Why is Biodiversity Important? Introductory slide Prior to beginning the discussion you may want students to take a few minutes to note down why biodiversity is important to them personally. Later they could share these notes with other students in the class and consider how their personal reasons fit in with the broader context of values of biodiversity presented during the class.
Biodiversity Values Are Subjective: perspectives and scales Values impact our decisions. Placing a value or set of values on biodiversity is often central to conservation decisions, and frequently a cause for debate over these decisions. For example, should an area be protected to save endangered species, maintained for economic reasons, such as logging, mining, or oil extraction, maintained for recreational use, or for its aesthetic beauty. Many conservation decisions are centered, either directly or indirectly, on values. This slide illustrates some of the viewpoints that diverse stakeholders bring to conservation decisions Depending on the size and length of the class, this slide can be presented in several ways. One option is to have students prepare an argument in advance to conserve a wetland or other area, ideally a place locally. Students in the class could be divided into several groups, for example, representing the perspectives of a logging company, a conservation organization, a government agency, and a recreational group. During the class students could then present their arguments in a debate format. Alternatively, this can be done informally during the class by setting aside five minutes for the students to consider (either in groups or pairs) some of the different perspectives each of the different stakeholders have towards the wetland depicted in the slide. In either case one can point out how values change over time. Are wetlands valued differently today then they were 200 years ago? If so, why?
The Value of Biodiversity The values people assign to biodiversity can be placed into two main categories: those that are intrinsic or inherent to the organism or ecosystem, and those which grow out of utilitarian, instrumental, or extrinsic uses or applications of biodiversity.
Intrinsic/Inherent Value Define intrinsic or inherent value. The intrinsic or inherent value of biodiversity refers to its right to exist, completely independent of any extrinsic or utilitarian values it might have to humans and to other biodiversity. Some of the more abstract extrinsic values are frequently misidentified as intrinsic values; for example, aesthetic value or the value of biodiversity to an ecosystem rather than to humans. This slide can serve as a starting point for discussion, depending on class time, size and level, any one of these topics could take 30-45 minutes to discuss. What role does intrinsic value play in existing conservation policy and laws? How do intrinsic values of biodiversity impact conservation decisions? Useful articles for this discussion include Lawton 1991, Callicott 1997, the Endangered Species Act, and the United Nations Charter on Nature 1982. Some teachers may prefer to present this slide, after the slides on extrinsic values, which are more concrete.
Prior to showing the next this slide and the following slide, ask the students to list some of the extrinsic or utilitarian values of biodiversity. This can be done as a group using brainstorming techniques, or in pairs or small groups initially and then as a class compiling the list. Using the list developed by the class examine the different categories of extrinsic values. Divide the list to show things that are “ direct use ” values or goods and those that are “ indirect use ” values or services . Then separate out those which are “ non-use ” values (i.e., bequest, existence, and potential values). Introduce the fact that there are several ways to categorize extrinsic values, and that many authors use slightly different methods, for example, some choose to place spiritual and cultural values as distinct from services such as pollination or nutrient cycling which are crucial to survival. Further, potential value is often included as a use value since potential value is based on the future use that biodiversity might have; others include this as a non-use value since it is, by nature, an abstract concept and the potential use that something might have is undetermined. Similarly with bequest value, if the idea is passing on something for the next generation to use, bequest value can be considered a kind of use value; but considering bequest value from a more abstract perspective renders bequest value closer to a non-use value, if the value lies simply in knowing that something will be there for the future regardless of whether it will be used. Were some values easier to think of than others? What kinds of values are easy to overlook? Categorizing Values In the conservation biology and ecological economics literature, there are many methods to categorize the value or worth of biodiversity. Often the value of biodiversity is subdivided into categories based on how biodiversity is used. Extrinsic value is a broad category encompassing many types of biodiversity values. Extrinsic values – also referred to as utilitarian or use values – include biodiversity ’ s direct or indirect use to other living things. This slide lists the major categories of extrinsic values, direct-use values or goods, and indirect-use values or services. It also includes a list of “ non-use ” values, potential, existence, and bequest values. Some include potential value as part of use value. We will examine each of these values in detail.
Direct Use Value: Goods This slide lists some of the different kinds of goods or products derived from biodiversity including food, building materials, fuel, paper products, fiber for clothing and textiles, industrial products, and medicine. In subsequent slides, several of these goods will be highlighted. [Note: The image depicts a man in Vietnam who is extracting bamboo for use as building material.]
