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Abandoned fish boat in sand hill |
Sand hill scene at coast
Guishan is located at southwest of Shanglin. This region of the coast belongs to sandy seashore, due to transportation and sediments carried from southwest seasonal wind and constant tides.
‘@‘@Normally, costal sand hills are usually developed at estuary or slow-flow curvy banks of a river. Sand hill of Guishan is more suitable for the later. Formation of coastal sand hill has four fundamental elementas:
1. enough supply of sands
2. enough support fo carry sands
3. stable slopes or banks
4. suitable location for sendiments
‘@‘@Furthermore, vegetatives, tides, wind direction, costal flow, rainfall, and human are all possible influences to this formation.
Sand Hill : By transportation of nature, sands are accumulated slowly. In an early stage, it is called an embryonic type sand hill. There are usually strong marks of wind direction on the sand hill, therefore some experts can tell the direction of seasonal wind by the shape of sand hills. The plants that can grow on the sand hills are saddle vine and other grass and vegetables that have an effect on keeping sands. Usually, sand hills are formed in front of or surrounding a windbreak.
Sand hills are poor at keeping water, therefore the plants are usually covered by sands. Plants growing here require less water, resistant to salts, and stays low and crawling at windless side of hills. It is rare to find organisms that live in sand hills. Ant-lion can be found in sandy places, and is the major consumer in the sand hill ecological system.
As sea wind blows up sands constantly, sands do not always stay in one place. Therefore, formation of sand hill scene and sand hill vegetatives are in a dependent mutualism relationship. Seashore Vegetable is resistant to dry and salty condition and coverage by sands. Its roots grows in all directions. However, whenever it stablizes itself in sands, it can stablize surrounding sands and keep growing out of surface. This way, it can intercept more blown sands. Vegetative and sand hill grows in the same rate. When sand hill is about half a metre high, Seashore Spiky wheat comes along. This plant is even more resistant to wind and dry condition, and eventually will take over the position of Seashore Vegetable. This sand hill will then become bigger and higher.
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