1) The study aimed to develop a grass cover map of Somuncurá Reserve in northern Patagonia, Argentina using Landsat imagery and determine which levels of grass cover guanacos select. 2) Random forest analysis of EVI and MSI bands from Landsat imagery produced a grass cover percentage map with a correlation of 0.776. 3) Analysis of guanaco census data found they significantly selected areas with 20-30% grass cover in most seasons over expected availability, selecting against areas with 10-20% grass cover in some seasons.

1. Guanaco and grassland distribution in
northern Patagonia, Argentina
AAG 2012
February 28,2012
Paul J. Haverkamp, Martin E. Zamero, Jonathan A. Greenberg,
Ricardo Baldi, Susan L. Ustin

2. Study Objectives
Hypothesis: Guanacos will select for areas
with the highest grass cover since grasses
are their primary food source.
• Objectives:
– Objective 1: develop a grass cover map of
Somuncurá Reserve using Landsat ETM+
imagery.
– Objective 2: determine which levels of grass
cover guanacos select in Somuncurá
Reserve.

3. Guanaco and Vegetation
• Grasses
– Preferred vegetation of guanacos (~65% of diet in
spring, ~45% of diet in summer)
– Tend to be sparse and interspersed with large
proportions of soil and shrubs
• Shrubs
– Less preferred in spring (~17% of diet), but greater
use in summer (~37% of diet)
– Varying densities of shrubs
• Forbes
– Varying preference
Baldi 1999. Ph.D. Dissertation.

4. Vegetation Transect Analysis
• Identified species (except grasses) and
grouped transects by percent of grasses,
shrubs, forbes, and soil/rock.
• Added GPS points to ArcGIS and added
transect cover values.

5. December 25, 2009

6. Color Infrared (CIR) of Study Site

7. Vegetation Transects

8. Random Forest Results
• Combination of EVI
and MSI gave the
best correlation.
• Pearson’s r = 0.776
– Test data comparing
actual to predicted
grass cover
• Grass cover percent
map

9. Study Objectives
Hypothesis: Guanacos will select for areas
with the highest grass cover since grasses
are their primary food source.
• Objectives:
– Objective 1: develop a grass cover map of
Somuncurá Reserve using Landsat ETM+
imagery.
– Objective 2: determine which levels of grass
cover guanacos select in Somuncurá
Reserve.

10. Guanaco Field Study Methods
• 10 wildlife and domestic animal censuses:
— Oct. 2007 — Dec. 2008
— Nov. 2007 — Aug. 2009
— Jan. 2008 — Oct. 2009
— Mar. 2008 — Dec. 2009
— Jun. 2008 — Feb. 2010
• 95 transects along road system totaling
over 327 km.
– Split based on fences, intersections,
topography changes, length.
– 500m buffer on each side of split.

11. Census Issues
• Not consistent in space or time.
• Censuses done when funding available.
• Measured in different parts of year.
• North and south parts of Somuncurá.

12. Animal Transects

13. Animal Transects

14. Guanaco Selection
Manly et al. 2002.

15. Census Analysis
• For each census :
– Guanaco observations per transect.
– Used Distance program to get effective strip
width (ESW) for each transect.
– ESW as buffer to find suitable guanaco
observations per transect, per census.
Thomas et al. 2010. Journ. Appl. Ecol. 5-14.

16. Census Analysis
• Buffered guanaco locations 75m for a 150m
diameter area used resource unit.
• Overlaid onto grass cover map and calculated
mean grass cover of the guanaco resource unit.
– Used resources of four grass cover classes.
• Overlaid ESW buffered survey transects on
grass cover map and retrieved pixel values.
– Available resources of four grass cover classes.

17. Selection Results
• Pearson’s Chi-square goodness of fit.
• Significant selection (using, observed
more or less use, based on available area
of grasses, expected)
– Nov. 2007 – XP2 = 14.249, p = 0.003
– Jan. 2008 – XP2 = 9.714, p = 0.021
– Dec. 2008 – XP2 = 19.322, p = < 0.0005
– Aug. 2009 – XP2 = 14.050, p = 0.003
– Oct. 2009 – XP2 = 39.282, p = < 0.0001
– Dec. 2009 – XP2 = 17.762, p = < 0.0005

18. Selection Ratios

19. Guanacos Selecting
• Selecting 20-<30% significantly more than
expected in each significant census except
January 2008.
• Selecting 10-<20% significantly less than
expected in Jan. 2008, Dec. 2008, and Dec.
2009.
• Aug. 2009 selected 40-<53% significantly less
than expected.
• Oct. 2009 selected 30-<40% and 40-<53%
significantly less than expected.

20. Spring Grass Cover Selection, Bi
October 2007 November 2007 October 2009
0.065
0.165 0.191
0.304
0.201
0.330 0.210
0.182
0.189
0.420
0.395
0.350
December 2009 December 2008
0.127 0.105
0.242 0.245 10-<20%
0.349 20-<30%
0.339
0.292 0.300 30-<40%
40-<53%

21. Summer Grass Cover Selection, Bi
January 2008 March 2008 February 2010
0.119
0.144 0.187
0.281 0.275 0.272
0.305 0.294
0.274
0.287 0.268
0.295
10-<20%
20-<30%
30-<40%
40-<53%

22. Fall Grass Cover Selection, Bi
June 2008
0.165
0.292
0.201
0.342
10-<20%
20-<30%
30-<40%
40-<53%

23. Winter Grass Cover Selection, Bi
August 2009
0.046
0.170
0.268
0.516
10-<20%
20-<30%
30-<40%
40-<53%

24. Interesting Observation

25. Interesting Observation

26. Interesting Observation

27. Acknowledgements
• CSTARS – UC Davis
• CONICET – Consejo Nacional de Investigaciones Científicas y
Técnicas CENPAT - Centro Nacional Patagónico
• Geography Graduate Group – UC Davis
• California Space Grant Consortium
• CODEMA – Consejo Provincial de Ecología y Medio Ambiente,
Provincia de Río Negro
• Wildlife Conservation Society
• Hemispheric Institute of the Americas – UC Davis
• Henry A. Jastro Shields Research Scholarship – UC Davis
• Pablo Raposo – Fieldwork
• Ana María Beeskow – Plant identification