Food Historically, humans have exploited thousands of plant species for food; today, however, most people on Earth depend on three staple crops (rice, wheat, and corn). Despite this dependence on few species, the genetic diversity in wild plants and animals remain important for creating new strains or breeds. Also, there are many species that one day could be a potential food source. Sorghum, emmer, and spelt, once widely grown grains, have been largely replaced by wheat. However, because of their unique environmental adaptations – sorghum, for example, can be grown in drier climates that do not support wheat – these grasses may become more important in the future if climatic conditions change. [Image is of rice paddies in Vietnam.]
Building Materials, Fuel, and Paper Products Trees and several grasses, most notably bamboo and rattan, are basic commodities used worldwide for building materials, paper products, and fuel. The worldwide production of timber and related products – including homes, furniture, mulch, chipboard, paper and packaging – is a multi-billion dollar industry. Outside of large market economies, products from particular species of wild-growing woody plants are key sources of shelter (e.g., termite-resistant support poles), household items (furniture, utensils, baskets, etc.), long-burning fuels, and dyes. One of the most important uses of wood is for fuel. According to the World Resources Institute, 63 percent of all harvested wood is used as fuel – whether burned directly or after being converted to charcoal. Fuelwood, charcoal, and other fuel from wood are the major sources of energy in low-income countries; the major consumers and producers of wood for fuel are Brazil, China, India, Indonesia, and Nigeria. [Image is of children in Vietnam preparing thatch for roofs.] Prior to showing the next slide ask students if they can guess how many of the leading prescription drugs have their origins in biodiversity. Students can also guess how many people in developing countries depend directly on plants for medicine.
Medicine People depend on biodiversity for medicinal purposes in two ways: directly as a primary source of medicine, and indirectly as a source of the chemical structures used in synthesizing drugs or service. [Image depicts medicinal herbs in a market in Bolivia.]
Traditional Medicine: Basis of Many Drugs This table gives some examples of Western drugs whose origins were from plants. Those noted in bold were originally used for tradition medicine. Instructor may choose to tell any number of stories of drug discovery based on plants used for traditional medicine, such as the use of foxglove for heart conditions, now the basis for digitoxin.
Indirect Use Values: Services This slide lists some of the different services provided by biodiversity. Ecosystem services encompass a wide variety of different resources, functions, and processes provided to humans and to other biodiversity. Unlike goods, these are often outside traditional economic markets, and thus more difficult to value monetarily. Several of the services of biodiversity will be examined in the following slides. Is it possible to place a value on ecosystem services, like nutrient cycling or watershed protection? Why is it helpful to do this? The article by Costanza and others (1997) can form the basis of a discussion on this subject
Global Processes: Atmospheric Regulation Forests and other vegetation modify climate in a variety of ways; they affect sun reflectance, water vapor release, wind patterns, and moisture loss. Photosynthetic biodiversity also has the potential to moderate the rising atmospheric carbon dioxide levels linked to global climate change by fixing carbon in organic matter. The evolution of photosynthesis is responsible for one of the most dramatic changes in the Earth's environment: the increase of atmospheric oxygen. 3.5 billion years ago, cyanobacteria, through the process of photosynthesis, released oxygen and helped to create the atmosphere we know today. The regulation of atmospheric oxygen depends on biodiversity. Carbon cycles between the land, atmosphere, and oceans through a combination of physical, chemical, geological, and biological processes. One key way biodiversity influences the composition of the earth ’ s atmosphere, and in turn its climate, is through its role in carbon cycling in the oceans
Global Processes: Climate Regulation Besides regulating the atmosphere ’ s composition, the extent and distribution of different types of vegetation over the globe modifies climate in three main ways: affecting the reflectance of sunlight ( radiation balance ); regulating the release of water vapor ( evapotranspiration ); and changing wind patterns and moisture loss ( surface roughness ). Vegetation absorbs water from the soil and releases it back into the atmosphere through evapotranspiration , which is the major pathway for water to move from the soil to the atmosphere. This release of water from vegetation cools the air temperature. In the Amazon region, vegetation and climate is tightly coupled; evapotranspiration of plants is believed to contribute fifty percent of the annual rainfall. Deforestation in this region leads to a complex feedback mechanism: as forest cover decreases, evapotranspiration rates decline, which in turn decreases rainfall and increases the area ’ s vulnerability to fire.
