Characteristics: Include climate, animals, vegetation and soil.
The tropical grassland biome is located between 5 and 10 degrees north and south of the equator. It appears as a transitional state between equatorial forest and desert, with mainly scattered shrubs and isolated trees on the open savannah. The climate is hot year round with two distinct seasons, the wet and dry season. The winter wet season lasts for only 1-2 months where precipitation>evaporation and is around 1200mm. The temperatures on the grassland equatorial biome fringes are 22 degrees in the wet season and 28 degrees in the dry season, and on the desert grassland fringes 18 degrees in the wet season and 32 degrees in the dry season. The ITCZ (inter tropical convergence zone) is created by intense heating of the sun overhead causing the rising and cooling of air forming clouds when water droplets coalesce at the dew point. Cumulo nimbus clouds forms and convection is created. The dry season is dominated by high pressure systems and trade winds generated by the compression heating of air at 30 degrees north and returning towards the equator.
The soil conditions are created by the seasonal rains. During the wet season precipitation is in excess and there is a surplus of water which is leached into the soil carrying with it nutrients promoting growth. The growth season as a result is very short. Silica is also leached downwards and chemical weathering of the bedrock occurs as dissolved C02 forms weak carbonic acid along with the dissolved minerals. During the dry season evaporation exceeds precipitation so salts are returned to the surface forming a concrete-like literate layer which if broken exposes the crumbly earth below to erosion forming deep gullies. The thin litter layer which is susceptible to erosion or destruction by fires prevents root systems drying out in the intense sun by forming a protective layer. The soil has a distinct red colour as a result of the insoluble oxides of aluminium and iron, which is higher up than for example in the deciduous woodland biome due to the absence of a larger litter layer and higher precipitation.
Adaptations of vegetation and animals
Animals and vegetation are adapted to the 2 distinct seasons on the Savannah grasslands. The animals are therefore migratory and typically have long legs or wings in order to travel large distances. These include Zebra, many species of deer, rhino, wilder beast, elephant, carnivores such as lions, cheetahs and leopards and decomposers. Elephants have adaptations for example to cope with the high temperatures for much of the year; their large ears provide a surface area from which to lose heat. Decomposers also play a vital role in the ecosystem as they transfer nutrients from decaying animals and plants back into the soil (nitrogen cycle) which promotes growth. This is especially important as the plants are the primary producers that effectively support the entire ecosystem.
Vegetation is also adapted to cope with the two very different seasons. Grasses grow in tufts in order to protect root systems as well as form a protective layer during the dry season by losing their leaves – deciduous. They have xerophytic adaptations such as small thin or spine leaves such as the umbrella thorn and elephant grass.
Trees also grow where more moisture is available but are usually sparse especially on the desert margin. The Baobab tree has a wide trunk – up to 10m wide in order to conserve water, as well as fire resistant bark to protect against bush fires as well as those started by humans. The acacia tree also has fire resistant bark and a deep root system enabling it to grow in clusters, unlike the baobab which has a wider root system reducing the competition of other plants around it.Human activity and its impact
Human Impacts
The tropical grassland biome is a fragile ecosystem home to many endangered species and is therefore difficult to restore to its natural beauty if disturbed. There are many human activities which threaten the longevity of the ecosystem and centre around different interest groups such as the indigenous Masai, tourists, locals, conservationists and the Tanzanian government. The main threats to the ecosystem are Poaching, Population growth, poverty and small scale agricultural techniques such as burning.
Poaching is a major issue in the Serengeti ecosystem part of the tropical grassland biome. Despite stringent laws restricting poaching around 40000 animals are killed every year; these include mainly wilder-beasts but also zebra and gazelle. This is a problem as poaching causes humans to encroach on natural habitats causing damage to grazing pastures, foraging grounds and migratory corridors. This also brings invasive species into the park, reduces biodiversity and traps unwanted animals that may be endangered.
Another issue is population growth; the rural areas around the national park in recent years have experienced high population growth due to pull factors such as water availability, food availability through illegal poaching and natural minerals such as gold. Along with this has seen an increase in poverty as much of rural Tanzania is. This is an issue as pressure on land has caused the boundaries of the Park to be realigned 3 times in the last 20 years, reducing the original parks size by 15%. Overgrazing also damages natural grazing pastures and causes soil erosion leading to the soil becoming infertile. This is especially true with poverty stricken areas where poor access to mechanised agriculture has led to poor practices
Development is another major issue which threatens the sustainability of the ecosystem. Although it has been suggested as potential way forward to relive poverty, activities such as tourism and economic development have the potential to highly damage the park. Such as the airport in the western Serengeti and game hunting lodge run by the American company Grumeti. A new road system linking Amsha and Musama has the potential to damage a narrow migratory corridor used by wilder-beasts on the way to lake Victoria, by the increase in poaching caused by better access and introduction of new/invasive species as well as noise and air pollution.
Further issues are that of the annual burning of grassland areas at the end of the dry season, which promotes growth of young shoots. Although this does benefit both farmers and natural wildlife by providing grazing pasture, and the fires are quite well contained they do however, kill and young trees in the area not yet fire –resistant. This if done in the same areas annually can produce a uniform environment and doesn't provide all stages needed for different animals to feed off of such as trees ( fed on by giraffes).Contrasting management schemes of two biomes: Savannah grassland, Equatorial rainforest.
Contrasting Management Schemes
The tropical grassland biome and equatorial rainforest biomes are fragile environments which have considerable human threats to their ecosystem. These threats include population growth, poverty, poaching (40000+killed/year) and development in the Serengeti national park. In the equatorial rainforest biome the Amazon rainforest is under significant threat from population growth (drought in NE migration encouraged) and large scale developments including HEP (Belo Monte dam in the Amazon region 3rd largest scheme of its kind in the world), Mining (the largest iron ore extraction plant is located in Amazonia) and one of the largest threats is deforestation which has caused the destruction of vast quantities of the forest and most likely the extinction of many animals and plants along with it.
