introduction subalpine meadows play a crucial role in species diversity, supporting many endangered...
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Mesic and Xeric diversity in the Subalpine Elk Meadow
Robert McFadzeanVegetation Ecology Summer B Semester, July 2014University of Colorado, Boulder, COMountain Research Station
Introduction
• Subalpine meadows play a crucial role in species diversity, supporting many endangered species of plant and wildlife.
• Subalpine meadows are found where temperatures are too cold or snow covers the ground for too long for trees to grow.
Introduction
• Studies show that moisture gradients greatly affect the vegetation diversity. ‘Soil moisture is critically important for plant diversity patterns’ (Moeslund et al : 2014)
• Mesic soils which are not oversaturated tend to be richer in nutrients and support greater plant diversity. (Fund et. Al: 2014)
IntroductionH0: There is no difference in species diversity between Xeric and Mesic sites in Elk Meadow.
H1: There is a difference between Xeric and Mesic site diversity in Elk Meadow.
I expect to find greater diversity in the Mesic site.
Mesic Xeric
MethodsAnalyze plant diversity across Xeric (Dry) and Mesic (Wet) landscapes located within Elk Meadow.
Mesic
Xeric
The Elk Meadow (Google Earth 2014)
MethodsBoth Mesic and Xeric sites are located in the Elk Meadow in the sub alpine with 3% Slope 108 Degrees E at 2963 meters.
5 randomly selected 20 X 50 cm Daubenmire plots per site.
Each individual species abundance.
A soil sample and water content was taken at each site and rated on a 1-5 scale, dry being 1 and wet being 5.
The observations are not representative of the entire subalpine zone on the Coloradan Front Range due to pseudo replication.
The samples do however represent an accurate profile of the Elk Meadow.
MethodsI used the Jaccard’s Index to quantify the similarities in species diversity between the areas.
Student t-test was used to test differences in species diversity (Shannon-Wiener).
Mann-Whitney rank sum was used to test for the Species Richness and Evenness differences.
Results19 Species in total
Tim
othy
Gra
ss
Yarro
w M
ilfoi
l
Whi
te S
age
Pote
ntill
a ar
gent
ea
Puss
ytoe
s
Unkno
wn
Long
leaf
Ston
ecro
p
Pote
ntill
a ar
guta
Purp
le H
areb
ell
Rye G
rass
Wal
lflow
er
Poa
prat
ensis
Alpin
e St
rawbe
rry
Smoo
th B
rom
e
Hoary
Gol
den
Aster
Gentio
n
Golde
n Ban
ner
Frin
ged
Sage
Sedg
e0
10
20
30
40
50
60
70
80
90
Mesic vs Xeric Species Distribution at Elk Meadow
Mesic Species FrequencyXeric Species Frequency
Species
Frequency
Results
Average H(SW) Average Evenness Average Species0
1
2
3
4
5
6
7
8
9
10
Species Richness , Diversity and Evenness for Xeric vs Mesic Sites
XericMesic
Species Richness (Average Species), Diversity (H, Shannon Weiner) and Evenness
Average Values
P-Value (Mann-Whit-ney) for EvennessP = 0.30 NOT SIGNIFICANT
P-Value (Mann-Whit-ney) for Average Species P = 0.012 Significant
P-Value (T-Test) for Di-versity (SW) P=0.0013 Significant
ResultsJaccard’s Index: 0.42
Mesic Xeric42% Similar
Mesic Species42%
Unique Xeric Species
58%
Representation of Jaccard's Index
Discussion• Species Richness and the Shannon Wiener
Index are significantly higher in the Xeric areas of Elk Meadow.
• The Xeric site contained 11 Unique species of the total 19 species found at all sites.
• Evenness across the two sites were similar and not significantly different.
• Jaccard’s index shows a large difference in diversity.
• Observations indicate that productivity is higher in the Mesic areas given the visible biomass of species present.
Discussion
Mesic areas tended to have great abundance of species which were there.
‘Shifts in plant species composition toward more diverse communities and toward communities characteristic of more xeric environments are also expected, further lowering productivity without a change in mean soil moisture.’ (Knapp et al: 2002)
Further research looking at the biomass within the two sites including measuring species heights could shed light on the differences seen.
ConclusionsThe subalpine Elk Meadow is more diverse in species within Xeric areas than Mesic Areas.
Although Xeric areas are more diverse in Elk Meadow, the productivity of the Mesic areas may be greater.
Both Xeric and Mesic areas share similar Evenness.
Further research should include measuring the heights and basal area of species.
References1. Fund, W. (2014). Qilian Mountains subalpine meadows.
Retrieved from http://www.eoearth.org/view/article/155625
2. Knapp AK, Fay PA, Blair JM, Collins SL, Smith MD, Carlisle JD, Harper CW, Danner BT, Lett MS, McCarron JK. 2002. Rainfall variability, carbon cycling and plant species diversity in a mesic grassland. Science 298: 2202–2205.
3. Moeslund JE, Arge L, Bøcher PK, Dalgaard T, Ejrnæs R, Odgaard MV, Svenning J-C (2013) Topo-graphically controlled soil moisture drives plant diversity patterns within grasslands. Biodivers Con- serv. doi:10.1007/s10531-013-0442-3
4. Mueller-Dombois, D. Ellenberg, H. Aims and Methods of Vegetation Ecology. The Blackburn Press. Caldwell, New Jersey US. 2002. 62-63.
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