# Presentation: 067011

## STRATIFICATIONPLOT PLACEMENTCONTROLSStrategy for Monitoring Post-fire Rehabilitation Treatments

**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**

## Monitoring Approach

- Objectives
- Stratification
- Control Plots
- Random Sampling
- Data Quality
- Statistical Analysis
- Repeatable, objective field methods    using Rangeland Monitoring Database

## Stratification

- Division of treatment areas into defined monitoring units with similar characteristics
- Decreases variability, increases precision
- 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

**Notes:**
Monitoring units are areas located within a particular part of the landscape where vegetation, soil type, management, recent activities (seedings etc..) and current status are relatively similar.  All areas within a monitoring unit should respond similarly to the treatment.
 Stratification decreases variability by partitioning factors known to increase variability into separate monitoring units.  Less variability means increased precision and higher levels of confidence in the data.
Stratification helps to determine success at the project level by decreased variability and defined area of interest leading to high quality quantitative data.  Helps to determine success at the regional scale by being able to group similar monitoring units that receive similar treatments and look at overall success.  Beyond determining success, we should be able to identify trends, patterns, and problems etc. that will aid future planning, monitoring, and research.

## Stratification

- Monitoring Units may vary across the landscape and be separated by other monitoring units.

**From Herrick et al 2005b**

## Stratification Background Information

- Aerial photographs
- Soil Surveys
- Determine what mapping units cover the treatment area
- Can you identify the soil series within the mapping units?
- What ecological sites are within the mapping units?
- How do you determine the ecological sites?

**Notes:**
Aerial photographs (recent and pre-fire) can be used to identify areas that may be problematic for stratification such as areas of successful seeding that needs to be accounted for, or disturbed areas that should be excluded from monitoring.
Soil surveys are extremely important for stratification.  They help identify both soil types that may respond to treatment differently.  Also to identify ecological sites.  Some areas do not have current soil surveys.  Soil series descriptions may give you a hint of potential problems that may be encountered during monitoring (e.g. clay soils).  
 Gather GIS layers.  Determine any reclassification of DEM data (slope, aspect, elevation classes).  Create map with all relevant GIS layers.
** slide for resources on the web – Web soil survey, NRCS soil survey downloads etc.?

## Stratification Background Information

- GIS Layers
- Digital Elevation Model (DEM’s)
- Land management activities (grazing allotments, previous seedings and fires etc.)
- Fire and treatment perimeters for current project
- Soils
- Roads, streams and other geographic features that would be avoided

## Stratification Background Information - Resources

- 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](http://soildatamart.nrcs.usda.gov/Default.aspx)_
- USGS Seamless Data Distribution _[http://seamless.usgs.gov/](http://seamless.usgs.gov/)_
- Official Soil Series Descriptions _http://soils.usda.gov/technical/classification/osd/index.html_

## Stratification Identifying Ecological Sites

- Each plot must have Ecol. Site identified
- 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).
- Consist of site characteristics, plant communities, site interpretations, and supporting information
- Identify ecological sites using soil and landform indicators (soil surveys)

## Soil maps

- 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 ***component***: soil series + slope and surface texture modifier

**Notes:**
In most areas of the US, we do have soil surveys. We will spend the next 1⁄2 hour learning how to use soil surveys to help identify ecological sites.

## 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)
- 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***

## Using soils to identify ecological sites 

- 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
- 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.

## Stratification Identifying Ecological Sites

- Determine soil mapping unit
- Examine soil mapping unit description (220)
- Determine soil series within mapping unit.

## Stratification Identifying Ecological Sites

**Dig soil pits to identify soil series and associated ecological sites**

**Ninemile and Carvix Soil Series**

## Slide 14

## Stratification Identifying Ecological Sites

## Stratification Criteria

- Treatment type
- Soil type / ecological site
- Slope / aspect / elevation
- Multiple polygons/ minimum size
- Each stratification criteria doubles number of monitoring units (if all are monitored)
- What criteria will reduce variability the most?

**Notes:**
Treatment type: drill/broadcast seeding, different seedmixes, contractors, equipment, treatment timing etc...  Any reason that may cause you to believe the outcome might be different.  This would include partial treatments due to weather or other factors. 
 Soil Type/Ecological site:  Ecological sites are “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.”  Mapping units are areas of similar soils that are mapped in a soil survey.
 Slope/aspect/elevation:  Partially addressed by soil type/ecological site.  But any areas that are not treated can be excluded using DEM’s to create the desired classes such as slopes > 20% etc...
 Multiple polygons:  Depending on the stratification factors, you may end up with a monitoring unit that has multiple polygons.  In this case it might be useful to reject polygons with small areas.  In this case you would want to set a minimum size for polygons that would be sampled.  If all the polygons are too small the stratification is too fine and you will probably need to reduce the number of factors.  Should focus on monitoring units that are most common/important/expensive.

