Download Notes towards Biodiversity Chapter 3

Notes towards Biodiversity Chapter 5
Introductory/Title Slide (1)
Hello. My name is Gwen Raitt. I will be presenting this chapter on why we are losing
biodiversity.
We have a Responsibility… To Ourselves!
Biodiversity is an important part of our environment. Biodiversity loss directly affects
human well-being (Brown 2001). There are those who are not willing to believe that
humans are causing biodiversity loss (Miller 2002). Environmentalists present evidence
that human actions at all levels of society are causing biodiversity loss (see McNeely et
al. (1995), Swanson (1995a), Dobson (1996), Brown (2001) and Miller (2002) among
others). Our responsibility is to find out for ourselves. (1) How we affect the
environment as a species. Are the environmentalists right? (2) How we affect the
environment individually. (3) How we can reduce our individual impact on the
environment. Action starts with individuals. This chapter outlines the reasons why
humans as a species have a negative impact on the environment.
Causes of Biodiversity Loss
A multitude of different factors affect the direct causes of biodiversity loss viz. habitat
destruction, fragmentation and degradation including overexploitation. This diagram
aims to give a broad overview of the factors causing biodiversity loss and may not be
complete. The arrows indicate the direction of influence. The following slides discuss
various aspects in more depth. Key references on the causes of biodiversity loss include
McNeely et al. (1995) and Swanson (1995a). Remember that biodiversity loss covers
loss at all levels of biodiversity (ecosystem, species and genetic diversity).
Direct Causes of Extinction
The following paragraphs detail the factors directly causing extinction by directly using a
species, using habitats and using resources leading to decreased numbers of populations,
population size and sometimes individual fitness.
Habitat destruction and fragmentation are linked because fragmentation is the result of
the patterns of habitat destruction. The picture shows the habitat destruction (in the form
of deforestation) and fragmentation in the Brazilian province of Rondonia.
Habitat destruction (defined as the process of removing a habitat-type and replacing it
with another (Wikipedia Contributors 2006a)) is considered the most important cause of
biodiversity loss (Ehrlich 1988, Lovejoy 1997, Barbault and Sastrapradja 1995, McNeely
et al. 1995). Habitat destruction may be caused by the expansion of agriculture
(McNeely et al. 1995, Dobson 1996, Lévêque and Mounolou 2001, Pietra 2002,
Wikipedia Contributors 2006b), aquaculture (McNeely et al. 1995, Beveridge et al.
1997), forestry (McNeely et al. 1995, Wikipedia Contributors 2006b) and urbanization
(Dobson 1996, Pietra 2002). Fishing with explosives and/or poisons destroys marine
habitat (McNeely et al. 1995, Pietra 2002). Military uses may also result in habitat
destruction, for example the use of Johnson Atoll for setting off nuclear explosions made
it unsuitable for life (Pietra 2002).
Habitat destruction reduces the area available to species and ecosystems usually resulting
in a reduction in genetic diversity (a level of biodiversity) as fewer
individuals/populations of a given species are present. If the area is great enough, may
remove entire ecosystems thereby reducing ecosystem diversity (a sometimes overlooked
level of biodiversity). The link between the size of an area and the number of species
able to survive in it was mentioned in Chapter 4.
Habitat destruction is compounded by habitat fragmentation (Dobson 1996). Habitat
fragmentation follows a pattern: the total area of the habitat is reduced, habitat patches
are fragmented into smaller patches, the average size of each habitat fragment is
decreased and habitat fragments are isolated from other habitat areas (Dobson 1996,
Wikipedia Contributors 2006c). Fragmentation results in an increase in the amount of
habitat edge and a decrease in the amount of interior habitat (Wikipedia Contributors
2006c). Isolation affects the availability of pollinators for plants and consequently results
in Allee effects and so reduced seed set and sometimes reduced seed viability e.g.
Primula sieboldii in a reserve surrounded by the urban environment of Greater Tokyo
may experience no seed set in individuals that are not able to self pollinate as a result of
the absence of queen bumblebees, the pollinator of Primula sieboldii (Washitani 2000).
