Photo credit: Steven Wayne Rotsch/Painet Inc.

Eleanor Burkett, University of Minnesota Extension, 888-241-0720

Beaver are both loved and despised. On one hand, they are great conservationists — doing their part to create important habitat for fish, waterfowl, birds, frogs, and mammals. On the other hand, when they plug culverts causing road flooding, damage forests and home landscapes, or cause flooding where not wanted, they are considered a nuisance. They can also spread disease-causing organisms such as giardia.

Beaver were nearly trapped to extinction around 1900. They made a comeback and are found throughout most of North America. The habitats beaver often create are wetlands, which add to the diversity and abundance of plant and animal species. Wetlands also help to slow spring runoff, reduce downstream flooding and erosion, and filter sediments and pollutants.

Beaver live anywhere they can find a year-round source of water that doesn’t fluctuate too dramatically or move too fast. They build dams using trees, fencing materials, rocks, planks, wire, mud, and just about anything they can find. In Minnesota, beaver lodges must be deep enough to allow for entering and exiting under winter’s ice. Lodges can house anywhere from four to ten animals in a family group. These large rodents are herbivores, feeding mainly on tree saplings, preferring fast-growing species such as aspen and willow, but will also feed on grasses, agricultural crops and aquatic plants. They like to forage near water and store food supplies underwater for winter feeding. Beaver can have a great impact on an ecosystem because they:

• are the only animals other than humans that can cut down mature trees,
• concentrate their tree felling and foraging in the relatively narrow band of forest surrounding their ponds, and
• remove far more vegetation than they consume because they use it for building dams and lodges, as well as for food. (Haemig, 2006)

In preparing shelter and food for winter, beaver tend to cause the greatest nuisance for property owners in the fall.

If beaver are causing you problems, it is best to find a solution to live with them. Often when trapped and removed, other beaver will quickly move into the area. They can migrate from miles away, and survivors will reproduce to the habitat’s capacity.

If beaver are eating your trees, it is best to build fences around the trees using hardware cloth or 2- by 4-inch wire fencing (be sure to allow space around the tree for growth); chicken wire is okay for small trees, but needs to be placed near the tree to prevent beaver from crushing them, then eventually replaced as the tree grows. Low fences can also be used to protect a group of trees and does not necessarily need to surround the entire area because beaver dislike being away from water. Removing small woody vegetation may help make the area less desirable. Removing dams may discourage beaver, but check with the Minnesota Department of Natural Resources for assistance and permission if necessary.

For more information about beaver management, visit the Purdue University Web site at www.entm.purdue.edu/Wildlife/Wildlife%20Information.htm#Beaver.

References:

• “Beavers: Wetlands and Wildlife.” The Beaver, 2002. Online: http://www.beaversww.org/beaver.html, accessed February 4, 2007.
• Haemig, P.D. Beaver and Trees, 2006. Ecology. Info #19. Online: http://www.ecology.info/beaver-trees.htm, accessed February 4, 2007.
• Living with Wildlife: Beaver

. Online: http://www.aphis.usda.gov/ws/nwrc/is/living/beavers.pdf, accessed February 4, 2007.

Cindy Hagley, Minnesota Sea Grant, 218-726-8713

Adult geese and goslings can cause problems for lawns.

People who work in natural resources or water quality disciplines and interact with the public get a lot of questions every year related to geese problems. Knowing a little bit about Canada geese can help make it easier for us to live with each other.

Those of us who grew up in the 1960s and 70s got very excited by the rare sound of Canada geese migrating overhead in spring and fall. Nowadays the much more routine sight of geese is just as likely to trigger very different emotions because they have become a nuisance in many areas. What has changed? The geese that migrate through the state are actually a different subspecies of Canada goose than the ones that have adopted our urban lakes and lawns and often remain throughout the winter. Populations of the pesky giant Canada goose, nearly eliminated from the region by the 1930s through wetland drainage and uncontrolled hunting and egg collection, have recovered and found everything they need to survive right in our backyards, including public parks, golf courses, beaches, playgrounds, and lawns.

