The Anthropogenic Impacts On Biodiversity Environmental Sciences Essay

Introduction

‘Anthropocentrism’ or being ‘Anthropogenic’ in nature refers to the way of thinking that regards humans as the source of all value and is predominantly concerned with human interests. (Carter, N, 2003, p. 14) Biodiversity is the abundance of different species and ecosystems in nature making it the earth’s most valuable resource. Biodiversity is of very much importance as it boosts the productivity of the ecosystem where each species, no matter how small, all have an important role to play. In other words, there would be no population of humans without biodiversity but the irony is that, the biodiversity is decreasing at an alarming rate due to the various human activities which is also referred as the “biodiversity crisis.”

The three main factors impacting the biodiversity as a whole may be listed as: population growth, overconsumption and technology. This essay will describe how and where the biodiversity has been impacted at very great extents because of the above mentioned factors.

Population growth of the humans can be considered as the root of the problem of the loss of ‘biodiversity’. According to Ehrlich (The Population Bomb, 1968 as cited in Cahn, A and O’Brien, R, 1996), the human population has been doubling every 37 years and if this continued for the next 900 years, then the world population will be nothing less than sixty million billion people implying that there will be about 100 persons for each square yard of the Earth’s surface, land and sea. The human population now is at 6 billion; with an annual global growth rate of 1.8%, three more people that are added to the earth every second. (Quebec biodiversity, 1994) The simple fact that the countries are not able to feed their populations shows that they are overpopulated. With such high rates of increase in human inhabitants, the problem of the need to convert the natural habitats to land for human consumption becomes obvious. This ultimately results in five primary processes of degradation namely: over harvesting, habitat fragmentation, habitat destruction, alien species introduction and pollution. (Biodiversity and Human Health, 2001) It is the anthropogenic nature of the humans to rule the environment by spreading to new habitats in order to find newer food sources. The innovative man has always been discovering various types of technologies right from the technology of the ‘spear and arrow’ to the modern technology of ‘the harpoon, gun-powder and the drift nets’ helping him to over harvest on the various species. According to the Fisheries Agency, Japan consumes about 60,000 tons of fish a year, mainly the three blue fin tuna species which is more than 75% of the world’s annual catch and also other countries, such as the U.S. and Russia, are catching up with the Japanese as a result of which the blue fin tuna has been becoming very hard to find and the prices for these species have hit the extremes. (Tuna Shortage in Japan, 2007) Apart from overconsumption, humans have also been demonstrating their anthropogenic nature by wasteful ‘mass kills’ where the entire herds of some species are slaughtered. A classic example of this is the “Dumfries fish killing festival” of Scotland where individuals have been killing fish in the ‘Galloway’s River Urr’ as a part of the ‘Grande Internationale World Flounder Tramping Championships’ where the person who captures the most number of fish by the unorthodox method of treading on the fish is awarded by giving three bottles of whisky, £150 and also the title of ‘The Undisputed Champion Of The World. (Facebook, 2010) Also the ‘Denmark’s Gruesome Festival of mass killing dolphins and whales to prove adulthood’, where nearly 1,000 whales and dolphins are killed annually. (Think about it, 2009) This clearly shows the man’s exploitation of the natural resources exceeding their cycling capacity. Natural resources are classified as renewable and non-renewable resources. Forests and wild-life are considered as renewable resources because of their ability to regenerate by reproduction but the rate at which humans have been utilizing the so called natural resources is very much of a concern. The extensive use of forest lands for timber and other valued wood resources has resulted in the loss of habitats for hundreds of species. And with the increase in human inhabitants arises the need to convert natural habitats to land for more human consumption. The innovative man has been able to exploit the forests and its resources for his selfish needs with the use of new machines and better means of transport. Clearing a dense forest has become much easier now. Humans have been able to sustain their growth by converting natural habitats to fields where food can be produced. At least 23 percent of the earth’s land is being used for agriculture. Most tropical forests were not greatly disturbed in the past mostly because of their inaccessibility and other factors but now the trend has been changing with the increase in the demand for the various raw materials used in plastic production. Tropical forests have been disappearing rapidly as a result of the need of the humans to make room for more farms of timber used for construction and also used as a fuel. Deforestation has alarming global consequences such as: extinction of species (plants and animals) and climate change. Although the tropical forests cover only about 7 percent of the Earth’s dry land, they are home to half of all the species on Earth. Many species have micro-habitats or in simple terms, they are present only in those small areas in these forests and due to this their extinction is very much at stake because of the deforestation here. The edges of the deforested fragments dry out because of incoming hot winds as a result of which the matured rain forest trees die standing at the margins and eventually the biodiversity is lost. This also has a devastating effect on the tropical soils as the soil cover in the tropical rain forests is very thin and with deforestation, over time all the minerals in the soil are lost because of the high temperatures and heavy rains. (Deforestation in the Amazon, 2010)

 

(Tropical Deforestation, 2007)

 

(Deforestation in the Amazon, 2010)

