MBSS

MBSS Round Four Design Summary

 

The Maryland Department of Natural Resources (DNR) will begin Round Four of the Maryland Biological Stream Survey (MBSS) in the spring of 2014. The MBSS is a stratified-random, survey that provides essential information on the ecological condition of Maryland streams for the State’s natural resource managers. The primary goal for of the Fourth Round of the MBSS is to document changes in stream conditions over time. Round Four will also provide status information at the large watershed (basin) and statewide scales.

Return to the overview of Round 4

Survey Design

The Round Four MBSS will include sampling over the 5-year period of 2014-2018. The sites will be sites previously sampled during Rounds 1 and 2 of the MBSS. These “repeat” Round Four sites will be randomly selected from the originally randomly selected sites in Round 1 (R1) during 1995-1997 and Round 2 (R2) during 2000-2004. The R1 repeat sites will be sampled in 2015-2017, following the same annual allocation of sites so that the period between sampling will be 20 years for each site. The R2 repeat sites will be sampled 2014-2018, following the same annual allocation of sites so that the period between sampling will be 14 years for each site.

The following number of repeat sites will be sampled each year using the design of the original round:

Year
R1 Sites
R2 Sites
R4 Core Sites
Targeted R4 Sites*
2014
--
48 sites in 16 PSUs
48
7
2015
54 sites in 6 basins
51 sites in 17 PSUs
105
7
2016
54 sites in 5 basins
51 sites in 17 PSUs
105
TBD
2017
45 sites in 5 basins
51 sites in 17 PSUs
96
TBD
2018
--
51 sites in 17 PSUs
51
TBD
Total
405
TBD

*As of December 2013, this final number of sites has not been determined. The final number will most likely consist of repeat sampling all MBSS sites that were sampled during R1 and R2 in certain “special interest” watersheds. An example of this targeted sampling is Mattawoman Creek – described below. Other targeted sampling sites and watersheds will be added to each year’s effort after determination of the priority “special interest” watersheds.

A total of 153 sites from R1 and 252 sites from R2 for 405 core repeat sites will be sampled in Round Four.

The sample design for the repeat sites from R1 will follow the R1 design of random selection of stream reaches from strata defined by basin and stream order, specifically equal probability of selection in 1st, 2nd, and 3rd order streams within each of 17 basins statewide. Three repeat sites will be randomly selected from the R1 sites in each stratum, where possible (some strata have low numbers of R1 sites to select from).

The sample design for the repeat sites from R2 will follow the R2 design of random selection of stream reaches from Primary Sampling Units (PSUs) that generally equate to Maryland 8-digit watersheds (which are combined when they are small to make 84 PSUs statewide). Three repeat sites will be randomly selected from the R2 sites in each PSU.

Given that R1 and R2 used different sample designs and stream network map scales (R1 sites were selected from a 1:250,000-scale map and R2 sites were selected from a 1:100,000-scale map), the inter-round comparison of repeated samples will be conducted separately for each round. The R1 comparison will be a 20-year comparison; the R2 comparison will be a 14-year comparison. Each of these inter-round comparisons will have the ability to detect a stream ecological condition change of 0.20-0.25 BIBI units with 80% probability.

Mattawoman Creek Watershed Intensification

To increase the density of samples in Mattawoman Creek, a watershed of special interest, all sites sampled in this watershed in R1 and R2 will be repeat sampled in Round Four. Specifically, the 7 sites sampled for R1 in 1995 will be repeat sampled in 2015, while all 10 sites sampled for R2 in 2000 will be repeat sampled in 2014.

To obtain site access permissions, landowners for the first 10 sites per strata randomly selected for Round Four from R1 and R2 will be identified and letters requesting permission will be mailed. The goal will be to obtain permissions for twice the number of sites to be sampled per stratum (i.e., 2x3=6) and to provide them to DNR.

Additions and Modification to Sampling and Assessment Protocols

The Round Four MBSS will sample the same parameters sampled during R3, with one addition and one modification. Geomorphological assessments will be added. This addition will consist of a rapid assessment of geomorphology at randomly-selected Round Four sampling sites (exact protocols to be determined) and detailed geomorphological assessments (consisting of cross-sections, longitudinal profiles, and pebble counts) at all MBSS Sentinel Sites. By increasing the time and area searched, the stream salamander sampling protocol has been modified from R3 to provide a greater likelihood of collecting stream salamanders. The goal is to support the development of a salamander index of biotic integrity, a biological indicator that will be especially useful in small headwater streams with naturally depauperate fish assemblages. More detailed descriptions of these Round Four sampling protocols will be included in an updated version of the MBSS sampling manual, scheduled for completion by February 2014.