The problem is that too many geese can result in significant concerns** including:

• fecal contamination;
• water quality problems, including nutrient and bacteria additions;
• aggressive bird behavior, especially during breeding seasons;
• interference with human activities like picnics and swimming;
• aircraft collisions and airport approach safety;
• disease transmission among birds;
• erosion and grazing damage where waterfowl congregate.

(**D.L. Sperling,Wisconsin Natural Resources magazine, December 1998.)

So what can you do if geese have moved in with you? Probably the simplest solution is to try and see the world from a goose’s viewpoint. Geese are often nuisances because they are looking for the same real estate as humans – nearby water, lots of grass (their preferred food source), and few places where predators can hide. As our shorelines become more developed and urbanized, we create more and more habitat for geese, but there is good news – some simple solutions not only reduce goose problems but also help protect the water quality of our lakes and streams. Reducing the size of your lawn and increasing the native shrubs and perennials near the water’s edge will make your property less attractive to geese, especially if there is dense, native vegetation along the shoreline. Doing this removes the feeding habitat and eliminates their “escape route” from predators. Shorelines that are allowed to grow over with tall grasses and shrubs are not only less attractive to geese but also help to reduce water quality impacts from erosion, sedimentation, and nutrients that can come from urban lawns. Not only that, but less lawn means less of your time at the lake is spent on lawn care!

Many more suggestions for goose control can be found at: www.wnrmag.com/stories/1998/dec98/geese.htm.

Karen Terry, University of Minnesota Extension Service, Regional Extension Educator, 218-998-3927

Mussels are fascinating but can be hard to know because they spend most of their lives buried in the bottom of Minnesota’s lakes and streams. When people do happen to find them, they often call them clams, but mussels and clams are not the same. They are both mollusks, but the biggest difference is that mussels are capable of making pearls and clams are not. Minnesota’s clam species are very small, but our mussel species can be as big as dinner plates.

This giant floater is just one of Minnesota’s many native mussel species. Photo credit: MN DNR

Minnesota’s mussels have interesting names like spectaclecase, pistolgrip, heelsplitter, and wartyback. There are nearly 50 species of native mussels in Minnesota, but many of these are listed as endangered, threatened, or of special concern. One of the most imperiled groups of living things nationwide, mussels depend on clean water and diverse fish communities to survive. A healthy population of mussels is a good indicator of a healthy lake or river.

Mussels do not have eyes, legs, or fins. Throughout their lives, they move by floating downstream, hitching a ride on fish, or by anchoring with their ‘foot’ and pulling themselves along slowly. To reproduce, males release sperm into the water and the females draw it in to fertilize their eggs, which they brood internally. The females later release the tiny larvae, called glochidia, into the water. The glochidia then attach to a fish for the next stage of their lives. Many mussels require a certain species of fish to attach to, and if that mussel does not find that species of fish, then the glochidia will likely die. Glochidia that do latch onto the right fish attach to the fish’s gills, fins, or scales and live as parasites until they are old enough to drop off, settle to the bottom, and begin life on their own. Mussels live from 10 to 30 years.

This DNR mussel researcher is sorting mussels by species. After they are identified, they will be measured and recorded to create a list of mussel species in the water body. Photo credit: MN DNR

Native people used mussels for food, jewelry, and utensils. More recently, shells were used to make buttons for clothing, and they are still used in some places to make cultured pearls. Because mussels reproduce slowly, over-harvesting decimated many populations. Today it is illegal to harvest mussels in Minnesota.

To learn more about mussels, look for empty shells in the shallow water along shore. You can study the shell as long as you return it to the place you found it, but it is illegal to pick up live mussels without a permit. More information can be found in the small spiral-bound book, “Field Guide to the Freshwater Mussels of Minnesota,” available from Minnesota’s Bookstore, 651- 297-3000 or 800-657-3757.

