scipaper grassland

GRASSLAND ECOSYSTEMMethods of Vegetation Analysis using Plot Sampling

A Scientific PaperPresented to Prof. Karyl Marie F. Dagoc of the Department of Biological Sciences

College of Science and MathematicsMSU-Iligan Institute of Technology

Iligan City

In Partial Fulfillmentof the Requirements in

Bio 107.2 – General Ecology LaboratorySecond Semester 2015-2016

Presented by

Mitchelle Dawn E. Paye

April 04, 2016

ACKNOWLEDGEMENTS

The researcher would like to express her heartfelt gratitude to all the people, who in one way or another have guide, assisted, and helped her in the success of this scientific paper;

To Professor Karyl Marie Fabricante - Dagoc for the guidance and help in doing the field sampling.

And above all, to the Almighty Father, for giving His strength, hope, and wisdom all throughout the process of making this scientific paper.

Mitch

ABSTRACT

A grassland is a region where the average annual precipitation is great enough to support

grasses, and in some areas a few trees. The purpose of this study is to determine the species area

curve, cover estimation of vegetation, zonation and density estimation of a grassland ecosystem.

Two sampling techniques was used, plot sampling and transect sampling. In plot sampling, it

used quadrat while in transect sampling was through transect line. A 10m transect line was laid

and 1 square meter quadrat was put in the area within the transect line. A series of procedure was

conducted to obtain the desired result. Results showed in the examination of species area curve

that as the area increases, the species also increases. Density of species, dominance and

frequency were computed. Using the data from the different sampling techniques on the species

composition and the number of individuals per species, the diversity index was measured or

computed. It was found that its diversity index is 0.4025. this means that the species found is

diverse. The species richness also was found to be 4 which means that the species are quite

abundant.

INTRODUCTION

Grassland ecosystem is a biological community that contains few trees or shrubs,

characterized by mixed herbaceous or non-woody vegetation cover and is dominated by grasses

or grasslike plants. Grasslands occur in regions that are too dry for forests but that have sufficient

soil water to support a closed herbaceous plant canopy that is lacking in deserts (Encyclopedia

2002). Semenoff J. (2011) describes grassland that in both temperate and tropical grasslands, the

land is mainly flat. The soil is very rich and fertile in the temperate grassland created by the

growth and decay of deep grass roots. The tropical grassland is less rich because nutrients are

removed by occasional heavy rain. In both grasslands, strong winds may cause oil erosion.

Using plot and transect sampling as a tool in ecological research, the different factors will

be determined. It would be impossible to count all the plants in a habitat, so a sample is taken. A

tool called a quadrat is used in sampling plants. It marks off an exact area so that the plants in

that area can be identified and counted. According to Sutherland(2006), quadrats can be used to

measure density, frequency, and cover or biomass. They are used to define sample areas within

the study area. Williams C.B. (1950) stresses that the relation between the distributions of

species and individuals in the original population and in a series of quadrats depends on three

variables which are the sizes of quadrat, number of quadrats and richness of flora.

In addition, Fidelibus, M. and Aller, R.(1993) states that the appropriate size for a

quadrat depends on the items to be measured. If cover is the only factor being measured, size is

relatively unimportant. If plant numbers per unit area are to be measure, then quadrat size is

critical. A plot size should be large enough to include significant numbers of individuals, but

small enough so that plants can be separated, counted and measured without duplication or

omission of individual. A 0.5-1.0m2 is suggested for short grassland or dwarf heath.

The objectives of this experiment are to train the students on the principles of plot and

transect sampling as applied in ecological research, to determine the cover and density estimates,

the species area curve and the density of plant species in a grassland ecosystem, to construct a

zonation of diagram of a grassland ecosystem, and to be able to interpret the implication of

different combined parameters.

MATERIALS AND METHODS

The field study was conducted at Global Steel Field, Suarez, Iligan City for grassland

ecosystem sampling on March 12, 2016. It had a good weather condition. The grassland was

easily disturbed by humans because many events such as soccer and Frisbee are held there. The

sampling started at around 7:00am.

Figure 1. View of the sampling site, Global Steel Field, Suarez, Iligan City

The procedure was followed from the Laboratory and Field Manual of General Ecology.

A. Species Area Curve

The area to be sampled were randomly selected in a grassland ecosystem. The

10m transect line which was calibrated per meter was laid first in the area to be sampled.

Using 1m2 quadrat, it was positioned to the area that corresponds to the selected grid.