In the Amazon rainforest, a gap of eighty metres blocks the movements of most of the
understorey birds, many insects and some mammals (Dobson 1996). Edge effects
include higher predation and parasitism rates than are present in interior habitat, e.g.
woodland birds in the U.S.A. are disappearing from forest/woodland fragments because
the nests are preyed on by American blue jays (Cyanocitta cristata), crows (family
Corvidae) and raccoons (Procyon lotor) and parasitized by the brown-headed cowbird
(Molothus ater) (Dobson 1996).
The habitat patches left after fragmentation may not be (in fact, often are not) large
enough to retain the local ecosystem – an immediate loss of biodiversity at the ecosystem
level that is compounded by the loss of species (this biodiversity loss affects both the
species and genetic levels of biodiversity) because of lack of ecosystem functions such as
pollination.
Habitat degradation results in the loss of biodiversity at the genetic and species diversity
levels. If any form, or combination of forms, of degradation reaches levels beyond the
thresholds that the ecosystems can ‘tolerate’, habitat degradation becomes habitat
destruction via the progressive loss of ecosystem function. Habitat degradation may
result from several causes.
The invasion of exotic species degrades natural systems. Exotic species arrive in three
ways: accidental introductions, escapes from ‘controlled’ introductions and deliberate
introductions (McNeely et al. 1995, Lévêque and Mounolou 2001). For more
information on exotic species and their impacts, see the Invasion Biology course, the
GISP website: http://www.gisp/, and McNeely et al. (1995).
Pollution is a cause of degradation that directly affects the atmosphere, hydrosphere and
lithosphere (McNeely et al. 1995). The main source of atmospheric pollution is the
combustion (and/or heating) of fossil fuels and solid waste (e.g. plastics) (McNeely et al.
1995, Miller 2002). Atmospheric pollutants include heat (Miller 2002), heavy metals
(McNeely et al. 1995), particles of matter (Brown 2001), gases (e.g. chlorofluorocarbons
(CFCs), methane (CH4), carbon dioxide (CO2), ammonia (NH3), nitrogen oxides (NOx),
ozone (O3) and sulphur dioxide (SO2)) (McNeely et al. 1995, Leemans 1996, Miller
2002) and poisons (e.g. dioxins – a group of chlorinated hydrocarbons) (Brown 2001,
Miller 2002). Aquatic pollutants include acid (McNeely et al. 1995), heat (Miller 2002),
heavy metals (McNeely et al. 1995, Pietra 2002), nutrients (McNeely et al. 1995,
Beveridge et al. 1997, Pietra 2002), particulate matter (Brown 2001, Pietra 2002),
poisons (McNeely et al. 1995, Pietra 2002) and oil (Miller 2002, Pietra 2002). Soil
pollutants include acid (McNeely et al. 1995), heavy metals (McNeely et al. 1995),
nutrients (Dobson 1996), oil (Miller 2002), poisons (Dobson 1996) and salts (McNeely et
al. 1995). Noise is also a form of pollution (Miller 2002). This list is not comprehensive
since strictly speaking, pollutants include any chemical that does not naturally occur in
the ecosystem.
The gases polluting the atmosphere are causing climate change by raising the temperature
(Leemans 1996, Miller 2002). Carbon dioxide (CO2) is a major greenhouse gas (Dobson
1996). This temperature increase is already regarded as having negative impacts such as
increasing the power of storms. If the changes are not reversed, the problems will
multiply (rising sea levels are predicted) and intensify (McNeely et al. 1995, Brown
2001).
Overexploitation is known to have caused a number of species extinctions (Smith et al.
1995, McNeely et al. 1995) thereby degrading the ecosystems of which they formed part.
The reasons for overexploitation are survival needs (e.g. wood for fuel in India of which
a big part of the demand is urban based) (McNeely et al. 1995), cultural traditions (e.g.
the hunting of hornbills in northeast India) (McNeely et al. 1995) and as a supplementary
source of cash income (e.g. the illegal wildlife trade and poaching of rhinoceros horns
and ivory (Miller 2002)) (McNeely et al. 1995). The effects of overexploitation are not
limited to the exploited species, but are felt throughout the ecosystem (Coleman and
Williams 2002).
