WATER’S MUSCLES: MUSSELS? By Maggie

WATER’S MUSCLES: MUSSELS?

Native mussels are the muscle of freshwater. The more of them you have, the greater the water body health is. Similarly to muscles’ dual roles as support and movement of the body, mussels fill specific roles and provide unique environmental services. Quite impressive for such a small creature!

FOOD WEB

Mussels are thoroughly ingrained in the food web of Wisconsin water bodies. These invertebrates are effective at filtering bacteria and plankton out of the water. They can then convert the nutrients into forms accessible to higher trophic levels.

COMMENSAL RELATIONSHIPS

Some species of mussel are also indubitably paired with certain fish species; reproduction for all mussels involves the young mussels, called glochidia, attaching to the fleshy parts of fish. Mother mussels have developed species-specific lures in order to attract the correct type of fish. For example, the Higgins’ eye mussel has developed a minnow-look-alike lure in order to attract bass and walleye. Once attached, the glochidia will grow and develop without harming the fish (commensalism).

QUALITY MONITORS

Like all living creatures, mussels require certain parameters in order to successfully live. Common across all species is the quality of water. The sensitive nature of mussels means they require habitats with pristine water in order to thrive. A large population of one or multiple species represents a high quality of water. Also, depending on the mussel species present and their requirements, information about the substrate and fish species in the water system can be gleaned.

HISTORY-KEEPERS

Individual mussels can be examined for better understanding of lake history. Mussels will grow rings on their shell during each year of life. Certain characteristics of the shell will also reveal hints about the water quality during that time. Being able to read these details will broaden the understanding of past lake history and dynamics.

POTENTIAL HARM

Unfortunately, since the conditions necessary for happy mussels are exceptionally pristine, anything that reduces the quality of water will negatively affect mussel populations. Some common sources of harm include pollution, invasive species, over harvesting, abundant silt and habitat change:

-Industries on moving water bodies will discharge some level of pollutant. Abundance and concentration will determine the extent of its impact on the overall water quality.

-Zebra mussels and other exotic species can out compete the natives since there are no natural predators and they can grow exponentially.

-Over harvesting has occurred in recent history with the growing interest of pearls for fashion purposes.

-Disturbance on the habitat can result in siltation, or excess fine soil being put into the system. A build up of silt can reduce the respiration capability of mussels.

-Dramatic habitat changes tend to be due to human intervention. Dams in particular cause flowing water to stagnate, which reduces the exposure of mussels to nutrients.

Due to such a wide range of harm, half of Wisconsin’s fifty-one mussel species are listed as threatened or endangered. Nature is extraordinary in the fact that it can undergo change to a certain extent without unraveling. We, as neighbors, need to understand how our actions impact the system and actively promote water body health. Water cannot afford to lose its muscles! 

* On August 25th, we have a new program: Native Mussel on the Manitowsih River Canoe Adventure! You can sign up now: https://www.z2systems.com/np/clients/nldc/event.jsp?event=36173& * 

Submerged trees in your Waters!- By Brad

Whenever you come across a tree that has fallen into the water, do you think that the tree no longer serves a purpose or that it should be taken out of the water? This is where people are often times mistaken, myself included. For centuries human beings have altered our landscapes through the removal of trees to build the homes and buildings that we see today. By taking down trees around lakes and removing those that have fallen in the water, the habitats and communities are also removed. The natural growing cycle is stopped by the removal of trees, with seedlings prevented from reaching the ground after falling from both submerged and standing trees. However, thoroughly educating people about why these trees are so important may change the way that they think about their property, saving trees on land and in the water.  

Educating people about the importance of trees along lakes is vital because even though trees that have fallen into the water have ended their life on land, they have begun a "second life" submerged in water. What this means is that a tree once again plays a significant part in nature. Something that is often times over looked is that for a roughly about a season after the tree has fallen into the water it will still contain its leaves, offering the highest habitat complexity for underwater species. These trees are also home to a large variety of fish such as largemouth and smallmouth bass, walleyes, bluegills, northern pike, and even musky.

Submerged trees have multiple purposes for a wide variety of fish. For example largemouth and smallmouth bass prefer to build their nests near logs or submerged branches because it helps protect their eggs from predators by giving the fish less of a perimeter to cover in protecting its young from lurking predators. When fish hatch they often live within the branches. If there are no trees for them to hide in, some fish populations may decline dramatically. Large predators such as musky or northern pike use submerged tress to ambush their prey as it swims by. Also those species of fish such as walleyes who prefer low light conditions use the shade provided by tree branches to ambush prey during the day.

