Chapter 5: Biodiversity

Main messages

Biodiversity provides the basis for ecosystems and the services they provide, upon which all people fundamentally depend. The following are the main messages of this chapter:

People rely on biodiversity in their daily lives, often without realizing it. Biodiversity contributes to many aspects of people’s livelihoods and well-being, providing products, such as food and fibers, whose values are widely recognized. However, biodiversity underpins a much wider range of services, many of which are currently undervalued. The bacteria and microbes that transform waste into usable products, insects that pollinate crops and flowers, coral reefs and mangroves that protect coastlines, and the biologically-rich landscapes and seascapes that provide enjoyment are only a few. Although much more remains to be understood about the relationships between biodiversity and ecosystem services, it is well established that if the products and services that are provided by biodiversity are not managed effectively, future options will become ever more restricted, for rich and poor people alike. However, poor people tend to be the most directly affected by the deterioration or loss of ecosystem services, as they are the most dependent on local ecosystems, and often live in places most vulnerable to ecosystem change.

Current losses of biodiversity are restricting future development options. Ecosystems are being transformed, and, in some cases, irreversibly degraded, a large number of species have gone extinct in recent history or are threatened with extinction reductions in populations are widespread and genetic diversity is widely considered to be in decline. It is well established that changes to biodiversity currently underway on land and in the world’s fresh and marine waters are more rapid than at any time in human history, and have led to a degradation in many of the world’s ecosystem services.

Reducing the rate of loss of biodiversity, and ensuring that decisions made incorporate the full values of goods-and-services provided by biodiversity will contribute substantially towards achieving sustainable development as described in the report of the World Commission on Environment and Development (Brundtland Commission report).

• Biodiversity plays a critical role in providing livelihood security for people. It is particularly important for the livelihoods of the rural poor, and for regulating local environmental conditions. Functioning ecosystems are crucial as buffers against extreme climate events, as carbon sinks, and as filters for waterborne and airborne pollutants.
• From the use of genetic resources to harnessing other ecosystem services, agriculture throughout the world is dependent on biodiversity. Agriculture is also the largest driver of genetic erosion, species loss and conversion of natural habitats. Meeting increasing global food needs will require one or both of two approaches: intensification and extensification. Intensification is based on higher or more efficient use of inputs, such as more efficient breeds and crops, agrochemicals, energy and water. Extensification requires converting increasing additional areas of land to cultivation. Both approaches have the potential to dramatically and negatively affect biodiversity. In addition, the loss of diversity in agricultural ecosystems may undermine the ecosystem services necessary to sustain agriculture, such as pollination and soil nutrient cycling.
  
• Many of the factors leading to the accelerating loss of biodiversity are linked to the increasing use of energy by society. Dependence on and growing requirements for energy are resulting in significant changes in species and ecosystems, as a result of the search for energy sources and of current energy use patterns. The consequences can be seen at all levels: locally, where the availability of traditional biomass energy is under threat, nationally, where energy prices affect government policies, and globally, where climate change driven by fossil fuel use is changing species ranges and behaviour. The latter is likely to have very significant consequences for livelihoods, including changing patterns of human infectious disease distribution, and increased opportunities for invasive alien species.
• Human health is affected by changes in biodiversity and ecosystem services. Changes to the environment have altered disease patterns and human exposure to disease outbreaks. In addition, current patterns of farming, based on high resource inputs (such as water and fertilizers) and agricultural intensification, are putting great strains on ecosystems, contributing to nutritional imbalances and reduced access to wild foods.
• Human societies everywhere have depended on biodiversity for cultural identity, spirituality, inspiration, aesthetic enjoyment and recreation. Culture can also play a key role in the conservation and sustainable use of biodiversity. Loss of biodiversity affects both material and non-material human well-being. Both the continued loss of biodiversity and the disruption of cultural integrity represent obstacles towards the attainment of the Millennium Development Goals (MDGs).

Biodiversity loss continues because current policies and economic systems do not incorporate the values of biodiversity effectively in either the political or the market systems, and many current policies are not fully implemented. Although many losses of biodiversity, including the degradation of ecosystems, are slow or gradual, they can lead to sudden and dramatic declines in the capacity of biodiversity to contribute to human wellbeing. Modern societies can continue to develop without further loss of biodiversity only if market and policy failures are rectified. These failures include perverse production subsidies, undervaluation of biological resources, failure to internalize environmental costs into prices and failure to appreciate global values at the local level. Reducing the rate of biodiversity loss by 2010 or beyond will require multiple and mutually supportive policies of conservation, sustainable use and the effective recognition of value for the benefits derived from the wide variety of life on Earth. Some such policies are already in place at local, national and international scales, but their full implementation remains elusive.

Introduction

The understanding of the importance of biodiversity has developed in the 20 years since the report of the World Commission on Environment and Development (Brundtland Commission). There is increased recognition that people are part of, not separate from, the ecosystems in which they live, and are affected by changes in ecosystems, populations of species and genetic changes. Along with human health and wealth, human security and culture are strongly affected by changes in biodiversity, and associated impacts on ecosystem services.

As the basis for all ecosystem services, and the foundation for truly sustainable development, biodiversity plays fundamental roles in maintaining and enhancing the well-being of the world’s more than 6.7 billion people, rich and poor, rural and urban alike. Biodiversity comprises much of the renewable natural capital on which livelihoods and development are grounded. However, ongoing, and in many cases, accelerating declines and losses in biodiversity over the past 20 years have decreased the capacity of many ecosystems to provide services, and have had profound negative impacts on opportunities for sustainable development around the planet. These impacts are particularly pronounced in the developing world, in large part due to the patterns of consumption and trade in the industrial world, which themselves are not sustainable.

If future concerns are not taken into account, and the products and services provided by biodiversity are not managed effectively, future options become limited or are eliminated, for rich and poor people alike. While technological alternatives to some of the services provided by biodiversity are available, they are typically more costly, compared to the benefits derived from well-managed ecosystems. Biodiversity loss particularly affects the poor, who are most directly dependent on ecosystem services at the local scale, and are unable to pay for alternatives. Although the private, more restricted, financial benefits of activities that result in the loss of biodiversity, such as the conversion of mangroves to aquaculture enterprises, are usually high, they often externalize many of the social and environmental costs. The overall benefits are frequently considerably less than the societal, more distributed, benefits that are lost along with the biodiversity, but for which the monetary value is often not known. For example, the loss of mangrove ecosystems contributes to declining fisheries, timber and fuel, the reduction of storm protection, and increased vulnerability to the impacts of extreme events.