Agriculture and Forestry
Agriculture causes the destruction, fragmentation and degradation of natural habitat and
thus loss of all levels of biodiversity (McNeely et al. 1995). The contribution of the
following aspects of agriculture to the loss of biodiversity is briefly discussed.
Domestication is defined as the process by which a biological organism is habituated to
survival in proximity to humanity. The physiology, life cycle and behaviour of
domesticated organisms have been changed by human control of their environment and
human selection of individuals to meet human requirements (Wikipedia 2006d).
Domestication freed humanity from total dependence on the local natural environment
for survival and allowed the manipulation of natural resources for the benefit of mankind
(McNeely et al. 1995). This resulted and continues to result in destruction natural habitat
to provide habitat for domestic organisms (McNeely et al. 1995, Swanson 1995b, Miller
2002). Most of the natural habitat in developed countries has already disappeared so
there is now little habitat destruction but in developing countries, habitat destruction is
continuing, in part because the use of already domesticated organisms is easier because
there is an abundance of information on these species and their production and tools for
their production (Swanson 1995b, Tisdell 2003).
Increasing the yield of a given crop or type of animal causes loss of genetic diversity
within the species of crop or animal (because high yielding breeds replace others) and
loss of the natural biodiversity of the area through degradation of natural habitats
(Krautkraemer 1995, McNeely et al. 1995, Swanson 1995b, Dobson 1996, Brown 2001,
Miller 2002, Tisdell 2003). The following methods of increasing yield result in
biodiversity loss through increasing uniformity: selective breeding (Krautkraemer 1995,
McNeely et al. 1995, Swanson 1995b, Dobson 1996, Miller 2002), irrigation (McNeely
et al. 1995, Dobson 1996, Brown 2001, Miller 2002), mechanization (McNeely et al.
1995, Swanson 1995b, Tisdell 2003), chemicals (McNeely et al. 1995, Dobson 1996,
Miller 2002) and biotechnology (Pietra 2002).
Forestry causes natural habitat destruction, fragmentation and degradation and thus loss
of biodiversity. The following aspects of forestry may contribute to the loss of
biodiversity: species selection(McNeely et al. 1995), harvesting methods such as clear
felling (McNeely et al. 1995, Brown 2001) and shifting to plantations i.e. domestication
(McNeely et al. 1995).
Aquaculture and Fisheries
Aquaculture causes in habitat destruction and habitat degradation and thus biodiversity
loss in both marine and freshwater habitats. The following aspects contribute to
biodiversity loss: provision of infrastructure and technology (Beveridge et al. 1997,
Pietra 2002), waste production (Beveridge et al. 1997, Pietra 2002), introduction of
exotic species (Beveridge et al. 1997) and selective breeding (McNeely et al. 1995). The
picture shows aquaculture using cages.
Fisheries cause habitat degradation and habitat destruction in both marine freshwater
habitats and thus biodiversity loss (McNeely et al. 1995, Coleman and Williams 2002).
The following aspects contribute to biodiversity loss: improved technology which
facilitates overexploitation (McNeely et al. 1995, Brown 2001), harvesting methods
which catch organism indiscriminately and damage the seabed (McNeely et al. 1995,
Coleman and Williams 2002, Pietra 2002). The picture shows a commercial fishing
vessel.
Marine fisheries are threatened by the loss of rivers, mangroves, estuaries, coastal
wetlands and reefs. These habitats are the spawning grounds and nurseries of the
harvested fish (Brown 2001).
Industry and Urbanization
Industry may be defined as any group of businesses that use the same method of
generating profits or alternately as a section of economic production dedicated to
manufacturing (Wikipedia Contributors 2006e). Industry is the means of converting
natural capital into selected goods and services (Swanson 1995b). This process involves
both habitat destruction and habitat degradation. Causing pollution is cheap but cleaning
up pollution is expensive (Clark 1995) and would lower profits. Industry promotes
urbanization and vice versa (Miller 2002).
Urbanization refers to the expansion of urban areas (Cornell Cooperative Extension
2004) or the expansion of the proportion of the population in urban areas or the increase
of this proportion over time (Wikipedia Contributors 2006f). This expansion results in
habitat destruction and habitat degradation (Pauchard et al. 2006). Urban areas get their
resources from elsewhere. This means that people are not in close association with the
resources that they are using which affects their attitude to resource use (Gadgil 1995).
