This document summarizes a study that measured species diversity along a 20 meter transect line laid along a river in the Philippines. Shannon-Wiener and Simpson's indices were used to analyze the diversity of 357 individuals from 19 species collected along the line. The Shannon-Wiener index value of 2.44 indicated high species diversity. The Simpson's index value of 0.114358103 also indicated high diversity, with a diversity index of 0.89. In conclusion, the study found high species richness but uneven distribution, and overall high species diversity in the sampling area.

1. Orpilla, Sanchez, Suelo, Tabafunda, Valerio, & Villahermosa / Ecological Sampling I: The TransectLine Method
© College of Education, Don Mariano Marcos Memorial State University-North La Union Campus
1
Ecological Sampling II: Measuring Species Diversity
Lester E. Orpilla1 Mark Harold A. Sanchez2 Jhomarie I. Suelo3
Judy Ann L. Tabafunda4 Jonalyn M.Valerio5
and Orpha Grace A. Villahermosa6
Abstract— The study aimed to measure stability to determine if an environment is degrading, compare tw o or more environment and eliminate
the need for extensive list. The study w as conducted at Don Mariano Marcos Memorial State University-North La Union Campus, Sapilang,
Bacnotan, La Union particularly along the river. A 20 meter transect line w as laid on the ground of the sampling station follow ing the flow of the
river. A sample of all the species touching the ground w ere collected, recorded, and photographed along the w hole length of the line. Shannon-
Weiner Index and Simpson’s Index w ere used to compute the species diversity of the samples. It w as found out that that the samples recorded
have high species diversity.
Index Terms— biodiversity, diversity, diversity indices, Shannon–Wiener Index, Simpson’s Index, species richness, speciesevenness, speciesdiversity.
——————————  ——————————
1 INTRODUCTION
Biodiversityis a measure that combines richness and
evenness across species. It is one of the primary interests of
ecologists, but quantifying the species diversity of ecological
communities is complicated. Itis often measured becausehigh
biodiversity is perceived a synonymous with ecosystem
health. In general diverse communities are believed to have
increased stability, increased productivity, and resistance to
invasion and other disturbances.
In addition toissues ofstatisticalsampling, the rather
arbitrary nature of delineating an ecological community, and
the difficulty of positively identifying all of the species
present,species diversity itself has two separate components:
1.) the number of species present (species richness), and 2.)
their relative abundances (termed dominance or evenness).
The two main factors taken into account when measuring
diversity because it provide important information about
species rarity and commonness in a population.
Diversity indices provide information about the
composition of a community. It provides important
information about species rarity and commonness in a
population.
Determining which community has greater species
diversity is easy when either species richness or evenness is
held constant while the other parameter varies, but often
communities will vary in both richness and evenness.
Scientists havedeveloped a varietyof mathematical equations
(or indices) that incorporate both species richness and
evenness into a single measure of species diversity (e.g., the
Shannon-Wiener Index and Simpson’s Index). Different
diversity indices assign different weightings to species
richness and evenness, so the so most useful index to choose
depends on the circumstances.
Here, we will explore two measures of biodiversity:
The Shannon index (Hʼ, also termed the Shannon-Wiener
index) and the Simpson index (  ).
2 METHODOLOGY
2.1 Description of Study Site
The study was conducted on June 24, 2014 at Don
MarianoMarcosMemorial State University-North La Union
Campus,Sapilang,Bacnotan,La Union as shown in Figure 1.
Figure 1. Study map ofthe Sapilang Creek atDMMMSU-NLUC, Sapilang,
Bacnotan, La Union showing the location of the sampling area.
The sampling area is specifically located in upper
portion of the tributary creek, western part of the bridge
followingtheflow ofwater. Theyellow dot indicatestheplace
where the transect line is conducted.
2.2 The Transect Line Method
A 20 meter rope was laid along the upper portion of
the creek, going down. Sample of all species touching the
transectlinewerecollected and placed in an improvised paper

2. Orpilla, Sanchez, Suelo, Tabafunda, Valerio, & Villahermosa / Ecological Sampling I: The TransectLine Method
© College of Education, Don Mariano Marcos Memorial State University-North La Union Campus
2
 
