An
ecological survey provides a snapshot outline view of what a particular area was like at
the time of surveying. The purpose of the ecological surveys presented here is two-fold:
- To document any
differences between the vegetation of differently managed sections of the project site.
- To observe how each
section has changed from one year to the next.
These changes will have
been brought about as a direct result of the management regimes being used on the project
site, as well as by the environmental conditions which have been prevalent over the
preceding year(s).
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In the initial stages of the restoration experiment when plants
first began to colonize the newly bare site, the most important factor influencing the
development of the vegetation was the process of natural succession. Section 5 (left, in 2005) is the control section and has
had no management at all since the experiment began in 1993. This section shows clearly
what would have happened over the whole site if natural succession had been allowed to
take place unhindered.
(Find out more about
succession here) |
In the
other sections which are brushcut at certain times of
year, natural succession to woodland was effectively halted as soon as the cutting
regimes were initiated in1995/96. What then remained was the unending competition (battle
for space and resources) between the colonizing plants which were able to withstand
the brushcutting regimes.
The balance of 'power'
(dominance) between individual plants in each of the sections is constantly changing,
depending on both the external management and fluctuating environmental conditions. For
example, a lengthy, summer drought will have a much more negative impact on grasses than
on heathers, which are adapted to withstand such conditions. Such a drought would give
heathers the opportunity to increase their dominance on the site at the expense of the
grasses. Factors such as weather, microclimate, nutrient status and physical
condition of the soil, insects and other animals selectively feeding on the plants,
may influence the whole project site equally, or only some parts of it.
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Brushcutting at a particular season may have an adverse effect on
some species (e.g. Bluebells - left) and it may then take them all year to recover
(if indeed they do recover) giving other species a chance to dominate in the meantime. |
The
different management regimes applied to each section apart from the control section, are a
constant factor. The same management is applied to all of the vegetation within each
section, each year. One can therefore say with confidence that a very great
proportion of the observed differences between sections is a direct result of
the type of management applied.
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Common sense also tells us this because one only has to look at
the sections to see that they are different and that the visible differences follow the
boundaries of the sections. Indeed, the boundary markers are in many cases no longer
necessary to define each section. |
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Differences in vegetation have led to corresponding
differences in the animal life in each section, despite the fact that there are no
boundaries to animal movement. Different plant architecture means that certain spiders are found
in some sections and not in others. The spider Agelena labyrinthica (left) occurs only in those sections
which have become most like heathland. (The vegetation elsewhere is less suitable for the
attachments of its funnel-shaped web.) |
Grasshoppers
abound in the more grassy sections and different butterflies selectively visit different
sections in search of particular flowers and caterpillar food plants for egg laying. Although the ecological surveys were only documenting vegetation on the
project site, some data has been gathered on the fauna of the project site and this will
be published at a later date
To summarize, the
different management methods used on the project site are having a profound impact on the
composition of the vegetation in the differently managed sections. These differences are
now clearly visible at a glance.
The ecological surveys
document these increasing differences in detail and show how the site has changed since
the initiation of the experiment. Data acquired over a long time span will allow the
more directional changes in vegetation resulting from the effects of the constant
management, to be picked out from any fluctuations caused by variations
in environmental conditions.
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