In addition to the values of biodiversity for the supply of particular ecosystem services, biodiversity also has intrinsic value, independent from its functions and other benefits to people. The challenge is to balance the cultural, economic, social and environmental values so that the biodiversity of today is conserved and used in a manner that will allow it to be available for and to sustain the generations of the future. Biodiversity management and policies have an impact upon all sectors of society, and have strong cross-cultural and cross-boundary implications. Policies relating to issues such as trade, transport, development, security, health care and education all have impacts on biodiversity. Discussions on access and benefit sharing relating to genetic resources, one of the provisions of the United Nations (UN) Convention on Biological Diversity (CBD), show that understanding the full value of biodiversity is not simple. In addition to the gaps remaining in the understanding of biodiversity and ecosystem functioning, each individual stakeholder may hold different values for the same attribute of biodiversity. Building a fuller understanding of these values will require considerable additional research, and increasingly comprehensive, interdisciplinary and quantified assessments of the benefits that biodiversity provides to people’s health, wealth and security.

The relationships among biodiversity and the five main themes assessed in this chapter – livelihood security, agriculture, energy, health and culture – clearly demonstrate the importance of biodiversity to these aspects of human well-being. Biodiversity forms the basis of agriculture, and enables the production of foods, both wild and cultivated, contributing to the health and nutrition of all people. Genetic resources have enabled past and current crop and livestock improvements, and will enable future ones, and allow for flexibility according to market demand and adaptation according to changing environmental conditions. Wild biodiversity is perhaps of greatest direct importance to the one billion people around the world who live a subsistence lifestyle. The decline of this diversity has considerable implications for their health, culture and livelihoods. Supporting services, such as nutrient cycling and soil formation, and regulating services, such as pest and disease control, flood regulation and pollination, underpin successful agricultural systems, and contribute to livelihood security.

Cultural ecosystem services are being increasingly recognized as key determinants of human well-being, including through the maintenance of cultural traditions, cultural identity and spirituality. Among the wide range of other benefits from biodiversity, it has enabled the production of energy from biomass and fossil fuels. Such use of biodiversity has brought tremendous benefit to many people (see Box 5.2), but has had some significant negative knock-on effects in the form of human-induced climate change, and habitat conversion. These trade-offs, inherent in so much of biodiversity use, are becoming increasingly apparent, as there are greater demands for ecosystem services.

Box 5.2 Value of biodiversity and ecosystem services[12]

Honey bees (Apis mellifera, Apis mellifica) provide regulatory services through pollination. (Credit: J. Kottmann/WILDLIFE/Still Pictures) The supply of ecosystem services depends on many attributes of biodiversity. The variety, quantity, quality, dynamics and distribution of biodiversity that is required to enable ecosystems to function, and the supplying benefits to people, vary between services. The roles of biodiversity in the supply of ecosystem services can be categorized as provisioning, regulating, cultural and supporting (see Chapter 1), and biodiversity may play multiple roles in the supply of these types of services. For example, in agriculture, biodiversity is the basis for a provisioning service (food, fuel or fiber is the end product), a supporting service (such as micro-organisms cycling nutrients and soil formation), a regulatory service (such as through pollination), and potentially, a cultural service in terms of spiritual or aesthetic benefits, or cultural identity. The contributions of biodiversity-dependent ecosystem services to national economies are substantial. The science of valuation of ecosystem services is new, and still developing basic conceptual and methodological rigour and agreement, but it has already been very instructive, since the value of such services is generally ignored or underestimated at decision and policy making levels. Identifying economic values of ecosystem services, together with the notions of intrinsic value and other factors, will assist significantly in future decisions relating to trade-offs in ecosystem management. Value of: Annual world fish catch – US$58 billion (provisioning service). Anti-cancer agents from marine organisms – up to US$1 billion/year (provisioning service). Global herbal medicine market – roughly US$43 billion in 2001 (provisioning service). Honeybees as pollinators for agriculture crops – US$2–8 billion/year (regulating service). Coral reefs for fisheries and tourism – US$30 billion/year (see Box 5.5) (cultural service). Cost of: Mangrove degradation in Pakistan – US$20 million in fishing losses, US$500 000 in timber losses, US$1.5 million in feed and pasture losses (regulating provisioning services). Newfoundland cod fishery collapse – US$2 billion and tens of thousands of jobs (provisioning service). Of those ecosystem services that have been assessed, about 60 per cent are degraded or used unsustainably, including fisheries, waste treatment and detoxification, water purification, natural hazard protection, regulation of air quality, regulation of regional and local climate, and erosion control (see Chapters 2, 3, 4 and 6). Most have been directly affected by an increase in demand for specific provisioning services, such as fisheries, wild meat, water, timber, fibre and fuel.

People directly use only a very small percentage of biodiversity. Agriculture reduces diversity to increase productivity for a component of biodiversity of particular interest. However, people rely indirectly on a much larger amount of biodiversity without realizing it. There are bacteria and microbes that transform waste into usable products, insects that pollinate crops and flowers, and biologically diverse landscapes that provide inspiration and enjoyment around the world. Such ecosystem services, or the benefits derived from biodiversity, are ultimately dependent on functioning ecosystems. However, the amount of biodiversity required to enable ecosystems to function effectively varies enormously, and how much biodiversity is needed for the sustainable supply of ecosystem services in the present, and into the future, remains largely unknown.

Despite the critical need for more effective conservation and sustainable use, the loss of biodiversity continues, and in many areas is currently increasing in magnitude. Rates of species extinction are 100 times higher than the baseline rate shown by the fossil record (see Box 5.3). The losses are due to a range of pressures, including land-use change and habitat degradation, overexploitation of resources, pollution and the spread of invasive alien species. These pressures are themselves driven by a range of socio-economic drivers, chiefly the growing human population and associated increases in global consumption of resources and energy, and the inequity associated with high levels of per capita consumption in developed countries.