As a result a zoning system has been developed in the Central Amazonian conservation complex which lies in an isolated part of the forest in the river Negro water basin (a tributary of the river Amazon). The complex covers an area of 6 million hectares (2nd largest area of protected rainforest). There are zones which have varying levels of development allowed in them. The first is the primitive zone which has the largest area of natural beauty where no development of any kind takes place. The second zone is known as the Special use zone where services which work towards the protection of the primitive (and other zones) are located. The last zone is the Marimua sustainable development zone which is open to some development by locals only as all commercial exploitation of the forest is banned. This zone is managed by a variety of groups including the locals, government, commercial industry operators and representatives from the mining and logging industry and conversationalists. The scheme has helped to protect the forest but also increase its productivity in a sustainable way (especially in the MSDZ).
In contrast to this scheme the protection of the Serengeti ecosystem is done on a much smaller scale and involving actions of locals taking smaller steps to achieve sustainable development and reduce threats to the ecosystem. The park is designated as a UNESCO world heritage. The management has consisted of working with locals to maintain a co-operative approach to the issue of poaching. Previous ‘top down’ approaches were ineffective as locals believed they had a right to use the park (much or rural Tanzania is poverty stricken).The authorities view has changed to work with locals as they are key in ensuring the sustainability of the ecosystem. Some controlled and licensed poaching is allowed which also helps to control population numbers to keep in balance with resources and gives some unprotected areas outside the park more protection (though less poaching). Population growth is being managed thought education; there are 75 ‘conservation clubs’ at local schools and trips to the park for both children and adults to see what conservation can achieve first hand. Poverty is another threat that is managed by using sustainable economic development such as taking advantage of traditional practices of basket weaving and honey production to achieve economic growth (as opposed to large scale development which damage the ecosystem). Some villages have also become centres for tourists. Development is being addressed by promoting eco-tourism where possible. The management strategies developed are vastly different due to the scale of the measures involved. The Serengeti ecosystem management focuses on local development to alleviate underlying problems of poverty and population growth, whereas the equatorial rainforests focuses on minimising the exploitation of the rainforest for economic gain.Development issues relating to: Biodiversity and sustainability.
Potential for sustainability
The tropical Grassland biomes potential for sustainability lies in the ability of conflicting groups who have different interests in the park to come to a compromise. With the issue of poaching the park authorities have realised the importance of working with local people to ensure the longevity of the ecosystem and changes their view on poaching to a more co=operative approach. The local people must benefit from the park as well in order to for the conservation measures to be effective. Therefore controlled and licensed hunting is allowed to take place which benefits locals as well as protecting areas outside the parks boundary. It is also important in keeping the population of animals such as wilder beast and zebra in balance with the resources available. To reduce the impact population growth has on the parks ecosystem there have been measures such as raising awareness though education. 74 schools have ‘conservation clubs’ and the park hold regular visits for both adults and children to increase awareness and show what conservation can do first hand. Local people are also involved in land use planning and local policies. Population growth and poverty is being managed so to reduce poverty through sustainable methods as opposed to large scale development which may damage the ecosystem. Sustainable tourism is a suggested way forward with locals using traditional products such as basket weaving and honey production a viable economic activities, some local settlements have even become tourist hubs within themselves.
To reach the full potential of sustainable development around the Serengeti ecosystem other measures must also be upheld, such as making population growth part of the conservation policy and increase awareness on a global scale. Factors accounting for differences in biodiversity on a global scale.
Biodiversity
The main factor influencing biodiversity is climate, and secondary influence is soil type, the differences between the tropical grassland biome and equatorial rainforest biome as a result are:
Biodiversity is directly in-proportional to the limiting factor. In extreme environments the climate is the limiting factor (e.g Artic tundra and Sahara desert. Human limiting factors can be seen in the deciduous woodland biome e.g. agriculture and the tropical rainforest biomoe (Amazonia) e.g. mining, deforestation, HEPand lastly in the Serengeti ecosystem e.g. population, poverty, poaching, development, Malaysia - deforestation.
Further reading :The need for biodiversity in pharmaceutical industry (cure could possibly be extinct) - The value of this industry e.g. Costa Rica receives 2% of royalties made from 20% of its products, Madagascan periwinkle ingredient in cancer drug vincritinie – no profits from this exploitation (more from coffee and banana exports) – If the country doesn’t benefit why would it work towards protecting biodiversity.
- NPP energy, precipitation, growing season, litter layer, decomposers, growth rate, (species in one area), (adaptations to cool climate)
- (2 seasons)(Adaptations)(Populations depend on ITCZ rain
- Soil type similarities
- Extreme environments (global scale)
- Impact of human activity (deciduous not allot left) (pressures in biomes)Why we should be concerned about biodiversity (global scale)
Biodiversity is directly in-proportional to the limiting factor. In extreme environments the climate is the limiting factor (e.g Artic tundra and Sahara desert. Human limiting factors can be seen in the deciduous woodland biome e.g. agriculture and the tropical rainforest biomoe (Amazonia) e.g. mining, deforestation, HEPand lastly in the Serengeti ecosystem e.g. population, poverty, poaching, development, Malaysia - deforestation.
Further reading :The need for biodiversity in pharmaceutical industry (cure could possibly be extinct) - The value of this industry e.g. Costa Rica receives 2% of royalties made from 20% of its products, Madagascan periwinkle ingredient in cancer drug vincritinie – no profits from this exploitation (more from coffee and banana exports) – If the country doesn’t benefit why would it work towards protecting biodiversity.