Starting with the smallest subquadrat (10cm x 10cm within the m2 quadrat), the present

plant species were counted. The size of the subquadrat were then doubled and the number

of plant species within the new area were recorded. The doubling and counting steps

were repeated until the number of species counted at each doubling of subquadrat size

leveled off no new species. The number of species were plotted against the quadrat size

to obtain the species-area curve.

B. Cover Estimation of Vegetation

For the Direct Estimation of Top Cover, it was estimated visually for the whole

quadrat. The species were recorded to the nearest percent. The total for all species and

bare ground was equal to 100%.

For the Subquadrat Estimation of Top Cover, the percentage cover of each species

was estimated in 25 of the 100 10cmx10cm subquadrats or every fourth subquadrat. The

results were summed up and the mean was calculated to obtain an estimate of cover

percentages for the 1 m2 quadrat.

For the 50% method, the number of quadrats were recorded in which the species

occupies greater than or equal to 50% of the area. Since many subquadrats will contain a

species mix where no single species reach 50%, then the summed values for this method

will lie below 100%.

The Braun-Blanquet 5 Point Scale uses the following scale to visually

estimate the cover of each species and bare ground for the square meter plot.

+Very rare Less than 1%

1 rare 1-5%

2 occasional 6-25%

3 frequent 26-50%

4 common 51-75%

5 abundant 76-100%

Using the Domin Scale, the cover of each species was visually estimated

for the 1 square meter plot using the following scale:

+ A single individual

1 Scarce, 1-2 individuals

2 Very scattered, cover small less than 1%

3 Scattered, cover small 1-4%

4 Abundant, cover 5-10%





9 Abundant, cover greater than 75% but not complete

10 Cover practically complete

C. Zonation and Density Estimation

The calibrated 10m transect line was laid down across the study area by

connecting each end. The number of plants (per species) which touched or physically

intercepted by the transect line was identified and counted. The plants whose aerial

foliage overlies the transect was included. Using a tape measure, the distance

intercepted by each plant was measured. Plant height was noted. The distance between

the plants were measured in a continuous manner. Begin at one end of the line, only

include that was touched by the line or those that are intercepted within 1cm strip of

the line. A zonation diagram was made by indicating the intercepted distance using

brackets. Plant height, type of substrate and depth of standing water (if present) was

noted. The data was recorded.

The following formula was used for the computation of:

Density of species = No. of individuals of a species

Total area sampled

Relative Density = Density of a species______ x 100Total density of all species

Dominance of a species = Total area covered by a speciesTotal area sampled

Relative dominance = Dominance of a Species x100

Total dominance of all species

Frequency of a species = number of quadrats where a species occurs

Relative frequency = Frequency value for a species x 100

Total frequency of all species

For the computation of the diversity measurements, the data from the different sampling techniques on the species composition and number of individuals per species, the diversity values were computed using the Simpson’s and Shannon-Weinner’s indices. The equation is given below:

Simpson’s index D=∑i=1

R

Pi2

Shannon-Weinner’s index H '=∑i=1

R

Pi log Pi

Where Pi is the proportion of each species out of the total number of individuals recorded.A community software can also be used such as PAST.

RESULTS AND DISCUSSIONS

The following data were obtained from the procedure.

Based in our data, as the sampled area increases, the number of plant species also increases. See table below.

Subplot number Cumulative area sampled(cm2)

Number of Species

Number of new Species

Cumulative number of new Species

1 100 2 - 0

2 200 2 0 0

3 900 2 0 0

4 1600 3 1 1

5 2500 3 0 1

6 3600 4 1 2

7 4900 5 1 3

8 6400 6 1 4

9 8100 7 1 5

10 10000 7 0 5

Table1. Data for generating species area curve.

Table 1 shows that the highest number of species in the quadrat is 7 and the lowest is 2.

Subplot numbers 9 and 10 has the highest species number. In subplot number 2,3,5, and 10 there

was no new species found which means that no additional species occurred. It is just a repetition

of the plant species found. The rest subquadrat has 1 new species. This means that only 1 species

were added in every doubling of subquadrat.

0 2000 4000 6000 8000 10000 120000

1

2

3

4

5

6

7

8

Area (cm2)

Num

ber o

f Spe

cies

Figure 2. The species -area curve

The number of species found from 100cm2to 2500 cm2 is very close and have equal

number of species in some areas. Number of species in areas 100, 200 and 900 square meters has

an equal number. However, it increases gradually starting from 3600cm2 to 10000cm2. This

simply implied that in the beginning, only few species can be found and increases on the later

part. Based on the graph, it rises rapidly on second half part. Thus, the larger the area, the larger

the species can be found in it and increases (refer to Figure 2).

On the estimation of top cover in quadrat, species found to dominate the area compared

to rest of the species(see table below).

