BLM AIM Strategy (Assessment, Inventory, and Monitoring)

contributed by Genevieve Tucker and Jason Karl

Description and Uses

The Bureau of Land Management’s AIM (Assessment, Inventory and Monitoring) strategy, published in 2011, was developed to allow land managers to gather data in a consistent and efficient manner, to be used at the field office, regional and national levels. The AIM strategy provides methods, protocols, and principles for collecting quantitative data on the status, condition, trend, amount, location and spatial pattern of sustainable resources on public lands. The AIM strategy is built upon five basic components: (1) the development and application of a consistent set of core methods for measuring ecosystem indicators; (2) development and implementation of a statistically valid—and defensible—sampling framework; (3) application and integration of remote sensing technologies; (4) electronic data capture and management; and (5) structured implementation based on the particular management objectives and local ecosystems relevant to a project.

One of the goals of the AIM strategy is to establish conceptual ecological models, which can then facilitate management decisions to maintain or restore ecosystem capacities. Sustainable terrestrial systems are described and monitored through three attributes: soil/site stability, hydrologic function (water cycle), and biotic integrity. These attributes will be measured using a set of core indicators for terrestrial and aquatic ecosystems. Unique models will be established for each ecological site (i.e., groupings of similar soils and climates that support similar types and amounts of vegetation) to ensure that assessment and management are tailored to match the potential and ecological processes on each type of land.

The three major components of the AIM Strategy are assessment, inventory, and monitoring. Assessment is an estimation or judgment of the status of ecosystem functions, structures or processes within a specified geographic area (such as a watershed or group of contiguous watersheds). The assessment is conducted by gathering, synthesizing, and interpreting information from observations or data from inventories and monitoring. Information for an assessment can be qualitative or quantitative. An assessment characterizes the status of resource conditions so that the status can be evaluated (e.g. relative to land health standards). Inventory is defined as (1) the gathering of baseline information (including quantitative data, cultural knowledge, and qualitative observations); or (2) the systematic acquisition and analysis of resource information needed for planning and management purposes; or (3) an extensive point-in-time survey to determine the presence/absence, location, or condition of a biotic or abiotic resource. Monitoring encompasses the systematic collection of data over time to evaluate whether objectives of land health standards are being achieved and to evaluate effectiveness of management actions.


Core indicators are components of a system that are used for the measurement and analysis of key ecosystem attributes and for determining terrestrial and aquatic status. The indicators also allow for data to be collected and then compared at field office, regional, and national scales. Most of the core indicators are compatible with standardized monitoring techniques used by other agencies (e.g., NRCS, USFS). In order to meet local information needs related to management questions or specific ecosystem characteristics, the core and contingent indicators can be supplemented with additional indicators.

Core indicator data may be used in conjunction with remotely sensed data (data collected by a device, e.g. low-flying aircraft or satellite, that is not in direct contact with the object of interest). The AIM strategy emphasizes the use of remotely sensed data as a tool to improve monitoring efficiency and to determine the spatial distribution of indicators within the reporting units characterized by field data. Remote sensing data can supplement field data by providing the location, amount and spatial pattern of resources and the status, condition and trend of these resource attributes across broad geographic extents.

Aquatic Indicators

The aquatic AIM strategy is currently under development and more information will be available soon. The following is a list of proposed core indicators for use in aquatic ecosystems. 1. Temperature 2. Macroinvertebrate ratio 3. Bankful width 4. Stream gradient 5. Streambank stability 6. Residual pool depth

Measuring the Indicator

The methods for measuring core indicators were selected based on the following requirements: well documented, widely used, easy to implement, and minimal potential for bias. The protocols should be carefully followed in order to ensure that data collected from different areas can be compared or combined. Quantitative vegetation data, such as Line-Point-Intercept, Canopy Gap Intercept, and Vegetation Height can be used together to create a comprehensive view of vegetation in an area.

Advantages and Limitations

Data acquired using the AIM Strategy will need to be maintained, updated, and available for current and future use. Monitoring data represent a data management challenge because the integrity and reliability of the data must be maintained through time if reliable resource trends are to be established. Effective data management will enable the BLM to determine if public lands are moving toward desirable conditions or resource objectives. The BLM has developed the TerrADat database system as the enterprise database to house data collected through BLM’s various AIM projects. For more information on TerrADat, or to inquire about obtaining AIM data, see the links below.

The AIM Strategy will enable the BLM to collect quality field data and move forward in a strategic, coordinated manner by standardizing protocols and incorporating current technologies to address resource questions. However, the core terrestrial indicators are not intended to provide specific information regarding the status and vulnerability of wildlife species/populations/habitats. In 2009, the BLM partnered with the Heinz Center, U.S. Fish and Wildlife Service, state wildlife agencies, and partners to identify wildlife-based conservation targets and performance indicators. State wildlife action plans will be updated to incorporate the conservation targets and performance indicators and, where possible, will be incorporated into the integrated approach.

The BLM will use information derived from AIM-Monitoring to make necessary management adjustments to meet resource objectives described at project, resource management, and/or national program levels. Reporting at multiple scales will inform decision makers on the effectiveness of management actions, opportunities for adaptive management, and evaluating the monitoring program itself.

Additional Information and References

AIM Monitoring: A Component of the BLM Assessment, Inventory and Monitoring Strategy (Taylor et al., 2014)

Bureau of Land Management: Assessment, Inventory and Monitoring Strategy for Integrated Renewable Resource Management (BLM, 2011)

BLM Core Terrestrial Indicators and Methods: Technical Note 440 (BLM, 2011)

Additional Information Outline of core indicators and methods:

BLM Response to climate change:

Roudabush, R. 2011. BLM Monitoring Strategy: Sustainable Rangelands Roundtable. powerpoint_2011Nov_SRR.pdf

MacKinnon, W.C., Karl, J.W., Toevs, G.R., Taylor, J.J., Karl, M. Spurrier, C.S. and J.E. Herrick. 2011. BLM Core Terrestrial Indicators and Methods. Tech Note 440. US Department of the Interior, Bureau of Land Management, National Operations Center, Denver, CO.

Taylor, J., Toevs, G., Karl, J., Bobo, M., Karl, M., Miller, S., and C. Spurrier. 2012. AIM-Monitoring: A Component of the BLM Assessment, Inventory, and Monitoring Strategy. US Department of the Interior, Bureau of Land Management, National Operations Center, Denver, CO.

Toevs, G.R., Taylor, J.J., Spurrier, C.S., MacKinnon, W.C., and M.R. Bobo. 2011. Bureau of Land Management Assessment, Inventory, and Monitoring Strategy: For integrated renewable resources management. Bureau of Land Management, National Operations Center, Denver, CO.

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