Wisconsin Department of Natural Resources
State restricted

Reed Canary grass infestations

Source: Wisconsin DNR Wetland Assessment Team

Date: Data continuously updated. Metadata last updated 5/08

This map is a comprehensive state-wide map of reed canary grass infestations in wetlands only. For this reason, only wetlands are visible on this map. All other land cover types were masked out prior to analysis. We recognize that reed canary grass can grow outside of wetland areas; therefore, this map does not depict reed canary grass present in non-wetlands.

The pilot study revealed that reed canary grass growing as an understory in a wooded area is not accurately picked up by the satellites. Trees and woody shrubs tend to block the satellite from "seeing" the groundcover. Therefore this map is only believed to be accurate for open-canopy wetland types such as emergent or wet meadow, but not reliable for assessing the understory of forested wetlands.

The wetland mask used was developed from the WISCLAND land cover wetland boundaries. WISCLAND was completed in 1991, making the data currency at present over 15 years old. The vector data from the Wisconsin Wetland Inventory (WWI) was used to create the WISCLAND wetland boundaries. The WWI was not orthorectified at the time, creating the need to manually warp the arcs to fit the imagery. Although WISCLAND employed the WWI for its wetland boundaries, the scale of recommended use decreased from 1:24,000 for WWI to 1:40,000 for WISCLAND. In addition to the effects caused by rasterization, the scale change is also due to the fact that WISCLAND, although started with 30m pixels, was generalized to areas no smaller than four contiguous pixels; making their minimum mapping unit five acres. Only individual wetlands less than one acre were not generalized.

The data shown on this map have been obtained from various sources, and are of varying age, reliability and resolution. This map is not intended to be used for navigation, nor is this map an authoritative source of information about legal land ownership or public access. Users of this map should confirm the ownership of land through other means in order to avoid trespassing. No warranty, expressed or implied, is made regarding accuracy, applicability for a particular use, completeness, or legality of the information depicted on this map.

For more information, please see Wisconsin wetlands: Assessment reports and maps.