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AQUATIC LIFE
Aquatic Life In The Mountains
The abundance and diversity of aquatic
habitats in the North Cascades ecosystem is one of the characteristics
that makes this area unique. In North Cascades National Park (NP), over
500 lakes and ponds are scattered throughout the mountain landscape.
These natural environments are home to native aquatic life including
plankton, aquatic insects, frogs and salamanders. To visiting onlookers,
the natural backdrop of these lakes and ponds makes them appear
pristine, but ongoing stresses may be affecting the health of these
ecological systems.
Park resource mangers are monitoring these
lakes and ponds to determine their chemical and physical status. Acidic
deposition (acid rain) and nutrient-laden atmospheric deposition may be
altering the chemical composition of lakes and ponds. This could be
causing acidification and nutrient enrichment harmful to the sensitive
balance of aquatic life. The physical and chemical properties of lakes
and streams can also be affected by direct human influences. Trampling
and destruction of vegetation around shorelines leads to erosion,
sedimentation and changes in nutrient inputs. Introduction of non-native
species causes environmental disturbances, and historic mining activity
may have led to the contamination of some water sources.
Aquatic resource managers from North Cascades
NP are working with the North Coast Cascades Network, the United States
Geological Survey and the National Park Service's Water Resources
Division in developing a long-term ecological monitoring program for
lakes and ponds. This will allow them to determine if acid rain and
visitor use are affecting the health of these fragile but valued
environments.
www.nps.gov/noca/Ltem/index.htm
Silver Lake
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Weeding And Wetland Restoration Around Ross
Lake
Non-native plants and animals threaten
natural ecosystems around the world. National Parks are no exception,
though they exist in part to preserve natural environments. Introducing
non-native plants, often in gardens or on farms, can have unintended
consequences. Reed Canary grass is just one of the problem plants that
threaten biodiversity in the North Cascades. Vegetation surveys around
Ross Lake identified many infestations of this non-native grass, ranging
from individual plants to 5-acre patches. Seattle City Light's Ross Dam
inundated 26 miles of the Skagit River and created a seasonally
fluctuating lakeshore where there was once over 11,000 acres of riparian
and wetland habitat. This habitat had served as a resting stop for over
150 species of migratory birds and winter range for many mammal species.
It was a breeding ground for approximately 75 species of birds that
wintered south of the United States, many of which are declining in
population.
Reed Canary grass, an aggressive non-native
that invades disturbed areas, is pervasive throughout the western United
States and extensive in the lower Skagit Valley. Its thick shoots and
root systems begin growing early in the season, excluding native wetland
plants and preventing natural establishment of riparian forests. The
grass thrives in nutrient rich stream outlets where water levels
fluctuate; the same conditions found around Ross Lake. Native fish and
other animals are not well adapted to spawn or reproduce in Reed Canary
grass thickets. The grass threatens the habitat of animal and plant
species on federal or state rare and endangered Species lists including
Bull Trout, Cascade Frog, Harlequin Duck and Bald Eagle. Reed Canary
grass also directly affects habitats that support 27 Washington State
listed plant species.
Non-native invasive species like Reed Canary
grass need to be removed in order to protect the rivers and streams of
the North Cascades National Park Service Complex. If the park staff used
just chemical treatment, it would likely need to be repeated every few
years, and success would probably be minimal. Instead, the Park Service
is trying a creative, multi-faceted approach combining the efforts of a
plant ecologist, exotic plant management crew and plant propagation
employees to restore wetlands around Ross Lake. They are using the logs,
root wads and other woody debris which washes into Ross Lake annually to
recreate nutrient rich wetlands. In the past, Seattle City Light (SCL)
crews collected this wood and burned it. In 2004, the park crew instead
used some of the wood (1,320 cubic yards) to mimic naturally occurring
wetlands and riparian areas still found in adjacent drainages. These new
riparian areas allow planting a diversity of native plant species and
the shading out of the Reed Canary grass.
Agency cooperation will expand this
alternative wood use. Rather than burning woody debris, Seattle City
Light will deliver it to restoration sites on Ross Lake to cover areas
devoid of vegetation or occupied by Reed Canary Grass. Native plant
species either salvaged on site or propagated in the Park nursery, will
be planted to create native plant communities which mimic those lost to
the reservoir. Community volunteers will help monitor and maintain the
native plantings in the years ahead.
In summer 2004 the park's resource management
staff also began treating Reed Canary grass around Ross Lake with
glyphosate herbicide. Areas near Big and Little Beaver, Dry Creek and
Lodgepole Camps were sprayed. The park staff believes that the key to
preventing re-infestation or future invasion by other non-native species
is the placing of woody debris and then planting native species. Few
exotic plant removal projects include this revegetation component. The
project is developing methods which may serve as a model for other areas
such as the U.S. Forest Service's nearby Baker Lake, the National Park
Service's Lake Chelan, Lakes Ozette and Crescent at Olympic National
Park and neighboring areas in Canada such as Manning Provincial
Park.
Stream Habitats
After any rainfall, the surge of rushing water
can be seen and heard just about anywhere within North Cascades National
Park. The park's dynamic glaciers and steep mountains feed over 4,000
miles of streams and rivers. The status of these streams is the focus of
a number of projects in the Inventory and Monitoring Program.
Aquatic resource program activities have
included stream amphibian and fish inventories to determine what species
are living in the park's streams. Working with other parks in the North
Coast and Cascades Network, as well as the U.S. Forest Service, data
sets can be established that outline what aquatic life inhabits streams
across the region. These inventories can be used to ask further research
questions and establish monitoring programs.
Program activities have also included benthic
macro-invertebrate (BMI) monitoring in streams. BMIs are organisms that
have no backbone and spend a portion or all of their life living along
the bottom of streams. Many BMIs are the larval forms of flying insects
like mayflies and are an important food source for fish, birds and
amphibians. Their abundance, diversity, sensitivity to environmental
changes and inability to travel far distances make them ideal for
monitoring stream conditions.
In addition to looking at aquatic life within
streams, researchers also monitor physical and chemical attributes of
streams to see how natural and human-caused disturbances affect these
waterways. Currently, streamflow variability in small streams at North
Cascades and Mount Rainier is being assesed by a graduate student from
the University of Washington.
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