Responses to the continuing loss of biodiversity are varied, and include further designation of protected areas, and, increasingly, the improved management for biodiversity in production landscapes and seascapes. There are recent signs of an emerging consensus that biodiversity conservation and sustainable development are inextricably linked, as for example illustrated by the endorsement by the 2002 Johannesburg World Summit on Sustainable Development (WSSD) of the CBD’s 2010 target, and its subsequent incorporation into the Millennium Development Goals.

Global Overview of the Status of Biodiversity

Ecosystems

Fig 5.1 Status of the terrestrial eco-regions. Note: An ecoregion is a large unit of land containing a geographically distinct assemblage of species, natural communities, and environmental conditions.^[1]

Ecosystems vary greatly in size and composition, ranging from a small community of microbes in a drop of water, to the entire Amazon rain forest. The very existence of people, and that of the millions of species with which the planet is shared, is dependent on the health of our ecosystems. People are putting increasing strain on the world’s terrestrial and aquatic ecosystems (see Chapters 3 and 4). Despite the importance of ecosystems, they are being modified in extent and composition by people at an unprecedented rate, with little understanding of the implications this will have in terms of their ability to function and provide services in the future ^[13]. Figure 5.1 depicts an analysis of the status of terrestrial ecosystems.

For more than half of the world’s 14 biomes, 20–50 per cent of their surface areas have already been converted to croplands ^[14]. Tropical dry broadleaf forests have undergone the most rapid conversion since 1950, followed by temperate grasslands, flooded grasslands and savannahs. Approximately 50 per cent of inland water habitats are speculated to have been transformed for human use during the twentieth century ^[15] (see Chapter 4). Some 60 per cent of the world’s major rivers have been fragmented by dams and diversions ^[16], reducing biodiversity as a result of flooding of habitats, disruption of flow patterns, isolation of animal populations and blocking of migration routes. River systems are also being significantly affected by water withdrawals, leaving some major rivers nearly or completely dry. In the marine realm, particularly threatened ecosystems include coral reefs and seamounts (see Box 5.4).

Box 5.4 Deep-sea biodiversity[17]

The deep sea is increasingly recognized as a major reservoir of biodiversity, comparable to the biodiversity associated with tropical rain forests and shallow-water coral reefs. The wealth of diverse deepsea habitats – hydrothermal vents, cold seeps, seamounts, submarine canyons, abyssal plains, oceanic trenches and recently-discovered asphalt volcanoes – contain a vast array of unique ecosystems and endemic species. Although the magnitude of deep-sea diversity is not yet understood (only 0.0001 per cent of the deep seabed has been subject to biological investigations), it has been estimated that the number of species inhabiting the deep sea may be as high as 10 million. It is believed that the deep seabed supports more species than all other marine environments. Marine biodiversity and ecosystems are threatened by pollution, shipping, military activities and climate change, but today fishing presents the greatest threat. The emergence of new fishing technologies and markets for deep-sea fish products has enabled fishing vessels to begin exploiting these diverse, but poorly understood deep-sea ecosystems. The greatest threat to biodiversity in the deep sea is bottom trawling. This type of high seas fishing is most damaging to seamounts and the coldwater corals they sustain. These habitats are home for several commercial bottom-dwelling fish species. Seamounts are also important spawning and feeding grounds for species, such as marine mammals, sharks and tuna, which make them very attractive fishing grounds. The long life cycles and slow sexual maturation of deep-sea fish make them particularly vulnerable to large-scale fishing activities. The lack of data on deep-sea ecosystems and associated biodiversity makes it difficult to predict and control the impacts of human activities, but current levels of bottom trawling on the high seas is unlikely to be sustainable, and may even be unsustainable at greatly reduced levels. Effective management measures for deep-sea fisheries and biodiversity need to be established. Conservation of marine ecosystems has recently extended to the deep sea with the designation in 2003 of the Juan de Fuca Ridge system and associated Endeavour Hydrothermal Vents (2,250 metres deep and 250 kilometres south of Vancouver Island, Canada) as a marine protected area. There are several mechanisms to conserve deep seas, such as the 1982 UN Convention of the Law of the Sea (UNCLOS), 1995 UN Fish Stocks Agreement (UNFSA), International Seabed Authority (ISA), 1992 Convention on Biological Diversity (CBD) and the 1973 Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). However, these mechanisms need more effective implementation if deep-sea ecosystems are to be conserved and sustainably used. Examples of species inhabiting the deep sea. False boarfish, Neocytlus helgae (left) and cold water coral, Lophelia (right). (Credit: Deep Atlantic Stepping Stones Science Party, IFE, URI-IAO and NOAA (left), UNEP 2006b (right)) The seafloor off Northwest Australia showing dense populations of corals and sponges before trawling (left) and after trawling (right). (Credit: Keith Sainsbury, CSIRO)

The fragmentation of ecosystems is increasingly affecting species, particularly migratory species that need a contiguous network of sites for their migratory journeys, species that rely on particular microhabitats and those that require multiple types of habitats during different life cycle stages.

Species

Invertebrates, including butterflies, comprise the vast majority of species. (Credit: Ngoma Photos)

Although about 2 million species have been described, the total number of species range between 5 and 30 million ^[18]. Much of this uncertainty relates to the most species-rich groups such as invertebrates.

Current documented rates of extinction are estimated to be roughly 100 times higher than typical rates in the fossil record ^[19]. Although conservation success in the recovery of several threatened species has been noted ^[20], and a few species that were presumed extinct have been rediscovered ^[21], it is feasible that extinction rates will increase to the order of 1,000–10,000 times background rates over the coming decades ^[22].

Fewer than 10 per cent of the world’s described species have thus far been assessed to determine their conservation status. Of these, over 16,000 species have been identified as threatened with extinction. Of the major vertebrate groups that have been comprehensively assessed, over 30 per cent of amphibians, 23 per cent of mammals and 12 per cent of birds are threatened ^[23].

