the pictures are not cited, although this is minor. Second, the objectives are given as statements, and we believe the objectives would be more effective if phrased as questions. Also, each of the eight experimental units will be tested for merely two weeks. Is it possible that more time should be allotted for observations? If two weeks is reasonable, perhaps this should be substantiated somewhere in the rationale or methods. Most importantly, the anticipated outcome section states that if this experiment is successful, these findings can be directly applied to preventing Didymo permanently in nature; how exactly would hydrological control methods be applied in a natural stream setting? The steps that would be taken for this to occur should be outlined or at least briefly mentioned. Lastly, even if this study was successful, the study makes no suggestion about the need for further research. We believe that if no follow-up research occurs, the findings of this study cannot be substantiated.
Rock snot (Didymosphenia geminata) is an aquatic invasive alga common in hundreds of North American rivers and streams. Rock snot grows dense mats that cover the bottom of the stream floor and hinders water activities like boating and fishing. The potential habitat distribution in the US for rock snot is the subject of Sunil Kumar and colleagues’ research study, which is funded by EPA Region 8, the Natural Resource Ecology Laboratory at Colorado State University, and the USGS Fort Collins Science Center. Kumar et al. used prediction models (GARP, CART and the Maxent) to determine the areas in the US most likely to successfully support rock snot. Environmental variables characterizing climate, topography, bedrock geology and hydrology were considered in the Maxent model, which proved to be the most successful in predicting host sites for rock snot. Researchers learned that environmental conditions like elevation and temperature varied greatly where rock snot was discovered. Additionally, Kumar et al. noted that the potential control of a stream’s water flow could be the foundation for a rock snot management method.
Frontiers in Ecology and the Environment 7: 415-420 (2009).
In 2007 the New York State Department of Environmental Conservation (NYSDEC) announced the first recorded instance of didymo in New York, found in the Batten Kill section of Washington County. The invasive specie tends to spread into new locations via the felt soles of fly fisher’s boots and is currently impossible to eradicate once present in a new area. Resembling degraded cardboard, Didymosphenia geminata covers water beds in heavy mats. Once these mats have overtaken the floor of the water source, fishermen have increased difficulty maneuvering among the infested waters, bottom dwelling organisms are smothered, and the food chain as a whole is disrupted. NYSDEC Commissioner Pete Grannis reasons that a the process of checking, cleaning, and drying gear thoroughly must become a common chore among outdoor water enthusiasts if the spread of didymo is to be hindered. Vermont has taken legal action in an attempt to thwart the aquatic invader, passing a law that will ban felt-soled angling boots by 2012. Still some believe that this will prove ineffectual, and that didymo will continue to spread through the laces and fabric present on the boots.
Didymo clearly constitutes a considerable threat for admirers of the outdoors and the ecosystem alike. I feel that because aquatic invasive species like didymo are becoming such a conspicuous problem, stronger measures should be taken to hamper their dissemination. For instance, before acquiring a fishing license, it should be required that anglers take a brief quiz on the proper methods for checking, cleaning, and drying their gear. Those who argue that the elimination of felt-soled boots is a futile effort have a valid point. Didymo will likely be able to spread through other pieces of equipment or find transportation in other fabrics. Once prevention has failed, the next steps will be control and eradication. Scientists will need to research new ways to impede the propagation of this invasive organism, whether they be chemical or biological. However, this will give rise to a new set of problems, as the use of chemicals can easily pollute the surrounding environment and the introduction of new species intended to control didymo can have similar destructive consequences.
The situation surrounding didymo, though interesting, leaves several questions unanswered. For instance, scientists have determined with absolute certainty that felt-soled boots can lead to the spread of didymo, but is there any evidence to suggest that the elimination of these boots will lead to a significant decline in the dissemination of this organism? Common sense suggests that the answer is no, as only a single drop of water can transport the organism and didymo will likely find an alternate means of moving about from one water source to the next. This leads to yet another set of questions: is there any effective method of disinfection that can be easily applied to fishing gear? If so, can it be applied to felt-soled boots? If the answers to these questions is yes, then perhaps the ban on these boots is superfluous, and the complaints of fishermen can be mitigated by permitting the continued use of felt-soled boots.
“Rock Snot.” It sounds like a gag item a 13-year old created with a chemistry set—or perhaps just the nickname he came up with to annoy his sister. The reality, however, is not funny. “Rock Snot” is actually the nickname for a freshwater algae Didymosphenia geminata, or didymo for short. How serious is it? In New Zealand, didymo is considered a dangerous enough biosecurity threat that there is a penalty of up to 5 years in jail and $100,000 for knowingly spreading it. And in North America – specifically New England – it might just be the most devastating invasive species to hit the waters of Vermont and New Hampshire since Eurasian milfoil.
Didymo is one of eight related species of algae originating in Russia’s Lake Baikal—and the only known algae to have taken on invasive characteristics. It has been found in some northern European rivers for at least a hundred years, but recently (for reasons not yet completely apparent) has begun to spread around the world widely and aggressively, preferring cold, shallow, well-oxygenated, but nutrient-poor waters (such as are common in the mountainous areas of New England). Once didymo invades a river, there is no known way of eradicating it.
What makes didymo so damaging, according to the Global Invasive Species Database, is that it “forms massive blooms that have a range of adverse effects on freshwater ecosystems, as well as human and economic effects.” In the worst case, it can grow from bank to bank across an entire stream, in a thick mat covering the entire bottom to a depth of several inches, smothering rocks and submerged plants. Studies show that hese blooms can reduce the amount and availability of suitable habitats, and when large enough mats are present, they can reduce the size of some larval aquatic insect populations, depriving fish of prey.
There has been considerable scientific study regarding the transport of this invasive species, and debate has settled upon the felt soles of fishermen’s “waders.” Fly fishermen value the felt soles for their ability to cling to rocks too slippery for normal rubbers to adhere to, but, as stated in the class article, if ever there were a perfect medium on which a microscopic invasive species could emigrate to another environment, felt would be it. In my opinion, I am shocked by the counter argument of the fly fishermen, who cite cost effectiveness and seem to belittle the issue of invasive species transport in the face of their own personal fishing success (they also claim that other parts of the boot could attract didymo, and while this may be true, felt is by far the worst material, as well as being almost impossible for a regular fisherman to adequately clean). Granted, fishermen value their pristine rivers and lakes arguably higher than anyone else – they definitely derive the most utility from them – but the fact remains that they are the source of the problem. Perhaps a regulation prohibiting felt soles for fishermen who would actually pose a risk of transporting invasive species (that is, fishermen who travel a specified distance, such as international travel) is in order. But fishermen who stay in-state don’t seem to carry any risk.