Invasive Species Update
What We’re up Against
The land, water and other natural resources in Nebraska are being impacted by an increasing number of invasive species. For example, there are approximately 500 non-native plants in Nebraska. Many have no documented negative impact, but others are quite damaging. Dr. David Pimentel and colleagues estimate that there are over 50,000 plant, animal and microbe invasive species in the United States. They estimate that we are spending more than $120 billion dollars annually dealing with problems caused by invasive species. Globally, $1.4 trillion dollars is spent on invasive species each year: this is nearly 5 percent of the global economy. Thus, from an economic standpoint, invasive species are certainly a cause for concern. The ecological and environmental impacts of invasive species are much more difficult to quantify, but in Nebraska invasive species are the most commonly identified threat to our natural legacy, as identified in the Nebraska Legacy Plan.
Threats to Nebraska’s Water
Communities of invasive species that often go undetected are those that are hidden below water. In Nebraska we rely on our water sources for a number of activities: agriculture, recreation and consumption, to list a few. Aquatic invasive species threaten the quality and availability of water for our vast demands. One species that has received much attention in Nebraska recently is the zebra mussel. Zebra mussels (and their close relative, quagga mussels) are often referred to the most important biological invasion into North America, both for the ecological and economical stress they cause. They can have profound effects on the ecosystems they invade, as they outcompete native species for food and other resources. They are notorious for clogging water supply pipes of power plants, public water supply plants and industrial facilities, which costs millions of dollars to clean up. They can even cause major problems to irrigators by clogging up pipes and degrading systems. Zebra and quagga mussels can greatly impact recreation; they attach to and clog boat engines, encrust fishing equipment and foul beaches with sharp-edged shells. The Aquatic Nuisance Species Task Force estimates that the Great Lakes region alone spends over $30 million a year on zebra and quagga mussel control.
This Time Last Year
In the summer of 2010 Nebraska was seemingly free and clear of zebra mussels. But in the fall of 2010 Nebraskan’s were hit with devastating news … twice. In September 2010 officials at Offutt Air Force Base Lake indicated that the prior treatment to eradicate zebra mussels had failed; adult zebra mussels had been found on their sampling structures, again. Then in November 2010 the Nebraska Invasive Species Project received a report from a Boy Scout that he had seen a zebra mussel at an Omaha lake while collecting cans for recycling. Shortly after, the Nebraska Game and Parks Commission and Nebraska Invasive Species Project confirmed this report: zebra mussels were now confirmed in Zorinsky Lake—less than 25 miles from Offutt Base Lake. The multiagency task force decided that it was our responsibility to try something to control this new infestation at Zorinsky. Based on previous research in other states, Zorinsky Lake was drawn down approximately 20 feet throughout the winter to freeze/dry out the invasive species.
Fast Forward
In April 2011 the Nebraska Invasive Species Project was awarded a $100,000 grant from the Nebraska Environmental Trust to develop an Aquatic Invasive Species Prevention Program and received additional funding from Nebraska Game and Parks Commission to “beef up” our zebra mussel sampling. In May technicians hired by the UNL Invasive Species Project (Nebraska Cooperative Fish & Wildlife Research Unit) began sampling Zorinsky Lake each week for veligers. Due to the high risk of zebra mussel exposure to nearby lakes, samples were also collected from Papio and Salt Valley lakes every other week (and at various reservoirs across the state by Nebraska Game and Parks Commission and other collaborating agency staff). To date, samples have been collected from over 40 reservoirs statewide. Analysis by Nebraska Invasive Species Project staff and the Aquatic Invasive Species lab in Montana report promising results … so far, all samples have come back negative for zebra or quagga mussels. Great news; looks like the infestation was limited to Zorinsky Lake, for now.
