Download Measuring Soil Biodiversity in invertebrates

Effect of sunlight on
biodiversity of soil
invertebrates
Loretta McNamee
Undergraduate Student
(Environmental Biology Concentration), Department of
Biology, Tennessee Tech University , Cookeville, TN
38505
Introduction

What is biodiversity?

Very important starting point to explaining patterns
of community dynamics and structure

Soil Invertebrates are detritivores.

Influence many soil properties, which influence
above-ground plant abundance
(Dr Brown’s Ecology website.
http://iweb.tntech.edu/cabrown/Ecology.htm.2006)
Introduction continued…




Studies suggest presence of plants affect soil communities.
They provide nutrients that organisms need to survive
(Dunfield 2003)
Soil invertebrate prefer to occupy areas that are artificially or
naturally covered, due to more moisture in the soil. (Ferguson
2004)
One study showed that many chemical and physical properties
of the soil differ based on its location (Pankhurst 1992).
The forest or canopy environment of the biodiversity
experiment should have more invertebrates present. This would
coincide with hypothesis that stated the canopy habitat would
have a greater soil biodiversity. (Chamberlain 2006)
Objective



To examine biodiversity in soil invertebrates
in two distinct communities.
canopy communities- those in forest
locations in which sun does not shine directly
on the soil.
open ground communities- in a field, where
the sun shines directly on the soil, potentially
drying it out
Hypothesis


Hypothesis: I predict that the canopy
community will have a more diverse
selection of soil invertebrate;
therefore it will show more soil
biodiversity.
Null Hypothesis: there is no
difference in biodiversity of soil
invertebrate in the two communities.
Methods and Materials



Location was on the TTU campus in back of
the varisty baseball field
8 samples from each community, 1 collection
(16 total)
Samples were collected by using shovel and
placing each different sample into a plastic
bag.
Methods and Materials



Placed samples into its own
Berlese Funnel
Funnel with mesh filter placed
in a mason jar and put under a
lamp.
After a week obtained samples
in the bottom of funnel,
identified and counted each
species
Reference: Dr. Brown's Lab Handouts
Statistical Tests performed
1. T-test: tests the hypothesis that two population
means are different
2. Kolmogorov-Smirnov test: compares the distribution
of the two habitats
3. Species diversity Measurements: Simpson and
Shannon Indexes (H&D, E&J)

Sources: t-test and Kolmogorov-Smirnov Test
Results
Table 3: Forest Data table


More species were
found in the open
ground data, but more
species were identified
in Forest data
Shows Pi, which is
needed to perform
species measurements
Species
Collembola
Beetles
Annelids
Thysanura
Millipede
Centipede
Mite
Abundance
Pi
12
5
2
2
1
1
1
0.500
0.208
0.083
0.083
0.042
0.042
0.042
Cumulative
Pi
0.500
0.708
0.792
0.875
0.917
0.958
1.000
Table 4: Open ground data
Species
hymenoptera
Mites
Annelids
Beetles
Collembola
Abundance
Pi
22
19
5
4
1
0.431
0.373
0.098
0.078
0.020
Cumulative
Pi
0.431
0.804
0.902
0.980
1.000
Results
Cumulative # of species
encountered
Species accumulation Curve for Forest Data

It takes more individual
organisms to reach a new
species for the open
ground data

Accounts for the higher
abundance of species,
but lower number of
species found in open
ground
8
7
6
5
4
Series1
3
2
1
0
0
5
10
15
20
25
30
# of individual organisms encoutnered
Cumulative # of species
encountered
Species Accumulation Curve for open Ground
Data
6
5
4
3
Series1
2
1
0
0
10
20
30
40
50
# of individual organisms encountered
60
Results


Difference in slopes
suggests a difference
between communities
Forest data has a
steeper slope, so less
even
However, so small
doesn’t impact data as
much
Rank-Abundance Curve
Proportional Abundance

0.60
0.50
0.40
Forest data
0.30
Open Ground data
0.20
0.10
0.00
0
1
2
3
4
5
Species Rank
6
7
8
Statistical test Results
t-Test: Two-Sample Assuming Equal Variances
Mean
Variance
Observations
Pooled Variance
Hypothesized Mean
Difference
df
t Stat
P(T<=t) one-tail
t Critical one-tail
P(T<=t) two-tail
t Critical two-tail
Variable
1
0.343
0.215
7
0.161
0
12
-0.240
0.407
1.782
0.815
2.178

t Stat < t Critical twotail, accept null
hypothesis

Dcrit > Dmax in the
Kolmogrov-Smirnov
test
Variable
2
0.394286
0.107562
7
Discussion




