Threats to biodiversity hotspots
Referring to examples, discuss the threats to biodiversity hotspots and why these threats could prove critical (15 marks) Biodiversity hotspots are areas in the natural environment that contain some of the biggest concentration of flora and fauna in the world, often containing many rare and endangered species. However many of these ecosystems are threatened by the likes of climate change, increased urbanisation/land use and tourism developments which can prove critical for the wellbeing of their environment.
One area that has witnessed degradation in recent years is Galapagos which is an example of a biodiversity hotspot that is threatened by alien species. This island off the coast of Ecuador is home to a huge range of these ‘alien species’ with up to 60% of the 180 endemic plants in Galapagos now considered under threat. There has been 490 introduced insect species on the island, and 43 species of other invertebrates – of these, 55 are high risk with the potential to cause severe damage to native biodiversity. New vertebrate species arrive every year and aggressive invasive species such as mainland snake predators could soon establish themselves in Galapagos.
The new alien species destroy the natural landscape of the environment, eating food that is only for the animals living within the ecosystem. This threatens biodiversity and could prove critical as the environment is being destroyed and species may also become extinct as a result of alien species. However, actions have been taken to preserve the unique biodiversity of the area, these include: eradicating rodents and feral cats and removing the quinine tree, which is one of the most serious alien plant invaders.
The Arctic is an example of a biodiversity hotspot under threat by global warming. The tundra, with its rare arctic plant ecosystem, will shrink as rising sea levels are drowning coastal areas. Increased forest fires and insect infestations are expected to destroy coniferous forests and therefore reduce both the biomass and the biodiversity. Global warming will also result in warmer sea temperatures, thus having negative implications on the sea life; the number of marine fish species will decline and reduce fish stocks as a result. Fragile food webs could become easily damaged leading to a loss of tundra mosses that provide food for animals such as reindeer.
Declining deer numbers will affect species that hunt for them, such as wolves and so this will lead to a domino effect, resulting in a decline of species within the food chain. Climate change can prove critical as what the Arctic is facing will also affect ecosystems much further south as many migrant bird species depend on summer feeding and breeding grounds in the Arctic. In the future, migrant birds will have to fly further north and spend more time searching for suitable feeding areas – therefore the threats to biodiversity hotspots are also effecting other nearby ecosystems.
Deforestation is also a highly critical threat to ecosystems as the clearance of forests results in the loss of biodiversity and resources for the indigenous populations. It will also have a negative knock-on effect on the food chain, as aforementioned. However there are also wider environmental impacts as the removal of forest cover leads to increased soil erosion which in turn increases the negative effects flooding.
Over exploitation of the environment puts bio diverse areas under threat such as overfishing in the North Sea, for example, unbalances food webs, which in turn, can lead to species become extinct. However the impacts can be reduced with relatively simple solutions such as creating hedgerows, ponds and shelter belts. Tourism can also be seen a threat and damaging ecosystems for example, trampling, increased urbanisation and pollution will threaten local ecosystems and could potentially prove critical in the long run. However because tourism often contributes highly towards the growth of the local economy (some even rely on it) it is difficult to use some of these solutions if they impair tourist activities or are visually polluting etc. Because tourism supports the local economy, such as providing more job opportunities for people in that area and preserving cultural heritage it is difficult to choose between maintaining an areas biodiversity and helping the locals to thrive.
Mangrove ecosystems are critical for marine and freshwater biodiversity, enabling fish, shrimp larvae and crabs to grow and produce. Shrimp farming in Thailand poses a large threat to mangroves, although it has been practiced in Thailand for over 60 years, between the 70’s and 90’s, the coastal shrimp aquaculture industry has expanded dramatically due to the encouragement of the Thai government in an effort to boost the economy. One of the impacts of shrimp farming is the discharge of waste into mangroves, which has harmful effects on the vegetation. Depletion of biodiversity in shrimp farms and their surrounding areas could also prove critical as combined with other threats such as over-harvesting, the number of mangroves could rapidly decrease.
The destruction of mangroves means the benefits of them cannot be used for example they cannot effectively act as a buffer, which would normally lessen the danger of hazards such as hurricanes and cyclones. It is questionable whether the typhoon in 2001’s devastating effects could have been lessened if mangroves were better intact. A knock on effect of this is the coastline will erode quicker due to having no barrier, the wearing away of the land and taking of sediments/rocks along with means houses are vulnerable to these kinds of hazards and could potentially have to re-locate.
In conclusion humans are having a constant and critical effect on biodiversity hotspots. However it can be argued that some are less critical and more easily manageable than others. For example global warming threats to the Arctic are harder to control for than using zoning strategies in Thailand.