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STRATIFICATION PLOT PLACEMENT CONTROLS Strategy for Monitoring Post-fire Rehabilitation Treatments Troy Wirth and David Pyke USGS – Biological Resources Division Forest and Rangeland Ecosystem Science Center Corvallis, Oregon U.S. Department of Interior U.S. Geological Survey Supported by USGS - BLM Interagency Agreement #HAI040045
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Monitoring Approach Objectives Objectives Stratification Stratification Control Plots Control Plots Random Sampling Random Sampling Data Quality Data Quality Statistical Analysis Statistical Analysis Repeatable, objective field methods using Rangeland Monitoring Database Repeatable, objective field methods using Rangeland Monitoring Database
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Stratification Division of treatment areas into defined monitoring units with similar characteristics Division of treatment areas into defined monitoring units with similar characteristics Decreases variability, increases precision Decreases variability, increases precision Data collected is then inferred to be representative of the entire monitoring unit. Data collected is then inferred to be representative of the entire monitoring unit. Stratification into monitoring units helps to determine success at the project level - and eventually at a regional scale Stratification into monitoring units helps to determine success at the project level - and eventually at a regional scale
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Stratification Monitoring Units may vary across the landscape and be separated by other monitoring units. Monitoring Units may vary across the landscape and be separated by other monitoring units. From Herrick et al 2005b
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Stratification Background Information Aerial photographs Aerial photographs Soil Surveys Soil Surveys Determine what mapping units cover the treatment area Determine what mapping units cover the treatment area Can you identify the soil series within the mapping units? Can you identify the soil series within the mapping units? What ecological sites are within the mapping units? What ecological sites are within the mapping units? How do you determine the ecological sites? How do you determine the ecological sites?
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Stratification Background Information GIS Layers GIS Layers Digital Elevation Model (DEM’s) Digital Elevation Model (DEM’s) Land management activities (grazing allotments, previous seedings and fires etc.) Land management activities (grazing allotments, previous seedings and fires etc.) Fire and treatment perimeters for current project Fire and treatment perimeters for current project Soils Soils Roads, streams and other geographic features that would be avoided Roads, streams and other geographic features that would be avoided
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Stratification Background Information - Resources Web Soil Survey http://websoilsurvey.nrcs.usda.gov/app/ Web Soil Survey http://websoilsurvey.nrcs.usda.gov/app/ http://websoilsurvey.nrcs.usda.gov/app/ Soil Data Mart http://soildatamart.nrcs.usda.gov/Default.aspx Soil Data Mart http://soildatamart.nrcs.usda.gov/Default.aspx http://soildatamart.nrcs.usda.gov/Default.aspx USGS Seamless Data Distribution http://seamless.usgs.gov/ USGS Seamless Data Distribution http://seamless.usgs.gov/ http://seamless.usgs.gov/ Official Soil Series Descriptions http://soils.usda.gov/technical/classification/os d/index.html Official Soil Series Descriptions http://soils.usda.gov/technical/classification/os d/index.html
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Stratification Identifying Ecological Sites Each plot must have Ecol. Site identified Each plot must have Ecol. Site identified Not all Monitoring Units are defined by one Ecol Site. Not all Monitoring Units are defined by one Ecol Site. An ecological site is a “distinctive kind of land with specific characteristics that differs from other kinds of land in its ability to produce a distinctive kind and amount of vegetation” (NRCS). An ecological site is a “distinctive kind of land with specific characteristics that differs from other kinds of land in its ability to produce a distinctive kind and amount of vegetation” (NRCS). Consist of site characteristics, plant communities, site interpretations, and supporting information Consist of site characteristics, plant communities, site interpretations, and supporting information Identify ecological sites using soil and landform indicators (soil surveys) Identify ecological sites using soil and landform indicators (soil surveys)
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Soil maps Soils are grouped into soil mapping units because we often cannot map soils at the scale at which they occur Soils are grouped into soil mapping units because we often cannot map soils at the scale at which they occur Soil map unit: includes one or more dominant soil map unit components + inclusions (minor map unit components) Soil map unit: includes one or more dominant soil map unit components + inclusions (minor map unit components) Soil map unit component: soil series + slope and surface texture modifier Soil map unit component: soil series + slope and surface texture modifier
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A soil map unit can be: An ASSOCIATION of two or more soils that occur in a repetitive and predictable pattern (e.g. low ridges & swales) An ASSOCIATION of two or more soils that occur in a repetitive and predictable pattern (e.g. low ridges & swales) A COMPLEX of two or more soils that usually do not occur in a predictable pattern at a mappable scale (e.g. coarse and fine soils in a river floodplain) A COMPLEX of two or more soils that usually do not occur in a predictable pattern at a mappable scale (e.g. coarse and fine soils in a river floodplain) A single soil series (but even these map units usually have “inclusions” too small to be mapped). Sometimes call a CONSOCIATION A single soil series (but even these map units usually have “inclusions” too small to be mapped). Sometimes call a CONSOCIATION
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Using soils to identify ecological sites An ecological site can include more than one soil series, provided that the soils are similar An ecological site can include more than one soil series, provided that the soils are similar A soil map unit can include more than one ecological site. Soil map units often include many different soils, with different potentials to support plant communities A soil map unit can include more than one ecological site. Soil map units often include many different soils, with different potentials to support plant communities Even a soil series can include more than one ecological site. Soil surface texture often varies within a soil series. Soil surface texture is very important in distinguishing ecological sites. Even a soil series can include more than one ecological site. Soil surface texture often varies within a soil series. Soil surface texture is very important in distinguishing ecological sites.