It was concluded that there was no difference in the two distinct habitats;
forest habitat and open ground habitat. This does contradict the original
hypothesis that stated that there would be a distinct difference in the two
habitats.
Although the results show that the two distinct communities showed no
difference in species diversity, most previous long term studies show a
great difference.
One study showed that many chemical and physical properties of the soil
differ based on its location (Pankhurst 1992). These chemical and
physical properties influence what type of organisms can survive in that
type of soil.
The amount of moisture or the amount of carbon would affect such
property. Other studies suggest that the presence of plants (alder) affects
the communities in the soil (Dunfield 2003, Chamberlain 2006).
Discussion




Agrees with Dunfield’s study suggests that the plants provide
nutrients that the soil organisms can use for survival. While
the Chamberlain study suggests that a large presence of alder
is the reason for a high abundance of Collembola.
Disagrees with the studies that stated the forest or canopy
environment of the biodiversity experiment should have had
more invertebrates present.
Interspecific and intraspecific competition has a lot to do with
species abundance (Heemsbergen 2004)
A bigger sample size and more distinct habitats would have
helped the experiment be more accurate.
Conclusions

No difference in invertebrate biodiversity between
the two distinct habitats

Accepted the null hypothesis, rejected my hypothesis

Forest Data was found to be less even than open
ground, but had more species found

Both Kolmogorov-Smirnov and t-tests statistically
showed no difference
Works Cited

Briones, M.J.,Ostle N.J., Garnett M.H. 2006. Invertebrates increase the sensitivity of nonlabile soil carbon to Climate Change. Soil Biology & Biochemistry 39(3): 816-818

Chamberlain, P.M., and McNamara, N.P.2006 Translocation of Surface litter
into Soil by Collembola. Soil Biology & Biochemistry. 9:2655-2664.

Dunfield, K.E., and Germida, J.J. 2003. Impact of Genetically Modified Crops on Soil and
Plant Associated Microbial Communities. Journal of Environmental
Quality. 33:799804.

Ferguson, S.H., and Berube, D.K. Invertebrate Diversity under Artificial cover in
Carbon
Relation to Boreal Forest Habitat Characteristics. Canadian Field-Naturalist.3:
386-394.

Heemsbergen, D.A., Berg, M.P., Loreau, M., van Hal,J.R..2004.Biodiversity effects on soil
processes explained by Interspecific functional dissimilarity.(Reports).
Science 306: 1019-1021.
Effect of sunlight on biodiversity of soil
invertebrates
Loretta McNamee
Biology Department of Tennessee Technological University, Cookeville, TN 38501
•Soil biodiversity is the number and
abundance of species inhabiting a
community
•Research has also been conducted
on the chemical properties of soil and
how it affects the invertebrate
•Carbon is a huge factor, which is
somewhat dependant on if and how
much the sun hits the soil
•Research shows that plant
abundance directly affects
invertebrate abundance, because
plants provide so many nutrients for
the soil invertebrates to survive
Objective & Hypothesis
The objective of this study is to examine
biodiversity in soil invertebrates in two
distinct communities; canopy and open
ground.
•Based on the objective, this experiment
tested the null hypothesis that sunlight
has no affect on the biodiversity of soil
invertebrates
Results
Conclusion
•As shown in Figure 1, This graph shows that the forest
data is less even then open ground data due to the steep
slope on the graph.
•It was found that there was no
difference in the two distinct
habitats
•Table 1 shows the statistical measurements of species
diversity that was needed to produce the species
abundance curve
Statistical
Measurements
Forest
Data
Open
Ground
Data
Species Richness
(S)
7
5
Shannon Diversity
Index (H)
1.48
1.23
Simpsons Diversity
Index (D)
3.20
2.93
Shannon Evenness
Index (J)
0.763
0.767
Simpsons Evenness
Index (E)
0.457
•Therefore, the null hypothesis
was accepted
•These findings disagreed with
many other studies before, in
which they found differences
in soil biodiversity.
Rank-Abundance Curve
Proportional Abundance
Introduction
0.60
0.50
0.40
Forest data
0.30
Open Ground data
0.20
•Forest data showed more
species evenness than that of
the Open Ground data
0.10
0.00
0
1
2
3
4
5
6
7
8
Species Rank
0.586
Acknowledgements
Methods & Materials
•This experiment somewhat followed the basic methods
outlined by Dr. Brown in his Ecology Lab handout.
•Took 8 samples from each habitat, which was a total of 16
different soil samples.
•Each sample was placed into a Burlese funnel in order to get
the specimen out of their natural habitat of the soil
•Species were collected and counted to form the basic data
set
•T-test and Kolmogrov-Smirnov test were both used to
perform statistical analysis on the data collected.
•Dr. Morgan for his help in this
semester long process
•Dr. Brown for using his set-up
•TTU Biology Department for the
use of the media
•Emily Shrum for help along the
way