Attitudes
Attitudes to biodiversity are linked to culture and reflected in the way natural resources
are used (McNeely et al. 1995). Attitudes, opinions and tastes are formed (Rowthorn and
Brown 1995) and are changed by internal social interactions and/or external influences
(McNeely et al. 1995) such as other cultures. Traditional attitudes are being influenced
by interactions with ‘western’ culture and markets (McNeely et al. 1995). Marketing is a
tool used to influence people’s opinions by presenting information and/or propaganda.
Companies that harm the environment market misinformation to confuse the public into
supporting them against changes in legislation, etc. (Brown 2001). The picture shows a
pack of cigarettes. The tobacco industry marketed lots of misinformation.
Environmentalists use marketing to promote the retention of biodiversity through
conservation (Rowthorn and Brown 1995). As the distance/separation from a resource
increases, the concern for that resource decreases so for example, urbanization decreases
the concern for natural resources (Gadgil 1995).
The Failure of Economics to Value Biodiversity
The failure to value biodiversity results in habitat conversion that is both economically
and environmentally inefficient (McNeely et al. 1995). There are several factors which
result in economics failing to value biodiversity. The nature of the benefits may cause
them to be overlooked since many of the benefits of natural resources are diffuse public
goods and the market for them is poorly developed (McNeely et al. 1995, Southgate
1995). Unequal access to property rights contributes to failing to value biodiversity as
access is skewed in favour of urban dwellers and habitat conversion to agriculture
(McNeely et al. 1995). Markets do not reflect all natural resource use. Many resources
are used without entering the markets (McNeely et al. 1995, Lévêque and Mounolou
2001). The picture shows an informal market in Cape Town. Economics fails to
consider the high risk value of biodiversity loss (McNeely et al. 1995). The risk is high
because there is uncertainty (McNeely et al. 1995, Perrings 1995) cause by imperfect
understanding of ecosystems and the services they provide, the often irreversible nature
of biodiversity loss (McNeely et al. 1995) (a local extinction may be recolonized from
elsewhere but a global extinction is irreversible) and an inability to use substitutes for
functions even though their loss is theoretically reversible (McNeely et al. 1995).
Economic indicators (e.g. the Gross National Product) are flawed because they rely on
one attribute (monetary value) and assume that it captures all the important values
(McNeely et al. 1995, Miller 2002), they do not separate the positive and negative
impacts of economic activity (McNeely et al. 1995, Miller 2002), they hide the extreme
inefficiency of natural and human resource use because only the money spent is
measured, not the value received (Miller 2002) and they do not show income distribution
(Miller 2002). The result of this failure to value biodiversity is that conservation is seen
as a burden not an opportunity (McNeely et al. 1995). (See also the slide in chapter 3 on
monetary value and societal control)
Legislation, Taxes and Subsidies
Both companies and governments select countries globally to avoid legislation
(environmental, financial or social) that hampers their activities (McNeely et al. 1995).
Most of the oceans are not protected by any national legal jurisdiction or effective
international agreements for biodiversity protection (Miller 2002).
The Kyoto protocol (on reducing carbon emissions), which the USA did not sign, does
not protect biodiversity (Schulze et al. 2002). Primary natural forests are not protected
because they are not man-made and so are not credited as carbon (C) sinks towards the C
reduction. The support for fast-growing plantations (of mostly alien species) only
considers the increase in stem wood, not the C balance of the ecosystem. The normal
practice of forestry is not included in the counting of C emissions. Developed countries
shift food and wood production to developing countries (where the C emissions are not
counted) and then plant trees in their own countries (which are credited). Deforestation
in developing countries is not counted but reforestation as plantations is (Schulze et al.
2002).
Subsidies are used encourage environmentally harmful activities (Brown 2001). The
principal subsidized activities worldwide are food production (including fishing though
the fishing capability exceeds the sustainable fish catch), driving cars (by for example
construction and maintenance of roads) and using fossil fuels (Brown 2001). Extraction
industries such as mining and forestry receive subsidies (Brown 2001). Subsidies can
also be used to promote environmentally friendly activities (Brown 2001).
