The Diversity of 2 Fields No sheep Sheep

What we will study 1.Difference between the diversity of vegetation in the 2 fields 2.Differences between the invertebrate population diversity of the 2 fields 3.Differences between the population sizes of a specific invertebrate species of the 2 fields

Vegetation Sampling Two types: –Frame quadrat –Point quadrat Use mainly for plants and vegetation but can also be used for sedentary animal species Quadrats

Frame Quadrat Use for sampling: Percentage cover Population density

Point Quadrat Use for sampling: Frequency

Random sampling Needed to get rid of any bias in the results Method: 1.Divide the sample area into a grid 2. Use a random number tables to select the specific quadrats for sampling

Sample size Sample size (quadrat size) Number of species in sample

Number of samples Cumulative number of species Number of samples (quadrats)

Method: Mark-release-recapture 1. Capture a sample of individuals 2.Mark the captured individuals 3. Release the captured individuals 4. Allow time for re-integration 5. Capture a second sample of individuals Invertebrate sampling

Mark-release-recapture: Assumptions 1.Number of animals in a population does not change between the two samples 2.Marked animals are allowed to mix thoroughly with the population again when released 3.Marking does not affect the animal in any way

Pitfall trap

Total number of individuals captured in 2nd sample Mark-release-recapture Number of individuals in a population = Number of individuals marked and released in 1st sample x Total number of marked individuals in 2nd sample Based on the fact that the proportion of marked animals in the 2 nd sample is the same as the proportion of marked individuals in the population as a whole

No sheep

Sheep

Vegetation results for Sheep field

Vegetation results for No-Sheep field

Invertebrate diversity results

Species % cover Results for % Vegetation cover Sheep No-Sheep

Index of Diversity N = total number of organisms of all species present in a community n = total number of organisms of each individual species The resulting figure on its own is not very useful but allows for comparisons

54(54-1) 8(8-1) + 9(9-1) + 13(13-1) + 7(7-1) + 5(5-1) + 4(4-1) + 2(2-1) + 6(6-1) 2862 (8x7) + (9x8) + (13x12) + (7x6) + (5x4) + (4x3) + (2x1) + (6x5) d = Diversity for Sheep Field

Results for Invertebrate Species A Population Size Total population size (Sheep) = 34 x 28 4 = 238 Total population size (No-sheep) = = 37 x

Summary of findings 1.Vegetation diversity Field with sheep had fewer species of plant but had one or two dominant species 2.Invertebrate diversity The field with no sheep had a greater diversity of invertebrates than the field with sheep 3.Invertebrate Species A population size The field with no sheep had a much smaller population of invertebrate species A than the field with sheep