Ecosystem Study

When conducting an ecosystem study it is important to follow procedures to ensure care of the ecosystem and accuracy of results. The following procedures should be followed for ecosystem studies:

1. Generate a map of the ecosystem/habitat site

There are two types of maps which should be created; Simple Map and Profile Map

• Simple - plan view, prepared using a baseline and measuring tape.
• Profile - prepared using metre sticks, a spirit level and a measuring tape.
• Mark in any distinctive physical features e.g. streams, trees, ponds, rock, paths etc. Show scale.

2. Identify plants and animals

Use an expert, pocket guide or a key and follow the countryside code.

• Only collect organisms if it is absolutely necessary and you cannot identify them in the field.
• Return organisms to the habitat if possible.
• Leave the habitat as you found it.
• Beware of dangers such as deep water, thorns, stinging insects.

Having identified plants and animals:

• Draw and label 5 plants and 5 animals.
• Study one in detail – include the way in which the organism gets its food (mode of nutrition). Draw the reproductive parts of a flower and the method of pollination.
• The habitat of each of the 10 organisms should be identified on the original map.

3. Estimate numbers of plants and animals

• A qualitative study records the presence or absence of species.
• A quantitative study measures the number of each species.
  • Subjective – a personal judgement as to the number (not recommended as it may vary from person to person)
  • Objective – an independent method of calculating numbers is used.

Objective quantitative studies

• Quadrats:
  • Allows for the approximate calculation of % cover of plants or stationary animals (use % area covered in each quadrat or use a graduated quadrat) 
  • Frequency - the likelihood of finding a named species with any one throw of the quadrat e.g. slugs found in 4 out of 16 gives a frequency of 4/16 x 100 = 25 %. This method is fast and easy. However, it is dependent on organism and quadrat size and presumes that organisms are evenly distributed throughout habitat.
     
• Transects:
  • Line transect  (rope marked at intervals – record what touches the line and measure environmental conditions at each).
  • Belt transect – take quadrats in a line.
     
• Capture – recapture method:
  • Assumptions:
    • Marking must not harm the animals e.g. make it more visible to predator
    • Animals are dispersed evenly in the habitat (not bunched e.g. colonies of ants)
    • Animals are restricted to local area
    • Marked animals must be given time to integrate with the unmarked population

4. Measure the environmental (abiotic) factors

Three abiotic factors are measured (e.g. see table below). Results should be related to the choice of habitat selected by each organism (10) identified in the study.

Aspect can affect the following:

• Temperature (thermometer) - if south-facing it will receive more sun – warmer and brighter and therefore flowers will flower earlier than north-facing slopes.
• Wind (anemometer & wind gauge) - Plants grow better on sheltered side.

Soil pH can determine growth of specific species e.g.:

• Acidic soil allows mountain ash, gorse, holly, birch to grow
• Neutral/basic soil allows hawthorn, ash, blackthorn, elder to grow

Light intensity can affect the following:

• Light – increases the number of flowering plants
• Shade e.g. under laurel shrubs - ivy
• Organisms show many adaptations that allow them to survive in their habitat.

5. Analysis & Presentation of results:

• Use tables, lists, charts, graphs, diagrams, histograms.
• Include food chains, food webs, pyramid of numbers (identify the role of the organism in energy transfer).
• Identify local ecological issues related to the woods.
• Produce peport
• Note potential sources of errors in an ecosystem:
  • Human error - from mistakes in measuring (judgement) or recording.
  • Changing conditions, both natural e.g. seasonal: autumn – summer, or artificial e.g. pollution.
  • Accidental discoveries may be recorded – e.g. rare animal (bird of prey) may be present on a rare occasion or at night (owl) or shy animal discovered by quiet walker and not all members of a group.
  • Sample size - habitats studied may not accurately reflect the overall ecosystem if the habitat is too small to include all animals and plants or if only a few habitats are studied.
  • Quadrats are limited by the size of species (trees too large, animals moving too fast) (The Physics Teacher, 2018)

When analysing and presenting results, organism adaptations to their habitat may be structural, competitive or behavioural.

When reporting results, it is also important to include the types of organisms and vegetation found in the habitat, common invertebrate species found in the habitat and predator species to those invertebrates (see below table)