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Plant Distribution - Lythrum salicaria, Purple Loosestrife, New York State (Shapefile : 2000)
MapsheetNew York State State
ProviderNational Atlas
FormatShapefile .shp
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Coordinate System not available | not available
Datumnot available
Publication date 200008
Date added or updated not specified
Purple loosestrife is considered an invasive species. Its displacement of native species in wetlands has led to the loss of suitable habitat for wildlife. This data set contains county-level distribution information for Purple loosestrife (scientific name - Lythrum salicaria) in the United States. The collection year of the specimen is included. These data come from the U.S. Department of Agriculture's Natural Resources Conservation Service's PLANTS Database. This data set portrays the county-level distribution of Lythrum salicaria (common name - purple loosestrife) in the United States of America. These data come from the U.S. Department of Agriculture (USDA) Natural Resources Conservation Service's PLANTS Database, which is the de facto Federal standard for information about the distribution and nomenclature of U.S. plants.
These data are intended for geographic display and analysis at the national level, and for large regional areas. The data should be displayed and analyzed at scales appropriate for 1:2,000,000-scale data. The U.S. Geological Survey assumes no responsibility for the use of these data.
Supplemental Information
These data are primarily derived from examination of herbarium specimens of purple loosestrife gathered from several institutions. The essence of each record is the institution where the specimen resides, the State and county where it was collected, and the year of collection. Thus these data are structured to allow an analysis of the spread of this introduced noxious weed over time. Note that there are hundreds of herbaria in the United States, and a relatively small number were consulted to build this data set. For this reason, as well as the general unreliability of county-level distribution data (not all counties have been surveyed with equal effort, not all populations have been found, populations sometimes disappear, and plants sometimes move rapidly or are misidentified), these data can provide only a rough cumulative record of the distribution of this plant. This data set contains many records derived from the Cooperative Agricultural Pest Survey (CAPS). These CAPS data are thus somewhat different than the herbarium-derived county records because of the thorough systematic approach--all parts of each State were carefully surveyed--and because these surveys were conducted for different States in different years. Therefore CAPS surveys do not present a linear picture of spread of this weed through time as herbarium records do, since the latter are generally gathered with consistent effort in different years and places. To create similar maps <>, wdlytht.dbf can be joined to the 2000 county boundaries available from the National Atlas download page, <>. For more information on purple loosestrife, please see <> in the USDA PLANT Database. Also take a look at ITIS, the Integrated Taxonomic Information System: <>
Topicsbiota, environment
File size17 kilobytes
Use constraintsNone. Acknowledgment of the USDA Natural Resources Conservation Service and (or) the National Atlas of the United States of America would be appreciated in products derived from these data.
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