• Bias: purposely choosing sample sites to get ‘good results’ or avoid work.

• Too Few Sample Sites: may not give accurate representative results.

• Surveyor Variation: students vary in ability, commitment and interest.

• Equipment Quality: measurement and trapping success will be affected.

• Changing Nature: results may depend on the time of day, season or year.

• Chance: cannot survey every square centimetre so even with many sites some species may be missed.

• Improper Trapping Techniques: all evasive species may not be captured and/or insufficient numbers captured in follow up surveying.

Ecological Fieldwork: Principles and Practices

Grassland Habitat

Description of Habitat: General Map and/or Photographs taken at different seasons.

Climate: Cold Temperate Oceanic

Grassland Diversity of Living Organisms

• Kingdom Monera: bacteria - saprophytic, nitrogen fixing, nitrifying bacteria.

• Kingdom Fungi: yeast of leaves, common field mushroom.

• Kingdom Protoctista: Amoeba in damp soil, Pleurococcus on rock and tree bark.

• Plant Kingdom: grass, daisy, buttercup, dandelion, clover, bramble, oak, ash.

• Animal Kingdom: rabbit, fox, aphid, earthworm, sparrow, hawk, mouse, badger.

Microhabitats within the Grassland Habitat Soil, ditch, oak aerial system, hedgerow, stone wall, oak root system.

• A study to discover which species are present in the habitat.

• The study will also include absence of expected species.

• The unexpected presence or absence of species can indicate unusual environmental conditions.

• Identification keys, charts, books can be used to name species.

Quantitative Survey A study to measure the distribution, population, frequency or cover of a species.

Display of Results Graphs, histograms, bar charts, pie chart, flow charts and maps can give a much clearer report of the survey results than a long piece of prose.

Local Ecological Issues Related to the Grassland Habitat

• Bird and rabbit kills by local domestic cats.

• Exotic garden plants colonising the habitat.

• Fragmented distribution of daisies and buttercups due to recreational use.

• Increased sparrow population due to local bird feeders.

Mandatory Activities

Identification Using a Key

The field key below is a dichotomous key. It is a sequence of pairs of statements only one of a pair applies to the organism you to identify.

1      (a) Animal with backbone 2         (b) Animal without backbone 3

2.     (a) Covering of feathers 4         (b) Covering of hair 5

3.     (a) Tough hard outer body 6         (b) Soft body 7

4.     (a) Red feathers covering upper chest - Robin         (b) Large black and white - Magpie

5.     (a) Dog-like, long bushy tail - Fox         (b) Long ears, short white tail - Rabbit.

6.     (a) Three pairs of legs - Insect         (b) Four pairs of legs - Spider

7.     (a) Segmented body - Earthworm         (b) Unsegmented - Slug

Identification Steps for Spider: 1(b), 3 (a), 6 (b).

Description of Earthworm from Key: segmented body, soft, no backbone.

Conduct a Quantitative Survey of Plants, e.g., distribution of daisies

• Method: Line Transect (x3)

• Set a measuring tape straight across the habitat in the direction of change in an influential environmental factor e.g. soil water, pH, and nitrogen content.

• On a map of the habitat mark the trace of tape - this is a line transect.

• Walk beside the line and indicate, on the map, the position of each daisy plant touched by the line.

• Repeat the process twice more from other start positions.

• Combine the results to establish the daisy distribution.

• Relate the distribution to the variation of the environmental factors.

• A map is an appropriate mode for the display of the results.

Conduct a Quantitative Survey of Animals, e.g., fieldmouse population Day 1

• Capture field mice using small mammal traps.

• Record the number of captured mice e.g. 20.

• Mark each with a dab of red paint on the belly surface.

• Release each at their capture site.

• Allow time for the mice to readjust to normal conditions.

Day 2

• Capture field mice as before.

• Record the number captured e.g. 18.

• Record the number of recaptures (marked mice) e.g. 6.

• Return the mice to the habitat at their capture site.

Calculation:              Population      =        Day 1 Captures x Day 2 Captures                                                                        Number of Recaptures

= 20 x 18         6

= 60 mice

Change in population over a year is best displayed as a graph.

Determining the Frequency of a Plant Species

• Method: many random quadrats e.g. 100.

• Randomly pick quadrat sites within the habitat.

• At each quadrat record the plant species present.

• For each species record the number of quadrats is was found in.

• This number is its frequency if a hundred quadrats were used.

Frequency is the percentage occurrence of a species with a large sample of randomly chosen quadrats.

Suitable Quadrat Size: 1/4 m² (0.25 m² ).

Frequency is displayed clearly as a bar chart.

Determining the Percentage Cover of Sedentary Species

Textbook Diagram: pin-frame

• Method: pin-frame.

• Set out a straight transect line across the habitat.

• Place the pin-frame beside the line at the start.

• Push down each pin, to the ground, and record the species touched.

• Move the frame to the next half-metre and repeat.

• Record the total number of pins used.

• For each species record the number of ‘hits’.

• Calculation:                Percentage Cover = Number of ‘Hits’ x 100

                                                                          Total Number of Pins

Percentage cover is the proportion of ground screened or occupied by a species.

Percentage cover is distinctly presented as a pie chart or histogram.