The relationship between submerged trees and fish is influenced by the orientation of the tree in the water. More numbers of fish use trees that have more branches and are larger than those that do not. This is because fish have more places to hide and feel more protected from predators. But smaller trees that are bunched together can hold as many fish if not more than larger trees that have fallen into the water. Also trees that are located near plant beds create more complex habitats that fish can thrive in.

For those lakes that have a low abundance of trees along their shorelines or in the water, other man-made structures know as fish cribs can be placed in the water. Fish cribs are a Lincoln-log type box design that is often times weighed down by rocks or cement and is used to hold fish for habitat management. Even though this idea sounds great, human made structures do not always replace natural structures for fish. The best solution for keeping trees in the water along shorelines, is to inform the public about their significance to both the environment and life below the water. So the next time you see a tree next to the shore about to fall over or one that is already in the water, think about how much aquatic life it is supporting and will support for years to come!

Meet the Monarchs Butterflies by Kurt

Pollinators are an indispensable part of the world's ecosystem. They carry pollen from one plant to another, helping them to reproduce. 75% of the world's flowering plants and 75% of our crops rely on pollinators like bats, bees, beetles, and butterflies. Without pollinators, foods such as blueberries, cherries, apples, almonds, coffee, and chocolate would disappear!

One of the most charismatic and unusual pollinator is the monarch butterfly. The caterpillars are recognizable for their yellow, black, and white striped body and the adults for their vibrant orange wings. Monarchs are peculiar in that they rely solely milkweed plants: it is the only plant they lay eggs on and the only plant they feed upon as caterpillars.

We've raised monarchs for the past 20 days or so. They started out as minuscule eggs on milkweed leaves. After hatching, they ate and grew rapidly. Between 10 to 15 days they increased their size and weight almost 3,000 times! Most of them have entered the chrysalis stage of their development. In another 10 days or so, adult monarchs will emerge into the world. 

When fall comes around, our monarchs will undergo one of the greatest migrations on earth. Hundreds of millions of butterflies will swarm over the country in a smoky ochre-hued cloud to descend upon high-elevation fir forests in central Mexico and the sunny coasts of central and southern California. The migrations require the butterflies, weighing not much more than a paperclip, to cover distances between one and two thousand miles. To accomplish this, monarchs need to cover between 25 to 30 miles a day!

Unfortunately, the monarch population has dropped by 90% since 1980, when populations first started to be monitored. This drop in population can be attributed to several different factors. The first and most important factor is the overall loss of milkweed throughout the United States. Milkweed is lost for a variety of reasons: herbicide use, increasing urbanization in milkweed growing areas, widespread industrialized farms, and drought conditions in many parts of the western U.S. Illegal logging in Mexico has also resulted in habitat loss in the monarch's overwintering grounds.

People throughout the United States can take small yet significant steps to help. The first is to plant milkweed. There are over 100 native milkweed plants, many of which are used as food for monarchs. Individuals can also plant pollinator-friendly plants, like butterfly weed, zinnia, and sunflowers. Monarchs need the nectar for energy to breed, to complete their migration, and to build energy reserves for the long winter. People should avoid using pesticides as well. The general pollinator population is plunging, but with a little awareness and some small actions we can collectively make a huge impact.  

  

For the Love of Biking, Hiking and More! By Neva

So many trails!

I have always enjoyed biking, running, and hiking. I love to find new bike routes and new trails. Having the opportunity to live at the North Lakeland Discovery Center, I have been gifted with so many trails to explore! I have set a personal goal for the summer to get out on a trail once a day. Here are some of the highlights so far!

When I was hired here at the Discovery Center, I received lots of information in the mail about the area. When I opened the brochure for WinMan Trails, I thought “Why haven’t I been here?” That afternoon, my friend and I made the drive down. We were mind-blown! WinMan Trails are super! I have been back many times since. Whether you are a novice or an expert mountain biker, there is something for everyone. There are all kinds of challenges for riders, like the bridge on the right.

 This bridge drops off onto a large rock. On the Bridge Trail, a highlight is definitely the bridge below, featuring rollers and embankments.

 I really enjoy biking on the paved trail from Manitowish Waters to Boulder Junction. It goes right by the Discovery Center, so I just hop on and go! It parallels highway K, but it’s perfectly placed in the pines.  This trail is a great place to run as well.

Another great spot to hike, run, or bike is the Van Vliet Hemlocks State Natural Area. The old-growth hardwood hemlock forest blew me away, and I was fascinated by the fact that a couple hundred years ago, this is what most of Wisconsin had looked like. The forest is very dense, so it is extremely mosquito-ridden, but well worth it.

Last but not least, it’s wonderful to be able to walk right out my cabin door onto a trail here at the Discovery Center.  We have 12 miles of trails here, including a bog boardwalk.  The trails go through uplands and lowlands, and the Big River trail parallels the Manitowish River.

Happy trails!