To understand trends in extinction risk, the conservation status of an entire species group must be assessed at regular intervals. Currently, this information is only available for birds and amphibians, both of which indicate a continuing increase in the risk of extinction from the 1980s to 2004 ^[24].

The threat status of species is not evenly distributed. Tropical moist forests contain by far the highest number of threatened species, followed by tropical dry forests, montane grasslands and dry shrublands. The distribution of threatened species in freshwater habitats is poorly known, but regional assessments from the United States, the Mediterranean Basin and elsewhere indicate that freshwater species are, in general, at much greater risk of extinction than terrestrial taxa ^[25]. Fisheries have also been greatly depleted, with 75 per cent of the world’s fish stocks fully or overexploited (see Chapter 4).

The Living Planet Index measures trends in the abundance of species for which data is available around the world ^[26]. Despite the fact that invertebrates comprise the vast majority of species, trend indices for invertebrate groups only exist for a very small number of species groups, such as butterflies in Europe ^[27]. The existing limited information suggests that invertebrate and vertebrate population declines may be similar, but further studies are required ^[28].

Genes

Genetic diversity provides the basis for adaptation, allowing living organisms to respond to natural selection, and adapt to their environment. Genes therefore play a strong role in the resilience of biodiversity to global changes, such as climate change or novel diseases. Genes also provide direct benefits to people, such as the genetic material needed for improving yield and disease resistance of crops (see the Agriculture section) or for developing medicines and other products (see the Health and Energy sections).

Over the past two decades, many of the world’s most important agricultural crops have lost genetic diversity due to changes in agricultural practices ^[29]. The continued loss of genetic diversity of such crops may have major implications on food security (see Agriculture section). The amount or rate of loss of genetic diversity is poorly known, but inferences can be made from documented extinctions and population declines, which suggest that substantial genetic loss is occurring ^[30].

Global responses to curb biodiversity loss

Fig 5.2 Examples of state, pressure and response indicators that have been adopted by the convention diversity to measure progress towards the 2010 target.^[2]

In 2002, parties to the CBD committed themselves to actions to “achieve, by 2010, a significant reduction of the current rate of biodiversity loss at the global, regional and national levels as a contribution to poverty alleviation and to the benefit of all life on earth” (Decision VI/26, CBD Strategic Plan). Setting this target has helped to highlight the need for improved biodiversity indicators, capable of measuring trends in a range of aspects of global biodiversity. It has also helped to galvanize the scientific community to try to develop indicators capable of measuring trends in the various aspects or levels of biodiversity. Figure 5.2 provides a sample of global biodiversity indicators that will be used to measure progress towards the 2010 target. They measure trends in vertebrate populations, extinction risks for birds, global consumption and the establishment of protected areas ^[31].

The population and extinction risk indices demonstrate a continuing decline in biodiversity, and the ecological footprint indicates that consumption is rapidly and unsustainably increasing. These trends do not bode well for meeting the 2010 biodiversity target at a global scale. Responses to the continuing loss of biodiversity are varied, and include further designation of land and areas of water within protected areas, and increasingly, the improved management for biodiversity in production landscapes and seascapes. The protected areas coverage indicator demonstrates a promising trend in the form of a steady increase in the area under protection.

During the past 20 years, the number of protected areas grew by over 22,000 ^[32] and currently stands at more than 115,000 ^[33]. However, the number of protected areas and their coverage can be misleading indicators of conservation (especially for marine areas), as their establishment is not necessarily followed by effective management and enforcement of regulations ^[34]. Also the percentage and degree to which each ecosystem is protected varies greatly. Roughly 12 per cent of the world’s land surface is included within some kind of protected area, but less than one per cent of the world’s marine ecosystems are protected, with the Great Barrier Reef and the northwestern Hawaiian islands making up one-third the area of all marine protected areas (Figure 5.3) ^[35].

Fig 5.3 Degree of protection of terrestrial eco-regions and large marine ecosystems. Note: All IUCN protected area management categories combined.^[3]

In addition to ensuring the effective management of protected areas, emphasis will increasingly need to be placed on the conservation of biodiversity outside protected areas, and in conjunction with other land uses if the rate of loss of biodiversity is to be reduced. The establishment of new policies and processes at all scales, the reemergence of sustainable agricultural practices, the further development of collaboration among sectors, including corporate partnerships between conservation organizations and extractive industries, and the mainstreaming of biodiversity issues into all areas of decision making, will all contribute to a more secure future for biodiversity, and for sustainable development.

Over the last 20 years environmental issues have increasingly been recognized as important in the development sector at a global scale. The commitment by parties to the CBD to achieve a significant reduction in the rate of biodiversity loss by 2010 as a contribution to poverty alleviation and the benefit of all life on Earth, the endorsement by the 2002 Johannesburg World Summit on Sustainable Development (WSSD) of the CBD’s 2010 target, and the incorporation of the 2010 biodiversity target into the Millennium Development Goals as a new target under Goal 7 on environmental sustainability are some examples. A framework for action was proposed at WSSD to implement sustainable development policies, which covered five key areas (water, energy, health, agriculture and biodiversity - WEHAb), This “WEHAB” framework provided a focus, and confirmed the recognition of biodiversity as a key component of the sustainable development agenda.

Drivers of Change and Pressures

Deforestation in Serra Parima, Orinoco River basin. (Credit: Mark Edwards/Still Pictures)

Currently, population growth and patterns of consumption, which lead to increased demand for ecosystem services and energy, are the most important drivers affecting biodiversity. These drivers result in pressures that have direct impacts on ecosystems, species and genetic resources (see Table 5.1). Human activities cause changes in both the living and non-living components of ecosystems, and these pressures have increased dramatically over the past few decades.

Drivers and pressures seldom act in isolation. They tend to interact in synergistic ways, and their impacts on biodiversity are more than the sum of the effects of the individual drivers and pressures themselves ^[36]. Additionally, the interaction shows considerable regional variation (see Chapter 6). Drivers and pressures act at different temporal and spatial scales. For example, sediments from deforestation in the headwaters of the Orinoco River, deep in South America, have impacts far out in the Wider Caribbean Sea basin, changing the nutrient availability and turbidity of the waters ^[37].

