Global Marine Biological Diversity

A Strategy For Building Conservation Into Decision Making

Elliott A. Norse

• Publisher: Island Press
• Year: 2013
• Print ISBN: 9781559632560, 9781559632553
• eBook ISBN: 9781610912723
• Subtopic: Marine Biology

Global Marine Biological Diversity presents the most up-to-date information and view on the challenge of conserving the living sea and how that challenge can be met.

CHAPTER ONE

Conserving the Living Sea

IN 1741, the crew of a Russian ship stranded on Bering Island in the cold North Pacific discovered huge sea creatures in the surrounding waters. Unlike the seals and whales that the sailors knew, these four- to ten-ton mammals grazed the abundant seaweeds like cattle. The hungry men devised a method of killing the beasts, and found the meat and fat delectable. On reaching safety, they told others of their good fortune. More ships came, taking advantage of this bounteous food source, until, in 1768, sailors killed the last Steller’s sea cow (Hydrodamalis gigas) (Figure 1-1). From its discovery by Western civilization to its extinction took only 27 years (Reynolds and Odell 1991).

What was lost? Steller’s sea cow was a magnificent species, possibly the largest herbivore in the world, one shaped by the same forces that shaped our own species. It was one of only two members of its family; the other, the dugong (Dugong dugon), a smaller sea cow of the tropical Indian and Pacific Oceans, is now endangered in most of its range. Steller’s sea cow apparently was ecologically important. In prehistoric times, it had ranged widely in the North Pacific, and its grazing probably played a major role in kelp forest ecosystems (Dayton 1975). It was a species that could have benefited humans as a resource. Its gut microorganisms could well have been used to generate fuel gas using seaweed as a feedstock. And, as a source of food for humans, Steller’s sea cow was unique: Not only was it delicious, but it grazed marine pastures that cattle and sheep cannot. Whether our interests are ethical, ecological, or economic, the extinction of Steller’s sea cow was a tragedy.

Although this drama unfolded two and a half centuries ago, it cannot be dismissed as the kind of error humankind made only in the past, before the genesis of modern conservation. Rather, as the 20th century ends, we are playing countless variations on the same theme, in the tropics and the cold regions, in countries rich and poor, on land, in fresh waters, and in the sea. The wealth of life on Earth is now being—or is about to be—lost at a rate exceeding any in 65 million years, since a global disaster (probably the impact of a comet or asteroid) killed off the dinosaurs and vast numbers of other species.

Figure 1-1. Steller’s sea cow. European hunters drove this gigantic seaweed-grazing mammal to extinction 27 years after its discovery in the North Pacific Ocean. Loss of genes, species, and ecosystems is a rapidly worsening problem in the sea, as on land.

This present-day global mass extinction event differs from those of the past: It is not due to the inevitable momentum of a mindless mass of rock. Rather, it is because an intelligent species threatens life on our planet, a species able to recognize its impact and change its course.

The ethical implications of this mass extinction are enormous and must not be ignored. Religions, philosophies, and laws honored throughout the world make humans responsible for actions affecting other living things. Humankind, the other animals, plants, and microorganisms share a common ancestry on the tree of life that goes back 3.5 billion years; the same processes that created us created them as well. But in a world in which hunger, disease, ethnic strife, social upheaval, political oppression, and extreme disparity in wealth plague our species, some people might think that the loss of biological diversity is less important than pressing human needs, such as economic development and national security.

This attitude ignores one fundamental fact: Humans are utterly dependent on other living things. Every breath we take, every bite of food we eat, and every drop of water we drink comes from the diversity of life. Living things are our resources and the life-support systems that maintain conditions in which we can survive and prosper. Living things are the basis of economic development and national security. Without them, we would all soon be starving, thirsting, roasting, choking for breath, and drowning in our wastes.

Our species now faces its greatest challenge: how to provide for the needs of ever-growing numbers of people without degrading the biological, chemical, and physical systems essential to our survival and well-being. Since the first United Nations (UN) Conference on the Human Environment in Stockholm in 1972, it has become increasingly clear that economic advances cannot be sustained unless we maintain the health of our environment. Stopping the loss of biological diversity is absolutely essential if we are to meet human needs.

For the most part, attention to the loss of biological diversity has focused on the land, particularly the world’s tropical rainforests. These ecosystems are exceptionally rich in species and are indeed imperiled, but they are far from the only ones in desperate need of attention. Other terrestrial ecosystems, including tropical dry forests, temperate coniferous forests, grasslands, and mediterranean shrublands, merit far more attention from scientists, citizen activists, and decision makers. Freshwater wetlands, the great floodplain rivers, and the great African Rift lakes do as well. And so does the sea.

