To Study Plant Population Density And Frequency By Quadrat Method Pdf
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- 3. How to measure: Measuring vegetation characteristics per area
- Theory & Procedure, Study of Plant Population Frequency by Quadrat Method NEET Notes | EduRev
Although simple in principle, biomass measurements are tricky in practice. The basic technique for measuring biomass is the harvest method: Simply remove biomass, dry it in an oven to remove water, and weigh it. Because the water content of plants can vary dramatically day to day, even hour to hour, drying to get "dry weight" is a more stable measure of biomass than is fresh weight.
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The percentage frequency should be calculated and entered in the practical observation and record note book. Examiner need not consider this experiment for Board Practical Examinations. To study population density and percentage frequency of different plant species of a given area by quadrat method. The number of individuals in a population never remains constant. It may increase or decrease due to many factors like birth rate, death rate, migration, etc. The number of individuals of a species presents per unit area or space of a given time is called population density.
A quadrat is typically a square frame constructed of plastic or pvc pipe, metal rod, or wood that is placed directly on top of the vegetation. Quadrats are also commonly called "plots. Quadrats do not have to be square but their area must be known. Other quadrat shapes commonly include circles and rectangles. Square quadrats can be any size. Common sizes include: 25 by 25 cm, 50 by 50 cm, 1 by 1 m and similar sizes in feet.
The goal of most rstoation and revegetation projects is to recreate the plant cover, distribution, and species compostion of the site prior to disturbance, or of a comparable less disturbed reference site. Accurate data on community compostion is desirable for the planning and evaluation of these projects. The selection of sample site can be based typical sites releve , random samples, systematic samples in a regular pattern, or by a combination of random and systematic selection Greig-Smith, Although the releve method uses subjective choice of sample locations, the process of recording data is relatively rapid and nonmathmatical. Systematic and random methods, which are commonly used in the United States, are more conductive to statistical analysis. In the field, random sampling may be much less convenient than systematic sampling, but the regular sampling of a population showing periodic variation would not bvbe representative of a population as a whole Eberhardt and Thomas, The selection of an appropriate sampling technique depends upon the type of data needed, the size of the sampling site and the number of available workers.
3. How to measure: Measuring vegetation characteristics per area
A population is a group of individuals of the same species which inhabit a particular space at a particular time. The number of individuals in a population never remains constant. It may increase or decrease due to many factors like birth rate, death rate and migration. The number of individuals of the species in any unit area at a given time is its population density. The unit area may be as small as 5 square centimeters to as large as 10 square metres, depending on the size and nature of the plant community under study.
Theory & Procedure, Study of Plant Population Frequency by Quadrat Method NEET Notes | EduRev
In ecology it is useful to know the frequency of certain plant species in a certain place, or at a certain time. Frequency can be defined as the degree of uniformity of the occurrence of individuals of a species within a plant community. However, finding the frequency of plant species is very difficult for a large populations or extensive habitats. A widely used method for plant frequency sampling is by quadrat method.
Scientists study population size and density using a variety of field sampling methods, including quadrats and mark-recapture. Population size and density are the two most important statistics scientists use to describe and understand populations. Its density is the number of individuals within a given area or volume. These data allow scientists to model the fluctuations of a population over time.
A.2. Quadrat Sampling Method
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