Transcript Slide 1

Assessing the Interannual
Variation in Vegetative Response
to Climate in Spring Valley, NV
Lorenzo Apodaca
2/13/12
Effects of climate change
Lengthening of growing season
Reduction in total winter snow pack
Increase in water stress
Changes in species composition
Shifts in plant ecotones
Spread of invasive species
Spring Valley
Directly west of GBNP
(NE NV)
Mainly mixed shrubland
Location of one of the
towers in Snake Range
transect
Goal : Establish empirical relationship
between big sagebrush growth ring
indices and remotely-sensed NDVI
Linking plant growth response to past
climate variability
Relationship between wood
development and seasonal
precipitation
119Sample
stems from
collection
withincomplete
the valley
Stem Stats
• Avg. ring count = 45 (s = 14)
• Max. count = 77
• Min. count = 22
• 60% of stems date up to 1970
Skeleton Plot
Skeleton Plot
10
50
45
8
1974
1989
6
35
1996
1959
2007
2002
4
30
25
20
2
15
0
0
1950
1950
10
1960
1960
1970
1970
1980
1980
1990
1990
2000
2000
2010
2010
Precipitation (cm)
40
Average Growing Season NDVI for Each Year
Average growing season NDVI
0.35
SV1
SV2
SV3
SV5
SV6
SV7
Average Growing Season NDVI
0.30
0.25
0.20
0.15
0.10
0.05
0.00
1985
1990
1995
2000
2005
2010
Future Work
• Ring indices of all 128 sagebrush stems
samples and sites
– Requires accurate dating of all stem rings
• Determine ring signal beyond the site level
• Examine relationship between ring indices
and NDVI
– Between growth/development and climate
Acknowledgements
UNLV Advisory Committee
Dr. Dale Devitt
Dr. Lynn Fenstermaker
Dr. Stan Smith
Dr. Paul Schulte
Devitt Lab
Lena Wright
Amanda Wagner
Brian Bird
Special thanks
Fred Landau
Ely BLM
Funded by NSF
EPSCoR seed grant
Devitt et al, Ecohydrology 2010.
SV25-2
2D Graph 5
3.0
2.5
Ring Index
2.0
1.5
1.0
0.5
0.0
1960
1970
1980
1990
2000
2010