Grassland Quadrat Sampling

and Physico-chemical Biological factors of Lake

Grassland• Grassland- terrestrial biome consisting

mainly of grasses and few trees and shrubs.

• Quadrat- a square or rectangular plot that encloses the sample

• Species Area curve- a method used to determine the size of the quadrat

• Species richness- refers to the abundance of the species

• Species evenness- equal distribution of the species in a given area.

Species-Area Curve• graph of relationship between number of

species (richness) and area sampled

• Use to determine the size of the the quadrat

• Important in determining the diversity of the area.

• applications– determine adequate community area– estimate sampling adequacy (no. of

Community)– Compare the biodiversity (different

species in an ecosystem

1 m2

4 m2

32 m2

64 m2

Species Area Curve

2 m2

8 m2

16 m2

Species-Area Curve

0

10

20

30

40

0 10 20 30 40 50 60 70

Quadrat Area (m2)

Nu

mb

er

of

Sp

ec

ies

(R

ich

ne

ss

)

Quadrat Parameters• Frequency-the frequency of quadrats

occupied by a given species

number of quadrats in which species occurs

• Frequency (F) = ---------------------------------------------------------- X 100

Total number of quadrats

frequency of a species

Rel. Frequency (RF)= -------------------------------------------- X 100

total frequency of all species

Quadrat Parameters• Abundance- compares the number of plants

of that species with the total number of plants of all species in the study area:

number of plants of a certain species • Abundance (A) = ------------------------------------------------------- X 100

Total number of plants

Quadrat Parameters• Density-closely related to abundance but

more useful in estimating the importance of a species is the density. It is defined as the number of plants of a certain species per unit area:

number of plants of a certain species

• Density (D) = --------------------------------------------------------------- X 100

Total area sampled

density of a species

• Relative density (RD)= -------------------------------------------- x 100

total density for all species

Quadrat Parameters• Cover-the proportion of the total area occupied by

the species.

-also commonly called dominance:

Total area covered by a species

Cover (C) = --------------------------------------------------------- X 100

Total area sampled

• Relative cover, like relative frequency and relative density, gives a better indication of the importance of a species than does the absolute value:

cover for a species

• Relative Cover (RC) = -------------------------------------------- X 100

Total cover for all species

• Since it is considered as a grassland the most abundant is the grass e.g. carabao grass, lemon grass

• Least abundant is the weeds e.g. Mimosa Makahiya

• Importance Value- is used to determine the most abundant species by adding the relative values.

Lake Physico-chemical Factors

Definition of Terms

• Lake- a lentic freshwater ecosystem

• Limnetic- refers to the water present in the lake

• Benthic- refers to the bottom or floor of the aquatic ecosystem

• Riparian- the edge of the lake; the boundary of the aquatic and terrestrial ecoystem

Limnetic Zone• Parts of the limnetic zone

1. Epilimnion- upper layer of water where light can penetrate. Also known as photic zone

2. hypolimnion- lower layer of water where light cannot penetrate. Also known as aphotic zone

3. metalimnion- the boundary between the photic and aphotic zone. Also known as the compensation depth.

Benthic Zone• Parts of the benthic zone

1. Littoral zone- portion covered with water and light reaches the substratum.

2. riparian zone- similar with supralittoral

3. benthos- refers to the organisms present in the benthic zone.

4. profundal zone- lower portion of the aphotic zone rich in organic materials.

Light Penetration

• Secchi Disc- the instrument use in measuring the light penetration.

Average light Penetration = disappearance + reappearance

2

Percent Light Penetration = Average Light Penetration x 100

• Total depth

• Epilimnion- photosynthesis will take place; dissolved oxygen (DO) is abundant.

• Hypolimnion- respiration will take place; rich in CO2

• Metalimnion- equal amount of DO and CO2; also known as thermocline

Thermal Stratification• The varying temperature of the strata of lake water.

• Thermal inversion-the overturn of water due to changing temperature of the water layer.

•

• Warm water will rise while cold water sinks.

• What is the importance of thermal stratification and overturn?– Food distribution due to overturn

Total Suspended Solid• Small particles present in the water like silt,

plankton, etc.

• Procedure: pre-weighed filter paper filtering the suspended solids then air dried and weigh the filter paper again.

• TSS= Weight of Air dried filter paper- pre-weight of filter paper.

• Importance: affects the light penetration, temperature and photosynthesis in the epilimnion

Salinity, TDS and Conductivity

• Instrument used salinometer or SCT meter

• Salinity- amount of salts present in the water.

• TDS- total dissolved solids- the elements present in the water e.g. Ca, Magnesium etc.

• Conductivity- determines the ions present in the water.

• Importance- the elements, compounds and ions are the source of minerals needed by plants and animals in the water.

Dissolved Oxygen

• Instrument : DO meter

• The amount of oxygen traps by the molecules of water

• Produced by the atmospheric diffusion and photosynthesis of plants.

• Higher in epilimnion than hypolimnion.

• Importance: used by organisms in respiration; resulted to fish kill if there is deficiency of DO.

Nitrogen, Phosphorus, and Hardness

• Instrument used: Hach test strips

• Nitrogen- building structures of organisms e.g. component of protein. Derived from decomposing organic materials, fixed by nitrogen fixing bacteria and fertilizers

• Phosphorus- used in synthesis of ATP. Derived from decomposing organic materials, leaching of rocks and fertilizers.

• Hardness-amount of Ca, Mg and other metallic elements in the water. Originated from decomposing organic materials, leaching of rocks

pH• Amount of hydronium ions in the water.

• Low pH means acidic which is caused by nonmetallic oxide dissolved in water e.g. NO2, NO3, SO2, SO3 ,CO2

• Acidic lake reduced the DO and characteristic of eutrophic lake.

Aquatic Organisms• Plankton-floating organisms

1. Phytoplankton- floating microscopic plants

2. Zooplankton-poor swimming animals

Plankton Total count= Actual Count x Enumeration Factor

Enumeration Factor= 1000 mm3____

(50 mm) (1 mm) (1mm) (3)

Nekton- swimming organisms e.g fish

Benthos- organism present in the floor of the lake

Phytoplankton

Zooplankton

Achomosphaera Achomosphaera Adnatosphaeridium Alisocysta neptuni ramulifera multispinosum margarita

Hydrophytes

• - large aquatic plants classified as:

1. submergent- plants attached to the substrate and remained under the water.

2. emergent plants- plants attached to the substrate but emerged above the water.

3. Floating plants- plants living on the surface of the water

4. periphyton- plants attached on the surface of the rocks

5. riparian plants- plants living on the edge of the lake.