To help keep zebra mussels (and other unwanted species) out of Nebraska, we also hired staff to spend time at the boat ramps this summer. Located at Lake McConaughy, Harlan County Reservoir and roving around reservoirs in eastern Nebraska, invasive species staff conducted boater surveys, provided information on how to prevent the spread of zebra mussels and provided voluntary boat inspections. In our first summer we surveyed over 3,500 boaters and educated/trained over 12,000 individuals on Nebraska’s new Clean, Drain and Dry Protocol. Thanks to this new grant from the Nebraska Environmental Trust, we were also able to purchase decontamination units—used to decontaminate boats that are at high risk of spreading aquatic invasive species. Boater surveys were conducted to gauge the level of awareness about zebra mussels and to identify areas of the state that receive high out-of-state traffic (nonresident boaters have the potential to carry non-native species into Nebraska). Preliminary results from these surveys have some interesting trends. On average 70 percent of boaters in Nebraska are residents, but for Lake McConaughy boaters it’s more like 50 percent. Those not from Nebraska represent a diverse group: Nebraska receives boaters from over 25 different states. For Nebraskans, we also see fairly high levels of out-of-state travel. About 30 percent of Nebraska boaters have been (or plan on going) to reservoirs in other states. Where do they go? Most are visiting neighboring states like Colorado, Kansas, Iowa, but several boaters travel further to Minnesota, Illinois and further (all states with known zebra and/or quagga mussel infestations). As for zebra mussel awareness —we’re doing pretty good but still have some work ahead. Of course, the level of awareness varies by region of the state, but on average, about 75 percent of Nebraskans have at least heard of zebra mussels, where nearly 90 percent of non-resident boaters have. Both numbers are fairly high, but what we’d like to see is how this awareness changes the way boaters take care of their boats. While many boaters have heard of zebra mussels (and the problems they cause), only 32 percent of Nebraskan’s practice the Clean, Drain and Dry protocol (compared to 50 percent of non-resident boaters). So, we clearly have some more work to do.
As for Zorinsky Lake in Omaha, things are looking up. We detected no sign of zebra mussels (adults or larvae), the lake is refilling quickly and new fish will be stocked this fall. We anticipate a full recovery.
Plans for Next Year?
As we approach the fall of 2011, we are optimistic about all the happenings associated with the Aquatic Invasive Species Prevention Program: the Zorinsky Lake treatment, intensive zebra mussel sampling, our tremendous outreach efforts and surveys and so much more. We are processing all of the data from our summer surveys, and plan to conduct an additional mail/online survey this fall.
Boaters and anglers—plan on seeing us out there again next year. Preliminary analysis of surveys indicates that Lake McConaughy, Harlan County Reservoir and various reservoirs in eastern Nebraska are still at high risk for invasive species (zebra mussel) introductions. We will continue surveys and outreach at these locations but are hoping for expansion. We are currently applying for a grant from the Nebraska Environmental Trust in order to beef up our efforts for the next three years. Zorinsky Lake and Offutt Base Lake served as great warnings; given the opportunity, we would really like to increase prevention efforts across the state. In addition we hope to expand our program to include additional natural resources users that are impacted by other invasive species (waterfowl hunters and common reed, for example). We would like to follow the campaigns led by our neighboring states that empower recreationalists and sportsmen alike in the “fight against invasives.”
What Can You Do?
Help us in the fight against invasives. Learn to identify zebra and quagga mussels (and many other invasive species). Always Clean, Drain and Dry your boat after a day on the water; and check your boots and vehicle tires before leaving a recreational area for weeds. Invasive species can hitch a ride on your clothing, tires, boats and other items, then transfer to another field, lake or river. By following a simple procedure each time you leave a recreational area, you can help stop the spread of invasive species in Nebraska. Complete instructions and additional information can be found at the Nebraska Invasive Species Project website, http://snr.unl.edu/invasives/htm.
Karie Decker is the invasive species project coordinator for the Nebraska Cooperative Fish & Wildlife Research Unit at the University of Nebraska-Lincoln.
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