Sand dunes at Oxwich bay Essay
Oxwich bay is located in the south if Wales, and is one of the many and sand – dune complexes in Wales.
Most sand dune areas have a fragile ecosystem so they area generally given special protection rights. Oxwich bay is no exception and it has been made in to a National Nature Reserve.
Sand dunes are formed by longshore drift. Oxwich bay I no different from the way it was formed. Originally it was formed as a spit but as the sediment continued to build, dunes were eventually formed. This was not a quick process as it took million of years for the sand dunes to form from the original bay. Even though it did take millions of years for the sand dune to form they are still relatively shallow at only about 10 metres in height. The dune is also only a meagre 3.5 metres wide. This overall does not give a large physical feature.
This dune is also in a state of dynamic equilibrium. This mean it is in a constant state of change and it is not an unusual feature of and dunes. In Oxwich bay these changes show themselves as
1. The quantity of sand decreasing as one goes further west.
2. The height of the dune decreasing as one goes further west.
3. The amount of recreational use increasing as one goes further west.
The last point shows dunes are very popular for recreational use. Oxwich bay is no different in this matter and has many visitors each year.
All dunes are comprised of different sections. These are the
* Embryonic dune
* Fore dune
* Mobile yellow dune
* Fixed grey dune
* Dune slack
* Blow out dune
The dune that is the first permanent structural dune is the mobile yellow dune. This is 30 metres in height with only 20% of the sand it is comprised of exposed. This is the third stage of development for sand dunes. These sand dunes can increase in temperature and on a hot day the sand can reach up to temperatures of about 60’c. As this dune id one of the next stages the ecosystem develops. As the area is still not as stable as it will prove itself to be further down on the sand dune. As it is now only certain types of grass will grow as they are the only ones capable of adapting to the dune. The diagram below gives the grasses.
Sand sedge Sea holly
These grasses are especially adapted to this environment as they have long roots so they are able to take up water from lower down. As this area of the dune can get very warm it is useful that the leaves are flat and shiny so they do not loss too much water through evapo-transpiration.
The sand dunes face a few problems. While many would like to protect the land there is a large clash with the wish to use the land for recreational uses. One of the main human uses of the sand dune in Oxwich bay is by visitors. These people may have visited as student or simply to admire the scenery. There are over 300 000 visitors per year which include about 10 000 student studying the area.
While this encourages education of sand dunes, it can cause some area of the sand dune to be ruined. This is especially important as Oxwich bay contains at least half of Wales’ endangered species such as roughly 500 flowering plants, 160 birds, 270 beetles, 530 moths. This shows the variety of species in this delicate area.
All these visitors then lead to problems such as those explained below.
Erosion Caused by visitors trampling as they walk about the area.
Sand extraction Done to stabilize the area.
Water extraction Perhaps to remove water tables so there was more and available.
Development in nearby areas So that visitors may have somewhere to stay and other facilities.
Litter This war left behind by visitors.
Other problems were problems such as scrub and bracken invasion. This occurs when there is no management at all.
All of these problems make it important that there is some sort of management. This was in the form of different protective ideas. Below is a table describing them.
Adding more sand to the coast by creating groyne
Shaping the dune by moving material
Fencing the area to avoid erosion
Controlling the number of visitors
Maintaining and encouraging species diversity
Education about the dunes
Preserving the areas
Removing the more rare species
Separating the land into clearer regions
Creating more nature reserves
These are suggestion a to what could be done but personally I would create more restriction rather than modifying the area as I believe it is more important to protect the land than to use it for recreational uses. Perhaps another sand dune could be used a sacrificial site for educational purpose. This would mean that people would not lose out on all the aspect of the dune have to offer but there would also not be o much of a temptation to cause damage to certain areas. Though there may be other side effect such as a loss in tourism in that area and the inconvenience of having to travel further if on of the dunes I not near you, I still believe that the disadvantages are minor compared to the greater benefit.