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’ (M o e s l u n d e t a l :
2014)
•
Mesic soils which are not oversaturated tend to be
richer in nutrients and support greater plant
diversity. (Fund et. Al: 2014)
Question
Is there a difference in plant diversity within
Xeric and Mesic sites of Elk Meadow?
Introduction
H0: 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
Methods
Analyze plant diversity across Xeric (Dry) and Mesic
(Wet) landscapes located within Elk Meadow.
The Elk Meadow (Google Earth 2014)
Mesic
Xeric
Methods
Both 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.
Methods
I 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 (ShannonWiener).
Mann-Whitney rank sum was used to test for the Species Richness and
Evenness differences.
19 Species in total
Results
Mesic vs Xeric Species Distribution at Elk Meadow
90
80
70
60
50
Frequency
40
Mesic Species Frequency
30
Xeric Species Frequency
20
10
0
Species
Results
10
Species Richness , Diversity and Evenness for Xeric vs Mesic Sites
9
P-Value (Mann-Whitney) for
Average Species P = 0.012
Significant
8
7
6
Average Values 5
Xeric
Mesic
4
3
P-Value (T-Test) for Diversity
(SW) P=0.0013 Significant
2
P-Value (Mann-Whitney) for
Evenness
P = 0.30
NOT SIGNIFICANT
1
0
Average H(SW)
Average Evenness
Average Species
Species Richness (Average Species), Diversity (H, Shannon Weiner) and Evenness
Results
Jaccard’s Index: 0.42
Representation of Jaccard's Index
Mesic
Species
42%
Unique
Xeric
Species
58%
Mesic
42% Similar
Xeric
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.
Conclusions
The 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.
Questions
References