Transcript pptx - Niwot Ridge LTER

VEGETATION COMPOSITION IN
NIWOT’S RIPARIAN TUNDRA
Sean Race
Vegetation Ecology – Semester B 2014
Mountain Research Station. UC-B
Introduction

Question: Does proximity of riparian area in
alpine tundra affect the composition of the
vegetation found there?
 Are
certain species exclusive to particular areas of
the tundra?
Hypothesis


H0 : There is no relationship between proximity to
riparian area and vegetation composition
Alternate Hypothesis: There is a significant relationship
between proximity and vegetation composition

Prediction: Certain species will colonize the different parts of the
tundra based on proximity
Prior Research
Proximity to water influences the plant diversity and topography of
riparian zones compared to uplands (Elmore, Beschta 1987)
Species Richness increases as
distance from stream increases,
then falls gradually (Gregory et al. 1991)
Vegetation along arctic river systems is primarily determined by
moisture content and pH (Gould, Walker 1999)
Methods
Site 1 – Fourmile Creek tundra
Sites 2&3 – Niwot Ridge tundra
Elevation: 10961ft
Aspect: 120°SE
Slope: 2.5%
Elevation: 11041 and 11191ft
Aspect: 112 and 113°SE
Slope: 2% and 5%
Plotting techniques

5 Daubenmire plots in 10x5m area
0-5m from stream and 10-15m
from stream


Each replicate had 10 plots total
Measured avg. height, species, #
individuals, and phenological state
Results



Species Richness did not vary greatly between the
Riparian (25) and Off-Riparian (23) samples
More significant were changes in phenological state
and between individual species…
Jaccard Index: 0.6

# Common: 18

# Different: 12
P-value: 0.0002
Erigeron vs. Snow Buttercup Chi-Square(s)
Including all
cover classes
resulted in a
p-value of
.227.
Removing
cover class 1
(0-5%)
resulted in a
p-value of
.0125,
however
All Classes
Classes excl. 1
Yarrow (Achillea millefolium) Chi-Square
Species Evenness T-Test

No significant relationship between location
and species evenness was found
Species Evenness by Area
Riparian Mean: 82
Off-Riparian Mean:83
Evenness
Two-tailed p-value: .846
100
95
90
85
80
75
70
65
60
55
50
Riparian
Off-Riparian
Area Measured
Discussion

Differences in species richness and species evenness
were minimal between sites


However, vegetation composition based on phenological
state and individual presence/absence showed significant
trends
Results of Chi-Square tests and Jaccard Index suggest that
individual species composition is heavily influenced by
proximity to water source
Limits and Future Research

Major limits of this study included lack of 3 distinct
replicates


T-test on bounded data



More replicates for future studies
Possible ranking system?
A future study could survey larger areas to perhaps see
the affect of further distance (>15m) on vegetation
composition
Potentially look into differences between native and exotic
grass species…
References
Gould, W. A. and Walker, M. D. (1999) “Plant communities and
landscape diversity along a Canadian Arctic river.” Journal
of Vegetation Science, 10: 537–548.
Gregory, Stanley V and Swanson, Frederick J et al. “An Ecosystem
Perspective of Riparian Zones” Bioscience, Sep 1991: 41, 8.
Research Library Core pg. 540
Elmore, Wayne and Beschta, Robert L. “Riparian Areas: Perceptions
in Management” Rangelands, Dec 1987: 9, 6: 260-265.