Introduction

Park Resources

Watershed Approach

Participants

LTEM Components:
· Mandates, Goals, and Components
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· Geologic Resources
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· Atmospheric Resources
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· Aquatic Habitat
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· Aquatic Biota
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> Terrestrial Vegetation
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· Terrestrial Fauna
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· Human Resources
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· Cultural Resources
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North Cascades National Park Service Complex
 Long-Term Ecological Monitoring Conceptual Plan
Terrestrial Vegetation Chart

Abstract
Monitoring Components:

Abstract

The terrestrial vegetation of North Cascades NPS Complex is highly diverse, as a result of the co-occurrence of climatic gradients and topographic diversity over relatively short distances. Diversity is observed in terms of numbers of species, as well as spatial variation in distribution and abundance. Vegetative assemblages vary greatly from west to east, going from a marine-dominated environment (high precipitation) on the west side to a semi-arid environment on the east side (lower precipitation). High annual snowfall is the limiting factor to plant distribution and growth at higher elevations. There are over 1,500 vascular species in the park, with many additional lichens and mosses. There are 258 exotic plant species, especially along transportation corridors, near trails, and in riparian areas.

Patterns of vegetation distribution are also temporally dynamic. Large-scale disturbances (fire, cyclonic winds, insects) can remove the forest overstory over thousands of hectares, resulting in a new successional sequence of overstory and understory species. The size and frequency of these disturbances vary greatly among ecosystems. For example, fire is more common in drier east-side forests than in high-precipitation, west-side systems. However, fire exclusion has reduced the frequency of fire in east-side forests during the past century, leading to speculation that fires may now be larger and of higher intensity than in the past. Disturbance processes also act on a small scale, with windthrow, pathogens, and insects causing small gaps and affecting local in-growth and successional dynamics over time. Climatic variation is always an overarching factor that affects species regeneration and distribution on long time scales, resulting in non-equilibrium systems with unique assemblages of species co-occurring over centuries to millennia; plant species distribution is never static or in a "steady state."

Large-scale spatial patterns of vegetation have been affected by timber harvest activities outside the park boundaries over the last century. This creates habitat fragmentation and also impacts hydrologic resources within forest ecosystems. The spatial and temporal scales of disturbance from human impacts are normally quite different than scales of natural disturbance. There is also some disruption of vegetation within the national recreation areas and organized campgrounds, where trees are often removed to facilitate human activities, supply wood, and ensure safety.

Management considerations include: (1) detecting the effects of stressors (e.g., air pollutants), (2) protecting species of special concern, (3) reducing populations of exotic species where possible, (4) determining and maintaining natural vegetation dynamics and processes, including disturbance, (5) managing and mitigating the effects of human disturbance. While local issues, such as restoration of backcountry social trails and campgrounds, can be addressed with some success by intensive management, it is considerably more difficult to affect large-scale dynamics and processes. Large-scale management strategies must take into consideration the management objectives of adjacent agencies and landowners. It is also critical that other resources, especially the condition of streams and hydrologic systems, be incorporated in the monitoring and management of terrestrial vegetation within the park.

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Monitoring Component: Vegetative Assemblages and Processes

Monitoring/Research Questions: At large spatial scales, what is the distribution of vegetative assemblages, forest structure, and fuel loading? How are these characteristics changing over time?

Stressors And Related Factors: Atmospheric deposition, climatic change, fire exclusion.

What To Monitor: Species distribution and abundance, potential habitat, structure, ecosystem processes.

Justification: This will provide basic information about distribution and abundance of species and the basic factors that limit their regeneration and growth.

Description of Recommended Action:

  1. Ground truth and improve existing vegetation coverages recently developed by the NPS. Consider a crosswalk of classifications to plant associations used by the Forest Service on adjacent lands.
  2. Revise vegetation coverages for the park at 10-year intervals, if possible, based on continued ground truth, monitoring of permanent plots, and incorporation of new information (e.g., extent of disturbances).
  3. Develop a network of permanent plots based on vegetative assemblages representing major ecosystems in the park.
    1. Include climatic and elevation gradients
    2. Determine age of forest stands with initial inventory
    3. Identify geomorphic and soil characteristics
    4. Identify disturbance agents
  4. Utilize and/or link protocols with those used by other groups working with long-term monitoring of vegetation in the Pacific Northwest (Oregon State University network [Acker, Harmon], Mt. Baker-Snoqualmie National Forest [Henderson]).
  5. Consider monitoring the following:
    1. Structure and composition (perhaps 5-year interval)
      1. Forest density and structure (recommend 5-year interval)
      2. Determine shrub and ground cover (recommend 5-year interval)
      3. Temperature and precipitation measurements
      4. Link with vegetation modeling efforts (USGS-BRD, Forest Service)
      5. Down woody material and litter (recommend 5-year interval)
    2. Ecosystem processes (link components with air and water quality issues and components) on a subset of plots.
      1. Carbon/nitrogen ratio
      2. Litterfall
      3. Decomposition
      4. Mineral leaching

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Monitoring Component: Patterns of Natural Disturbance

Monitoring/Research Question: What are the extent and severity of natural disturbance events? How have disturbance patterns changed over time?

