This map viewer depicts the known locations of wetland and riparian plant communities, rare plants, and rare nonvascular species tracked by the Washington Natural Heritage Program (WNHP). These data are a subset of WNHP’s database of rare species and ecosystems. Wetlands being assessed by the Washington Wetland Rating System are considered to be Wetlands of High Conservation Value when they intersect a rare species or a rare/high-quality wetland or riparian community found in WNHP’s database.
Wetland of High Conservation Value (WHCV) - previously “Natural Heritage Wetland” - is a term used in the Washington Wetland Rating System to describe a wetland that supports an element occurrence (EO) recognized by WNHP. An EO refers to a specific location of a rare species or a rare/high-quality ecosystem type (see Natural Heritage Methodology). Known locations of any plant or nonvascular species considered to be Endangered, Threatened, or Sensitive are considered to be EOs. Wetland and riparian community EOs are prioritized for inclusion in our database based on a combination of the wetland type’s rarity or risk of extinction and its current ecological integrity. All occurrences of rare wetland types, regardless of their condition, are considered to be EOs, while occurrences of common wetland types are EOs only if they are in good to excellent condition (see Conservation Priorities decision matrix). Within this map viewer, WNHP rare plant and nonvascular EOs are found in the Known Rare Plants and Nonvascular Species of High Conservation Value layer, and wetland/riparian community EOs are found in the Known Wetlands and Riparian Plant Communities of High Conservation Value layer.
A WHCV may be designated based on the presence of a rare plant, rare/high-quality plant community, or both. In other words, a single wetland may have more than one EO present. The number of EOs does not change the WHCV-status within the context of the Rating System. However, wetlands supporting a high number of EOs are significant in terms of their concentration of rare species and/or plant communities.
Locations of Reference Standard Wetlands are also included in the map viewer. Reference Standard Wetlands are a subset of WHCV considered to be among the best examples of specific wetland types. These wetlands are generally located in areas with long-term protection status. Reference standard wetlands need to be anchored to a specific classification scheme and specific ecological condition criteria. Here, wetland Subgroups are used as the classification standard and ecological integrity (as measured by the EIA method) as benchmark conditions. Reference standard wetlands shown in the map viewer reflect ecological conditions representative of wetlands with minimal human-induced disturbance and/or the best quality wetlands for a given type remaining on the landscape. These reference standard wetlands can be used to identify restoration potential and benchmarks, mitigation performance standards, conservation priorities, or to provide benchmark data to help understand how wetlands respond to human-induced disturbance.
Disclaimers: Not every wetland in Washington has been visited by WNHP staff; additional sites that meet WHCV criteria may occur on the landscape. If you believe you've discovered a new location for a vascular plant or nonvascular species considered to be Endangered, Threatened, or Sensitive by our program, or discovered a rare or high-quality wetland ecosystem type, then see the 'Submitting Data to the Natural Heritage Program' section on our Data Products and Requests web page. WNHP scientists will review submitted data to determine whether the species or communities meet the standard for a new EO.
The accuracy of the boundaries of each EO varies depending on the quality of underlying data. Within the Data Dictionary, see 'Precision Code' for clarification.