Missouri Ecological 

Classification System
Missouri State Conservationist

I am pleased to share with you an innovative 

product that will enhance conservation planning 

and land management in Missouri. The 

cooperative effort to develop the information in 

this document included input from a wide range 

of technical experts representing three federal 

agencies, three state agencies and a diverse 

group of individuals.

We present to you a new concept for advancing the science, practice, and 

management of ecological sites throughout Missouri. Proper management 

of Missouri’s various ecosystems is critical to ensuring that we will have 

healthy soils and quality water for generations to come.

Information about specific ecological sites is available via the Web Soil 

Survey and NRCS’ online Field Office Technical Guide (eFOTG). There are 

links to both on the Missouri NRCS website.

I hope that you find this publication informative and useful. 

State Conservationist
The conservation of Missouri’s rich array of native plant and animal 

communities involves properly maintaining, enhancing and restoring 

these native ecosystems. In addition, land managers in Missouri are often 

charged with the difficult task of managing resources from a multiple-use 

perspective. An ecological classification system is a framework that allows 

landowners and natural resource managers to identify, map, and describe 

land with similar physical and biological characteristics (ecological sites) at 

scales suitable for use in natural resource planning and management.

Missouri Ecological Classification System

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What Are Ecological Sites?

Looking across a landscape it is not difficult to recognize that areas differ 

from others in kinds, size and amount of vegetation. These differences are 

used as the basic subdivision for inventory and analysis of landscapes. 

Ecological sites (ES) incorporate a land classification system that describes 

the ecological potential and ecosystem dynamics of land areas. 

Ecological sites are tied to USDA Major Land Resource Areas (MLRA) both 

structurally and ecologically (see map on Page 16). Within this framework, 

lands are classified considering discrete physical and biotic factors. Physical 

factors include soils, climate, hydrology, geology, and physiographic 

features. Biotic factors include plant species occurrence, plant community 

compositions, annual biomass production, wildlife-vegetation interactions, 

and other factors. Ecological dynamics such as grazing, fire and various 

management actions are important factors with ecological sites. As a result, 

a particular ecological site may feature several plant communities that occur 

over time or in response to specific management actions. They can be used 

to map the landscape and organize ecological information for purposes of 

monitoring, assessment, restoration, and management. 

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Ecological Site Cross Section
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Our Missouri naming procedure for ecological sites includes three basic 

criteria: soil/substrate, landform, and type of historic vegetational community. 

Examples of ecological sites in Missouri include: Loess Fragipan Upland 

Flatwoods; Alfic Chert Protected Backslope Forest; and Mollic Claypan 

Summit Prairie. 

How Are Ecological Sites Mapped?

A fundamental concept of ecological sites is their direct linkage to soil types, 

specifically the soil map unit components of the National Cooperative Soil 

Survey. Classification of land areas to ecological sites can be easily visualized 

via Web Soil Survey of the USDA Natural Resources Conservation Service 

(NRCS) or within a personal GIS via Soil Survey Geographic (SSURGO) 

digital soil data. This allows for mapping of ecological sites, as detailed 

soil mapping is readily available for Missouri. Ecological sites are linked 

to map unit components of one or more soil map units. A soil map unit 

may have several map unit components that cannot be mapped separately 

(because they are closely intermingled, for example), so soil map units may 

not correspond in a one-to-one fashion with ecological sites. 

How Are Ecological Sites Named?

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Mapping Ecological Sites

Comparison between a soil map (left) and an ecological site map from an area in St. Joe 

State Park near Farmington, Mo.
What Is An Ecological Site Description?

Information and data pertaining to a particular ecological site is organized 

into a reference document known as an Ecological Site Description 

(ESD). ESDs function as a repository of ecological knowledge regarding 

an ecological site. ESDs are maintained on the NRCS Ecological Site 

Information System (ESIS), which is the repository for information 

associated with ESDs and the collection of all site data. For Missouri, an 

additional initial location site for this information is the Missouri Field Office 

Technical Guide (FOTG). Regardless of location, these reports describe: 

the biophysical properties of ecological sites; vegetation and surface soil 

properties of reference conditions that represent pre-settlement vegetation, 

historical range of variation and proper functioning condition; state-andtransition model graphics and text; and a description of ecosystem services 

provided by the ecological site and other interpretations. 

A basic or provisional ESD for all ecological sites identified in Missouri is 

available on the Missouri Field Office Technical Guide, Section II - Natural 

Resources Information. Topics include: a Site ID name and number, 

Introduction, Physiographic Features, Soil Features, Ecological Dynamics, 

Reference Plant List, Wildlife Interpretations and Glossary. Certified ESDs 

will be accessed through Ecological Site Information System (ESIS) or the 

Web Soil Survey. 

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Ecological Site Description
What Is A State-And-Transition Model?

State-and-transition models (STM) are key components of ESDs. The 

patterns, causes, and indicators of transitions between different management 

states within an ecological site are described by state-and-transition models. 

