BIODIVERSITY AND NATURAL HERITAGE
Biodiversity, a contraction of the term
biological diversity, is a widely used term that attempts
to capture the complex composition and structure of all living
things. This makes it very
difficult to define in simple language, and there are more
than twelve formal definitions for what are basically the
units or groups in which living things are organized.
Three levels of biodiversity are generally recognized: the
genetic, species and ecosystems or community level (Noss,
1990; CBD, 1992) with some including a landscape level as
well (Noss, 1990; DEA&T, 1997). Not only is it a difficult
concept to define, biodiversity is also difficult to measure
in its entirety. The measurement of biodiversity includes
both the levels described above and its different components:
composition, structure and function. Due to the difficulties
of measuring numbers and differences at the genetic level,
the species and more recently the ecosystem level are the
most commonly measured and monitored levels. These are also
the most commonly used levels in indicator development and
measurement (Saunders et al., 1998; Le Maitre and Reyers,
2001).
Scientific and public understanding of the importance of
biodiversity is developing rapidly as more knowledge of the
nature, role and importance of biodiversity accumulates (DEA&T
1997; Chapin et al. 2000). Biodiversity has both an
instrumental and intrinsic value. Its instrumental value is
its use value to humans and includes the goods (fuel wood),
services (pollination), information (drug development) and
psycho-spiritual (tourism) value of biodiversity. The intrinsic
value of biodiversity is its inherent value, a value that
is there simply because that biodiversity exists and is not
dependent on its use by human beings. This is the same as
the intrinsic value of human life. Attempts have been made
to calculate the full economic value of the different types
of values that biodiversity has. This is a very difficult
task to accomplish and can be quite contentious.
South Africa contains a wealth of biodiversity within its
borders. It is ranked as one of the top 25 most biodiverse
nations in the world, and contains the 5th highest
number of plant species (Reyers et al., 2001). This
biodiversity stock is however not well protected, with South
Africa's protected areas covering less than 6% of the land
surface area (Reyers et al., 2001). The human population
size and its consumptive demands place increasing pressure
on these biodiversity stocks and thus the development of indicators
with which to monitor and safeguard these stocks is essential.
The need for indicators of biodiversity is also legally supported
in the Constitution (Act 108 of 1996) as well as the Convention
on Biological Diversity (ratified by South Africa in 1995)
and the White Paper on Biological Diversity (DEA&T, 1997).
All of the biodiversity indicators suggested in this report,
except for BD09 (see summary table below), have been put forward
for use by the Convention on Biological Diversity by the Subsidiary
Body on Scientific, Technical and Technological Advice (SBSTTA5
2000).
The development of indicators of biodiversity in South Africa
is a difficult task as data on biodiversity have only recently
been collated. Many databases on both the species and ecosystem
level stocks are inadequate in terms of the knowledge of the
units (species or ecosystems) and the survey intensity of
these units, with many areas being less well studied than
others. The information on pressures, responses etc. is even
less well collated with only very recent attempts at gathering
data on threats posed by land cover changes (Reyers et
al., 2001) and factors that threaten endangered species
(Cowling et al. 1999; Barnes, 2000). The data on threatened
species (an important indicator of threats) are generally
outdated and exist only for the well-known groups such as
mammals, birds, freshwater fish and butterflies. However work
is being done in this area and should be incorporated in these
indicators as it becomes available.
Natural heritage
Natural heritage is again another complex term to define,
and broadly includes all South Africa's geological formations,
landscapes, plants and animals (Pearson et al., 1998).
The Natural Heritage Act also includes all of South Africa's
rich variety of peoples and their cultural and historical
heritage. A number of organizations are involved. The Department
of Environment Affairs and Tourism maintains information on
the natural heritage areas which are listed under the World
Heritage Convention. They also maintain data on the privately
owned sites listed under the National Heritage Programme.
The Department of Arts and Culture, Science and Technology
is also required to report natural heritage resources in terms
of the Natural Heritage Act. The South African Heritage Resource
Agency was established in April 2001 to replace the National
Monuments Council (see the internet site: http://www.nationalmonuments.co.za)
and is charged with maintaining national databases on natural
heritage.
The World Heritage Convention (WHC, 2000) recognizes two
forms of heritage: cultural and natural. Cultural heritage
is defined as a monument, group of buildings or sites of historical,
aesthetic, archaeological, scientific, ethnological or anthropological
value. Natural heritage is defined as an outstanding physical,
biological or geological feature, including habitats of threatened
plants or animal species and areas of value on scientific
or aesthetic grounds or for conservation. South Africa currently
has four world heritage sites: Greater St Lucia Wetland Park;
Robben Island; Fossil Hominid Sites of Sterkfontein, Swartkrans,
Kromdraai and Environs; and uKhahlamba/Drakensberg Park. South
Africa also has a Natural Heritage Programme, which allows
private landowners to designate areas of land as Natural Heritage
sites. The site has to meet certain criteria listed in SANHP
(2000).
Natural heritage indicators are very seldom used in SOE
reporting (Pearson et al., 1998). Legal requirements
for these indicators should comply with the Natural Heritage
Act. Three indicators are proposed and require a register
of these resources, their status, activities, and public awareness.
Pearson et al. (1998) propose several others and these
should be considered for future State of the Environment reporting.
Much research is still required with experts in the relevant
fields to customize these indicators for South Africa and
to identify appropriate ways for classifying types of heritage
resources.
DESCRIPTION OF ISSUES
Humans are the ultimate threat to biodiversity, through
their high levels of consumption and inefficient use of resources
they threaten biodiversity in four main ways: land development;
pollution; overexploitation and introduction of non-native
species (WRI 2000). These threats are evident in a number
of ways in the environment and are included as a list of issues
that must be addressed.
