Procedures: Rare plant surveys

The Minnesota Biological Survey (MBS) conducts rare plant surveys primarily for vascular plants and has provided funding for limited moss and liverwort surveys.

MBS plant surveys are conducted to:

  • document new locations of rare plants
  • document new county and state records for plants
  • provide confirmation of plants recorded in vegetation samples (relevés)
  • better understand the current distribution and abundance of plants in the state

1. Review of existing information

Prior to conducting field surveys for rare plants in a particular county or region, information about the landscape and plants that may be present is reviewed. Some of the sources consulted are:

  • herbarium and historical records of plants (information about habitat, associated species and native plant communities, field identification characteristics, time of year when species is most visible or in flower or fruit, etc.)
  • aerial photos, maps (such as wetland, soil, lake, topographic, etc.), and associated data to aid in locating targeted habitats
  • recommendations from other botanists, plant ecologists, local land managers, and other knowledgeable individuals

2. Selection of targeted plants and survey sites

Based on review of existing information, the rare plants likely to be present in the county or ecological unit are identified. Sites and other habitats likely to contain areas of preferred habitat for the targeted plants are identified and a seasonal work plan is developed to optimize locating the targeted plants.

3. Field surveys

Botanists conduct field surveys for targeted plants mostly between late April and mid-September. Timing of searches for specific rare plants is determined primarily by the life history of the species (when does it flower or fruit?), with attention paid to variations in seasonal weather patterns. Plant collections are made using standard herbarium procedures.

4. Information management

Data collected during plant surveys are recorded on field forms, in electronic data files, and as museum voucher specimens. After field surveys are completed:

  • The identification of collected plants is verified using keys and by consulting with botanists. An archival quality label is prepared (including collector, date, location, etc.) and voucher specimens are deposited in the herbarium of the J. F. Bell Museum of Natural History at the University of Minnesota, where they receive final curation.
  • The specimen label information is recorded in the herbarium database. More detailed information related to rare plant collections is entered into Biotics in the Natural Heritage Information System (NHIS). Other plant collections provide confirmation of plants recorded in vegetation samples stored in the Relevé Database in the NHIS. All collections are used to update lists of documented plant species for each of Minnesota's counties .
  • Botanists contribute information to evaluations of sites that are important for rare plants and native plant communities. These site evaluations are used to guide conservation activity, such as special management to protect rare species and native plant communities or acquisition as a park or natural area.

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