The bar charts below illustrate the
distribution of individual plant species along the East/West Belt Transect. The red bars
represent the % cover of the plant species in each 1m quadrat along the line. This shows
where each species occurred on the line, as well as how much of it there was at each
point. The vertical scale is the same for each bar chart. The blue bars in the charts
represent the water depth, with maximum depth being 65cm.
These bar charts can be directly related to the plant zonation diagrams produced as part of the line transect
results. The species colours are co-ordinated between the diagrams and these charts.
Comparison of the two illustrates the difference in the type of results obtained using
line and belt transect methods.
Most species will have an optimum zone within their
range where the environmental conditions are best suited to their growth. In the diagrams
below, this zone will be indicated by the area where the species reaches its maximum %
cover. The percentage cover will often tail off gradually to either side of the optimum
None of the species below illustrate this pattern. This
is because the bulk of the transect crossed the marsh zone. Environmental conditions,
particularly in the marsh zone, are extremely variable locally, as are the water depths.
The water depths marked were correct at the time of the survey but they will of course
vary with the amount of water entering the wetland from rainfall and run-off. This means
that there may be several optimum places for a species in a particular zone. This can make
it difficult to pick out any particular pattern of distribution.
However, it is clear from the charts that both Water
Plantain and Greater Spearwort grow best where the water is deeper. Water Plantain is not
very dominant (the red bars are short) and grows best in shallower water than the
Wood Clubrush, Marsh Bedstraw and Water Mint are all
distributed widely along the transect with little discernible pattern. They all die out as
water depths begin to increase substantially. Wood Clubrush is the most dominant of the
three (it has the tallest red bars), whereas Marsh Bedstraw is the least dominant (the
shortest red bars).
Yellow Iris has a somewhat narrower range, but has a
similar dominance to Wood Clubrush.