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This layer includes non-tidal Benthic Index of Biotic Integrity (B-IBI) data (1996-2014) for randomly selected stations surveyed by the Maryland Biological Stream Survey (MBSS, http://dnr.maryland.gov/streams/Pages/mbss.aspx). The goals of the MBSS, which began in 1995, are to assess current condition and changes in ecological resources of Maryland’s 1st through 4th order non-tidal streams, as well as provide an inventory of biodiversity and identify effects of stressors on the natural resources (Stranko et al., 2014). The MBSS is a stratified random survey with a lattice design. Year and basin are included as strata and sampling is restricted each year to approximately one-third of the major drainage basins (Mercurio et al., 1999). At each MBSS sampling location, benthic macroinvertebrates are sampled from a 20 ft2 area with a standard D-net (Stranko et al., 2014). Community composition data is used to calculate a suite of summary metrics that are included in the calculation of a B-IBI for the Coastal Plain region (Southerland et al., 2005). This layer displays randomly selected MBSS stations that have been sampled within the Choptank by year. |