DSC-152: Section-A (Ecology and Ecosystems)

Practical 1: To study the allelopathic influence of plant species

Objective

To investigate the inhibitory (or stimulatory) effect of an extract from one plant species (the allelopathic plant) on the seed germination and seedling growth of another plant species (the target plant).

Materials

• Allelopathic plant: Leaves/stems of a known allelopathic plant (e.g., *Parthenium hysterophorus*, *Lantana camara*, Eucalyptus, Walnut).
• Target seeds: Easily germinating seeds (e.g., mustard, wheat, green gram).
• Petri dishes, filter paper, mortar and pestle (or blender), distilled water, measuring cylinder, weighing balance.

Procedure

1. Prepare the Extract:
   • Weigh 100g of fresh leaves of the allelopathic plant.
   • Grind them with 100 mL of distilled water using a mortar and pestle.
   • Filter the slurry through muslin cloth. This is the 100% concentration "stock solution".
2. Prepare Dilutions: Prepare different concentrations from the stock solution, e.g., 50%, 25%, 10%, and 0% (control, using only distilled water).
3. Setup Petri Dishes:
   • Line 5 petri dishes for each concentration (including control) with filter paper.
   • Place 10-20 target seeds in each dish.
   • Moisten the filter paper with the corresponding extract concentration (e.g., 5 mL).
4. Incubation: Keep the dishes in a dark place at room temperature for 3-7 days. Keep the filter paper moist.
5. Data Collection: After the incubation period, record:
   1. Germination Percentage: (Number of seeds germinated / Total seeds) × 100
   2. Seedling Growth: Measure the length of the radicle (root) and plumule (shoot) for each germinated seed.

Observation Table

Conclusion

Compare the germination % and seedling lengths of the treatments to the control. A significant reduction indicates a negative allelopathic (inhibitory) effect. Note if the effect is dose-dependent (i.e., inhibition increases with concentration).

Practical 2: To prepare a checklist of invasive species

Objective

To survey a designated area (e.g., college campus, local park, wetland) and prepare a list of invasive plant species present.

Materials

• Field notebook and pen
• Camera (or smartphone)
• Field guide for local flora, or plant identification apps
• List of known invasive species in your region (from government or research websites)

Procedure

1. Select Study Area: Choose an area for your survey. Disturbed areas like roadsides, wastelands, or water bodies are often hotspots for invasion.
2. Survey Method: Walk through the area systematically. You can use a "random walk" method or lay transects for a more structured survey.
3. Identify and Record:
   • When you encounter a plant, try to identify it using the field guide or app.
   • Take clear photos of the flower, leaf, and whole plant (habit).
   • Note down its name (scientific and common) and characteristics (e.g., herb, shrub, climber).
4. Prepare Checklist: Back from the field, cross-reference your list of identified species with the official list of invasive species for your region.

Observation Table (Checklist)

Practical 3: To study the plankton communities in a fresh water ecosystem

Objective

To collect, observe, and identify the common phytoplankton and zooplankton in a freshwater sample.

Materials

• Plankton net (with fine mesh, e.g., 50-70 µm)
• Sample collection bottle (attached to the net)
• Rope
• Sample storage bottle
• Preservative (e.g., Lugol's iodine or 4% formalin)
• Microscope, glass slides, coverslips, dropper
• Plankton identification charts/keys

Procedure

1. Collection:
   • Visit a freshwater body (pond, lake).
   • Throw the plankton net into the water and tow it slowly (horizontally or vertically) for several minutes.
   • This filters a large volume of water, concentrating the plankton in the collection bottle at the end of the net.
2. Preservation: Transfer the concentrated sample into a storage bottle. Add a few drops of Lugol's iodine. This kills, preserves, and stains the plankton (staining starch in algae).
3. Observation:
   • In the lab, shake the sample bottle gently.
   • Take one drop of the sample using a dropper and place it on a clean glass slide.
   • Gently place a coverslip over the drop.
   • Observe under the microscope, starting with low power (10x) and moving to high power (40x).
   • Use the identification keys to identify the different types of plankton.

Observation

Draw diagrams of the plankton you observe. Label them as Phytoplankton or Zooplankton and try to identify their genus.

• Common Phytoplankton: *Spirogyra*, *Volvox*, *Diatoms* (e.g., *Navicula*), *Closterium*, *Oscillatoria*.
• Common Zooplankton: *Daphnia* (water flea), *Cyclops*, *Rotifers* (e.g., *Brachionus*), *Amoeba*, *Paramecium*.

Practical 4: To study the road side species

Objective

To identify and list the common plant species growing along a roadside and note their adaptive features.

Materials

• Field notebook and pen
• Quadrat (e.g., 1m x 1m) - *Optional, for quantitative study*
• Measuring tape
• Plant identification guide

Procedure

1. Select Site: Choose a stretch of roadside.
2. Survey: Walk along the roadside and identify all plant species present from the edge of the road outwards (e.g., 0-2 meters).
3. Record: For each species, record its name and any visible adaptive characteristics.
   • *Optional Quantitative Method:* Place quadrats at regular intervals (e.g., every 5 meters) and count the number of individuals of each species within the quadrat to determine frequency and density.

Observation Table

Practical 5: Field report: Visit to a forest/ river/ wetland ecosystem

Objective

To visit a designated ecosystem (forest, river, or wetland), systematically record observations, and compile them into a formal field report.

Structure of a Field Report

Your final report should follow this standard scientific format:

1. Title Page: Title of the report, your name, course name, date, and location of visit.
2. Introduction:
   • State the objective of the field visit.
   • Describe the study area (location, geography, climate).
   • Mention the date and time of the visit.
3. Methodology:
   • Describe how you collected your data.
   • (e.g., "Visual encounter surveys," "Quadrat sampling," "Water sample collection," "Interviews with locals").
4. Observations and Results:
   • This is the main body of the report. Organize it logically.
   • Abiotic Components: Describe the non-living factors (e.g., soil type, air temperature, water turbidity, sunlight).
   • Biotic Components (Flora & Fauna): List the major plants and animals you identified.
     • For a forest: Note the different layers (canopy, understory, forest floor).
     • For a river: Note bank vegetation, aquatic plants, fish, insects.
     • For a wetland: Note emergent plants (like reeds), floating plants, and aquatic birds.
   • Ecosystem Structure: Describe food webs, species interactions (e.g., pollination, predation), and any signs of human impact (pollution, deforestation, conservation efforts).
5. Discussion:
   • Interpret your observations. Why is the ecosystem structured this way?
   • Connect your findings to ecological concepts learned in class.
   • Discuss the importance of the ecosystem and any threats it faces.
6. Conclusion: Briefly summarize your main findings and the key takeaways from the visit.
7. References (if any): List any field guides or sources you used.