4
many human activities which threat dragonfly populations.
Also, dragonflies, both in their nymph and adult stages,
are fiercely predatory. Consequently, the general
decline in insect populations which has taken place in
recent years because of widespread habitat destruction
and the use of insecticides has also affected dragon-
fly populations adversely.
The other side of the picture is that there is increasing
public awareness of the value of ponds and other water
resources for wildlife, and new reservoirs and flooded
gravel-pits have provided many new habitats, especially
in Essex. But the different dragonfly species have
different habitat requirements and so these changes
benefit only some species. Some, such as the well-
known 'banded agrion' damselfly tend to prefer unpolluted
flowing water, whilst others, such as the medium-sized
pale blue 'darter' dragonfly, the 'keeled Orthetrum'
(Orthetrum cancellatum), seem to specially favour
newly flooded sand and gravel pits. Others, such as
the 'blue-tailed damselfly' (Ischnura elegans) and
the large, brown-bodied, 'brown hawker' dragonfly
(Aeshna grandis) seem to be able to adapt to a very
wide range of habitats, including quite polluted water-
ways. The most favourable habitats, though, tend to
be shallow ponds or pits, in sheltered situations,
surrounded by rich emergent and marginal vegatation,
and not too closely over-shadowed by trees and shrubs.
A surrounding area of insect-rich, dry-land habitats
such as heath or woodlands is also an advantage.
Fingringhoe Wick Nature Reserve, in North East Essex,
is one of the best such habitats in Essex, with thirteen
species so far identified in the vicinity of Kitt's
pond. The Chelmer-Blackwater Canal, Epping Forest,
and Hatfield Forest also provide habitats for many
species of dragonflies.
The order Odonata, to which dragonflies belong,
includes both dragonflies, in the strict sense, and the
smaller, more delicate damselflies. The dragonflies
(Anisoptera) are the larger, more robust species, and
are conventionally sub-divided into two groups. The