At first, the need for marine conservation might seem strange. Humans do not yet live beneath the waves, and the vastness of the marine realm makes it appear inexhaustible and invulnerable. But that is how we once regarded the land. Since the Stockholm Conference, however, we have increasingly seen that the activities of billions of us are affecting not only the land, but the entire planet, including the 71 percent of it covered by oceans, coastal waters, and estuaries.

Reports from newspapers, radio, and television scarcely hint at the magnitude of the problem. They tell of growing numbers of shellfish beds closed due to pollution, of North Atlantic bluefin tunas (Thunnus thynnus) being fished to commercial extinction, of massive oil spills from tanker accidents. In these cases, the immediate causes are clear. But they also tell of Bangladeshis suffering from lowland flooding, thousands of dead seals washing up on North Sea beaches, blooms of toxic phytoplankton, and episodes of coral bleaching on the increase throughout the world’s oceans. Are these natural phenomena, or do they reflect the impact of humans on the sea? Our inability to provide definitive answers highlights how much is not known about marine species and ecosystems, including how we affect them.

Scientists are continually astounded by what is not known. Until 1938, coelacanths, a group of fishes related to the ancestor of amphibians, reptiles, birds, and mammals, were thought to have died out 70 to 80 million years ago. The discovery of one species (Latimeria chalumnae) off South Africa and the Comoro Islands in the Indian Ocean was one of the great biological finds of the century (Thomson 1991). Until 1977, no one suspected the existence of the most unusual ecosystems on Earth, the deepsea hydrothermal vents, whose spectacular animal communities are the only ones known not to depend on plant photosynthesis (Box 1-1). Not until 1989 did scientists realize that viruses play a far greater role in marine food webs than previously thought (Colwell and Hill 1992). And it was only last year that scientists (Grassle and Maciolek 1992) estimated that the deep sea could harbor 10 million species that have not yet been described and named, a diversity of species roughly comparable to that of tropical forests. The sea is far richer biologically than anyone had thought, and we still have much to learn about its patterns and processes.

Although humankind depends on the oceans in many ways, there have been few intensive studies of marine life. We know far less than is necessary to protect and use marine resources sustainably. Nonetheless, there is enough knowledge about threats to the sea and ways to diminish them to make major improvements now. The key question is whether individuals, groups, and nations can share this knowledge and use it locally, nationally, and internationally in ways that will benefit people on a sustainable basis.

As a companion document to the Global Biodiversity Strategy (WRI et al. 1992), Global Marine Biological Diversity: A Strategy for Building Conservation into Decision Making (The Strategy) offers a comprehensive summary of necessary background information, by examining the diversity of life in the sea and its importance to humankind, the similarities and differences between conservation on land and in the sea, the threats to marine biodiversity, and reasons why marine conservation and management efforts have not stemmed the loss of biodiversity. It then offers a goal whose achievement would allow humankind to save, study, and use the seas sustainably, a strategy for meeting that goal, an examination of tools available for conservation and management, and a candid look at the strengths and weaknesses of some existing efforts. Finally, it provides a set of concrete recommendations for actions that can be accomplished in the coming decade at local, national, and international levels that would markedly improve marine conservation and management.

BOX 1-1. Biodiversity at deep-sea hydrothermal vents

On an expedition near the Galápagos Islands in 1977, scientists discovered hot water issuing from deepsea springs. Surrounding these hydrothermal vents were remarkable communities of previously unknown animal species that live in a way unlike any that scientists had ever seen.

Scientists have since learned that hydrothermal vents occur along tectonic spreading ridges on the seafloor in all the oceans. Since the initial discovery of the vents at 2,500 meters (8,200 feet) in the East Pacific, dense communities of animals have been reported from undersea hot springs on both sides of the Pacific and on the Mid-Atlantic Ridge (Grassle 1986). Of 236 vent species listed by Tunnicliffe (1991), 223 are new to science. These belong to upward of 100 new genera and at least 22 new families.

Perhaps the most remarkable thing about the vents’ animals is their source of energy. Independent of sunlight and plant photosynthesis, they depend on chemosynthesis by bacteria. The bacteria make carbon compounds using energy from reduced sulfur compounds in fluid issuing from fissures and chimneys on the seafloor. This primary production supports the large biomass of invertebrates and fishes at hydrothermal vents. Within invertebrates such as the tube-worm Riftia pachyptila, the mussel Bathymodiolus thermophilus, and the large white clam Calyptogena magnifica, these bacteria live as mutualists inside their hosts’ cells and provide their hosts with food.