Since the Brundtland Commission report, the globalization of agriculture and inappropriate agricultural policies have emerged as leading drivers influencing the loss of species and ecosystem services. Globalization is leading to major changes in where, how and who produces food and other agricultural commodities. Global market demand for high value commodities such as soybeans, coffee, cotton, oil palm, horticultural crops and biofuels has resulted in substantial habitat conversion and ecosystem degradation. This has replaced diverse small-holder farms with larger monoculture enterprises. In other cases, globalization has concentrated and intensified production on the most productive lands, reducing net deforestation rates.

Virtually all of the factors leading to the accelerating loss of biodiversity are linked to the development of and increasing demand for energy by society. Of particular importance are the high levels of per capita energy use in the developed world, and the potential growth in energy use in the large emerging economies. The rapid increase in demand for energy has profound impacts on biodiversity at two levels ^[38]: impacts from the production and distribution of energy, and those resulting from the use of energy. Exploration for hydrocarbons, pipeline construction, uranium and coal mining, hydroelectric dam construction, harvesting for fuel wood and, increasingly, biofuel plantations can all lead to significant biodiversity loss, both on land and at sea.

The widespread anthropogenic changes to the environment have altered patterns of human disease, and increased pressures on human well-being. The loss of genetic diversity, overcrowding and habitat fragmentation all increase susceptibility to disease outbreaks ^[39]. Some ecosystem changes create new habitat niches for disease vectors, for example, increasing the risk of malaria in Africa and the Amazon Basin ^[40].

The Orinoco River carries sediment that originates from land degradation far away in the Andes all the way to the Caribbean. By contrast, the Caroní river water is clear blue, as it drains the ancient landscapes of the Guyana Highlands, where erosion is much slower. (Credit: NASA 2005^[4])

Trends in biodiversity over the next few decades will largely depend on human actions, especially those relating to land-use changes, energy production and conservation. These actions will, in turn, be affected by various factors including advances in our understanding of ecosystem services, development of viable alternatives to natural resources (especially fossil fuels), and the emphasis placed on the environment and conservation by developed and developing country governments alike. Efforts made to predict the prospects for species-level biodiversity have indicated that extinctions are likely to continue at a pace well above the background rate, with as many as 3.5 per cent of the world’s birds ^[41], and perhaps a greater proportion of amphibians and freshwater fish, being lost or committed to extinction by the middle of the century.

Climate change is likely to play an increasing role in driving changes in biodiversity, with species’ distributions and relative abundances shifting as their preferred climates move towards the poles and higher altitudes, leaving those endemic to polar and high mountain regions most at risk. In addition, changes in the ranges of vector species may facilitate the spread of diseases affecting humans and other species, for example, malaria and the amphibian fungal disease, chytridiomycosis.

The Telestes polylepis, a critically endangered freshwater species found in Croatia. (Credit: Jörg Freyhof)

Further pressure on biodiversity will result from the continuing increase in the global human population, which is predicted to reach 8 billion by 2025 ^[42]. All will require access to food and water, leading to an unavoidable increase in stresses on natural resources. The increased infrastructure required to support such a global population of more than 8 billion people will likely have particular effects on biodiversity in the future (see Chapter 9). The increased need for agricultural production to feed the population will likely be met largely by commercial intensification, with negative consequences for the genetic diversity of agricultural crops and livestock. Extensification will also help to meet the need, with a predicted additional 120 million hectares required by 2030 in developing countries, including lands of high biodiversity value ^[43].

Tropical forests are the terrestrial system likely to be the most affected by human actions in the first half of this century, largely through habitat conversion for agricultural expansion (including the growth of biofuel plantations). Ongoing fragmentation will result in the degradation of the largest remaining areas of species-rich forest blocks in Amazonia and the Congo basin. Marine and coastal ecosystems are also expected to continue to be degraded, with existing impacts, such as fishing, eutrophication from terrestrial activities and coastal conversion for aquaculture, increasing ^[44]. Large species, including top predators, will be particularly affected, with considerable declines and some extinctions likely.

Changes, both positive and negative, in biodiversity trends over the next few decades are inevitable, yet the details of these changes are not yet set in stone. Their magnitude can be somewhat reduced and mitigated by the further integration of biodiversity considerations into national policies, increasing corporate social responsibility activities and conservation actions. With commitment from governments, the private sector, scientific institutions and civil society, action can be taken to ensure progress towards the CBD 2010 target, the1 Millennium Development Goals, and beyond.

Environmental Trends and Responses

Biodiversity is closely linked to livelihood security, agriculture, energy, health and culture, the five themes analysed in this chapter. Of these themes, agriculture (in terms of food security) and energy were explicitly considered in the Brundtland Commission report, and with a focus on water and health, tie together the WEHAB framework for action arising from WSSD. These linkages are likely to emerge as the most critical in implementing actions that will result in truly sustainable development. Table 5.1 summarizes some of the impacts of major drivers on biodiversity, ecosystems and human well-being.

Table 5.1 Impacts on biodiversity of major pressures and associated effects on ecosystem services and human well-being.^[5]

Livelihood Security

Ecosystems provide critical services

Pita, Aechmea magdalane, a thorny-leaved terrestrial bromeliad, grows naturally in lowland forests of southeast Mexico. It is harvested for the commercial extraction of fibre used in the stiching and embroidering of leatherwork. One hectare of forest can provide up to 20 kilogrammes of pita fibre per year, generating an average cash income of US$1 000/ha. (Credit: Elaine Marshall)

Biodiversity contributes directly and indirectly to livelihood security (^[45]. Functioning ecosystems are crucial buffers against extreme climate events, and act as carbon sinks and filters for water-borne and airborne pollutants. For example, the frequency of shallow landslides appears to be strongly related to vegetation cover, as roots play an important role in slope stability, and can give the soil mechanical support at shallow depth. In coastal areas, mangroves and other wetlands are particularly effective in providing shoreline stability, reducing erosion, trapping sediments, toxins and nutrients, and acting as wind and wave breaks to buffer against storms. The role of inland wetlands in storing water and regulating stream-flow is both a function of their vegetative composition, which helps to maintain soil structure, and their characteristically gentle slopes.

