Voyageurs National Park

Voyageurs National Park

Natural World

Nature & Science

Voyageurs National Park is a mosaic of land and water, a place of interconnected waterways that flow west into the Rainy River, and eventually north as part of the arctic watershed of Hudson's Bay. It's a place of transition, between upland and aquatic ecosystems, southern boreal and northern hardwoods forest types, and both wild and developed areas.

The foundation of the park's landscape was sculpted by a series of glaciers that have scoured and carved the area over hundreds of thousands of years. The most recent period of glaciation ended just over 10,000 years ago, exposing ancient Precambrian rocks that formed over two billion years ago. The forests that now drape the upland portions of the park exist on a thin layer of soil that has formed in the comparatively short period of time since the last glacier receded.

People entered this region following the retreat of the glaciers. Early Native Americans were the first to make use of the abundant resources the lakes and forests provided, followed by Europeans and other native groups drawn to the area during the fur trade period of the late 1700s and early 1800s. Mining, commercial fishing, logging and recreational use brought more people to the region in the years that followed, evidence of which may be found in the park today.

We welcome you to learn more about the natural and cultural history of Voyageurs National Park, whether you visit by land, boat or from the comfort of your home computer.

Natural Features & Ecosystems

The glacially smoothed landscape of Voyageurs National Park is part of the Canadian Shield. This area of exposed Precambrian rocks formed two-billion years before the age of dinosaurs. The smoothed rocky outcrops and low elevations that now characterize the park's terrain provide little hint of the area's more dramatic history.

Study of the park's rocks has shown that what is now Voyageurs National Park was once an area where volcanoes erupted beneath an ocean that no longer exists.

They provide evidence that this area also contained mountains, and that beneath the surface of the archaic landscape were vast chambers of molten rock. These magma chambers cooled hundreds of millions of years ago, forming the granitic rocks that now comprise the Vermillion batholith.

These ancient rocks are found at the surface of the park because the passage of hundreds of millions of years has worn down the mountains. In geologically recent times, continental glaciers scoured the landscape, removing rotten rock and leaving behind a blank slate for the re-colonization of plants and animals.

When we think of the changes that have occurred in what is now Voyageurs National Park over this great span of years, the landscape and natural features that define it take on a kaleidoscopic quality--as glaciers, lakes and forests advance, retreat, change, disappear, and return again and again over time.

Environmental Factors

Fire, high winds, extreme cold and a changing climate are factors that have influenced the composition, structure and function of ecosystems within Voyageurs National Park for many thousands of years.

Today, in addition to these ongoing natural processes we must also consider the effects of human decisions, both locally and globally, on the park environment.

Logging, mining, fire suppression, dam building, the introduction of invasive non-native species, and a variety of industrial activities have all had an effect on the plants, animals, water and air quality within the boundaries of the park.

The National Park Service is responsible for conserving the natural and cultural resources within the park, and providing for their enjoyment by this and future generations.

In order to make informed decisions that support better land management, the park works with a number of partners to conduct research and monitor the health of Voyageurs' natural and human environment.

One of the most significant natural resource issues at Voyageurs National Park is the management of water levels in the Rainy Lake and Namakan basins. Water levels are regulated by the International Joint Commission (IJC), a board with representatives from the United States and Canada.

Water levels are controlled by a hydroelectric dam at the outlet of Rainy Lake and by regulatory dams on Namakan Lake's two outlets. These privately owned dams have been in place since the early 1900s.

Past research indicated that the management of the dams had created changes to the lake levels in the Rainy and Namakan basin that were resulting in negative impacts to the aquatic ecosystem.

In 2000 the IJC modified how it manages lake levels in a way that is expected to improve environmental conditions in the park. Voyageurs is currently working with a variety of partners to conduct research on several environmental factors that have been affected by lake levels in the past, including: fish communities, benthic organisms, common loon hatching success, muskrat abundance and survival, and wetland vegetation monitoring.

If the new lake level management system results in measurable benefits to the aquatic ecosystem it will likely remain in place.