Stressors And Related Factors: Fire, insects, fungal pathogens, wind.

What To Monitor: Map all small fires (< 4 ha) as points. Map fires > 4 ha as polygons. Map the severity of fires larger than 40 ha. Map insect and disease infestations that can be detected from the air (down to one tree per ha). Map wind damage that affects > 4 ha, with a focus on designated monitoring watersheds (Thunder Creek, Bridge Creek, Big Beaver, and Chilliwack River watersheds; Stehekin Valley).

Where To Monitor: Parkwide.

Justification And Other Information: Provides basic information for management decisions, highlights departures from historic conditions. These disturbances are major drivers of ecosystems. Monitoring of disturbance patterns, size, and distribution will potentially provide a large-scale tool for detecting changes.

Description of Recommended Action:

  1. Using satellite images, map the following watersheds, Thunder Creek, Bridge Creek, Big Beaver, Chilliwack, Stehekin Valley every 2-3 years to note changes in the following disturbances: disease, insects, windthrow, landslides, avalanche, human disturbance (developments, fragmentation). This may potentially be done on a 1-2 ha scale, depending on available imagery.
  2. Using fire records, map all small fires (< 4 ha) as points. All fires > 4 ha will be mapped as polygons.
  3. Using aerial photography and the severity classifications as defined in the Burned Area Rehabilitation Manual, map the severity of all fires > 40 ha.
  4. Using results of aerial photography (NPS and Forest Service), map tree mortality caused by insects and or diseases over the last 50 years (update annually).

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Monitoring Component: Species of Special Concern

Monitoring/Research Questions: What are the distribution and abundance of: rare, threatened, and endangered species; exotic species; and bio-indicators? What are the distribution, abundance, and population dynamics of ethnobotanical species?

Stressors and Related Factors: Climate, competition, disturbance factors.

What To Monitor: Rare, threatened, and endangered species; exotic species; bio-indicators; and ethnobotanical species.

Justification: Need to mitigate for management actions, meet federal and state requirements. There is interest in the use of sensitive indicators to monitor change.

Description of Recommended Action:

  1. Survey species to determine location, abundance, and habitat requirements.
    1. Include threatened and rare plants, Survey and Manage species (including fungi), exotic species and species of ethnobotanical importance
    2. Map distribution of potential habitat parkwide (GIS analysis)
    3. Survey potential habitat to establish distribution
    4. Select species suitable for biomonitoring as indicators of climatic change and air pollution; include linkages to climatological and air quality monitoring
  2. Develop monitoring protocols for measuring change over time.
    1. Develop system of setting priorities to determine which species to monitor
    2. Broad-scale patterns of invasion
    3. Methods to monitor status through demographics
    4. Effectiveness of biomonitoring indicators. Utilize existing methods and link with other programs (e.g., USGS-Biological Resources Division, Forest Service)
  3. Develop broader inferences at large spatial scales through linkages and data sharing with other agencies.

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Monitoring Component: Human Disturbance

Monitoring/Research Question: How much is visitor use altering vegetation, other biota, and soils? Are campsites and social trails changing in size and number?

Stressors And Related Factors: There is an anticipated increase in visitor use over the next few decades as the population in the Pacific Northwest increases, and other parks become more crowded. Day use in particular is expected to increase.

What To Monitor: Visitor impacts (make sure visitor use is also monitored from the perspective of Human Resources) in selected overnight and day-use areas will be monitored.

Where To Monitor: Monitoring locations should be representative of a variety of visitor uses, and in each of the climatic zones. Possible sites include: Cascade Pass, Boston Basin, one or more Ross Lake campsites, Fireweed, Maple Pass, Luna Peak vicinity, Copper Ridge, Wilcox Lakes.

Justification: The park has a mandate to protect natural resources for future generations. At present, overnight use is closely controlled. Day use is less regulated and quantified, and is expected to increase more quickly than other activities. It is desirable to detect unwanted changes as early as possible, especially in high-elevation areas where the vegetation recovers slowly.

Description of Recommended Action:

  1. Conduct low-level aerial photography (1:6000 or greater resolution if possible) to map selected camping, hiking and day-use areas every 3-5 years. Examine photographs for early warning signs of bare ground expansion (establish baseline).
  2. Record and map the areas where social trails and bare areas due to the above factors have been restored or revegetated, and then compare with future mapped areas.
  3. Assess available measures of ground-based sampling of human impact to determine what would be the best protocol (see methodologies used in other parks). Develop protocols, and measure them in a subset of the selected camping, hiking, day-use, and climbing areas on the same time frame as aerial photography.
  4. A potential application of data from this monitoring effort would be to develop and assess trends in human disturbance on the landscape that may help define the limits of acceptable change." This monitoring should be linked to measurements of the number of people using the area (day and overnight use).

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