** Add new slides to describe/demonstrate ecological site descriptions?
**add graphic at bottom showing multiple/small polygons

## Example Stratification Treatment perimeter and DEM

**Notes:**
1.  DEM of the area overlain by the fire perimeter.  Can use the DEM to create slope and aspect classes to include or exclude.

## Example StratificationTreatment perimeter with slope reclassification

**Notes:**
1.  Slope raster created from DEM

## Example Stratification Treatment perimeter with slopes < & > 15% slope

**Notes:**
1.  Reclassified the slope raster to have only two classes 1 = slopes less than 15%, and 2 = slopes greater than 15%.  Areas of greater than 15% slopes will be excluded from monitoring as they are likely rocky outcrops or weren’t seeded and don’t account for a large area anyway.

## Example Stratification Soil mapping units

**Notes:**
1.  Soil mapping units over the slope and fire perimeter. Can clip so you end up with just the mapping units of interest.

## Example Stratification Soil mapping units within treatment perimeter

**Notes:**
1.  Clipped soil map units. Can remove areas that will not be monitored – soil mapping unit 105 are lava flows and the small polygon for MU121 in the southwest corner.  

## Example Stratification Sample Areas

**121 Mcpan-Chijer complex**

**181 Starbuck-**
**        ****Mcpan-rock**
**        ****outcrop**

**Notes:**
Final monitoring units.  Also, erased the areas of > 15% slope.
MU121 Mcpan-Chijer complex both loamy 8-12” ARTRWY8/PSSP6 R011AY004ID
MU181 Starbuck-McPan-Rock outcrop:  
   Starbuck is shallow fractured 8-12” ARTRT/PSSP6 R011AY003ID
   McPan is Loamy 8-12” ARTRWY8/PSSP6 R011AY004ID

## Random Sampling

- Enables statistical inference to the monitoring unit
- GIS or traditional map grid
- Can use several types of random sampling (simple, stratified, and two-stage random sampling)
- Establish rejection criteria (slopes/roads/streams/rocks etc..)

**Notes:**
Random sampling within each monitoring unit allows statistical inference to entire monitoring unit.  Easier to do after you have eliminated the areas that will definitely not be monitored (slope, roads, streams with riparian areas etc.)
Concentrate on MU’s that are larger/more common or of greater interest than others.  Shouldn’t worry about minor units or polygons that are isolated or otherwise unimportant.  However, you need to specify when certain sites or polygons that were not sampled.
Simple random, restricted random, two stage sampling.  Simple random sampling may result in inadequate interspersion especially with irregularly shaped polygons.  Restricted random sampling involves dividing the monitoring unit into equal areas to aid interspersion.  Two stage samples may need to be used when there are multiple polygons.  Choose which polygons are going to be sampled and then place plots randomly in those areas.
Rejection criteria is anything that does not fit in with your defined monitoring unit.

## Random Point GenerationHawth’s Tools Features

- Input layer (polygon/raster)
- Minimum distance between points
- Stratified – (number of points)
- Stratified design
- Polygon unique id
- Number of points per polygon
- Density of points per polygon

**Notes:**
Hawth’s tool is a free extension for ArcGIS that can do a number of procedures for ecological studies.
Input layer will be your final monitoring unit.  This can be a polygon or a raster.
There are a number of options that you can choose from to run the procedure including:

## Slide 25

## Hawth’s Tools Main Screen

- 1. Generate Random points
-  Use for determining random plot locations
- Generate Regular points
- Other uses including separating polygons into roughly equal sizes

## Example Stratification (simple)Random point generation screen

## Slide 28

## Controls

- Was rehabilitation necessary?
- Plots that receive no treatment
- No seed
- No soil surface disturbance (affects bare ground and annual exotic abundance)
- Randomly place within monitoring unit prior to treatment implementation
- If controls are not possible, quantitative standards must be specified

**Notes:**
Randomly assign control plot locations and stake out with highly visible flagging so the drill operators can avoid them.
Control plots can be used to determine the effect of no treatment.  This is especially important when the treatment involves some sort of ground disturbance.
Also, Exotic species populations with and without treatment are important to estimate (cover).
Sometimes controls cannot be established.  In these cases, quantitative standards should be established to compare data in treatment plots.

## Controls

- Long-term monitoring – controls are highly valuable
- May not be able to distinguish between seeded and unseeded plants
- Help to determine persistence of seeding
- Helps to determine treatment effect
- Provides a measure of natural recovery

## Slide 31