5 threats to coastal sand dunes

5 threats to the stability of coastal sand dunes: Tourism activities; excessive grazing; invaded by other plants and animals; eroded when sea level rises; golf course, sand mining, placer.

Sustainable development of sand dunes requires proper understanding of its ecological law. These are the coastal areas rich in fine sand which are dry when the tide recedes, are heated by the sun, and have frequent strong winds of over 15 km / hour with sand dunes.

From the time of appearance to stability, sand dunes do not form a single form but form a row of alcohol parallel to the sea edge like sand waves. From the seaward edge of the land, you can meet a set of 5 rows of sand dunes with increasing stability, such as primitive alcohol - pepper alcohol - yellow alcohol - gray alcohol - mature alcohol. 5 rows of alcohol form a generation of sand dunes.

Painting of sand dunes.

Primitive spirits are small piles of sand lifted by the wind due to the presence of some kind of obstruction such as a piece of drifting wood stuck, dead seabirds, piles of seaweeds, wrecked wrecks ashore . Primitive spirits without plant residences, they can quickly disappear as well as quickly appear, until the first forms of grassy plants appear to fix them, turning them into alcohol for consumption.

The first species of plants that appear on the frontier are the herbaceous orchid species which are tough, salty, wind resistant and resistant to sand. They help the sand accumulate faster and the sand dunes also help to rise quickly to a height of about 5 m.

Yellow tincture appears after the body has accumulated much material and the first layer of humus on the surface of alcohol. Sand on alcohol is still slightly salty with mild alkaline pH with alkaline and alkaline earth accumulation, so it is often yellowish on the surface of alcohol .

The accumulation of plant humus makes the accumulation of nutrients and water vapor increase, making the vegetation on sand dunes more diverse. The height of yellow alcohol can reach 5 - 10m, plants can cover up to 80% of the area of ​​yellow alcohol. The first small reptiles and rodents also came to reside in yellow alcohols due to the abundance of plant food and moisture.

Gray dunes are the fourth generation of sand dunes, more stable and appear lower plants such as moss and lichen among shrubs, making vegetation cover on yellow alcohol can reach 100%. acreage. The clumps of shrubs appear to make the environment within a distance of 50-100m from the edge of the sea to become more favorable for the living world. Because the humus is accumulated into layers on the surface of the alcohol, the alcohol is gray, the pH gradually decreases, making the soil turn to sour.

Vegetation on diverse sand dunes.(Illustration)

The water that appears in the deep sand layer makes it possible for only plants with deep root roots to adapt. The height of gray sand dunes can reach 10 m.

Mature spirits appear hundreds of meters from the sea. Typical soil layers appear on the surface of the alcohol, resulting in the formation of woody vegetation and shrubs. This is also often the cultivation area of ​​the coastal population with the crop group that is usually timber trees, fruit trees and crops.

Between mature alcohols and gray alcohols, or alternating between mature alcohols, there are often oysters, which can be good quality fresh water, brackish water, even saltwater depending on the hydrological structure of the alcoholic region. The characteristics of these water bodies are a confined environment and often a favorable place for peat formation.

Coastal sand dunes are home to many small animals such as reptiles, rodents, insects, which are safe buffer zones between the sea and the mainland and are very vulnerable to human activities as well as to replace change the sea and climate dynamics regime.

A coastal area may have many generations of sand dunes appearing in different geological periods. The central coastal region of our country has 4 generations of sand dunes taken by the name of the sand, including: red sand dunes (oldest, only found in Ninh Thuan and Northern Binh Thuan), golden sand dunes, white sand dunes and gray gold sand dunes (youngest type). In Khanh Hoa, there are only 2 generations: white sand dunes and golden gray sand dunes in Dam Mon peninsula and Cam Ranh peninsula.

Coastal sand dunes are not only a field for coastal protection in low-lying coastal areas, they are also a unique ecosystem of coastal areas. Freshwater bags in sand dunes, natural tourist landscapes, many unique flora and fauna, land on mature sand dunes covered by plants are also fertile soil . are invaluable resources of sand dunes

There are 5 threats to the stability of coastal sand dunes, which are tourism activities that can lose vegetation cover, increase erosion and fire risk; Excessive grazing raises erosion, reduces biodiversity in alcoholic vegetation cover, especially grassland and animal manure, increasing the ability to enrich water bodies. In addition, sand dunes are easily encroached by other plant and animal species and are prone to erosion when sea level rises or is affected by storms. Agricultural activities, golf courses, road construction, sand mining, placer, shrimp farming on the sand, excessive pumping of groundwater . will also break the structure and stability of alcohol.

In recent years, the massive development of shrimp farming on sand dunes in many central provinces of Vietnam, the widespread exploitation of titanium mineral sand on coastal sand dunes has destroyed large sand dunes along the coast but natural But it took tens of thousands of years to create history.