Jeff Gunderson, Minnesota Sea Grant Program, 218-726-8715

Musky fishermen on Lake Vermillion pine for the “weed” beds that used to hold muskies, now gone because of hoards of plant-eating rusty crayfish. Some fishermen sing the praises of bass fishing along the edges of dense aquatic plant beds. Others recognize that many lakes’ fish populations have changed as aquatic plants have disappeared due to lakeshore development. What is the relationship between aquatic plants and fish populations? Sounds simple enough to answer until you sit down to consider the issue’s scope. There are so many species of plants and fish and variations in how they interact that it is an oversimplification to state that all fish depend on healthy native aquatic plant populations. Some fish species need aquatic plants sometime during their lives while others don’t.

I’ve spent most of my career focused on Great Lakes fishes. Many of those species don’t ever see a rooted aquatic plant and they do just fine, such as lake whitefish, lake trout, coaster brook trout, lake herring, deepwater chubs and sculpins. Other fish like largemouth bass thrive with more aquatic vegetation and have increased dramatically in some areas of the Great Lakes. Take Lake Erie for example – prior to the 1990s, poor water clarity in that very productive lake limited plant growth. But when the invasive zebra mussels and quagga mussels populations grew in the lake, they filtered the water and improved clarity to the point that aquatic plants began growing in areas that hadn’t seen them in close to 100 years. As a result, largemouth bass and sunfish increased in numbers and size in those areas where the plants began growing again.

What does this have to do with inland Minnesota? It reminds us that different fish species have different habitat requirements and that loss of critical habitat will result in loss of fish. As with Lake Erie, we may not know what we’re missing because the habitat has been altered for so long that we’ve forgotten how it was. Or a gradual decline in aquatic plant communities results in an almost imperceptible change in the fish community that is difficult to detect during a single generation. Changes may only become clear when you look through old photo albums at your cabin and realize your grandfather caught more of a particular fish species than you do.

One thing is sure – many fish species and other animals depend on healthy native aquatic plant communities for food, habitat, cover, and spawning or nesting sites. What we don’t know is how our individual actions add up to impact a lake. How many individual shoreland property owners (or rusty crayfish for that matter) each removing the aquatic plants on their shoreline does it take to change the lake’s habitat enough to impact its fish?

Without careful consideration about how our individual choices add up to impact lakes, pretty soon we are going to sound like our grandfathers talking about the good old days. New fishery management tools and regulations and the catch and release practices of many anglers, combined with taking care of fish habitat could help ensure that the good old days of fishing in Minnesota are still ahead of us.

Photo Credit: Douglas Jensen.

Doug Jensen, MISAC, communications, outreach and education committee chair, and Minnesota Sea Grant Program, 218-726-8712

Minnesota will soon have a comprehensive state plan to address aquatic and terrestrial invasive species. Several members of the Minnesota Invasive Species Advisory Council (MISAC, or mee-sack) including staff from the Minnesota Department of Natural Resources (DNR), Minnesota Department of Agriculture (MDA), and Minnesota Sea Grant met in 2005 to begin developing a draft plan.

In October, Minnesota reached a milestone. For the first time, 70 representatives from various businesses, government, and non-governmental entities, including the University of Minnesota Extension Service, gathered at a workshop to address terrestrial and aquatic invasive species.

Why a state plan? Both DNR and the MDA are mandated to administer invasive species response plans, and other organizations, including Sea Grant, were interested in creating a plan. Merging efforts into one plan provides a common structure for coordinating and guiding invasive species detection and response efforts, encourages input from partners, and improves access to funding.

Workshop attendees participated in breakout sessions according to their interests and indicated how their organizations would address invasive species prevention, early detection, management, and coordination efforts. This information will be used as input for the comprehensive state plan. Participant interest and contributions during the workshop demonstrated the relevance for the need to address invasive species issues through a comprehensive approach.

The workshop was sponsored by Minnesota Sea Grant through a grant from the Great Lakes Commission in collaboration with MISAC, the DNR, and MDA. According to workshop evaluations, the workshop was very successful:

• 89 percent of attendees felt the workshop was useful to address their organization’s invasive species-related mission, goals, and objectives
• 71 percent thought that the draft plan is on track to become a viable appoach
• 79 percent felt it brought together diverse stakeholders
• 78 percent were more than likely to implement aspects of the plan

Comments received on the draft will be considered during revision by MISAC. Once a revised plan is ready, it will be distributed to the public for comment. The plan is expected to be finalized by mid-2006. A synthesis of the workshop outcomes will be presented at a Great Lakes Regional Summit hosted by the Great Lakes Commission in 2006.

