The bar charts below illustrate the
distribution of individual plant species along the North/South 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
It is possible to see this broad pattern in the charts
of all the species below, except Alder.
The optimum zone for Rhododendron is in the dry land
area. As standing water appears in the wetland, the Rhododendron dies out and Soft Rush
takes its place. The Soft Rush is very dominant in this region, with a very high % cover.
Wood Clubrush, Reedmace and Marsh Bedstraw all occupy
the same general area in the marsh, where water depths are low. However it can be seen
that Wood Clubrush is more dominant and covers a much greater area than the other two
species (the red bars are much taller).
Environmental conditions in the different zones 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 (Alder). This can make it difficult to pick out any
particular pattern of distribution.