but the industry went into complete decline after the Enclosure Act of 1815
prevented free access to dunes.
Much more extensive changes to dune vegetation have been caused by the
grazing of domestic stock and rabbits (e.g., Ranwell 1960b; Plassmann et al.
2010). In terms of biodiversity, the levels of grazing intensity are critical.
Undergrazing can lead to rapid loss of species-rich grassland, while overgrazing
can eliminate sensitive, palatable species. Rabbit grazing, in particular, has played
a major role in shaping the sand dune community structure since they were
introduced, probably during the Roman Period some 2,000 years ago. The introduced disease myxomatosis decimated their numbers in the 1950s and this seems
to have been one of the factors that initiated dune stabilization. Changes in land
use, mainly abandonment of agricultural practices, have further exacerbated the
problem (Provoost et al. 2011). On the other hand, there is every possibility that
dune systems would be even more stable today in the absence of past human
activity (e.g., Hesp and Thom 1990).
8.5.3 Scrub Development
Scrub represents part of the natural succession on European dunes, often including
blackthorn (Prunus spinosa) and wild privet (Ligustrum vulgare), and these can be
important for certain bird species. However, there is now major concern regarding
the invasive spread of certain species, particularly sea-buckthorn (H. rhamnoides).
This species is not native to Wales, but has now become well established on a
number of dune systems, and has become particularly problematic at Merthyr
Mawr in South Wales. Over 52 ha have now been cleared at substantial cost. Much
of it was grubbed out using an excavator fitted with a weed rake, while herbicide
foliar spraying was used on smaller specimens. Several other sites have now been
identified as requiring intensive scrub control. Extensive scrub development can
severely restrict dune mobility.
8.6 Conservation Management and Restoration Strategies
8.6.1 Destabilization
A fully functioning dune ecosystem would normally include a range of successional
stages from pioneer, mobile dune vegetation and embryonic dune slacks through to
fixed dune grassland and possibly scrub and woodland on the landward perimeters.
This balance has now been lost on many dune systems with much of the early
successional vegetation confined to the seaward fringes. To restore this balance it is
now deemed necessary to introduce a degree of managed remobilization.
136
P. Rhind et al.
prevented free access to dunes.
Much more extensive changes to dune vegetation have been caused by the
grazing of domestic stock and rabbits (e.g., Ranwell 1960b; Plassmann et al.
2010). In terms of biodiversity, the levels of grazing intensity are critical.
Undergrazing can lead to rapid loss of species-rich grassland, while overgrazing
can eliminate sensitive, palatable species. Rabbit grazing, in particular, has played
a major role in shaping the sand dune community structure since they were
introduced, probably during the Roman Period some 2,000 years ago. The introduced disease myxomatosis decimated their numbers in the 1950s and this seems
to have been one of the factors that initiated dune stabilization. Changes in land
use, mainly abandonment of agricultural practices, have further exacerbated the
problem (Provoost et al. 2011). On the other hand, there is every possibility that
dune systems would be even more stable today in the absence of past human
activity (e.g., Hesp and Thom 1990).
8.5.3 Scrub Development
Scrub represents part of the natural succession on European dunes, often including
blackthorn (Prunus spinosa) and wild privet (Ligustrum vulgare), and these can be
important for certain bird species. However, there is now major concern regarding
the invasive spread of certain species, particularly sea-buckthorn (H. rhamnoides).
This species is not native to Wales, but has now become well established on a
number of dune systems, and has become particularly problematic at Merthyr
Mawr in South Wales. Over 52 ha have now been cleared at substantial cost. Much
of it was grubbed out using an excavator fitted with a weed rake, while herbicide
foliar spraying was used on smaller specimens. Several other sites have now been
identified as requiring intensive scrub control. Extensive scrub development can
severely restrict dune mobility.
8.6 Conservation Management and Restoration Strategies
8.6.1 Destabilization
A fully functioning dune ecosystem would normally include a range of successional
stages from pioneer, mobile dune vegetation and embryonic dune slacks through to
fixed dune grassland and possibly scrub and woodland on the landward perimeters.
This balance has now been lost on many dune systems with much of the early
successional vegetation confined to the seaward fringes. To restore this balance it is
now deemed necessary to introduce a degree of managed remobilization.
136
P. Rhind et al.