Current trends in land degradation and habitat loss continue to contribute to reducing livelihood options while heightening risks. Changes in land management, particularly the replacement of fire-adapted systems with other forms of land cover, can increase the intensity and extent of fires, increasing the hazard to people. Land-use change also influences climate at local, regional and global scales. Forests, shrub and grasslands, freshwater and coastal ecosystems provide critical sources of food and complementary sources of income (see Box 5.2). Fish and wild meat provide animal protein, while other forest resources provide dietary supplements. These ecosystem goods act as critical safety nets for millions of rural poor. Traditionally, access rights and tenure arrangements for these public goods have evolved to enable equitable distribution of such extractive activities. More recently, due to increased population densities and the introduction of market models, access to these common property resources has been increasingly restricted, with resulting impacts on rural livelihoods. With reliable access to markets, the commercialization of many wild-harvested products can be extremely successful in contributing to sustaining rural livelihoods ^[46].

Environmental degradation, combined with heightened exposure and vulnerability of human settlements to risk, contributes to vulnerability to disasters. Almost 2 billion people were affected by disasters in the last decade of the 20th century, 86 per cent of them due to floods and droughts (EM-DAT). Long spells of drought associated with the El Niño Southern Oscillation phenomenon (ENSO) contributed to forest fires in the Amazon Basin, Indonesia and Central America in 1997– 1998. In Indonesia alone, an estimated 45,600 square kilometres (km) of forest were destroyed ^[47]. In Central America, the loss of over 15,000 square kilometers (km²) of forests due to wildfires reduced the capacities of natural forests to buffer the impacts of heavy rainfall and hurricanes, and contributed to the devastating impact of Hurricane Mitch in 1998 ^[48]. These impacts spread beyond the tropics, as the large forest fires of California, Spain, Portugal and other Mediterranean countries in 2005 illustrated ^[49]. Furthermore, coral degradation has negative impacts on coastal communities (see Box 5.5). The clustering of climate-related and biological risks will also contribute to impacts on human well-being through events such as heat waves and crop failures. The impact on human health has been addressed in greater detail in the Health section.

Ecosystems minimize risks

The linkages between biodiversity and livelihood security are complex, and based on the intrinsic relationship between societies and their environment. Policies that can address both the risks and opportunities posed by rapid environmental changes will require a combined focus on ecosystem management, sustainable livelihoods and local risk management. For example, policies aimed at the improved management of water resources and the non-structural mitigation of weather-related hazards can contribute to the reduction of disaster risks by enhancing landscape restoration, coastal forest management and local conservation and sustainable use initiatives. In coastal ecosystems, restoring mangroves in cyclone-prone areas increases physical protection against storms, creates a reservoir for carbon sequestration and increases livelihood options by generating much-needed income for local communities ^[51]. Although the evidence base is varied, communities hit by the 2004 tsunami in South Asia reported less damage in areas with healthy mangrove forests than those with few natural sea defences ^[52]. India and Bangladesh have come to recognize the importance of the Sunderbans mangrove forest in the Gulf of Bengal, not only as a source of livelihoods for fishing communities, but also as an effective mechanism for coastal protection. Viet Nam is also investing in mangrove restoration as a cost-effective means for increased coastal protection (see Box 5.6). Similar benefits can be derived from coral reefs ^[53].

Agriculture

Links between biodiversity and agriculture

Fig 5.4 Contempolary extent of agricultural systems.^[6]

Agriculture is defined broadly here to include crops and agroforestry products, livestock and fisheries production. Of some 270,000 known species of higher plants about 10,000–15,000 are edible, and about 7,000 of them are used in agriculture. However, increased globalization threatens to diminish the varieties that are traditionally used in most agricultural systems. For example, only 14 animal species currently account for 90 per cent of all livestock production, and only 30 crops dominate global agriculture, providing an estimated 90 per cent of the calories consumed by the world’s population ^[55]. Despite its crucial importance in supporting societies, agriculture remains the largest driver of genetic erosion, species loss and conversion of natural habitats around the world ^[56] (see Figure 5.4).

Both cultivated and wild biodiversity provide services necessary for agriculture (see Table 5.2). Although seldom valued in economic terms, these services play a very significant role in national and regional economies. Different types of agricultural production systems (such as commercial intensive, smallholder, pastoralism and agroforestry systems) use these services to varying degrees and intensity. For example, the use of nitrogen-fixing legume trees in maize-based systems of Eastern and Southern Africa is helping local farming populations to increase per hectare production of maize without otherwise investing in inorganic fertilizers ^[57]. In addition, environmental benefits are gained through carbon sequestration and provision of fuel wood.

Habitat conversion is often justified as essential to increasing agricultural production, and trends in agricultural land use over the past 20 years are presented in Chapters 3 and 6. Although more than 300 000 km² of land have been converted to agricultural use in the tropics alone ^[58], much of this is of marginal use for agriculture or particular crops. This has led to inefficient use of resources, often resulting in degradation of land and ecosystem services (see Chapter 3). Some 1.5 billion people, about half of the world’s total labour force and nearly one quarter of the global population, are employed in agriculture, or their livelihoods are directly linked to it ^[59], and women make up the majority of agricultural workers. When agriculture on marginal lands is reduced and these lands are appropriately managed, ecosystems can recover, as demonstrated by the expansion of forests in parts of Europe, North America, Japan, China, India, Viet Nam, New Zealand and Latin America ^[60].

Table 5.2 Biodiversity benefits to agriculture through ecosystem services.^[7]

Meeting global food needs poses increasing challenges, and will require either intensification or extensification to increase agricultural productivity ^[61]. Intensified systems tend to be dominated by only a few varieties. This approach is usually associated with higher levels of inputs, including technology, agrochemicals, energy and water use. The latter three, at least, have serious negative impacts on biodiversity.

