8.7 Conclusions
Dune systems in Wales are clearly on a path of increasing stability and current
management prescriptions, such as recently introduced grazing, are failing to arrest
this change. It is assumed that some of the key drivers of this change, such as climate
change, raised levels of N deposition and raised CO 2 will continue to favor increased
biomass production. The recorded build-up of organic matter in the soil will reduce
the likelihood of dunes becoming more mobile and increase the need for anthropogenic intervention to both sustain current levels of mobility and to possibly return to
even greater levels of mobility on some key sites. The impact of sea level rise in the
short term is unlikely to induce substantial mobility, while in the long term its impact
on stability is dependent on a wide variety of factors, such as changes to long shore
drift associated with sea defenses and changing wave exposure associated with
bathymetric changes, making accurate predictions problematic.
Work to date has failed to quantify the relative contribution of different
mechanisms driving stabilization, such as enhanced nutrient inputs or modified
sediment transfer associated with climatic or sediment source issues. However,
0
20
40
60
80
100
120
0
1
2
3
4
5
6
7
Sand depth (cm)
%LOI, Block 1
Pre-ploughing
Post-ploughing
0
20
40
60
80
100
120
0
1
2
3
4
5
6
7
Sand depth (cm)
%LOI, Block 2
Pre-ploughing
Post-ploughing
0
20
40
60
80
100
120
6
6.5
7
7.5
8
8.5
Sand depth (cm)
pH (H 2 O), Block 1
Pre-ploughing
Post-ploughing
0
20
40
60
80
100
120
6
6.5
7
7.5
8
8.5
Sand depth (cm)
pH (H 2 O), Block 2
Pre-ploughing
Post-ploughing
(a)
(b)
(c)
(d)
Fig. 8.6 Soil parameters with depth pre-ploughing (gray diamonds) and 1 month post-ploughing
(black squares), showing Block 1 on left-hand side, Block 2 on the right-hand side respectively
for: a, b Organic matter content (%LOI), c, d soil pH (measured in de-ionized water). Bars show
±1 s.e. Adapted from Jones et al. (2010b)
8 The Impact of Dune Stabilization
139
Dune systems in Wales are clearly on a path of increasing stability and current
management prescriptions, such as recently introduced grazing, are failing to arrest
this change. It is assumed that some of the key drivers of this change, such as climate
change, raised levels of N deposition and raised CO 2 will continue to favor increased
biomass production. The recorded build-up of organic matter in the soil will reduce
the likelihood of dunes becoming more mobile and increase the need for anthropogenic intervention to both sustain current levels of mobility and to possibly return to
even greater levels of mobility on some key sites. The impact of sea level rise in the
short term is unlikely to induce substantial mobility, while in the long term its impact
on stability is dependent on a wide variety of factors, such as changes to long shore
drift associated with sea defenses and changing wave exposure associated with
bathymetric changes, making accurate predictions problematic.
Work to date has failed to quantify the relative contribution of different
mechanisms driving stabilization, such as enhanced nutrient inputs or modified
sediment transfer associated with climatic or sediment source issues. However,
0
20
40
60
80
100
120
0
1
2
3
4
5
6
7
Sand depth (cm)
%LOI, Block 1
Pre-ploughing
Post-ploughing
0
20
40
60
80
100
120
0
1
2
3
4
5
6
7
Sand depth (cm)
%LOI, Block 2
Pre-ploughing
Post-ploughing
0
20
40
60
80
100
120
6
6.5
7
7.5
8
8.5
Sand depth (cm)
pH (H 2 O), Block 1
Pre-ploughing
Post-ploughing
0
20
40
60
80
100
120
6
6.5
7
7.5
8
8.5
Sand depth (cm)
pH (H 2 O), Block 2
Pre-ploughing
Post-ploughing
(a)
(b)
(c)
(d)
Fig. 8.6 Soil parameters with depth pre-ploughing (gray diamonds) and 1 month post-ploughing
(black squares), showing Block 1 on left-hand side, Block 2 on the right-hand side respectively
for: a, b Organic matter content (%LOI), c, d soil pH (measured in de-ionized water). Bars show
±1 s.e. Adapted from Jones et al. (2010b)
8 The Impact of Dune Stabilization
139