Vegetation Sampling

Richard Remington

Logan Simpson Design’s biological resources staff is trained in a variety of vegetation sampling techniques. Vegetation inventory and mapping is a process that documents the composition, distribution and abundance of plant communities across the landscapes. Accurately describing and mapping vegetated land cover consistent with the national vegetation classification system is integral in providing comparable data in how vegetation is inventoried, studied, and applied to sound ecological science, land assessment, environmental planning and management.

 Vegetation sampling and mapping ranges from a broad scale delineation of ecological systems derived at a regional level to documenting fine-scaled vegetation associations and alliances at the local specific scale. Conducting detailed vegetation inventories and mapping are used in accuracy assessments of vegetation classes delineated on a vegetation map to provide the user with an estimate or index on the reliability that the vegetation type mapped actually matches the vegetation present on the ground.

Plant Identification, Biological ResourcesAt LSD we are merging consistency in vegetation sampling in the field with consistency in describing vegetation and mapping vegetation. Logan Simpson Design biologists and range management specialists recently completed a survey of 70 Natural Resources Inventory (NRI) segments on Bureau of Land Management (BLM) grazing lands in Nevada’s five southern-most counties and another 79 NRI segments on BLM lands in five western Nevada counties for the Natural Resources Conservation Service (NRCS) Nevada State Office.

According to the USDA Natural Resources Conservation Service, the NRI is a “statistically based sample of land use, natural resources conditions and trends, and is the most comprehensive databases of its kind ever attempted anywhere in the world.” Protocols for NRI require consistency in data gathering within individual field crews, as well as among several crews working at a regional and ultimately a national level.

A component of NRI data gathering, as well as for other land management activities by the BLM, includes analyzing Ecological Site Descriptions (ESD), conducting Interpreting Indicators of Rangeland Health assessments, and tree biomass and plant production estimations.  NRI assessments usually consist of surveying unique combinations of soil mapping units to determine the ESD associated with a particular soils association. The results of the vegetation surveys provide summarized data on plant composition, productivity and density; soil stability and soil horizon characteristics; seral stages (i.e., states and transitions), phenology; and departure from potential natural vegetation described by the ESD reference sheet.

LSD biologists and range staff then conduct proper functioning condition assessments and rapid stream assessments to determine the functional capacity and condition of streams. These approaches assess the physical functioning of riparian-wetland areas through consideration of hydrology, vegetation, and soil/landform attributes to determine the overall health of that area.  Systematic assessments of soils, vegetation, landform and land use all result in an expression of the vegetative land cover.

Knowing the accuracy of vegetation maps and relations of the biological resources and abiotic resources provide invaluable information in understanding the effects of past, and in assessing future land uses and environmental planning with natural resources.