Nonnative Species

Exotic species such as the spiny waterflea and rusty crayfish and fish diseases are threats to the aquatic ecosystems of regional lakes including those in Voyageurs National Park. Spiny waterfleas have recently invaded multiple lakes in the region, including the large lakes within Voyageurs National Park. Rusty crayfish have invaded at least one lake in Voyageurs National Park and many lakes in the region. Viral hemorrhagic septicemia (VHS), a fish disease, has not yet been introduced into any lakes in Minnesota, but has caused fish kills in most of the Great Lakes and in some inland lakes in Michigan and Wisconsin.

Spiny waterfleas are tiny (1/4-5/8”) crustacean zooplankton. They are native to Eurasia and were introduced into the Great Lakes from the ballast water of ships. They threaten the park’s aquatic ecosystems and fishing by competing with native fish for food and fouling fishing gear. Research has shown that the spiny waterflea can cause the following impacts:
*change the community composition of zooplankton
*compete directly with juvenile yellow perch and other small fish and minnows for food which could lead to a decrease in the abundance of these fish

These impacts could alter the food web; for instance, yellow perch are an important part of the diet of walleye, so a decrease in yellow perch abundance could hurt walleye growth.

Rusty crayfish are native to the Ohio River drainage but have invaded lakes in Wisconsin and Minnesota in recent years. They were found in Sand Point Lake in 2006. Rusty crayfish are more aggressive than native crayfish and can eliminate native crayfish and aquatic plants, causing great change to the aquatic ecosystem of invaded lakes. Please do not move live crayfish from one lake to another, and remember that it is illegal to use live crayfish for bait in any lake in Voyageurs National Park.

Viral hemorrhagic septicemia (VHS) is a viral fish disease that has been found in all of the Great Lakes except Lake Superior. It can kill many species of game fish including walleye and muskellunge. It could easily be spread to Minnesota lakes since many people travel between areas with infected lakes and Minnesota, and the virus that causes the disease can be spread by moving infected bait or water to uninfected lakes. Although VHS causes mortality in fish, it is not a threat to human health.

Spiny waterfleas are spread when either live adult waterfleas or viable resting eggs are transferred to a new body of water. Spiny waterfleas and viruses that cause fish diseases can be transported on bait buckets, anchor ropes, fishing line, boats, waders, and nets. Any gear that enters infested water and is transferred to another lake or river without being thoroughly dried (for at least 5 days) or washed with hot water (>140° F for at least one minute) could transfer exotic species and fish diseases.

The Minnesota Department of Natural Resources (DNR) has designated the following water bodies as infested: Rainy Lake, Rainy River, Namakan Lake, Kabetogama Lake, Sand Point Lake, Crane Lake, and Little Vermilion Lake. The infested waters designation triggers specific Invasive Species Laws that are listed on page 61 of the DNR’s 2008 Fishing Regulations handbook.

The National Park Service and DNR are working in concert to prevent the spread of the spiny waterflea, other exotic species, and fish diseases by:
*implementing Best Management Practices for visitors, partners, and staff
*conducting public education at boat launch areas about exotic species, invasive species laws, and Voyageurs National Park interim measures to prevent the spread of exotic species
*providing information about spiny waterflea, other invasive species, and fish diseases at park visitor centers, in park and DNR publications, and on the park website ( and the DNR website (

The National Park Service has adopted the following three interim measures to protect the interior lakes in Voyageurs National Park from the spiny waterflea, other exotic species, and fish diseases:
*artificial bait only (on all interior lakes only)
*no privately-owned watercraft allowed in interior lakes (the park will continue to provide canoes and row boats for rent through the Boats on Interior Lakes program and Commercial Use Authorizations on Mukooda Lake)
*no float plane landings on interior lakes

If you plan to recreate on the interior lakes in Voyageurs National Park, please follow these Best Management Practices:
* Bring a separate set of gear that is likely to contact lake water (including fishing gear) to use on the interior lakes, or before using any gear on an interior lake, make sure that all gear has been thoroughly dried for at least 5 days or washed with hot water (>140 degrees F) for at least one minute
*When leaving any lake, remove aquatic plans and animals, including gelatinous or cotton batting-like material from equipment, including fishing line