A large portion of deforestation in Brazil has been primarily because of land being cleared for pastureland by commercial and speculative interests. Between May 2000 and August 2006, Brazil lost nearly 150,000 km2 of forest and over 600,000 km2 of Amazon rainforest has been destroyed. About 60-70 percent of deforestation in the Amazon results from cattle ranches and the want for palm oil while the rest mostly results from small-scale agriculture. The numbers of endangered species in the forests of Brazil have been increasing at alarming rates because of the various anthropogenic activities of the humans as reported by the Associated Press. (Mongabay website, 2010) Deforestation and fragmentation is increasing at an alarming rate in Amazon. In Amazon nearly 2 million ha of land is deforested annually (Fearnside et al. 2005). Habitat fragmentation is a serious threat to species persistence in tropical forests (Ewers & Didham 2006). According to Wilcox and Murphy (1985), the effects of fragmentation are loss of original habitats, creation of edge effects, and isolation of habitat patches and this will affect the species composition. According to Turner and Corbett (1996), forest patches are further affected by invasion of further plant and animal species, and increased human exploitation such as hunting, burning, grazing, and extraction of resources. The greatest human impact in Southwest Australia has been the clearing of native vegetation for agriculture. Forest fragmentation differentially affects seed dispersal of large and small-seeded tropical trees (Cramer et al. 2007) Due to fragmentation, not only are individual species are affected but the plant- animal interactions are also affected (Andresen and Levey, 2004). In tropical regions, fragmentation affects the dispersal of large seeds to a greater extent than the small seed. Cramer et al. (2007), studied the seed dispersal of two Amazonian tree species, the large-seeded, mammal dispersed Duckeodendron cestroides and the small-seeded, avian dispersed Bocageopsis multiflora. The percentage, distance and distributions of Duckeodendron cestroides seeds were all reduced in fragments when compared to Bocageopsis multiflora. This is supported by facts such as, large – seeded plant species are prone to extinction, fragmentation affects large animal’s dispersers than small animal dispersers; and large and small seeded plants are linked differentially to primary and secondary habitats (Cramer et al. 2007). Large animals are for needed for dispersal of large seeds, and these animals need large home range but are affected by edge effects caused by fragmentation and also due to hunting. Primates are often absent from fragments (Gilbert and Setz, 2001). From Meehan et al. (2002), it is known that the extinction of frugivorous pigeons in Tonga (Polynesia) left 18 large-seeded plant species with no dispersers. From the work of Babweteera et al., (2007), the loss of elephants in Ugandan forests has left ‘Balanites Wilsoniana’ regeneration concentrated under parent plants and is greatly affected. Bush fires have been used for hunting and clearing land here. Although native plants are highly adaptive to fires, intensified burning changes the composition and condition of the natural vegetation. This has resulted in the spread of a root disease called “jarrah dieback” caused by the root fungus called ‘Phytophthora cinnamomi’ which has been spreading to other habitats, particularly in the ‘Stirling Range National Park’, where it has caused the loss of plants like the ‘Banksias’. (Conservation International, 2007) The tiger population in India is declining so fast that the whole population may be extinct here in the next 10 years because of deforestation and poaching. (Animal of the Day, 2010) In the forests of Armenia, habitat loss poses a particular threat to a range of species. Many species have been threatened to extinction because of the increasing use of land for agriculture. (National Report, 2002) The forests in Succulent Karoo have been affected badly by the diamond mining carried out in these areas. Approximately two-thirds of the South African coastline and almost the complete Namibian coastline have been mined for diamonds and other minerals like gypsum, marble, monazite, kaolin and titanium threatens the region’s biodiversity. (Conservation International, 2007) Destruction of habitats for requirements such as building of canals, dams and houses is the most important threat to biodiversity. The ‘Aswan High Dam’ located in Egypt, is an example for habitat destruction where the environmental side effects of the project have been disastrous with the spread of the disease called, ‘schistosomiasis’ which is spread by snails living in the irrigation channels here. (Quarterdeck, 1995)

A major contributor to depletion and extinction, after habitat loss, is the introduction of alien species. Man has always tried to introduce animals and plants familiar to him where ever he is. It started with the goats and pigs for familiar animal protein. These alien species damage the flora and fauna of the local area where they are introduced. The spread of these alien species replaces healthy, diverse ecosystems with biologically weak landscapes. Prior to the arrival of humans, there were a range of species of birds, invertebrates and plants in Hawaii but with the introduction of many plant and animal alien species, more than half the bird species and also many species of snails have become extinct. (Biodiversity and Human Health, 2001) Rabbits being introduced into Australia, Asian fish species put into the waters of Florida, introduction of Africanized bees into Brazil and also the introduction of rhododendrons into England are few examples of alien species that have destroyed the local plant and animal species. It is estimated that about 4,000 plant and 2,300 animal alien species are present in the United States at this time resulting in the endangering of more than 42% of the animal and plant species here. (Biodiversity Web, 2005) Also in the Nile river, despite the presence of a wide variety of fish, the region’s fishing industries struggled to grow because the fish that lived there were small-bodied and bony, not the kind they wanted thereby, there was a need for a larger and a more commercially desired fish for the fishing economy to grow. They introduced the fish species called the Nile perch, ‘Lates niloticus’. It grew far larger than many of the other Nile fish, and was perfect for commercial fishing purposes. Being carnivorous, the Nile perch made the smaller native fish its prey. As the population of the Nile perch grew, the populations of the other 150-200 of the native species have vanished entirely. Introduction of foreign species has had similar impacts in other waterways worldwide by making the simplified ecosystems unstable indefinitely. (Human Impacts on the Nile River, 2010)

ArcGIS map examining modern day fish biodiversity.

