Presentation on theme: "Studland Sand Dune Succession The field work is carried out from the beach inland, crossing the dunes at right angles. The transect line is sighted using."— Presentation transcript:
Studland Sand Dune Succession The field work is carried out from the beach inland, crossing the dunes at right angles. The transect line is sighted using surveying poles and the tape measure marks the line of transect.
Studland Sand Dune Succession The gradometer is used to measure the slope angle of every metre along the transect line. The instrument is levelled using the attached spirit level and the slope angle is read off using the attached protractor.
Studland Sand Dune Succession The quadrat is a 50cm x 50cm square. The quadrat is placed alongside the tape every 5 metres; this is called a systematic sample as it is done at regular intervals This is at the start of the survey; notice the high proportion of bare sand.
Studland Sand Dune Succession At each sample point the vegetation is identified with reference to a plant identification book. Each plant species is noted and the Domin scale is used to give the percentage cover of each species.
Studland Sand Dune Succession The tape measure marks the transect line as it crosses the first ridge which is dominated by marram grass. The soils are immature, being mainly composed of sand.
Studland Sand Dune Succession The transect has crossed the first ridge of marram grass and, on its landward side, heather becomes the dominant species. The field-work equipment, namely the sighting poles, tape, gradometer and quadrat, can be clearly seen.
Studland Sand Dune Succession Between the first and second dune ridges is the slack. The slack is much lower than the dune ridges and the water table may reach the surface. The damper conditions give rise to a cover of shrubs and small trees.
Studland Sand Dune Succession The damper conditions of the slacks give rise to a distinctive flora. The honeydew is a special plant found under these conditions. Tiny insects are trapped by the sticky leaves and the plant feeds on these insects.
Studland Sand Dune Succession The transect line has crossed the first ridge and slack, the latter shown by the shrubs, and is about to ascend the second dune ridge. Soil samples are also collected systematically along the transect line.
Studland Sand Dune Succession Soil samples are taken every 20 metres along the line of transect. A trowel is used to dig out the soil from 100 mm below the surface. The samples are labelled and sealed in plastic bags to preserve the water content of the soil. This sample is almost pure sand.
Studland Sand Dune Succession In the foreground is the top of the second dune, characterised by heather and a little marram grass. Beyond the second ridge the dune slopes steeply down to the second slack. Here there is a dense vegetation of trees and shrubs.