National Park Service

Sierra Nevada Network (SIEN)

Wetlands Monitoring

Ecologists establishing a wetland monitoring site in Yosemite National Park
Ecologists establishing a wetland monitoring site in Yosemite National Park. Photo by Peggy Moore.

Wetlands Monitoring Briefs

Wetlands Monitoring Reports

Wetlands Monitoring Protocol

Yosemite National Park Meadows Webpage

For more information contact: Jonny Nesmith

Wetlands Monitoring brief

Wetlands monitoring in the Sierra Nevada Network parks resource brief
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Importance & Issues

A wetland is an area of land that is saturated with water either permanently or seasonally. Wetlands are considered the most biologically diverse of all ecosystems, and in the Sierra Nevada, they support a disproportionate amount of biodiversity relative to the small portion (<10%) of the landscape they occupy. Plant life in Sierra Nevada wetlands includes sedges, grasses, mosses, shrubs, scattered trees, and numerous other moisture-loving flowering plants. Animals include frogs, toads, salamanders, birds, mammals, and invertebrates.

Sierra Nevada wetlands provide important habitat for invertebrates and animals that feed on them. White-lined Sphinx moth (Hyles lineata). Wetlands provide important habitat for invertebrates and animals that feed on them. White-lined Sphinx moth (Hyles lineata). Photo by Jeff Holmquist.

Wetlands provide critical habitat for a variety of wildlife, play an important role in the life cycle of many invertebrate and amphibian species, and provide a wide variety of ecosystem services such as nutrient retention, flood control, and sediment storage. Wetlands are also important aesthetic elements of Sierra Nevada landscapes and provide forage for wildlife and recreational and administrative pack stock.

Wetlands are vulnerable to a variety of stressors, from local site impacts to landscape-scale stressors. Following is a brief summary of major stressors and their impacts:

Invasive species Although high elevation wetlands in the Sierra Nevada have a low incidence of invasive non-native plant species, the threat of invasion is present and likely increasing. Park management programs emphasize detection and control of high-priority non-native species affecting park wetlands.

Land use changes Alteration of hydrologic regime due to the effects of ditching or ground water pumping can negatively affect biota and alter fundamental ecosystem processes such as production and decomposition. The Sierra Nevada parks receive considerable input from agricultural pesticides used in California’s Central Valley, and some pesticides may be impacting amphibian populations.

GrazingLivestock use in the Sierra Nevada was historically concentrated in wetlands, with very heavy stocking rates of both cattle and sheep in the late 19th and early 20th centuries leading to severe deterioration. Many wetlands still show evidence of historic livestock grazing in the form of altered hydrology and species composition. Sheep and cattle grazing no longer occur in Sierra Nevada Network parks, but on-going pack stock use can cause physical changes to wetlands, such as soil compaction or erosion, as well as impacts to vegetation and macroinvertebrate communities. Such use is monitored and regulated by park managers.

Climate changeContinued atmospheric warming and changes in precipitation patterns will affect hydrologic regimes and the underlying hydrology of local systems, through changes in the timing and amount of snowmelt. This has the potential to cause dramatic shifts in species composition and abundance within mountain wetlands.

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Monitoring Objectives & Approach

Installation of wetland vegetation monitoring plot in Devils Postpile National Monument. Installation of wetland vegetation monitoring plot in Devils Postpile National Monument. Photo by Linda Mutch.

We visit a set of randomly selected sites in Sequoia, Kings Canyon, and Yosemite every 1–4 years, and one site in Devils Postpile every year. Sites sampled are limited to ungrazed and lightly grazed wetlands. Two types of wetlands are monitored:

Fens – occur in basins, on slopes, or in association with distinct springs. They are perpetually saturated or flooded from groundwater sources. A major identifying trait of fens is they accumulate peat (decayed vegetation), enabling them to sequester carbon.

Wet Meadows – characterized by shallow water tables that persist through much of the growing season and fine-textured soils. Wet meadows rely on water from precipitation, groundwater, or surface flow. The high water tables often favor plant species that grow only in wetlands.


For these two types of wetlands we –

Determine temporal changes in hydrology by:

  • Measuring the distance between the ground surface and top of the water table (cm)

Estimate temporal changes in species composition and abundance of wetland vascular and non-vascular plants, and bare ground by quantifying:

  • Relative ground cover composition
  • Woody plant invasion
  • Vegetation structure
  • Vascular and non-vascular plant species richness
Jeff Holmquist uses dip net to sample invertebrates in a Sierra Nevada wetland. Using a dip net to sample invertebrates in a Sierra Nevada wetland. Photo by Jutta Schmidt-Gengenbach.

Evaluate temporal changes in the composition and relative abundance of wetland macroinvertebrate (arthropods and molluscs within size constraints) populations by measuring:

  • Aquatic macroinvertebrate abundance and Family richness
  • Terrestrial macroinvertebrate abundance and Family richness
  • Ant (Family Formicidae) abundance and species richness

Determine temporal changes in non-native plant species cover and dominance in structural plant layers.

Quantify and compare the status of fen and wet meadow wetlands by measuring groundwater hydrology; plant structure, species composition and abundance; bare ground; and aquatic and terrestrial macroinvertebrate abundance and richness.

Compare rates of change in wetland community characteristics between fen and wet meadow sites.

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Management Applications

Sampling water levels in a wetland well, Yosemite National Park. Sampling water levels in a wetland well, Yosemite National Park. Photo by Linda Mutch.

Wetlands provide many important ecological functions and recreational values in Sierra Nevada Network parks. This monitoring project will provide information to enhance management, interpretation, and research focused on wetlands:

Tracking change in wetland systems: monitoring a suite of indicators for wet meadows and fens will help managers document change in wetland condition, evaluate potential threats, identify areas of management concern, and provide a foundation for research projects to answer questions about potential causes of observed changes.

Detection of new non-native invasions: The monitoring of wetland plant and invertebrate communities provides an opportunity to detect new invasions of non-native species early enough for management actions to be effective.

Information for interpretation: Meadows and wetlands are focal areas for recreational use in the Sierra Nevada and add to the aesthetic value of Sierra Nevada parks and wilderness lands. This monitoring project links important components of meadows and wetlands (water, vegetation, and invertebrates). Information about how the dynamics among plants, animals, and water in wetlands are related and how they change over time provides opportunities to share compelling stories with park visitors about these important ecosystems.

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Project Cooperators

Last Updated: December 30, 2016 Contact Webmaster