(Human Impacts on the Nile River, 2010)

Climate change has significant impacts on ecosystems. It is predicted to be the greatest long-term threat to biodiversity in many regions and is listed as a key threatening process under the Threatened Species Conservation Act 1995 and the Environment Protection and Biodiversity Conservation Act 1999 (Commonwealth). The various technological developments made by man giving him an upper hand over other species come only at a price and this price is undoubtedly ‘pollution’. The use of various fossil fuels, petrochemicals and many other heavy metals has been increasing the greenhouse gas emissions. The drastic increase in the emission of green house gases has resulted in global warming and thereby causing a sea level rise and ultimately leading to melting. The oceans are being acidified due to the tremendous increase of the carbon content in the atmosphere which leads to the loss of biodiversity.  (Biodiversity Web, 2005)

(Global Issues, Climate Change and Global Warming Introduction, 2010)

(Global Issues, Climate Change and Global Warming Introduction, 2010)

The quantity of oceanic plankton on earth is being affected by the depleting ozone layer. The tiny organisms that float in the oceans are known as ‘planktons’ and they play a vital role in maintaining the marine biodiversity as they are major sources of food here. Therefore, a decrease in quantity will cause a domino effect in the marine food chain species which is dangerous for the marine plant and animal species. Even though there have been global warming instances in the past, the rate at which the temperature has been increasing now is what is alarming.

(Global Issues, Climate Change and Global Warming Introduction, 2010)

Strategies adopted by humans to mitigate these impacts:

Educational programmes are being introduced by governments to educate the populations on the importance of biodiversity. One such educational programme was initiated in the 1990s by the US Congress where they had set up an environmental education office to promote environmental education at all levels. The ‘Plant Conservation Alliance’ and the ‘U.S. Fish and Wildlife Service’ were the partners to the U.S government. In 2002, the UK along with all other Parties to the UN Convention on Biological Diversity (CBD), made a commitment “to achieve by 2010 a significant reduction of the current rate of biodiversity loss at the global, regional and national level as a contribution to poverty alleviation and to the benefit of all life on earth.” This commitment was subsequently endorsed by world leaders at the World Summit on Sustainable Development. At its meeting in Gothenburg in 2001 the European Council agreed to halt biodiversity decline with the aim of reaching this objective by 2010. The 2010 biodiversity target has become incorporated into the Millennium Development Goals (MDGs) – as one of the targets under MDG 7 (Ensure environmental sustainability). (Natural Environment Research Council, 2007)

The concept of ‘protected areas’ has been introduced for the conservation of the biodiversity. These are locations which receive protection by the enabling laws of each country or rules of international organizations. They include parks, reserves and wildlife sanctuaries and they also ‘Marine Protected Areas’ whose boundaries include some area of ocean. There are over 147,000 protected areas in the world with more added daily, representing a total area of 19,300,000 km2 (7,500,000 sq mi). (Green Facts, 2009) The governments have also been purchasing property rights for the sake of conservation taking over all the rights from the owner or it can purchase a conservation easement where it acquires rights necessary to protect the target species or ecosystem while leaving the owner free to use the land. This law also allows water rights to increase stream flows, and permits for grazing or the emission of air pollutants can be bought and retired. Like acquisition, regulatory approaches are being used by governments to limit the manner in which any activity can be carried out. Regulations are being enforced by governments by a wide range of sanctions. Sanctions carry additional internal (guilt) and external (bad publicity) costs for the individuals or the companies who violate the regulations. The example of biodiversity regulation is the U.S. Endangered Species Act (ESA). (U.S Environmental Protection Agency, 2009)

Another major strategy is to encourage private conservation action through incentives like tax credits and regulatory reliefs. The U.S. Fish and Wildlife Service’s “Safe Harbor” program is an example of a regulatory relief incentive. ‘Safe Harbor’ agreements assure landowners who improve habitat that they will not be responsible for protecting the increased populations of endangered or threatened species those lands may attract. (U.S Environmental Protection Agency, 2009) Finally, with the help of genetic engineering, using the various DNA techniques, different kinds of bacteria capable of synthesizing plants to be able to restrain to the changes in climate and also to avoid various diseases are being created by the modification of their genes.

I would like to conclude by saying that, the very little the governments do to save biodiversity, “What matters is the initiative taken by each individual human to save himself and his future generations” (or) “Only if the last tree has been cut down and the last river has dried to a trickle will man finally realise that we cannot eat money!”