Your management goal or question(s) will guide your analysis. Refer back to your completed Monitoring Design Worksheet and related GIS files to provide important context as you embark on your data analysis efforts. The following steps are a guide to preparing for both lotic and terrestrial data analysis (Figure 1).
In order to analyze your data correctly and with as little error as possible, you will first need to gather data and complete the documents below. If you have an active project, please start at step 1; however, if you are simply using already existing data, skip steps 1-2.
Step 1: Ensure field data and design tracking file submitted to NOC
One month after field data collection is completed:
QC your field data and submit all final field data to NOC/NAMC
- Complete final QC for terrestrial projects.
- For lotic projects, final data should be QCed and submitted after each trip but make sure the last trip’s worth of data has been submitted. Additionally verify that NAMC has received all field data by consulting the appropriate columns the design tracking file.
Review your Plot/Design Tracking for completeness and submit to NOC
Your Plot/Design Tracking should contain all points in your design for a given year and track all points that were evaluated. This information is submitted to the NOC in the form of a geodatabase populated with the points that make up the design; you should receive the template for this geodatabase along with your sampling design. Prior to the field season, you should submit this to the NOC so that design databases can be populated with this information. This information is then used in weighted analyses. However, even if you are not doing weighted analyses, design tracking files are still important because they are also used in the data QC process in tracking what plots/reaches were sampled. This tracking information will be updated by crew members via Field Maps throughout the season as sampling takes place.
If you do not have an active project, you can skip this step.
Step 2. QC & Store data and compute indicators
After receiving final data, the NOC/NAMC does additional QC and computes indicators using R scripts. Design tracking files are ingested into design databases and used in the data QC process to determine which sites were sampled. Computed indicators are then ingested into TerrADat and AquADat. Additional custom indicators may be computed using R. See the Data Access page for more information.
Step 3. Identify management goals & develop quantitative monitoring objectives including benchmarks
If you are a project lead, the monitoring design worksheet should contain the information needed for this step and should have been completed during the design phase of the project. Specifically, Steps 1-3 of the Monitoring Design Worksheet are needed for this portion of analysis. Additional resources for selecting benchmarks can be found here and additional resources specific for Lotic AIM data can be found within the Lotic Benchmark Tool (contact Janet Miller for access). If you do not have an active project but want to conduct an analysis on data that is already available, you may skip the step of filling out this worksheet, but you will need all the information below to fill out your Benchmark Tool.
- Management Goals
- Monitoring Objectives
- Reporting Units
- Description of Target Population
- Indicators of Interest
- Benchmarks
- Proportion achieving desired conditions (if doing weighted analysis)
- Original Strata used in the Design
Step 4: Gather and understand your field data
Terrestrial and lotic AIM data can be accessed at the BLM AIM Data Portal for BLM users. The public can access AIM data via the BLM’s Landscape Approach Geoportal.
- The BLM AIM Data Portal will be updated with field data from the previous field season in January or February of the following year. If there are terrestrial data needs prior to this, please contact the national data team. Contact Logan Shank for any immediate lotic data needs. The BLM’s Landscape Approach Geoportal is currently a year behind current data available to BLM users.
- For help interpreting terrestrial indicators and indicator metadata, contact Alex Laurence-Traynor (alaurencetraynor@blm.gov). For help interpreting lotic indicators and indicator metadata, contact Janet Miller (jlmiller@blm.gov).
Step 5: Gather GIS information related to your design (Terrestrial Only)
Reporting Units (ideally GIS files). These are specific areas where you need information such as indicator values.
Benchmark Groups (ideally GIS files, if applicable). These are groups of monitoring points that have the same benchmark for evaluating the success of a particular monitoring objective. For example, if you have points across your entire field office but want to evaluate a sage grouse habitat objective, only the points that are within sage grouse habitat should be considered for that particular objective.
Step 6: Determine appropriate analysis
There are many ways to use AIM data. You can look at individual AIM plots or a group of plots, and you can combine AIM with other types of information. There are many different analysis approaches that you are likely already familiar with. Because AIM data are often collected using a spatial random sample, one specific analysis option to consider is a weighted analysis. A weighted analysis produces the percentage of the resource in a given condition on the landscape, with known level of confidence. An example result of a weighted analysis is: “75% (+/- 8%) of brood-rearing sage grouse habitat is in suitable condition.” See the Terms and Concepts page for more information about weighted analyses.
Consider the following criteria suggesting that a weighted analysis may be appropriate for using AIM data to answer your management questions.
Criteria suggesting use of weighted analysis
- Policy requires weighted analysis (e.g., X% of resources are in a certain condition)
- Large area/stream extent
- More than 10 monitoring points are available from a probabilistic sample design, or capacity to collect this number is present
- Known level of confidence is desired
- More complex resource decisions
Many common land management decisions will not require a weighted analysis. For example, many grazing authorization renewals are for relatively small areas with insufficient capacity for collecting more than 10 monitoring plots/reaches. However, if your situation matches most of the criteria for weighted analysis and you are interested in this analysis, then you should consider a weighted approach. If you are unsure, but want to consider a weighted approach, please contact the National AIM team to discuss. Sage grouse habitat assessments and Land Use Plan effectiveness are common applications of weighted analyses.
See the examples of AIM data in use for options of how you can use AIM data.