Patti Novak-Echenique NRCS Nevada

State Rangeland Management Specialist Reno, NV

Ecological Sites A framework for

stratifying and describing rangelands for assessments, land suitability, and land management planning.

Land (soil)-based classification system

Criteria Separating Ecological Sites Abiotic factors (soils, climate, hydrology) that

influence plant production, composition, ecological processes

Significant differences in presence of species or species groups

Significant differences in the relative proportion of species/species groups

Significant differences in total annual production

Significant differences in response to management actions or disturbance processes

Ecological Site Determination Process Consult soil survey: maps, map unit

descriptions, ecological sites Determine map unit and landscape

position (slope, aspect, run-in, run-off) Remember: a map unit can have

contrasting components (up to 15%) Dig a hole to diagnostic horizon or

depth of 20 inches minimum

Ecological Site Determination Process Identify soil

characteristics – soil texture, root restricting layer (clay, hard pan), water table, dark colors

Determine soil component – a soil map unit component can be associated with only one ecological site.

Ecological Site Determination Process

Remember: a soil map unit can include more than one ecological site. Map units often include many different soils, with different potentials to support plant communities.

An ecological site can include more than one soil series, provided the soils are similar.

A soil series can include more than one ecological site. Soil surface texture often varies within a soil series. Soil surface texture is important in distinguishing ecological sites.

Ecological Site Inventory Production and composition by air-dry weight:

double-sampling, total harvest, ocular estimate Cover – species composition, bare ground, litter Rangeland Health Vegetative structure

Ecological Site Determination Process Soil surveys (hard copy) – map unit

descriptions list the ecological sites Web Soil Survey and Soil Data Mart – can

generate a list of possible ecological sites based on the map unit selected

Available Ecological Site Indexes – alphabetical, habitat type (or veg type), numerical

Ecological Site Keys – soils, environmental and vegetation characteristics

Humboldt County - West Soil Map Unit Ecological Site

Map Unit MLRA Sub-MLRA

Site Number

Name

104 – Anawalt-Devada-Tuffo complex Anawalt – 45% Devada – 25% Tuffo – 15% Rock outcrop 10% Softscrabble – 3% Puett – 2%

023 023 023 023 023

XY

XY

XY

XY

XY

021NV

031NV

020NV

007NV

030NV

Scabland 10-14 PZ Claypan 10-14 PZ Loamy 10-12 PZ Loamy 14-16 PZ South Slope 8-12 PZ

Creating ecological site maps Ecological site maps can be developed

from soil maps Like soil maps, ecological site map

units include associations and complexes of multiple ecological sites Web Soil Survey – generates ecological

site map of first listed in map unit Soil Data Mart – download spatial data

Creating ecological site maps Order II surveys - boundaries of ecological

sites can generally be determined directly from the soil map.

Order III mapping describes individual soil and plant components at association or complex levels.

Individual ecological sites must be delineated if individual soils in the association have different potential historic climax plant communities.

Ecological Site/State Maps

http://soils.usda.gov

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