To learn more about MISAC, please visit them on the web.

Sea Grant signs.

Submitted by: Barbara Liukkonen, Minnesota Sea Grant Program, 612-625-9256Recent news stories about finding zebra mussels in Mille Lacs have reminded us about the impacts that non-native plants, fish, and other animals may have on Minnesota’s waters, and highlighted the expense and effort needed to control them. While non-native species do not always pose a threat, some can out-compete native species, contributing to loss of native plant communities and habitat for fish and wildlife, resulting in economic and recreational impacts.

Non-native plants and fish are often the centerpieces of water gardens, adding interest and beauty, but if these species escape or are released in our lakes and streams, they may have significant ecological effects. In 2002, research at the University of Minnesota Horticulture Department, indicated it is easy to receive prohibited invasive species through catalogs and the Internet and that 92.5% of plant orders included unintended “hitchhikers.”

To further identify the potential for introducing aquatic invasive species through water gardening and to help stop the spread of those invasive species, a research study and outreach effort was sponsored by Minnesota Sea Grant in collaboration with the Minnesota Water Garden Society, the Department of Natural Resources, and the Minnesota Nursery and Landscape Association.

In 2004, we queried water gardeners, Master Gardeners, and shoreland property owners with an online or written survey, and conducted one-on-one interviews with 37 nursery and landscape design professionals in the Twin Cities and greater Minnesota. The survey tools were designed to measure awareness and knowledge levels, identify their sources of plants and information, characterize sales and gardening practices, investigate willingness to pay, and assess opportunities for educating customers and nursery employees.

Respondents indicated the threat posed by aquatic invasive species is of serious concern (91% consumers, 57% nursery professionals), but most were unable to correctly identify non-native, invasive species of concern in Minnesota. Few consumers (7%) purchase plants or animals over the Internet; 56% choose plants at local retail outlets. Most (86%) expressed a willingness to pay more for plants they were sure were free of hitchhikers.

Two thirds of the nurseries had received unintended plants or animals in shipments. Fewer than 15% of the retail outlets had a process in place to identify or eliminate 2 hitchhikers in their plant receipts. Only 25% had a process to prevent customers from receiving unintended plants in their purchases. Seventy five percent of retailers requested educational materials to train employees about risks and proper protocols. Nearly all retailers (95%) were willing to provide their customers with outreach education about aquatic invasive species.

After developing preliminary messages and graphics, we conducted focus groups with managers from large and small nurseries, pond designers and installers, state agency staff, Extension specialists, Master Gardeners, and representatives from the Minnesota Water Garden Society. From those meetings and subsequent conversations we refined the messages and finalized the design and layout of the materials.

The new educational materials include tip cards, plant sticks and tags for nurseries to include with potentially invasive plants, and posters. The posters are available in both an 8-1/2 by 11 inch format and a larger size (18 by 24 inches) for nurseries and garden centers to post.

In a pilot program this summer about 40 Minnesota nurseries, garden centers, and landscape businesses used the materials to inform employees and reach customers with the primary message, “Do Not Release” plants or animals from water features. We’re currently in the process of evaluating how the materials were used, customer response and interest, employee response, and willingness to pay for these or similar materials in the future.

Lake with snow.

Cindy Hagley, Great Lakes Environmental Quality Educator, Minnesota Sea Grant, (218) 726-8106

This year is the first in many where some parts of the state have had lots of snow. This is great for snowmobilers and skiers, but it can be tough on fish in shallow lakes. The long, snowy winters that cause many of us to head for Florida can be the death knell for “lake-locked” fish. Winter fish kills in shallow lakes are natural events, although, as with most things involving lakes, how we manage our shoreland can make the problem worse.

Understanding why this sometimes happens requires us to learn something about how lakes function. Fish, of course, need oxygen to survive, but many of us have never considered how oxygen makes its way into lakes. In summertime, there are several ways lakes become oxygenated. Wave action “stirs” it in, and long hours of sunlight allow algae and aquatic plants to generate plentiful quantities through photosynthesis. Highly oxygenated streams flowing into lakes are also a source.