Extensification relies on lower inputs, and generally on more land being used, often through habitat conversion. In many parts of the world, agricultural extensification involves converting more land for the cultivation of major commodities such as soybeans (Latin America and the Caribbean), oil palm and rubber (Asia and the Pacific), and coffee (Africa, Latin America and Asia), and it is exacerbated by the emergence of new markets for export. In Brazil, for example, the area of land used for growing soybeans (most of which are exported to China) grew from 117,000 km² in 1994 to 210,000 km² in 2003. This was driven by a 52 per cent increase in world consumption of soybeans and soybean products ^[62], and these figures continue to rise dramatically.

A major agricultural biotechnology innovation during the past two decades is the use of “transgenic” or living modified organisms (LMOs) to provide new attributes in different crops and breeds ^[63]. The technology is very young, and major investments are being made to enhance its contributions to human well-being and business stability. Research on LMOs has focused mainly on mitigating the impacts of pests and diseases, and there is evidence of reduced needs for pesticides and herbicides in some crops, such as cotton and maize, through genetic modification ^[64]. The global production of genetically modified crops (mainly maize, soybean and cotton) was estimated to cover more than 900,000 km² in 2005 ^[65]. The use of LMOs is, as for many new technologies, highly controversial, specifically in relation to the uncertain impacts on ecosystems (through escape and naturalization in the landscape), human health and social structures. There are concerns about how its introduction will affect poor people, whose livelihoods depend primarily on traditional low input agricultural practices. Increased research, monitoring and regulation are needed to ensure these negative impacts are avoided as this technology is developed (see Chapter 3). The Cartagena Protocol on Biosafety was negotiated and adopted under the CBD to develop a global framework for managing and regulating LMOs ^[66].

More recently, increasing attention is being given to the existing and potential impacts of climate change on agriculture. Issues include the timing of growth, flowering and maturing of crops, and the impacts of (and on) pollinators, water resources and the distribution of rainfall. There are also issues of changes in market structures, yields for different crops and strains, and the impacts of extreme weather events on traditional methods and livelihoods ^[67]. Models show that in some areas, specifically where low temperature is a growth-limiting factor, agricultural productivity may increase with climate change. In other areas, where water and heat are limiting factors, productivity may be severely curtailed ^[68].

Changes in production practices and loss of diversity in agro-ecosystems can undermine the ecosystem services necessary to sustain agriculture. For example, pollinator diversity and numbers are affected by habitat fragmentation ^[69], agricultural practices ^[70], the land-use matrix surrounding agricultural areas ^[71] and other land-use changes ^[72]. Although some of the crops that supply a significant proportion of the world’s major staples do not require animal pollination (such as rice and maize), the decline of pollinators has long-term consequences for those crop species that serve as crucial sources of micronutrients and minerals (such as fruit trees and vegetables) in many parts of the world.

Genetic erosion, loss of local populations of species, and loss of cultural traditions are often intimately intertwined. While rates of genetic erosion are poorly known, they generally accompany the transition from traditional to commercially developed varieties ^[73]. In crop and livestock production systems throughout the developing world, genetic erosion reduces smallholder farmer options for mitigating impacts of environmental change and reducing vulnerability, especially in marginal habitats or agricultural systems that are predisposed to extreme weather conditions (such as arid and semi-arid lands of Africa and India).

Implications for agricultural technologies and policy

Methodological and technological innovation

Since the Brundtland Commission report, agricultural research and development has made major advances in integrating conservation and development to mitigate loss of biodiversity, reverse land degradation and foster environmental sustainability. Much remains to be done to create the appropriate enabling environment in many countries, rich and poor alike, especially in eliminating anti-conservation regulations and inappropriate agricultural production subsidies.

Agriculture in a rain forest in Ghana, growing cassava and fruits such as bananas and papayas. (Credit: Ron Giling/Still Pictures)

A particular area of advancement is the use of innovative agricultural practices to enhance production while conserving native biodiversity ^[74]. Efforts to foster biodiversity-friendly practices by integrating trees on farms (agroforestry), conservation agriculture, organic agriculture and integrated pest management are all contributing towards the sustainability of production landscapes (see Chapter 3). Agroforestry, for example, has emerged as a major opportunity for achieving biodiversity conservation and sustainability in production landscapes ^[75], through three major pathways: reducing pressure on natural forests, providing habitat for native plant and animal species and serving as an effective land use in fragmented landscapes (see Box 5.7).

Integrated land management approaches are also helping to enhance ecosystem resilience through participatory processes that engage and empower farmers, strengthen local institutions and create options for value-added income generation. These approaches offer significant prospects for restoring degraded lands to enhance habitat connectivity and ecosystem processes. In the tropical forest margins, where slash-and-burn farming is a major cause of deforestation, knowledge of land-use dynamics has helped to identify practical options that are profitable for small-scale farmers and at the same time environmentally sustainable ^[76]. However, a major challenge to wide-scale implementation of these approaches is the lack of appropriate policy frameworks that align rural and agricultural policies with the protection of biodiversity and ecosystem services. Without such links, the value of integrated natural resource management ^[77] and ecoagriculture ^[78] innovations will remain marginal in ensuring the long-term viability of biodiversity.

Very substantial collections of plant genetic resources for food and agriculture are now maintained around the world through the Consultative Group on International Agricultural Research (CGIAR) system. These institutional gene banks are vital for safeguarding germplasm. Farmers have much to contribute at the local level in maintaining the viability of different varieties, such as is being done in an innovative partnership between the International Potato Center and local communities in Peru, an approach that produces income for the farmers while conserving genetic variability. This also helps maintain local ecological knowledge.

Policy options and governance mechanisms

Local and community initiatives remain crucial for supporting agricultural approaches that maintain biodiversity. It is challenging to expand these initiatives, since they are based on local differentiation and diversity, rather than homogenization and mass production. The development of recognized standards and certification for production methods can help give producers in these initiatives greater weight and value in the global market.

However, little progress has been made overall on institutionalizing a more diverse approach to production systems, and in monitoring its effects. The techniques that would support reduced pesticide or herbicide use, for example, have yet to be adopted in most countries, and the full value of the ecosystem services provided by ecologically oriented agricultural systems are only very slowly being recognized. Increased research, and the adoption of techniques, such as integrated pest management, can reduce the use of chemicals while providing important biodiversity conservation services. Similarly, remedial measures required to restore productivity to degraded lands are not being implemented on the scale required. The ecosystem approach can provide a framework for developing practices, such as riparian buffer systems, to both support biodiversity conservation, and assist in water management and purification.