Soil and water conservation: Biodiversity is also important for global soil and water protection. Terrestrial vegetation in forests and other upland habitats maintain water quality and quantity, and control soil erosion. In watersheds where vegetation has been removed, flooding prevails in the wet season and drought in the dry season. Soil erosion is also more intense and rapid, causing a double effect: removing nutrient-rich topsoil and leading to siltation in downstream riverine and ultimately oceanic environments. This example focuses on services provided by coastal wetlands and mangroves. Wetlands are ecosystems where water is present at or near the soil surface or root zone for part or all of the year; the vegetation found in these regions is adapted for these conditions. Wetlands are among the world's most productive ecosystems and provide a range of ecological services, including filtering excess nutrients, trapping sediments, minimizing damage to coastal areas from floods and waves, and providing critical habitat for many birds, fish, and shellfish – in particular the juvenile stage of several commercial fish. The services of a wetland are not easy to replace if they are removed. Dams and water treatment facilities are the engineering equivalent of a wetland, but are often very expensive to build and maintain. According to the US Army Corps of Engineers, without the 3,800 hectares of wetlands that exist along the Charles River in Boston, Massachusetts, flood damage would cost $17 million per year. This is one method to establish a value for biodiversity – by its “ replacement value. ”
Nutrient Cycling The flow of nutrients through an ecosystem is critical to its health. Biodiversity (including algae, fungi, bacteria, and insects) decompose organic matter, recycling and returning nutrients to soils. [The image is of a decomposing deer.]
Pollination and Seed Dispersal Approximately 90% of flowering plants depend on pollination by bees, birds, bats and other pollinators for reproduction. The loss of pollinators and the services they provide would drastically reduce the size of food harvests and threaten non-agricultural species with extinction. Besides pollination, biodiversity provides many other services to agriculture not detailed here, such as natural pest control and a genetic library for crop and livestock improvement.
Source of Inspiration or Information Humans have always relied on biodiversity to help understand and solve problems in the world around us. This slide examines some of the ways that biodiversity inspires us, from biomimicry to applied biology and medical models, as well as for scientific research and education. Discoveries made during scientific research have revolutionized many fields. A heat-tolerant enzyme found in bacteria living in the hotsprings of Yellowstone National Park in the United States is the underpinning of much of today ’ s genetic and biotechnology research. These heat-tolerant enzymes, known as taq enzymes, are used in the polymerase chain reaction (PCR) to replicate genetic material. From airplanes to velcro, the natural world has provided a source of inspiration to overcome challenges. This phenomenon is sometimes termed “ biomimicry ” as the technological innovation mimics something from the biological world. For example, Velcro was patterned after cockleburs, a plant that disperses its seeds via its sticky seed pods that attach to people or animals as they walk through a meadow.
Medical Models Biodiversity also provides a source of medical models to better understand diseases. Understanding how bears are able to hibernate may uncover new ways to assist trauma patients and treat kidney disease and osteoporosis. Bears hibernate for 150 days, stopping all normal functions (such as eating, drinking, urinating, and defecating). Bears are able to accomplish this arrest of bodily functions by lowering their body temperature only slightly – by 5 degrees Celsius. Scientists have discovered a protein that induces hibernation, slowing organ metabolism and blood coagulation. One application of this discovery could be to slow bleeding in trauma patients while in transit to the emergency room. During hibernation, bears are also able to recycle their urine and use it to rebuild tissue. This ability may be useful for treating kidney illnesses. Finally, bears also manage to survive hibernation with minimal bone loss, which may provide solutions for people suffering from osteoporosis.
Spiritual and Cultural Values Most cultures place distinct values on natural areas. Symbols from the natural world are used in art and literature; different cultures often place different values on biodiversity. Nature is often central to spiritual traditions. Many religions (from Buddhism to Christianity) seek to define humans ’ relationship to Nature. [This image from Bolivia depicts an Aymara man with the hide of an Andean cat ( Oreailurus jacobita ) , considered sacred by the Aymara people. Traditions vary in the Andean region, in some areas, hunting of the Andean cat is taboo, while in others, their skins are used in religious rites or as part of costumes for traditional dances.]
Aesthetic Value Another example of cultural values is the aesthetic value that different cultures find in biodiversity. In fact many of the first national parks and protected areas were created to protect beautiful and awe-inspiring landscapes. How do aesthetic values differ between cultures?
