Sampling locations are located along Interstate 40 Eastbound near the Jackrabbit Trading post (map)

This will be the sampling protocol that I use for collecting data in the field. I will be recording data on
- Habitat availability in two main categories (Tamarisk or Open) along transects at ever 5 meter interval.
- Camelthorn abundance and number of new shoots in 1 m2 quadrants for each of 4 habitat types: Grass, Fremont Cottonwood, Open, Tamarisk
- Soil texture along transects (clay or sand)
- Tamarisk stem number for Tamarisk surrounding Tam Quadrants
- Cottonwood DBH for Cottonwoods near CW Quadrants
- Grass ring inner diameter and outer diameter for Grass Quadrants and if Camelthorn is located in grass ring (yes no)

These data will be used to assess
  • Does camelthorn preferentially grow in open versus tamarisk dominated area?
  • Does camelthorn co-occur next to Cottonwood trunks or with in litter shadow?
  • Is camelthorn abundance is greater in sandy versus clay soil?
  • Does grass species is excluding camelthorn in the field? Are camelthorn excluded from growing through grass clumps and rings

Quadrants will be 1 meter squared and be paired among 4 habitat types: Grass, Cottonwood (CW), Tamarisk (Tam), and Open, with 20 quadrants for each type for an N= 80.

50 meter Transects:
1. Select transect location based on random number generator method. Use random numbers on excel. Select starting location on grid for E to W and N to S vector and locate area

2. Set up transect by stopping near to random point generated or near landmark species (Grass ring or Fremont). If transect random start point is within 50 m of focal species, orientate transect in direction where it will include focal species. (Figure 1)external image e_o3VUNEZU5BFKbHD4Obf1FF6FUF0zILOybCQa8TxqOCL9jgK9JZy0hTzLq0zLbKpuA2-ubM01ZVzvmrqEXhjnr4LoWIl11QSAxqSrOA1eP5DaDMMEg
Fig 1. Theoretical transect design with n =10. First transect start is located at blue pinpoint.

3. Take GPS point of starting location for transect. Walk transect out 50 meters.

4. Every 5 meters record if area is open or Tamarisk (Tam). If Tam is within 1 meter of transect on either side (including branches), record as Tam. If Tam is at least 1 meter on either side away from center of transect, record as open. (Figure 2)external image GBsR6YskeiW0ahPNCQ1cnCxAcHo2iK9-o5aw4_XbrKQDTnjI7HFiPpmypwlE1eKMDcidjA9cdj603vWb17-em1aDI4SgbFTdQSYrGhgu0PG7g9fLjPQ
Fig 2. Individual Transect data

5. Take data on soil type (clay or sand) along transect .

6. Randomly place four 1 m2 quadrats along length of transect using random number generator (50 sided dice) or close to focal species if present.
Record on where transect plot is located. Designate if plot is Tam, Open, CW, or Grass.

7. Record Camelthorn (CT) abundance and new shoot growth.

8. If Tam plot record number of stems of tamarisk surrounding quadrant

9. If CW plot record DBH of CW nearest to quadrant.
CW plots will be paired at 2 distances from tree. Quadrants will be at base of tree, and then 3-5m in litter shadow of tree.

10. If grass plot, record grass ring inner and outer diameter. Record if Tam is growing though grass rings (Figure 3)

Figure 3. Paired Grass Quadrants data to be collected.
Other notes:
-Target number of plots for each of the four types is 20. Target number of transects will be 10.
-For CWs look for tags to designate if they are located in Chevelon garden. Cross reference with Chevelon Garden Map .

Soil Sampling:

Additionally I will be sampling camelthorn whole plants and soil for 10 of each type of quadrant (40 total).
To discern if camelthorn are fixing nitrogen, N 15 levels in xylem sap should decrease with plant age and over growing season:
Xylem sap from plants will be assessed for N2 using methods available to discern N fixing rates of plants of different age ranges (small shoot, medium shoot, large old shoot)
Roots from the plant will be collected for fine root analysis under a microscope of mycorrhizal colonization and N fixing nodules.(pictures of this method will follow)

Additionally, soil around at two depths (10 cm and 30 cm deep) surrounding camelthorn plants will be collected to measure
- electrical conductivity (salinity)
- N and Phosphorus analysis
- Soil Texture