Species Direct Estimation

Subquadrat Estimation

50% Method Braun-Blanquet

Domin Scale

A 40% 48% 6% frequent 7B 25% 21% 14% frequent 1

C 15% 16% 3% occasional 2

D 3% 3% 0 rare +

E 7% 6% 0 rare +

F 7% 4% 0 rare 2G 3% 2% 0 rare 1

Table 2. Estimation of top cover

Species 1 Species 2 Species 3 Species 4 Species 1

Species 1 Species 2 Species 3 Species 4 Species 1

It can be deduced that Species A dominated the whole area in the quadrat compared to the rest of

the species. Species D, E, F, and G in 50% method doesn’t mean that there were no species being

observed. It only implies that the mentioned species did not reach 50% in all the subquadrats

since it was mixed and other species occupied the bigger space in the subquadrat (see Table 2).

The zonation diagrams below are constructed using the data collected for the zonation

and density estimation (see Appendix A).

Figure 3.1. Zonation diagram of plant species showing intercepted length covered by each plant (SIDE VIEW)

Figure 3.1 shows the zonation of each plant species in side view. It is depicted from the

figure that species 1 dominated the area. Species distance between 1-2 and 2-3 are quiet far from

each other.

Figure 3.2. Zonation diagram of plant species showing intercepted length covered by each plant (TOP VIEW)

Figure 3.2 is similar to Table 3.1 which shows the domination of species 1.

Species Density Relative

Density

Dominance Relative

Dominanc

e

Frequency Relative

Frequency

Importance

Value

A 2.3/m2 57.5% 0.66 66% 2 40% 163.5

B .9/m2 22.5% 0.17 17% 1 20% 59.5

C .5/m2 12.5% 0.07 7% 1 20% 39.5

D .3/m2 7.5% 0.1 10% 1 20% 37.5

Total 4/m2 100% 1 100% 5 100% 300

Table 3. Summary of data for density estimation

Based on the table above, it resulted that species A has the highest value compared to

the rest of the species. It can be clearly seen in the table that Species A has the highest density

estimation. In addition, the relative frequency of species B,C, and D is twice smaller that species

A. it can be inferred that Species A dominated in the sampling area selected.

Based on the collected data, it was computed using Simpson’s and Shannon-Weinner’s

indices for measuring diversity with the formula

D=∑i=1

R

Pi2 ; Where Pi is the proportion of each species out of the total number of

individuals recorded.

It was found that its diversity index is 0.48 which means that the species found were

diverse since it is quite far from 0 that means no diversity between the species. The species

richness of the area is 4.

CONCLUSION

This study uses two important sampling techniques, the Plot sampling and Transect

sampling. Plot sampling is very important in vegetation analysis. Using quadrats and transect

line, the species area curve, the cover and density of plant species were determined. The zonation

also of plant species were constructed showing intercepted length covered by each plant. Based

on the results, the smallest number of species found sing quadrat was 2 and the highest is 7. It

can be concluded that as the sampled area increases, the number of species found increases.

Thus, area is directly proportional to the number of species occurred.

In the cover and density estimation of vegetation, it was found that there is species

dominates the area being sampled compared to other species. Some of the species were comprise

only a very small amount of the area. This can be due to the competition of nutrient and other

factors of the different species.

The species in the area being conducted is diverse. Also, the species richness is directly

proportional to the area.

Errors are inevitable especially in the counting of species included in the quadrat so

careful counting must be taken in consideration.

APPENDIX

Raw data for Species Area Curve

Subquadrat Number of Species

1x1 2

2x2 2

3x3 2

4x4 3

5x5 3

6x6 4

7x7 5

8x8 6

9x9 7

10x10 7

Raw data for Subquadrat Estimation of top cover

Species 1st subquadrat (%)

2nd subquadrat (%)

3rd subquadrat (%)

4th subquadrat (%)

A 44 43 43 63

B 24 15 26 17

C 16 32 16 0

D 6 2 2 2

E 6 5 5 9

F 4 3 4 5

G 0 0 4 4

Raw data for density estimation

Species Number of Individuals Height (cm)

A 23 25

B 9 85

C 5 7

D 3 77

LITERATURE CITED

Aller, R. & Fidelibus M. (1993). Methods for Plant Sampling.

Semenoff, J. (2011). Grassland. 10.

Sutherland, W. J. (2006). Ecological Census Techniques: A Handbook. Cambridge University Press.

Williams, C. B., 1950. The application of the logarithmic series to the frequency of occurence of

plant species in quadrats. Journal of Ecology, 38: 107-138