National level legislative and policy measures on land tenure and land-use practices will be key to facilitating wide-scale adoption of proven biodiversity supporting methodologies and technological options in agriculture. The options offer practical solutions that reduce the impacts of agriculture on biodiversity, but need to be considered within a supportive policy framework that encompasses both commercial and small-scale agricultural production landscapes. At the global scale, ongoing international negotiations are addressing imbalances in markets, subsidies and property rights, all of which have direct links to land use in agriculture (see Box 5.8). However, there are still major challenges to the conclusion and implementation of the kind of agreements that would generate tangible impacts on biodiversity and agriculture, particularly in the developing world.

Energy

Links between biodiversity and energy

Fig 5.5 Primary energy supply from various sources and projections to 2030.^[8]

Many forms of energy are the result of a service provided by ecosystems, now or laid down in the form of fossil fuels far in the past. Conversely, society’s growing requirements for energy are resulting in significant changes in those same ecosystems, both in the search for energy sources, and as a result of energy use patterns. Given that energy is a fundamental requirement for supporting development in all economies, the challenge is to sustainably provide it without driving further loss of biodiversity. It is necessary to define the trade-offs required, and develop appropriate mitigation and adaptation strategies.

Demand for energy is projected to grow at least 53 per cent by 2030 ^[80]. Energy from biomass and waste is projected to supply about 10 per cent of global demand until 2030 (see Figure 5.5). However, this assumes that adequate fossil fuels will be available to address the majority of the increase in demand, and some have suggested this may not be realistic ^[81]. Energy-related carbon dioxide emissions are expected to increase slightly faster than energy use by 2030 (see Chapter 2).

Energy use has impacts at local, national and global levels.Pollution from burning fossil fuels , and the associated effects of acid rain have been a problem for European and North American forests, lakes and soils, although the impacts on biodiversity have not been as significant or widespread as cautioned in the Brundtland Commission report. While emission controls in Europe and North America led to a reversal of acidification trends, there is now a risk of acidification in other areas of the world, particularly Asia (see Chapters 2 and 3). Use of thermal and nuclear power results in waste disposal problems, as do solar cells, which can result in soil contamination by heavy metals. Desertification in the Sahel and elsewhere in sub-Saharan Africa has been linked in part to fuel demand from biomass (see Box 5.9) ^[82]. Indirect effects of energy use include both overexploitation of natural resources and greatly facilitated spread of invasive alien species through global trade, both made possible through cheap and easily-available energy for transport.

The impacts noted above are relatively localized and small in comparison to the potential impacts of climate change, which results largely from energy use (see Chapters 2, 3 and 4). As a result of climate change, species ranges and behaviour are changing (see Box 5.10 and Chapter 6), with consequences for human well-being, including changing patterns of human disease distribution, and increased opportunities for invasive alien species. Species most likely to be affected include those that already are rare or threatened, migratory species, polar species, genetically impoverished species, peripheral populations and specialized species, including those restricted to alpine areas and islands. Some amphibian species extinctions have already been linked with climate change ^[83], and a recent global study estimated that 15–37 per cent of regional endemic species could be committed to extinction by 2050 ^[84].

Box 5.9 Biodiversity and energy supply for the poor[85]

Fig 5.6 relationship between income and energy use in urban areas of 12 developing countries.[9] Biodiversity-based energy sources include both traditional biomass and modern biofuels. Ecosystems provide relatively inexpensive and accessible sources of traditional biomass energy, and therefore have a vital role to play in supporting poor populations (see Figure 5.6). If these resources are threatened, as is the case in some countries with extreme deforestation, poverty reduction will be an even greater challenge. Use of fuelwood can cause deforestation, but demand for fuelwood can also encourage tree planting, as occurs, for example, in Kenya, Mali and several other developing countries.

Climate change is also having impacts at ecosystem scales. By 2000, 27 per cent of the world’s coral reefs had been degraded in part by increased water temperatures, with the largest single cause being the climate-related coral bleaching event of 1998. For some reefs recovery is already being reported ^[86]. Mediterranean-type ecosystems found in the Mediterranean basin, California, Chile, South Africa and Western Australia are expected to be strongly affected by climate change ^[87].

Managing energy demand and biodiversity impacts

Few energy sources are completely biodiversity neutral, and energy choices need to be made with an understanding of the trade-offs involved in any specific situation, and the subsequent impacts on biodiversity and human well-being (see Table 5.3). Biodiversity management is emerging as a key tool for the mitigation of and adaptation to the impacts of climate change – from avoided deforestation to biodiversity offsets – while contributing to the conservation of a wide range of ecosystem services.

Table 5.3 Energy sources and their impacts on biodiversity. (See Figure 5.5 for percentage of total primary energy supply)

There are a number of management and policy responses to the increasing demand for energy and the impacts on biodiversity. One important response to the rising price of oil is increasing interest in other energy sources. Prime among these are biofuels, with several countries investing significant resources in this field (see Box 5.11). The world output of biofuels, assuming current practice and policy, is projected to increase almost fivefold, from 20 million tonnes of oil equivalent (Mtoe) in 2005 to 92 Mtoe in 2030. Biofuels, which are produced on 1 per cent of the world’s arable land, support 1 per cent of road transport demand, but that is projected to increase to 4 per cent by 2030, with the biggest increases in United States and Europe. Without significant improvement in productivity of biofuel crops, along with similar progress in food crop agricultural productivity, achieving 100 per cent of transport fuel demand from biofuels is clearly impossible ^[103]. In addition, large-scale biofuel production will also create vast areas of biodiversity-poor monocultures, replacing ecosystems such as low-productivity agricultural areas, which are currently of high biodiversity value. Current actions to address the impacts of climate change can be both beneficial and harmful to biodiversity. For example, some carbon sequestration programmes, designed to mitigate impacts of greenhouse gases, can lead to adverse impacts on biodiversity through the establishment of monoculture forestry on areas of otherwise high biodiversity value.

Avoiding deforestation, primarily through forest conserv