Notice that a couple of things are required for oxygen to be generated in lakes: sunlight so plants can grow, and water in contact with the atmosphere. In winter, both of these routes can be shut down. Aquatic plants can continue growing until light levels are reduced to about 1 percent of levels at the surface. This doesn’t sound like a lot of light, but in years when heavy snows cover lake surfaces for long periods, light levels can drop to the point that algae and aquatic plants not only can’t produce oxygen, but large quantities die and decompose.

Not only does the bacteria-driven decomposition process consume large quantities of oxygen, but shallow lakes often have plants growing throughout the lake, meaning lots of oxygen consumption when plants die. This can cause oxygen to drop to lethal levels, resulting in die-offs of fish already stressed by winter conditions. Deeper lakes usually have much less vegetation relative to lake volume, so winter oxygen levels tend to remain more stable.

In years when snow cover is light, like in the picture below, sunlight continues to penetrate into the lake, allowing plants to keep on growing and generating oxygen. Of course, these favorable growth conditions also tend to result in lake managers getting lots of calls from shoreland property owners because “the plants are taking over.”

Lake without snow.

So what is the connection between how we manage our shoreland property and fish kills? The more algae and aquatic plants living in a lake when it freezes, the higher the likelihood that a fish kill may occur. In addition to sunlight, algae and aquatic plants need nutrients, so anything we do that adds nutrients can increase the likelihood of a fish kill. Sediment entering a lake from an eroding shoreline or construction project carries nutrients, as does runoff from fertilized lawns or leaky septic systems. Sediment also carries organic matter which, when decomposed by bacteria, further depletes oxygen. There are many simple steps you can take to prevent excess nutrients and sediments from entering your lake. Probably the simplest and most effective is to retain or restore natural vegetation along your shoreline. For more ideas of ways to keep your lake healthy, take a look at Protecting our Waters: Shoreland Best Management Practices.

Mike Demchik, Former Regional Extension Educator, University of Minnesota Extension Service

Deer populations have been high in Minnesota for several years. However, even at fairly low populations, deer can severely damage forestry plantations, newly planted windbreaks, and home landscaping by repeatedly browsing (eating) foliage. This damage is particularly great if preferred browse species are planted or when highnutrition nursery stock is planted near wild-grown (often lower-nutrition) species. In general, deer will damage apple, basswood, white cedar, white pine, and many tree species often included in wildlife conservation plantings. Such species often eaten by deer include highbush cranberry, mountain ash, crabapple, hazelnut, and others. Additionally, in some parts of the state deer feed upon red/Norway pine, birch, maples and even young spruce tops. Only a few trees are not sought by deer: Russian olive, some honeysuckles, lilac, Scots pine, spruce (in most of the state), and balsam fir. However, when a deer population becomes large, even these are not safe.

So how do you protect trees from deer? While there are several ways to reduce deer damage, it is almost impossible to completely eliminate it. In other states, particularly Pennsylvania and New York (but also a few places in Minnesota), electric fencing keeps deer out of high-value plantings. This fencing is expensive and difficult to maintain, but has been shown to be effective. Typically, the fence uses seven strands of wire strung to 7 feet tall. Slanting the wires outward from bottom to top (20-30 degrees), can improve its effectiveness. For small or skinny plantings (like windbreaks), woven wire fences as low as 4 feet will help, as deer will seldom jump into a small, skinny area.

Tree shelters (called tree tubes by many people) are solid or mesh plastic tubes that protect the trees. These are held in place by a bamboo stake for the mesh tubes or a wooden stake for the solid tubes. The solid tubes are usually quite expensive (usually $3 or more) while the mesh tubes are less expensive (about $1) but flimsy and likely to be damaged. While these work well and the solid tubes provide the added benefit of reducing tree death during droughts (the air inside the tube is warm and moist), they are sometimes used by deer for rubbing antlers and can be damaged by bears. This means they require regular maintenance to be effective. Additionally, the trees inside the tubes can be more easily damaged by early winter freezes and exceptionally warm early springs. Even with these caveats, tree shelters provide good protection against deer browsing.