Species
diversity
The loss of habitat through direct habitat destruction and
transformation, as well as the degradation and fragmentation
of remaining habitat threatens biodiversity in a number of
ways. Some species may go extinct immediately because their
land area requirements are no longer met, others may constrict
their ranges. This constriction of ranges as well as the fragmentation
of what were once large continuous interbreeding populations
into fragmented sub populations also has severe genetic implications.
These smaller populations can lead to increased levels of
inbreeding, loss of genetic variation through random genetic
drift and the fixation of harmful mutations. Small populations
are also vulnerable to demographic and environmental stochasticity.
This leads to an increase in species extinction rates, an
increase in the number of threatened species and a decrease
in species and genetic diversity. Data collation to address
this issue is a difficult task because there is both a paucity
of species (and especially genetic data) and information on
threatened species is also difficult and expensive to collect.
The IUCN categories used for determining Red Data Lists are
not ideal and their limitations must be recognized in developing
them as indicators. Information on the species level will
always be constrained by:
- The lack of knowledge of many taxa which are ecologically
important (e.g. fungi)
- The generally incomplete taxonomic knowledge of the group
being monitored
- The lack of knowledge of the distribution of the species
- The lack of basic data on population sizes, dynamics and
trends for many species; this information is needed for
assessing, for example, extinction risk.
These limitations are not easily rectified and should not
be underestimated. But, at the same time, it is necessary
to have some indicators and for these indicators to be using
the same (or a comparable) baseline so that they can be used
to accurately identify temporal trends and assess the effectiveness
of responses.
The IUCN categorization process for threatened species is
very data intensive requiring information like range and population
size of species and changes in these sizes. An important issue
that is often overlooked is that the IUCN (1994) system was
not designed for the assessment of a portion of the total
population of a taxon (Gardenfors et al. 1999). The
criteria for the red list categories of IUCN (1994) and their
definitions are most appropriately applied to whole taxa at
a global scale rather than at a regional or national scale
(Gardenfors, 1996).
Habitat
change
Land use practices, over-harvesting of natural resources,
global warming, poorly planned and unregulated urbanization,
industrial and tourism development, pollution, population
growth, poverty, alien invaders, economically & culturally
under-valued resources, lack of bioregional conservation,
lack of SEA and EIA, and lack of environmental awareness causes
loss and change of habitat and has severe implications at
the ecosystem or landscape level. Degraded or transformed
ecosystems, which have lost many species, cannot function
properly and therefore the services and goods that we depend
on can no longer be provided. These changes to ecosystems
can have extensive effects. For example afforestation in a
catchment will alter downstream flows as far as the estuary.
In a water restricted country like South Africa, this kind
of habitat modification must be monitored. This is not only
of concern for human quality of life, but also impacts on
both the species and ecosystems within these landscapes, causing
chains of extinctions. These ecosystems are also more vulnerable
to invasions and further degradation.
Alien invasive organisms
Exotic alien species introduced to South Africa (either accidentally
or purposefully for commercial gain) are a serious biodiversity
threat especially in sensitive ecosystems and also in already
degraded ones. Vertebrate, invertebrate as well as plant species
have been introduced to most areas of South Africa and have
successfully established themselves in a large number of cases.
They can cause spread of disease, impaired ecosystem functioning,
species loss, loss of water resources, loss of biodiversity,
increased flooding, loss of production, loss in tourism revenue.
The Working for Water Programme and other groups were established
in recognition of these dangers and in an attempt to control
the effects and spread of invaders. Their removal is sometimes
not possible due to their success as invaders. Thus indicators
that track their development and spread are essential, especially
as an early warning system.
Resource harvesting
The over-harvesting of species, both at a commercial as well
as a subsistence level, threatens many target species, but
also has some indirect consequences (e.g. non-target fish
species caught in nets; oil spills in the commercial exploitation
of oil). This also leads to the degradation of ecosystems
structure and function. This is a difficult threat to regulate
and monitor, and indicators of trade and harvesting are essential
in order to ensure sustainability of use.
Genetically modified organisms
Pressure for increased productivity, reducing herbicide
and pesticide use, and multi-national biotechnology corporation's
marketing strategies has led to the proliferation of GMOs.
The lack of sufficient testing of the potential impacts of
GMOs, concern about implications of observed impacts, potential
for genetic pollution and cross-breeding, and possible super-invader
organisms leading to species loss are all valid concerns raised
about GMOs. There is still much research required into the
biodiversity threats posed by these organisms. The organisms
and their impacts must however be monitored through a system
of indicators.
Bio-prospecting (commercial exploitation
of biological resources through patenting and harvesting)
This form of exploitation leads to a loss of genetic diversity,
potential under-valuation of natural resources, as well as
a loss of opportunities for sustainable development. This
is a new form of exploitation and as such its effects are
little studied, but monitoring and regulation are essential.
The issuing of permits also needs to be regulated.
Resource
value
This issue addresses the economic value associated with
each of the resources available to us. The resource value
has been assessed in two different ways - firstly through
the number of jobs created, and secondly through the actual
economic contribution of that particular resource to the economy.
Natural
heritage resources
Uncontrolled development, land use change, landlessness,
population pressures, and urbanization not only threaten biodiversity,
but also threaten the natural and cultural resources in those
areas. This leads to a loss of cultural heritage, decreased
tourism interest, as well as a loss of biodiversity. In a
nation like South Africa, with its rich cultural and natural
heritage resources this form of threat needs to be evaluated
and monitored.
The four issues addressed directly through indicators in
this report include:
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