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Ecosystem Services

It is August, the wettest month during the rainy season in Laos. The sky darkens and heavy rain showers hit the Annamite region in Central Lao. Animals and humans seek for shelter and hold out until the rainfall is over. The rain comes down in buckets - up to 10 litres of rain per square metre pour noisily on the dense canopy of lush tropical vegetation. Water is rolling off from leaves in droplets forming small waterfalls, tree trunks are dark and shiny from the constant stream of water and the air is fresh and pure. A part of the rainwater will evaporate soon, while another part already streams downhill as surface water into the nearest rivers and lakes, but the forest soil absorbs the major part of rainwater.

Roots of a tree. Source: Fotolia

Think of soil as a sponge. Sponges are cavity systems consisting of countless pores in different shapes and sizes.
They are able to soak and store water. Soil functions in the same way as it also consists of pores that can store water. Forest soil is penetrated by millions of root canals from plants and tunnels dug by animals which support the infiltration of water. The pores are connected with each other, so that the water can move through the soil. Due to gravity, drop after drop flows through the different soil layers until it reaches a groundwater reservoir. During this journey, the forest soil purifies and filters the rain water.
The purification happens through biological, chemical and mechanical processes. The soil pores work like a sieve and hold back small pollution particles. Humus, the dark organic matter that forms in the soil when plant and animal matter decays, and clay bind pollution particles chemically and bacteria, fungi and other microorganisms convert the pollutants into harmless substances. Groundwater is used as drinking water, for the irrigation of crops and it is also a source of recharge for rivers, lakes, wetlands from where the groundwater can flow into the oceans. There, the constant global water cycle of evaporation, cloud formation, precipitation, surface runoff, infiltration and groundwater formation starts again.
After the rain shower, the dark clouds lift and the sun peeks through again. Now, the process of photosynthesis begins. By using the process of photosynthesis plants produce their own food. Humans inhale oxygen and exhale carbon dioxide, but plants do the exact opposite. This is why forests are often called the “green lungs” of the earth. All leaves have small pores with which they can filter carbon dioxide from the air.
The rain water absorbed by soil and roots is now passed through the vessels in the stem to the tree tops where every single leave is provided with water and minerals. Chlorophyll, the chemical which gives leaves their green color, is able to absorb the sun’s energy.
The energy is used to split the molecules of water and carbon dioxide into hydrogen, oxygen and carbon. Results of this chemical process are oxygen and glucose.
Oxygen is just a byproduct of the photosynthesis and released by the leaves into the atmosphere. But glucose is valuable nutrition for plants which they use in various ways. Without plants the earth’s atmosphere would not contain any oxygen.
Our planet developed into a livable place for animals and humans over millions of years because of the plants ability to produce oxygen and to store carbon dioxide. Moreover, forests provide clean and fresh air by filtering out pollution particles. This is why protecting forests is crucial to human survival and to combat global warming.
The ability of soil and plants to provide clean water and clean air are called ecosystem services. Ecosys tems, such as forests, provide many different kinds of services and they are all for free. But if humans do not protect forests and their ecosystem services they will pay a high price because all life on earth depends on them.
Four types of ecosystem services can be distinguished: supporting, provisioning, regulating and cultural services. Supporting services such as nutrient cycles, soil formation and habitat provision are the most important ecosystem as all other services depend on them. Services such as provision of water, food, raw materials and medicinal plants belong to the provisioning category. Regulation services include waste decomposition, purification of water and air, pest and disease control, pollination and climate regulation. Cultural services refer to nature’s role in the cultural heritage of humankind, e.g. books, myth, religion and beliefs, paintings and national symbols. Moreover, nature is a place for recreation and spiritual experiences.
Ecosystem services are for free and often invisible to the eye, but that does not mean we can take them for granted. Only healthy and biodiverse ecosystem can provide all the services and goods humans all depend on.
This article has been contributed by ProCEEd (Promotion of Climate-related Environmental Education), a project supported by the Federal Republic of Germany and implemented by the Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH and the Department of Environmental Quality Promotion of the Ministry of Natural Resources and Environment of the Lao People’s Democratic Republic.

(Latest Update
May 18,2017 )

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