 1NN
1nn



 ii

bag specimen and werelabeled species 1, species 2, species 3,
and soon, recorded theirabundance,photographed andwere
identified their scientific names.
2.1 The Shannon-Wiener Index
Species evenness, richness, and diversity indices as
Shannon-Weiner (Shannon and Weaver, 1949) and Simpson
Index (Simpson,1949)wereused to evaluate the bird species
diversity.Shannon-WeinerIndex assumes that individualsare
randomlysampled froman independentlargepopulation and
all the species are represented in the sample. Shannon
diversityis very widely used index for comparing diversity
betweenvarious habitats(Clarkeand Warwick, 2001). It was
calculated in ordertoknow the species diversity in different
habitat (Hutchison, 1970) based on the abundance of the
species by the following formula:
H' = -∑ 𝒑𝒊 (𝒍𝒏 𝒑𝒊)𝒔
𝒊=𝟏
Where,H ́ = Diversity Index ; Pi = is the proportion of
each species in the sample ; lnPi = natural logarithm of this
proportion.Thepresenceof one individual of a species is not
necessarily indicative of the species being present in a large
number.ThevalueofShannon Weiner DiversityIndex usually
falls between 1.5 and 3.5,only rarelyit surpasses 4.5. A value
near 4.6 would indicate that the numbers of individuals are
evenly distributed between all the species.
2.2 The Simpson’s Index
It measures the probability that two individuals
randomly selected from a sample will belong to the same
species.Simpsongavetheprobabilityof any two individuals
drawn from noticeably large community belonging to
different species.It has been measured by the given formula
where ni = thetotal numberof organisms ofeach individual
species
N = the total number of organisms of all species
 = is a measure of dominance and 1-  measures
species diversity
3. RESULTS AND DISCUSSIONS
Typical valuesofShannon-WeinerIndex aregenerally
between1.5 and 3.5 in mostecological studies,and theindex is
rarelygreaterthan 4.TheShannonindex increases as both the
richnessand theevennessofthecommunityincrease.The fact
that theindexincorporates both components of biodiversity
can be seen as both strength and a weakness. It is strength
becauseit provides a simple, synthetic summary, but it is a
weakness because it makes it difficult to compare
communities that differ greatly in richness.
Thecomputed Shannon-Weiner Index of the species
in the transect line method is 2.442629271. Since the index
value is high, this means that species diversity is high which
indicates less competitionbetween species. The Table 1 below
shows thecomputation oftheShannon-Weiner Index. Species
number 3 is the most abundant species.
Table 1.AbundanceofIdentified SamplingSpecies Present in
the Study Site
Species Scientific Name n
1 Arctostaphylos manzanita 3
2 Leucaena lecocephala 10
3 Vernonia cinerea 78
4 Lantana camara 43
5 Samanea saman 1
6 Mimosa pudica 8
7 Phyllanthus niruri 3
8 10
9 Centrosema sp. 8
10 10
11 Cymbopogonwinterianus 2
12 Clitoria ternatea 59
13 8
14 Cyperus esculentus 6
15 Brachiaria platyphylla 40
16 Digitaria sp. 13
17 Dactylis glomerata 17
18 Agrostis sp. 29
19 9
TotalNumbers of Individuals 357

3. Orpilla, Sanchez, Suelo, Tabafunda, Valerio, & Villahermosa / Ecological Sampling I: The TransectLine Method
© College of Education, Don Mariano Marcos Memorial State University-North La Union Campus
3
Table 1. Shannon-Weiner Index
Table 2. Simpson’s Index
Species ni ni/N ln(ni/n) − ∑(ni/Nxln(ni/n)
1 3 0.0084 -4.77912 -0.040160702
2 10 0.02801 -3.57515 -0.100144277
3 78 0.21849 -1.52103 -0.332325217
4 43 0.12045 -2.11654 -0.254932867
5 1 0.0028 -5.87774 -0.016464246
6 8 0.02241 -3.79829 -0.085115837
7 3 0.0084 -4.77912 -0.040160702
8 10 0.02801 -3.57515 -0.100144277
9 8 0.02241 -3.79829 -0.085115837
10 10 0.02801 -3.57515 -0.100144277
11 2 0.0056 -5.18459 -0.029045314
12 59 0.16527 -1.8002 -0.29751177
13 8 0.02241 -3.79829 -0.085115837
14 6 0.01681 -4.08598 -0.068671871
15 40 0.11204 -2.18886 -0.245250009
16 13 0.03641 -3.31279 -0.120633679
17 17 0.04762 -3.04452 -0.144977259
18 29 0.08123 -2.51044 -0.203929296
19 9 0.02521 -3.68051 -0.092785997
N=357 2.442629271
Species ni ni(ni-
1)
N(N-1) ni(ni-1)/
N(N-1)
1 3 6 127092 4.72099E-05
2 10 90 127092 0.000708148
3 78 6006 127092 0.047257105
4 43 1806 127092 0.014210178
5 1 0 127092 0
6 8 56 127092 0.000440626
7 3 6 127092 4.72099E-05
8 10 90 127092 0.000708148
9 2 2 127092 1.57366E-05
10 10 90 127092 0.000708148
11 2 2 127092 1.57366E-05
12 59 3422 127092 0.026925377
13 8 56 127092 0.000440626
14 6 30 127092 0.000236049
15 40 1560 127092 0.012274573
16 13 156 127092 0.001227457
17 17 272 127092 0.002140182
18 29 812 127092 0.006389072
19 9 72 127092 0.000566519
N=357 0.114358103

