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Good
reptile habitat consists of a varied vegetation structure and
south or south-easterly aspect. Preferred sites include hillsides,
banks, slopes and wet areas or semi permanent ponds with tussocky
grassland, bramble, bracken, gorse or, occasionally in
Herefordshire, heather. Small groups of young trees such as silver
birch, elder, or juniper reduce wind chill and create a
microclimate.
Early
in the spring collapsed dead bracken stands and bramble provide
cover and thermo regulation sites for newly emerged species such
as adder and viviparous lizard. Without a good height of sward
reptiles are vulnerable to predation from birds and mammals.
Hibernacula on hills or slopes will be situated out of the damp
and frost, under thick bramble, in mammal burrows, root systems,
or earthworks. These are essential to the wellbeing of a reptile
population; especially the grass snake and adder who tend to use
the same hibernacula each year. Their loss, either intentionally
or accidentally, will result in population decline. Therefore,
before any management for reptiles is planned, it is of the utmost
importance to locate the hibernacula or aggregation areas.
Reptiles, and in particular adders,
can be found in aggregations in spring on emergence, and in late
summer/early autumn when preparing for winter hibernation. At
these times any slopes and hillsides with a south facing aspect
should not be cut with machinery. Work parties or the rotational
cutting of small areas are preferable to the complete eradication
of bracken, but some cutting is needed to prevent the bracken from
taking over and shading a site in the late summer months. Thick
secondary tree growth and neglect on site also leads to shading
out and results in diminishing reptile populations. During winter
the scrub can be cut and the brash turned into refugia piles.
Placed in sunny areas these provide attractive refuge and basking
areas for reptiles. Also grass and vegetation cuttings can be
turned into attractive heaps for grass snakes and slow-worms.
Grazing by horses, cattle or sheep
is good for reptile sites, breaking up bracken, and opening areas
to the sun, but high stock density is detrimental. Overgrazing
will strip an area of reptile cover and the disturbance caused by
large numbers of stock can lead to a rapid decline in reptile
numbers. The use of “flying flocks” of sheep, which are brought
on to a site to graze only when required, prevents overgrazing.
Temporary exclusion fencing is another way of stopping damage to
sensitive areas.
A recent publication, Status of
the Adder Vipera berus, and the slow-worm Anguis fragilis, in
England (English Nature 2004 publication No. 546 John Baker,
James Suckling & Ruth Carey), states that habitat management is
the factor most frequently impacting on adder and slow-worm
populations. In spite of reports of individual sites being
harmed, habitat management or creation was regarded as a positive
factor at more than 40% of adder, and 50% of slow-worm sites.
Most adder populations in the Midlands are relatively low. A third
of adder and a quarter of slow-worm populations consist of fewer
than ten adults, so any drastic habitat management could result in
the loss or decline of fragile populations.
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Cut scrub built
into big piles |
Good
habitat management: cutting in strips leaving varying
vegetation |
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