A homemade alternative is to make individual fences 8 inches in diameter made of 4-6 foot tall turkey wire (1” X 2” holes). These work very effectively. The added benefit is that they are reusable and easy to remove (the deer will prune off any branches that grow through the wire). They cost a dollar or less each to make.

Sharon Moen, Minnesota Sea Grant Program

Unlike zebra mussels, most mussels make quiet, interesting, lovely neighbors. Mussels are found on every continent except Antarctica. Freshwater mussels are most diverse in eastern North America, where there are about 300 species (Europe only has 12 species). But they are one of the most endangered groups of animals in North America; about 71 percent of known species and subspecies are listed as endangered, threatened or of special concern. Common native mussels that you might encounter in your lake include:

Giant Floater (Pyganodon grandis– pictured above) Fatmucket (Lampsilis siliquoidea)

Paper Pondshell (Utterbackia imbecillis– pictured above) Eastern Elliptio (Elliptio complanata)

Reprinted with permission from Cabin Life, Cabin Living Magazine, April/May 2004.

Cindy Hagley, Great Lakes Environmental Quality Educator, University of Minnesota Sea Grant

Some of us prefer country living, with its lack of crowding, clean air and water, and wide-open spaces. Because in the country people are sparsely distributed, we tend to have to drive much farther to obtain the services we need. Others of us prefer the city, where high rise buildings make it possible for large numbers of people to congregate in relatively small spaces. In the “more productive” environment of the city, services are also concentrated in a small area and can be more easily obtained nearer to our homes. These services include shelter, food, water, medical care, security, and other basic human needs.

Fish are not so very different from us in terms of their basic needs, and, just like us, the number and variety of fish that occur in a particular lake are determined by the availability of essential “services.” In the case of fish, these include places to spawn and rear young fish, places for adults to feed, fish migration habitat, and vegetative cover for protection from predators.

The types of lakes we may enjoy most for swimming in are the least “productive.” In other words, they are less nutrient-rich and support less algae and fewer aquatic plants, fish, and the small aquatic animals (zooplankton) that many fish feed on.

Though not as much fun for swimming, a healthy, productive lake like this one is somewhat like our “city” environment. It can support high and diverse populations of fish.

What can you do to encourage good habitat conditions for fish in your lake? One of the most important habitat requirements for fish is aquatic vegetation. The following excerpt from Through the Looking Glass says it well:

“Any angler knows how important plants are to fish. Habitat created by aquatic plants provides food and shelter for both young and adult fish. Invertebrates living on or beneath plants are a primary food source. Some fish, particularly bluegills, also graze directly on leaves and stems.”

“Predatory fish cruise the shadowy plant beds in search of prey. The structure and density of the plant beds can determine whether predators will be well-fed or go hungry. Too few plants can limit the number of prey fish; plant growth that’s too dense can fence predators out.”

Through the Looking Glass… A Field Guide to Aquatic Plants Susan Borman, Robert Korth and Jo Temte 1997, 248 pp. http://www.wisc.edu/wisconsinpress/books/0519.htm

Just as in a city, where poor management can result in pollution, overloaded services, and a reduced quality of life, lakes receiving high concentrations of nutrients (phosphorus and nitrogen) from their watersheds can shift from being able to support high and diverse fish populations to a less stable, less diverse system. Excess nutrients can lead to the elimination of sensitive species, which are less able to cope with the adverse conditions that result from a lake becoming overly productive, or “eutrophic.” Long-lived species that reproduce slowly and require extended periods of stable conditions are most negatively affected in unstable, eutrophic lakes. Often, as lakes become more eutrophic, populations of the top predator species that we enjoy catching, such as walleyes, are reduced, and smaller less desirable species of fish increase.

Just as we work hard in our cities to develop effective comprehensive plans that will ensure a high quality of life in the future, we should work together to plan a healthy future for our lakes. Two of the most important steps we can take to ensure healthy fish populations are to maintain a healthy aquatic plant population and control nutrient inputs from the watershed.