Spiny waterfleas are readily spread to uninfested lakes due to their small size, hardiness, and a tendency to cling to equipment. When spiny waterfleas or other exotic species stick to equipment within infested waters and are transported to uninfested waters on this equipment without being desiccated or killed with hot water, they may start a new infestation. The interim regulations and Best Management Practices have been developed to eliminate the following likely means of transmitting fish disease and exotic species to the interior lakes of the park: using infested gear in the interior lakes, landing aircraft on the interior lakes during the open-water season, portaging private watercraft to interior lakes, and the use of any bait other than artificial bait in the interior lakes. Additional note: Although non-aquatic baits will not spread aquatic exotic species or fish diseases, some of the most common non-aquatic baits are exotic species, for example, earthworms (including nightcrawlers). Since exotics such as earthworms have negative effects on the terrestrial ecosystem (in addition to the negative effects that aquatic exotic species and fish diseases have on aquatic ecosystems), park management has chosen to allow only artificial bait on the interior lakes.

The park will conduct a program about exotic species and VHS for any interested party or organization.

To schedule a program call Tawnya Schoewe at 218-283-6600.

With your help and careful actions, we can try to prevent the spread of the spiny waterflea, other invasive species, and fish diseases. Stop aquatic hitchhikers!

Voyageurs National Park is located in the Southern Biome of the Northern Boreal Forest. A biome is a unit of land that is defined by climate and native vegetation. It's a place where predominantly northern hardwood forest and conifer-dominated southern boreal forest mix and meet.

The area is comprised of a variety of ecological systems, including fire-dependent forests, hardwood forests, peatlands, fens, marshes, rocky outcrops and lakeshore environments. Pine, spruce, and fir are the primary conifers in the park, with aspen and birch forming a high percentage of the deciduous trees.

Historically, fire and wind were the primary disturbance factors shaping the composition and structure of the park's forests. Today, the effects of extensive 20th century logging, changes in the abundance of herbivorous wildlife species, the introduction of invasive non-native species, and a changing climate are also affecting the forest and other plant communities at Voyageurs National Park.

Voyageurs is home to a diverse assemblage of wildlife, including over 240 species of birds, 10 species of reptiles and amphibians, 53 species of fish, 42 species of mammals, and countless invertebrates.

The park has two distinct but overlapping habitat types: the terrestrial, upland ecosystem and the aquatic ecosystem. Each has its own set of herbivores, insectivores, omnivores and carnivores, although some species cross the boundary to inhabit or get food from both.

The animals you might see on a visit to the park vary considerably with the seasons. During the warm months of summer the park is alive with the hustle and bustle of thousands of migratory birds, ranging from common loons, great blue herons and white pelicans to tiny neotropical warblers. Other park inhabitants, like the black bear, white-tailed deer, moose, red squirrel and other forest dwellers are also on the move. They are seeking food to regain strength after the harsh northcountry winter, enjoying the brief warmth and abundance of summer, and building up fat or food reserves to prepare for the next season of cold.

Winter is a time of ice and snow at Voyageurs, when the surface of the largest lakes in the park freezes and the park's wildlife are challenged by long periods of extreme cold. Many animals migrate or enter a state of dormancy to escape the elements. Others remain active, leaving tracks in the snow that allow park visitors to discover the comings and goings of Voyageurs' wildlife during the short days and long nights of winter.

During this cold season, wolves move in daylight over the frozen expanses of lake in search of their next meal. Snowshoe hares trade their grayish-brown summer color for a coat of white fur to blend in with their snowy surroundings. Black bears retreat to their dens, where expectant mothers will give birth to tiny cubs in the darkness of winter. Turtles burrow down in the mud to wait out the winter, emerging when longer days bring light and warmth back to the lands and waters of Voyageurs National Park.

Beneath the surface of the park's many lakes, fish and aquatic invertebrates inhabit their watery world through the warm months of summer and the cold of winter when the surface of the larger lakes may freeze to depths of over two feet.