4. Orpilla, Sanchez, Suelo, Tabafunda, Valerio, & Villahermosa / Ecological Sampling I: The TransectLine Method
© College of Education, Don Mariano Marcos Memorial State University-North La Union Campus
4
In the Simpson’s Index, the value of  ranges
between 0 and 1. With this index, 0 represents infinite
diversityand 1,no diversity. That is, the bigger the value of 
, the lower thediversity.This is neitherintuitivenorlogical,so
to get over this problem,  is often subtracted from 1 to give:
Simpson's Index of Diversity 1 -  .
The value of this index also ranges between 0 and 1,
but now, the greater the value, the greater the sample
diversity. This makes more sense. In this case, the index
represents the probability that two individuals randomly
selected from a sample will belong to different species.
The computed Simpson’s Index value of the species
recorded is 0.114358103and theindex diversity is 0.89 which
means that there is greater species diversity.
4. CONCLUSIONS
Based on the salient findings of the study, the
following conclusions can be drawn:
1. Thespecies richnessis high but species are not evenly
distributed;
2. Thereis high species diversityin thesamplingstation,
thus the environment is very stable;
3. Shannon Weiner Index and Simpson’s Index have
different ways of computing the species diversity but
they have the same interpretation;
4. Shannon-WeinerIndex and Simpson’s cannot include
all species from the community in the sample;
5. Thevalueof a biodiversityindex mayvarywith small
changes in thespecies data that it is calculated from,
but also with habitat type and time period; and
6. Diversecommunities areoften a sign of fragmented or
somewhat degraded sites where much of species
richness is contributed by disturbance species.
ACKNOWLEDGMENT
The authors wish to thank the following people for
helpingin the completion of the study: (1) Mr. Jomar L. Aban,
subject professor in BS 116 (Biotecniques) (2) Dr. Rosita P.
Abubo, Dean of the College of Education, DMMMSU-NLUC.
(3) Dr. Criselda G.Sario,SEd Chairman, College of Education,
DMMMSU-NLUC, (4) Mrs. Violita F. Collado, adviser of the
authors (5)theirparents for thefinancial and moral assistance.
REFERENCES
[1] Magurran,A.M. (2004).MeasuringBiological
DiversityBlackwell ScienceLtd,Oxford.
[2] Buckland,S.T., Borchers D. L., Johnston A., Henrys P.
A. & Marques T.A. (2007)LineTransect Methods for
Plant Surveys. . Retrieved July 2, 2014, from:
http://onlinelibrary.wiley.com/doi/10.1111/j.1541-
0420.2007.00798.x/abstract
[3] Cummings, J. & Smith D. (2001) The Line-Intercept
Method: A Tool for Introductory Plant Ecology
Laboratories Retrieved July 2, 2014, from:
http://ableweb.org/volumes/vol-22/13-cummings.pdf
[4] Bibi,F. And Ali, Z. (2013)Measurement of Diversity
Indices of Avian Communities at Taunsa Barrage
WildlifeSanctuary,Pakistan . Retrieved July 2, 2014,
from:http://www.thejaps.org.pk/docs/v-23-
2/23.pdf