Forest Succession: Comparison of Early vs.
Late Successional Sites
ALLYSON HAYNIE
Introduction
Methods and Materials
Discussion
Literature Cited
Results
•Ecological succession describes the
gradual change in plant and animal
communities in response to natural or
human-caused disturbances. (Smith and
Jones 2023) This study explores how
plant diversity and structure differ
between early and late stages of forest
succession. Primary succession begins in
areas without previous life, such as after
a volcanic eruption. (Environmental
Science Handbook, 2024) In a series of
experiments, succession was observed
in both early and late sites when
students traveled to the Noxubee
National Wildlife Refuge to collect data.
Four hypotheses are tested in this
experiment:
•Hypothesis 1 null: No difference in
species diversity between early and late
succession sites.
•Hypothesis 1 alternative: Species
diversity differs between early and late
succession sites.
•Hypothesis 2 null: Woody plant
distribution remains consistent across
sites.
•Hypothesis 2 alternative: Woody
plant distribution varies between sites.
•Based on importance values,
American
sweetgum
and
loblolly pine
were the
top two species at both early and late
successional sites.
•The rank abundance plot showed a
steeper slope at the late site,
indicating dominance by fewer species
and lower evenness. In contrast, the
early site had higher species richness
and a greater Shannon diversity index
(3.007 vs. 2.776), reflecting more
diverse plant life.
•The average distance between woody
plants was slightly shorter at the early
site (5.432 m) than the late site (5.610
m), but the difference was not
statistically significant.
•A t-test value of 0.684 supports failing
to reject the second null hypothesis—
there is no significant difference in
spatial distribution.
•However, the first null hypothesis is
rejected. The early site’s higher
diversity and richness support the
conclusion that species diversity differs
between successional stages. Reduced
diversity in the late site may result
from competitive exclusion by
dominant species.
•Succession is an important topic that
allows researchers to learn more about
the environment what species need to
be protected. (Chang and Turner 2019)
•Students are evenly divided into groups
and taken to different sites of
succession at the Noxubee Wildlife
Refuge in Starkville, MS.
•They are given 5 flags, to distribute
among their sites.
•The groups are given a set of 5 random
numbers between 1 to 50 which
represent a meter on their transect.
•A line transect was used to measure
tree species in four quadrants.
•Teams recorded species type,
abundance, and size using plant ID apps
and meter sticks.
•Data from disturbed and undisturbed
sites were compared to identify
successional differences.
•All data collected from the experiment
was then recorded in an excel
document.
•Environmental Science Handbook.
Introduction to Primary Succession
. Green
Earth Publishing, 2024.
•Smith, J., and L. Jones.
Principles of Ecological
Change
. EcoScience Press, 2023.
•Chang, Cynthia C., and Benjamin L. Turner.
"Ecological Succession in a Changing World."
Journal of Ecology
, vol. 107, no. 2, 2019, pp.
503–509.
Early Late
Shannon Diversity 3.007 2.776
Species Richness 32 26
Distance (mean+/-
SD)
5.432+-
3.188
5.61+-
3.590
LATE
SPECIES p q d A I
LOBLOLLY PINE 0.075 0.267 0.323 28938.9
73
0.664
AMERICAN
SWEETGUM
0.158 0.400 0.052 4630.32
6
0.610
WHITE OAK 0.092 0.267 0.134 12066.0
93
0.493
WATER OAK 0.092 0.233 0.098 8791.79
4
0.423
AMERICAN
HORNBEAM
0.142 0.233 0.046 4122.11
3
0.421
EARLY
SPECIES p q d A I
AMERICAN
SWEETGUM
0.217 0.367 0.193 31641.27
6
0.776
LOBLOLLY PINE 0.083 0.233 0.152 24902.73
5
0.468
RED MAPLE 0.067 0.200 0.041 6797.906 0.308
BLACK OAK 0.042 0.133 0.097 15909.52
6
0.272
FLOWERING
DOGWOOD
0.058 0.167 0.044 7215.767 0.269
•The table shown above depicts the accurate
measurement of diversity and abundance in the
sites that were studied. Both Shannon Diversity
and Species richness were calculated to find the
number of new species in each site. The
distance represents the trees distance from the
points placed by flags in the transects.
•The graph to the right depicts both X and Y
axes with the X axis being the rank of each
species and the Y axis representing the relative
abundance of the species.
The tables on the left highlight the
five most common tree species at
each site, listed from highest to
lowest in abundance.
• “p” represents the species’ relative
abundance, or its proportion of the
total tree population.
• “q” is the relative point frequency,
showing how often the species
appeared across sampled points.
• “d” refers to relative dominance,
indicating how much of the total
basal area is made up by that
species.
• “A” is the total basal area for each
species.
• “I”, the importance value, combines
p, q, and d to reflect the species'
overall role in the ecosystem.