Ecological Value: Does Diversity Make Communities More Resilient Natural communities are finely tuned systems, where each species has an ecological value to the other species that are part of that ecosystem. Species diversity increases an ecosystem ’ s stability and resilience, in particular its ability to adapt and respond to changing environmental conditions. If a certain amount, or type (such as a keystone species) of species are lost, eventually it leads to the loss of ecosystem function. Many ecosystems though have built-in redundancies so that two or more species ’ functions may overlap. Because of these redundancies, several changes in the number or type of species may not impact an ecosystem. However, not all species within an ecosystem are of the same importance. Species that are important due to their sheer numbers are often called dominant species . These species make up the most biomass of an ecosystem. Species that have important ecological roles that are greater than one would expect based on their abundance are called keystone species. These species are often central to the structure of an ecosystem; removal of one or several keystone species may have consequences immediately, or decades or centuries later (Jackson et al. 2001). Ecosystems are complex and difficult to study, thus it is often difficult to identify keystone species. In the following example, the impact of removing an individual or several keystone species from kelp forest ecosystems in the Pacific is examined.
Kelp Forest Food Webs Kelp forests, as their name suggests, are dominated by kelp, a brown seaweed of the family Laminariales. They are found in shallow, rocky habitats from temperate to subarctic regions, and are important ecosystems for many commercially valuable fish and invertebrates. Sea otters ( Enhydra lutris ) are considered a keystone species, as a result of their role in structuring the kelp forest habitats found off the coast of western North America. These illustrations show kelp forest food webs in the presence and absence of sea otters, and demonstrate how the loss of this keystone species can drastically alter and reduce ecosystem function and complexity.
Non-Use or Passive Values There are several less tangible values that are sometimes called non-use or passive values, for things that we don ’ t use but would feel a loss if they were to disappear; these typically include existence value , the value of knowing something exists even if you will never use it or see it, and bequest value , the value of knowing something will be there for future generations. Economists sometimes use surveys to estimate these values, asking for example what someone is willing to pay to simply know that tigers exist even if they will never see or use one. Potential or option value refers to the use that something may have in the future; some authors consider this a form of use value, but here it is included within the passive values based on its abstract nature, for example, a plant may have a potential value but until this value is realized, this value is uncertain; once the plant ’ s value is recognized, it is a use value.
Why Do Values Matter? Values are central to conservation decisions, and conservation biology has even been termed a “ value-laden ” science (Soul é 1985). When we measure biodiversity or set conservation priorities, we must decide which species, populations, or ecosystems to study, monitor, manage, or conserve, and these choices depend upon what we currently value. What role do some of the values discussed today have in conservation decisions in your community? globally? See also the Teacher’s Guide for additional discussion questions.
Transcript of "Why is biodiversity important"
Why is Biodiversity Important? Presentation Working version, December 2003 prepared by M.F. Laverty and E.J. Sterling Reproduction of this material is authorized by the recipient institution for non-profit/non-commercial educational use and distribution to students enrolled in course work at the institution. Distribution may be made by photocopying or via the institutions intranet restricted to enrolled students. Recipient agrees not to make commercial use, such as, without limitation, in publications distributed by a commercial publisher, without the prior express written consent of AMNH. All reproduction or distribution must provide full citation of the original work and provide a copyright notice as follows:"Copyright 2003, by the authors of the material, with license for use granted to the Center for Biodiversity and Conservation of the American Museum of Natural History. All rights reserved." This material is based on work supported by the National Science Foundation under the Course, Curriculum and Laboratory Improvement program (NSF 0127506), and the United States Fish and Wildlife Service (Grant Agreement No. 98210-1-G017).Any opinions, findings and conclusions, or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the American Museum of Natural History, the National Science Foundation, or the United States Fish and Wildlife Service.
Categorizing ValuesDirect Use Indirect Use Non-Use ValuesValue(Goods) Value (Services)Food, medicine, Atmospheric and Potential (or Future value eitherbuilding material, climate regulation, Option) Value as a good orfiber, fuel pollination, service nutrient recycling Cultural, Spiritual Existence Value Value of knowing and Aesthetic something exists Bequest Value Value of knowing that something will be there for future generations
Medical Models Hibernating bears may improve the treatment of: – trauma patients – kidney disease – osteoporosisSource: New Jersey Fish and Wildlife
Spiritual and Cultural Values• The survival of natural areas and species are important to different cultures around the world.• Thousands of cultural groups in the world, each have distinct traditions and knowledge for relating to Source: Projecto Gato Andino Bolivia, Villalba & Bernal, 1998 natural world
Ecological Value: Does DiversityMake Communities More Resilient? • Resilient ecosystems are characterized by: – Constancy (Lack of fluctuation) – Inertia (Resistance to perturbation) – Renewal (Ability to repair damage) • Not all species are critical to an ecosystems function; many fill redundant roles; basis for community resilience and integrity • If too many species or keystone species are lost, eventually it leads to the failure of ecosystem function