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/