Taxes on environmental harmful industries are a potential tool for reducing biodiversity
loss but vested economic interests make changes in governmental policy difficult (Brown
2001). President George Bush of the USA (picture right) is known to have interests in
the oil industry.
Property Rights and Access Regulation
Property rights concern controlling access to a resource, obtaining it or guaranteeing it –
i.e. the rights to whatever value is derived from the use or exchange of a resource
(McNeely et al. 1995). Social status affects access to property rights. Those with a
higher social status have greater access to resources. Over-consumption is more
damaging than poverty – economically powerful countries can protect their own
resources while using the markets to access poorer countries resources by creating a
demand for the resources which prompts the poorer country to harvest unsustainably to
tap into the market (McNeely et al. 1995) to gain foreign currency. This is promoted by
the International Monetary Fund’s conditions (see the slide on Debt). Property rights are
more easily available to urban males working in the formal economic sector than to rural
people (McNeely et al. 1995). Property rights are often granted for conversion of natural
land to ‘productive’ use (McNeely et al. 1995, Myers 1995, Southgate 1995) – those who
use the natural vegetation sustainably lose out (McNeely et al. 1995). The lack of
property rights causes overexploitation because there is no reason to plant trees if one
will not own them say a year later (McNeely et al. 1995, Sedjo and Simpson 1995).
Open access causes overexploitation because the users act for individual gain only
(McNeely et al. 1995, Miller 2002). Communal access control is an effective way of
regulating resource use (McNeely et al. 1995, Miller 2002).
Information is a tool of power. Access to information affects resource use. Information
has biases that favour literate people and widespread languages. Intellectual property
rights limit the spread of information (McNeely et al. 1995).
Conversion, Specialization and Globalization
Conversion refers to the shifting of capital from one form to another (Swanson 1995b).
Biodiversity is natural capital and may be converted to human preferred capital
(Groombridge 1992, Swanson 1995b). The law of economic specialization indicates that
productivity increases as the homogeneity (uniformity) of production methods increases
(Groombridge 1992). Mass production of a single product is cheaper than lower
production of a variety of products (Groombridge 1992, Swanson 1995b). This is
because capital goods are used in the production of a particular item (Groombridge 1992,
Swanson 1995b). In agriculture, the capital goods are machinery and chemicals
(Groombridge 1992, Swanson 1995b). Capital goods and information are breed and or
species specific (Swanson 1995b, Tisdell 2003). The more uniform the agricultural
product, the easier it is to apply capital goods to it (Swanson 1995b). Agricultural
specialization promotes the conversion of natural capital to agriculture (Swanson 1995b).
Globalization covers the complex economic, political, social and technological changes
that increase the interdependence and interaction of entities (companies, governments and
people) in disparate locations (Wikipedia Contributors 2006g) i.e. changes that promote
global interactions. Globalization causes the spread of specialized products and changes
in human attitudes (Groombridge 1992, McNeely et al. 1995). Globalization separates
resource management from the resource users which removes local feedback mechanisms
(McNeely et al. 1995). Specialization and globalization are synergistic (Tisdell 2003).
Conversion, specialization and globalization promote homogenization of the biosphere
(Groombridge 1992) which causes biodiversity loss.
Debt – The Driver of the Global Economy
Debt is what is owed. Normally, this refers to money but it is not limited to money
(Wikipedia Contributors 2006h).
The International Monetary Fund (IMF) attaches conditions such as structural adjustment
programs to its loans (Wikipedia Contributors 2006i). Critics say that the demands made
in structural adjustment programs (see Additional Notes) cause economic stagnation and
retard social stability (Wikipedia Contributors 2006i, j). Critics blame the IMF for
Argentina’s economic crisis in 2001 (Wikipedia Contributors 2006i).
The national debt of developing countries limits their development and harms
biodiversity by causing over exploitation of natural resources for foreign currency and
decreasing the money available for spending on the subsistence agriculture sector – i.e.
poverty reduction (Myers 1995). The link between national debt and biodiversity loss in
tropical forest countries is so strong that a $ (US) 5 billion debt reduction reduces annual
deforestation by between 250 and 1 000 km2 (Myers 1995).
