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Montana Field Guide

Ecological Systems in Montana

Ecological Systems Field Guide Help

The Field Guide help is divided into sections. Overview covers the background and history of this guide. How to Use the Guide covers navigation and search topics. The last section, Guide Contents, highlights the information sections of the Ecological Systems account pages.


Heritage Program ecologists, working with information gleaned from other Rocky Mountain Heritage Network partners, recently completed the "Ecological Systems Field Guide" for Montana.  This encyclopedic website provides extensive, detailed profiles of the ecological systems mapped in Montana for the 2010 Montana State Digital Infrastructure (MSDI) Land Cover and Land Use theme.

Ecological systems are groupings of biological communities occurring in similar physical environments, and influenced by similar ecological processes such as flooding, fire, wind, and snowfall.  The ecological system concept was developed to provide a mappable unit that could be classified from aerial or satellite imagery, and that would be easily identifiable in the field by land managers, resource specialists, and planners (Comer et al. 2003).  Systems typically occur on a landscape at scales of tens to thousands of acres, and generally persist in a recognizable state for 50 or more years.

The Field Guide offers a broad range of information, including a general description or summary of the system, diagnostic characteristics, similar systems, spatial pattern, environment, general vegetation, specific plant alliances and associations, dynamic processes, management and restoration considerations, and associated animal species.  Photos and Distribution Maps are also provided.  Users can view lists of ecological systems by land cover class or category or by name.  Within each description, links to our Animal Field Guide allow the user to explore Montana’s biodiversity.

How to Use the Guide

The Ecological Field Guide was designed to be easy to use and to explore.  We encourage you to take some time to look around the site and see all of the ecological systems that provide habitat for Montana’s plant and animal species.

Finding an Ecological System
Search by Name
The Montana Online Field Guide is searchable through the Search Field Guide dialogue (located at upper right of the page).  Type the entire ecological system name. the name of a species in its title (e.g., “Ponderosa”) or a descriptive term from its title (e.g., “Grassland”) and the search results will provide all ecological systems matching the search query.
Search by Grouping
The ecological systems in the Montana Online Field Guide are currently organized in an increasingly more specific navigation tree, corresponding to the mapping levels in the MSDI Land Cover Land Use theme and the Ecological Systems Map Viewer.  This three-level grouping goes from Land Cover Class (e.g., Human Land Use, Forest and Woodland, Alpine, etc) at the broadest scale to Land Cover Category (e.g., Alpine Sparse and Barren, alpine Grassland and Shrubland) to ecological system at the most detailed scale.  Selecting a Land Cover Class will branch the tree into the more specific groupings (Categories).  Continuing this approach will lead to an individual Montana ecological system.  It is also possible to move from the Ecological System level to the upper levels by using the navigation pathway located in the upper left-hand corner under the photo banner.  Click to any level previously selected to return to that step in the process.  This method allows for easy movement between ecological systems of interest.
Navigating the Guide

Navigation of the Online Field Guide can be accomplished by either using the back and forward buttons on your browser or by the “hotlinked” navigation pathway found under the photo banner.  Either method will allow movement back and forward to previously observed pages.

Guide Contents

Below are brief descriptions of the topics found in the Ecological Systems Field Guide.  If a heading is missing from the page you are viewing, it means there is no information available for that topic.

State Rank
The Montana Natural Heritage Program (MTNHP) is part of the international Heritage network, whose member programs have adopted a suite of factors to use in assessing the conservation status of plants, animals, ecological communities and ecological systems.  These factors can be applied to highlight systems having particular threats or declining distribution trends that warrant special attention.  We have recently assigned proposed state ranks to all the mapped ecological systems in Montana.  A detailed explanation of the codes is available, as well as an explanation of the factors which we applied, here.
General Description
This section summarizes the general distribution, environment, and vegetation characteristic of this system in Montana.
Diagnostic Characteristics
The unique physical aspect(s) of the system separating it from systems similar in composition or distribution.
Similar Systems
Links to mapped systems with similar characteristics.
The distribution of the system on the landscape.  This includes information on elevation, aspect and slope where these are diagnostic factors.
Ecological System Distribution
Mapped density of the system by 7.5 minute (1:24,000) USGS quad.  Note: the system may occur in areas that are not shown, but those occurrences may be too small to have been classified from satellite imagery.
Spatial Pattern
Ecological systems tend to have distinct spatial patterns: matrix, large patch, small patch, and linear.  Grasslands and forests, which cover extensive areas, are generally considered to occur as a matrix, with large and small patches of other ecological systems (e.g., wetlands, badlands, wet meadows) embedded within them.  Most riparian systems are linear, following river corridors.  Depending on the spatial pattern, ecological systems will respond differently to disturbance.  For example, matrix systems like grasslands usually have a wide tolerance for drought, fire, insects, etc., and disturbances tend to be confined to small areas.  These are the most persistent kinds of ecological systems, as well as the ones that often cover extensive and contiguous areas.  Large patch systems usually have a more narrow range of tolerance for disturbance, and events like fire or insect outbreaks can substantially alter the extent of a particular patch.  Small patch systems usually cover between one and 100 acres.  These systems can be completely eliminated by disturbance, and natural successional patterns may cause them to shift from one type to another.  Linear systems are also susceptible to disturbance, particularly human-caused disturbance.
Elevational range, climate, soils and landform characteristics characteristic of most occurrences of the system.
The plant communities and species that are frequently seen within this ecological system.  Not all communities and species will occur in every mapped occurrence of a system, especially when the system occurs across several environmental gradients.
Alliances and Associations
Vegetation alliances are groups of plant communities that share a diagnostic species, usually occurring in the overstory.  Vegetation associations –another term for plant communities- are assemblages of species that respond similarly to climatic, soil, topographic, geological, hydrologic, historical and other environmental conditions.  Here we list the alliances and associations that have been documented in Montana.  Note: the list of associations has not yet been compiled for each ecological system.
Dynamic Processes
The environmental forces (e.g., fire, flood, wind, human activities) that drive the development, distribution and succession of the ecological system.
Key strategies to maintain the dynamic processes governing the system.
Restoration Considerations
General guidelines for restoring systems or their components following disturbance or degradation.
Species Associated with this Ecological System
Vertebrate animal species that breed, migrate or winter in and through the system.  Click the link for a more detailed description of these species.
Original Concept Authors
The Heritage Network individuals or group who first described this system across its entire range.
Montana Version Authors
The Montana Natural Heritage Program ecologists who developed the Montana-specific descriptions for the system.
Version Date
The date of the last substantial revision to the entry.
The classification codes and map identifiers that will allow users to crosswalk the ecological system to other classification schemes, and the professional references gathered and used to present the scientific information in the Online Field Guide entry.
  • Comer, P., D. Faber-Langendoen, R. Evans, S. Gawler, C. Josse, G. Kittel, S. Menard, M. Pyne, M. Reid, K. Schulz, K. Snow, and J. Teague. 2003. Ecological Systems of the United States: A Working Classification of U.S. Terrestrial Systems. NatureServe, Arlington, Virginia