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Stratification Identifying Ecological Sites Determine soil mapping unit Determine soil mapping unit Examine soil mapping unit description (220) Examine soil mapping unit description (220) Determine soil series within mapping unit. Determine soil series within mapping unit.
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Stratification Identifying Ecological Sites Dig soil pits to identify soil series and associated ecological sites Ninemile and Carvix Soil Series
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Stratification Identifying Ecological Sites
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Stratification Criteria Treatment type Treatment type Soil type / ecological site Soil type / ecological site Slope / aspect / elevation Slope / aspect / elevation Multiple polygons/ minimum size Multiple polygons/ minimum size Each stratification criteria doubles number of monitoring units (if all are monitored) Each stratification criteria doubles number of monitoring units (if all are monitored) What criteria will reduce variability the most? What criteria will reduce variability the most?
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Example Stratification Treatment perimeter and DEM
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Example Stratification Treatment perimeter with slope reclassification
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Example Stratification Treatment perimeter with slopes 15% slope
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Example Stratification Soil mapping units
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Example Stratification Soil mapping units within treatment perimeter
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Example Stratification Sample Areas 121 Mcpan-Chijer complex 181 Starbuck- Mcpan-rock outcrop
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Random Sampling Enables statistical inference to the monitoring unit Enables statistical inference to the monitoring unit GIS or traditional map grid GIS or traditional map grid Can use several types of random sampling (simple, stratified, and two-stage random sampling) Can use several types of random sampling (simple, stratified, and two-stage random sampling) Establish rejection criteria (slopes/roads/streams/rocks etc..) Establish rejection criteria (slopes/roads/streams/rocks etc..)
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Random Point Generation Hawth’s Tools Features Input layer (polygon/raster) Input layer (polygon/raster) Minimum distance between points Minimum distance between points Stratified – (number of points) Stratified – (number of points) Stratified design Stratified design Polygon unique id Polygon unique id Number of points per polygon Number of points per polygon Density of points per polygon Density of points per polygon
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Hawth’s Tools Main Screen 1. Generate Random points Use for determining random plot locations 2.Generate Regular points Other uses including separating polygons into roughly equal sizes
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Example Stratification (simple) Random point generation screen
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Controls Was rehabilitation necessary? Was rehabilitation necessary? Plots that receive no treatment Plots that receive no treatment No seed No seed No soil surface disturbance (affects bare ground and annual exotic abundance) No soil surface disturbance (affects bare ground and annual exotic abundance) Randomly place within monitoring unit prior to treatment implementation Randomly place within monitoring unit prior to treatment implementation If controls are not possible, quantitative standards must be specified If controls are not possible, quantitative standards must be specified
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Controls Long-term monitoring – controls are highly valuable Long-term monitoring – controls are highly valuable May not be able to distinguish between seeded and unseeded plants May not be able to distinguish between seeded and unseeded plants Help to determine persistence of seeding Help to determine persistence of seeding Helps to determine treatment effect Helps to determine treatment effect Provides a measure of natural recovery Provides a measure of natural recovery
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