Poverty and Migration
Poor people have a higher than average population growth because children help with
labour and provide security for the future (Myers 1995, Miller 2002). Those with limited
access to resources depend on the local environment for survival (Gadgil 1995). The
poor usually do not have control over the resources they use and therefore often use them
unsustainably (Gadgil 1995, Miller 2002). The above factors result in overcrowding,
resource depletion and forced removals which force people to migrate to urban areas
(Gadgil 1995, Brown 2001, Miller 2002) and natural areas (Gadgil 1995, Myers 1995).
Migrants do not know the resources of the natural areas they migrate to so the natural
resources of the new area may be overexploited and destroyed before the people are able
to adjust (McNeely et al. 1995). Migrants bring domesticated species with them
(McNeely et al. 1995). Waves of human migration in the past are linked to waves of
extinction (McNeely et al. 1995, Anderson 1999).
Economic Growth
Economic growth may be defined as increase in the ability to supply goods and services
for human use (Miller 2002). It is normally measured by an increase in indicators such as
the Gross National Product (GNP), the Gross Domestic Product (GDP) and the Gross
World Product (GWP) (Miller 2002). The graph shows the gross world product 1950—
2004. Economic growth may be achieved by: population growth (because this increases
the number of both producers and consumers), increased per capita (per person)
consumption or both of the above (Miller 2002). This means that economic growth is
achieved by increased resource consumption. Increased resource consumption results
increased pressure on natural environments and the sequential use of natural resources
(Gadgil 1995, Coleman and Williams 2002). The natural resources are used in order of
their quality with the best (or preferred) resources are used first followed by the next best,
etc. (Gadgil 1995).
Economic growth does not reduce poverty. Since 1960, the gap between the wealthy and
the poor has increased. The wealthy have gotten richer and the poor, poorer (Miller
2002).
Human Population Growth
The human population is growing exponentially at a rate of 1.35% per year (Miller 2002).
At this rate it takes: 1.6 years to add 129 million people – the number killed in all wars
fought in the past 200 years, 3.4 years to add 276 million people – the size of the United
States’ population in 2000, 15 years to add 1.26 billion people – the size of China’s
population in 2000 (Miller 2002). Both human birth and death rates are declining but
death rates have dropped faster than birth rates (Miller 2002).
Humans already use 40% of the Net Primary Productivity (NPP) of the earth (Dobson
1996). How much more will we be able to use?
Family planning is the crucial to stabilizing human populations (Brown 2001). Educating
women and providing them with safe means to control fertility reduces the birth rate
(Dobson 1996, Brown 2001, Miller 2002).
Concluding Remarks
Governments do not adequately protect biodiversity. In the U.S.A., development of the
Tellico dam received, through congress, exemption from environmental laws and
continued despite a negative net economic return and the potential loss of the snail darter
fish (Percina tanasi) (Krautkramer 1995, Dobson 1996). Conservation sites may be
selected for their aesthetic or recreational value rather than for there ecological value as
happens in the USA – in the USA recreational users are objecting to the reintroduction of
grizzly bears into wilderness areas. In Hawaii, the sites with the highest avian diversity
are not protected (Krautkramer 1995). Business has more power than government. Both
the global economy and the human population are expanding so resource demands are
also increasing (McNeely et al. 1995, Swanson 1995c). Reducing poverty is essential to
preserving biodiversity (Myers 1995). The expanding economy resembles a pyramid
scheme (my opinion). Pyramid schemes eventually collapse and the lower levels lose
their investments (Wikipedia Contributors 2006k). The economy reflects the power of
human greed. Those with access to more resources have more opportunities to express
this greed, for example companies that lobby against environmental legislation that will
affect their profits (by, for example, forcing them to clean up their pollutants). Since they
are often funding contributors to political ‘powers’, they have leverage - the threat of
stopping funding to the political ‘powers’. All anthropogenic damage to the biosphere
(and hence biodiversity) is the result of human choice. Every individual has the power of
choice. The choices of individuals affect the preservation or loss of biodiversity.
Last slide
I hope that you found chapter 5 informative and that you will enjoy chapter 6.