Step 6: Apply Stratification and Select Monitoring Locations

Step 6: Apply stratification and select statistically valid monitoring locations

In this step you will document the process of creating, reviewing, and finalizing the sample design.  Additionally, document how the design(s) were created, what revisions were made and why. If the design process or sample sufficiency analysis resulted in different sample sizes than those identified in step 4b, document those changes here as well. Consult with the national AIM team to implement this step.

  • Standard AIM statistically valid monitoring designs are developed using the GRTS method (Stephens and Olsen 2004). 
  • Several tools are available to complete statistically valid monitoring designs.  The standard approach is to use the master sample point draw which makes designs more consistent and facilitates analysis and reporting.  For more information, please visit the Understand the Master Sample page.
  • For terrestrial projects in small geographic areas, one-year designs or designs that exclude some areas of the landscape, we recommend the web-based Spatially Balanced Sampling tool hosted by the Jornada Landscape Toolbox.  Either approach can result in a statistically valid design and data that can be uploaded to the national AIM database.
  • Once a draft design has been created, review the draft design to make sure it will meet design criteria described in steps 1-4.
  • Evaluate the need for intensification of sample points within reporting units. Questions to ask when reviewing your draft design include:
    • Do I have enough points in all of the areas for which I need data?
    • Are there any areas that were left out of the design that should have been included?
    • Do you notice any inappropriate clumping (i.e., too many points) of points in a certain area(s)?
  • If needed, work with the NOC, NAMC, or Jornada to refine the sample design.
  • Once the final design is achieved, document the following in step 6: what tool was used to create the design(s), who ran the design(s), what (if any) modifications were made to the draft design(s), and where the design files are stored. If modifications were made, please include an updated and final version of the Sample Design Table in Step 6 as well.

Step 6 Example: Select Monitoring Locations

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Step 6: Apply stratification and select statistically valid monitoring locations

Terrestrial – Monitoring locations were selected by the Jornada using the terrestrial master sample tool (Figure 4).  This tool relies on the GRTS method which produces random, spatially balanced points across the landscape of interest (Stevens and Olsen 2004).  The ID team reviewed the points to make sure that they met the design criteria described in steps 1-3.  During that review, the interdisciplinary team noted that in Year 1, more points were needed to report on sage grouse habitat conditions in the Box Elder SFA and the Sheeprocks GRSG Population areas in order to satisfy immediate reporting needs.  Points were “borrowed” from later years of the design (Years 2-5) in order to provide additional points to be sampled the first year (Figure 5).  The design was finalized on March 22, 2016 and is stored on the local field office share point drive.

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Figure 4. Final terrestrial monitoring design for the BLM district to address management and monitoring objectives.

 

Aquatic – In total 50 sample reaches were selected for potential sampling (i.e., base reaches) and over double that number as were selected as replacement reaches for failed reaches (i.e., oversample reaches = 100). All 50 sample reaches were selected for the RMP effectiveness monitoring design by the NOC using the aquatic master sample tool. However, due to errors in the NHD layer the draft design revealed that  no points had been generated in the Sheeprock Sage Grouse area. Therefore, 10 additional reaches (and 30 oversample or replacement reaches) were selected to intensify the sample design in the Sheeprock Sage Grouse Habitat Area using an R script.

The design was finalized on April 17, 2016.  More information can be found in the aquatic design metadata file that is stored with the other design files on the local field office share point drive.

Figure 5. Locations of final aquatic AIM design points in the West Desert District, UT.

 

Helpful Documents and Links

Monitoring Design Worksheet

Monitoring Design Worksheet Instructions

Jornada Landscape Toolbox

Understand the Master Sample

Web-based Spatially Balanced Sampling Tool

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