State-and-transition models synthesize literature, field data, and informal 

knowledge tied to a particular ecological site to distinguish changes in 

vegetation and soils that are reversible versus changes that are not. The 

models describe the major states, community phases (i.e., easily-reversible 

variants of states), and transitions or pathways between communities 

and states. Transitions contain information about mechanisms, triggers, 

thresholds, and indicators of threshold development. A native woodland 

state being converted to non-native pasture grasses and then converted to 

cropland is an example of three distinct states associated with a particular 

ecological site. Management actions, such as conservation practice 

implementation, grazing management, and other land use decisions are a 

significant part of the described state-and-transition model. 

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State-And-Transition Model
How Is Missouri Developing Ecological Sites?

The Missouri ecological site description project is a team effort with a 

wide range of technical experts. NRCS and the Missouri Department of 

Conservation are leading this effort along with the University of Missouri, 

Missouri Department of Natural Resources, Forest Service, and U.S. Fish 

and Wildlife Service. Missouri is using a framework based on soil properties 

for identifying ecological sites.. Statewide, the project has identified eight 

essential soil properties that have significant influence on vegetation and 

site productivity: landform, parent material, root restriction, base saturation, 

drainage, texture, flooding, and ponding. 

The development process in Missouri involves five steps: 1) group soils into 

potential ecological sites that have similar properties; 2) analyze the spatial 

distribution of potential ecological sites and individual map units and make 

adjustments where needed; 3) overlay potential ecological sites with the 

historic vegetation data to develop potential reference plant communities 

(PRPC); 4) sample current vegetation to validate PRPCs; and 5) identify, 

map, and describe ecological sites. 

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How Are Ecological Sites Used?

Ecological sites and associated information (ESDs) are used to stratify 

the landscape for monitoring and assessment, interpretation of resource 

hazards and opportunities, and to prioritize and guide management actions. 

ESDs are developed and maintained by NRCS and its partners, and used 

by the Missouri Department of Conservation, the Missouri Department of 

Natural Resources, the Nature Conservancy, and many other Missouri 

entities.

Ecological sites (ES) help us understand how ecosystem attributes vary 

within and among regions, and they can be a positive influence in helping 

to develop sound management goals and objectives. There are many ways 

in which this work can be used. Silviculture, wildlife management, resource 

planning, natural community management, ecosystem restoration, private 

lands conservation, and scientific research can all benefit when considering 

ecological sites. Specifically:

• ESs can be used to define forest stand mapping units, increase 

understanding of species site relationships, and help understand 

appropriate management strategies.

• ESs can help understand, manage, and restore native ecosystems. An 

understanding of the environmental factors associated with Missouri’s 

native landscapes is imperative in order to manage our great diversity 

of natural communities in the state.

• ESs can be used to allocate appropriate conservation-related costshare programs and practices, such as bottomland tree plantings, 

forest stand improvement, native grassland plantings, and wildlife 

restoration activities. 
Knowledge of ecological sites and their potential uses can assist 

landowners in wisely managing their land for current needs and also for 

future generations.

Meeting The Needs of Future Generations

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Summary

Missouri is part of a nationwide effort to describe and map managementscale ecological site conditions, to be used as a basis for guiding costshare programs, land management and conservation planning. Missouri 

ecological sites are a multi-agency team effort with a framework that can 

help drive resource planning and management at a variety of scales, from 

eco-region, to landscape, and finally to the field and farm size. Ecological 

site information will be available via the NRCS Web Soil Survey, USDA 

Ecological Site Information System website, and the Missouri Field Office 

Technical Guide. 

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Additional Resources

Web Addresses

Missouri Field Office Technical Guide: 

http://www.nrcs.usda.gov/wps/portal/nrcs/main/national/technical/fotg 

Ecological Site Information System:

http://esis.sc.egov.usda.gov/

Web Soil Survey:

http://websoilsurvey.nrcs.usda.gov/app/HomePage.htm

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Contact Information

For additional information on the Missouri Ecological Classification 

System, contact:

Missouri Department of Conservation

Ecological Classification System Program Coordinator

Resource Science Division

3500 East Gans Road 

Columbia, MO 65201

573-882-8388 Ext 3941

Natural Resources Conservation Service

State Soil Scientist

Parkade Center, Suite 250

601 Business Loop 70 West

Columbia, MO 65203

Phone: (573) 876-0900

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Major Land Resource Areas in Missouri

107B: Iowa and Missouri Deep Loess Hills

108D: Illinois and Iowa Deep Loess and Drift, Western Part

109: Iowa and Missouri Heavy Till Plain

112: Cherokee Prairies

113: Central Claypan, Western Part

115B: Central Mississippi Valley Wooded Slopes, Western Part 

115C: Central Mississippi Valley Wooded Slopes, Northern Part 

116A: Ozark Highland

116B: Springfield Plain

116C: St. Francois Knobs and Basins

131A: Southern Mississippi River Alluvium 

134: Southern Mississippi Valley Loess 

Missouri ecological sites are tied to USDA Major 

Land Resource Areas (MLRA)

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USDA is an equal opportunity provider and employer.

March 2013