The animals of the hydrothermal vents have a high degree of endemism. At least 158 of the vent species are known from only a single hydrothermal vent field, and the overwhelming majority of the others are endemic to a single spreading ridge. In general, the closer the vent fields, the more similar their faunas.

Hydrothermal vents are isolated and short-lived-issuing heated water for perhaps a few decades—hence local vent populations appear to be short-lived, disappearing when vents stop discharging warm water and colonizing new vents as they begin discharging. Although population densities and endemism are high at hydrothermal vents, species diversity is low compared with many other deepsea ecosystems (Tunnicliffe 1991; Grassle 1989), but consistent with other deepsea ecosystems that are disturbed often.

The fossil record suggests that humans originated in Africa a few million years ago, perhaps some distance from the coast, and our dependence on the sea might have been limited to breathing the oxygen created by marine organisms and living in climates shaped, in large part, by marine ecosystems. Even if some humans foraged along the shore and our wastes entered the sea, our limited numbers and technologies prevented significant effect on the sea for our first few million years.

However, since the advent of agriculture, writing, metallurgy, and cities in the last 10,000 years, our populations and technologies have been increasing dramatically. Now billions of us crowd the Earth, mainly in the coastal zone or in drainages that empty into the sea. Moreover, technologies that either intentionally or inadvertently change the environment are increasing at an astounding rate. The oceans are the primary sink for substances we discharge into the atmosphere and waterways. The well-being of humankind increasingly depends on the well-being of the sea. And this connection goes both ways: The health of the sea now depends on what our species does.

Life in the sea is roughly 1,000 times older than the genus Homo. Since its origin, marine life has responded to changes: global geochemical changes and drifting continents, cataclysmic volcanic eruptions and asteroid impacts, changes in climate and the evolution of new enemies. Now the sea—indeed, the entire biosphere—faces an unprecedented threat: exponentially increasing, unrelenting stresses from human activities. Virtually all of humankind already suffers from the environmental damage we cause, and great numbers of people die from it, especially in the poorer countries. The acceleration in environmental impacts cannot fail to harm us more and more. If our species can understand both the vulnerability and the resilience of the living sea and the rest of the biosphere, we have an opportunity to act in our own interest and benefit from life’s products and services in perpetuity. If we do not—if we fail to relieve the stresses that we impose on the biosphere—the relatively brief story of the human species will almost certainly come to an inglorious end. The Strategy is written in the hope that we can act effectively and soon enough to prevent that from happening.

CHAPTER TWO

Marine Biological Diversity: Definition and Importance

BY EXAMINING the molecular basis of life, scientists have concluded that all known living things share a common origin; there is a fundamental unity of life on Earth. No less remarkable, however, is the diversity of life, that is, biological diversity.

What Is Biological Diversity?

The central idea in the definition of biological diversity most used by conservation biologists and decision makers is that the diversity of life occurs at several hierarchical levels of biological organization. Although biologists have been interested in diversity for decades, the term “biological diversity” (which is sometimes shortened to “biodiversity”) appeared in conservation publications only about 1980, and its originators either did not define it (Lovejoy 1980) or defined it inadequately (Norse and McManus 1980). The most widely used definition of biological diversity (Norse et al. 1986) considers three levels: genetic, species, and ecosystem diversity. An alternative scheme (Soulé 1991) defines five levels, splitting genetic and ecosystem divers...

Table of contents

• About Island Press
• Title Page
• Copyright Page
• ABOUT THE EDITOR
• ABOUT THE CO-SPONSORS
• Table of Contents
• Preface
• ACKNOWLEDGMENTS
• CONSULTATIONS FOR THE STRATEGY
• Executive Summary
• CHAPTER ONE - Conserving the Living Sea
• CHAPTER TWO - Marine Biological Diversity: Definition and Importance
• CHAPTER THREE - Marine and Terrestrial Conservation
• CHAPTER FOUR - Threats to Marine Biological Diversity
• CHAPTER FIVE - Impediments to Marine Conservation
• CHAPTER SIX - The Goal and the Strategy
• CHAPTER SEVEN - Tools for Conserving Marine Biological Diversity
• CHAPTER EIGHT - Existing Marine Institutions and Instruments
• CHAPTER NINE - Recommendations for Implementing The Strategy
• APPENDIX A - Acronyms
• APPENDIX B - Institutions Mentioned in the Text
• APPENDIX C - Legal Citations
• APPENDIX D - Endangered Marine Animal Species
• Literature Cited
• Glossary
• Index
• Island Press Board of Directors