Showing papers on "Biodiversity published in 1991"

Conserving biodiversity in managed forests : lessons from natural forests

Abstract: In this article, the authors review patterns of disturbance and succession in natural forests in the Coastal Northwest and compare structure and composition across an age gradient of unmanaged stands. Stand and landscape patterns in managed forests are then examined and compared with those in natural forests. They draw on the results to offer guidance on the management of Coastal Northwest forests that are dedicated to both wood production and conservation of biodiversity. Finally, the authors suggest that the lessons learned from natural forests here may be useful in other biomes, where unmanaged forests are rare and standards for designing seminatural forests are not available.

Biodiversity Studies: Science and Policy

Abstract: Biodiversity studies comprise the systematic examination of the full array of different kinds of organisms together with the technology by which the diversity can be maintained and used for the benefit of humanity. Current basic research at the species level focuses on the process of species formation, the standing levels of species numbers in various higher taxonomic categories, and the phenomena of hyperdiversity and extinction proneness. The major practical concern is the massive extinction rate now caused by human activity, which threatens losses in the esthetic quality of the world, in economic opportunity, and in vital ecosystem services.

Battle Against Extinction: Native Fish Management in the American West

Abstract: In 1961 the Green River was poisoned and its native fishes killed so that the new Flaming Gorge Reservoir could be stocked with non-native game fishes for sportsmen. This incident was representative of water management in the West, where dams and other projects have been built to serve human needs without consideration for the effects of water diversion or depletion on the ecosystem. Indeed, it took a Supreme Court decision in 1976 to save Devils Hole pupfish from habitat destruction at the hands of developers. Nearly a third of the native fish fauna of North America lives in the arid West; this book traces their decline toward extinction as a result of human interference and the threat to their genetic diversity posed by decreases in their populations. What can be done to slow or end this tragedy? As the most comprehensive treatment ever attempted on the subject, Battle Against Extinction shows how conservation efforts have been or can be used to reverse these trends. In covering fishes in arid lands west of the Mississippi Valley, the contributors provide a species by species appraisal of their status and potential for recovery, bringing together in one volume nearly all the scattered literature on western fishes to produce a monumental work in conservation biology. They also ponder ethical considerations related to the issue, ask why conservation efforts have not proceeded at a proper pace, and suggest how native fish protection relates to other aspects of biodiversity planetwide. Their insights will allow scientific and public agencies to evaluate future management of these animal population and will offer additional guidance for those active in water rights and conservation biology.

Diversity and the tropical rain forest

Abstract: The tropical rain forest is the most exuberant manifestation of nature's diversity, and the abundance of life it nurtures has captured the fascination of scientists since the time of Darwin A single tree in the rain forest may support as many as 150 species of beetle alone, and 300 different kinds of trees may inhabit a single hectare That same hectare may be home to over 41,000 different species of insects Why are there so many species? Why do tropical forests in particular contain so many species of trees--or for that matter, of birds, reptiles, or almost anything else? What can we learn by studying this remarkable diversity and what can be done to preserve it? In this sumptuously illustrated volume, veteran scientist and teacher John Terborgh shows how scientists approach these critical questions At the heart of the study of biodiversity is the investigation of the ecological processes that accommodate diversity and the evolutionary processes that generate it Separate in principle, these two sets of factors are intricately interwoven, and it is this complex interrelationship that Diversity and the Tropical Rain Forest seeks to unravel The book begins with an overview of the results of evolution as expressed in large-scale phenomena--the patterning of tropical vegetation on climatic gradients, the adaptation of plants to a wide range of soil conditions, and the contrasting degrees of diversity found in temperate versus tropical forests The ensuing chapters on ecology examine the rain forest on a smaller scale, presenting the most recent theories of how the dynamic relationships between plants and animals, under the influence of the tropical climate, have maintained such aprofusion of forms of life The focus then returns to evolution, as Terborgh examines the mechanisms that generate diversity, the checks and balances that govern the extinction of species, and the similar evolutionary adaptations of organisms living continents apart In concluding, Dr

The Conservation atlas of tropical forests

Abstract: Recognizing that sound information is vital to the progress of conservation, IUCN have gathered together a visual portfolio of maps of rain forests in Africa. The accompanying text analyzes the extent and causes of deforestation and points a way towards sustainable forest development. The atlas is divided into two parts. Part 1 describes the issues: history of forests and climate in tropical Africa; biological diversity in the moist forests of the Afrotropical region; case studies in conserving large mammals; forest peoples; links between population, environment and agriculture; African timber trade; forest management; protected areas system; and the future for Africa's tropical forests. Part 2 contains the country studies with each chapter including a detailed map of the rain forests. The accompanying text describes in detail the current situation in that country.

Designing and Testing Sampling Protocols to Estimate Biodiversity in Tropical Ecosystems

Abstract: Sampling methods to estimate total species richness of a defined area (conservation unit, national park, field station, "community") will play an important role in research on the global loss of biodiversity. Such methods should be fast, because time is of the essence. They should be reliable because diverse workers will need to apply them in diverse areas to generate comparable data. They should also be simple and cheap, because the problem of extinction is most severe in developing tropical countries where the scientific and museum infrastructure is often still rudimentary. In the past, two scientific fields have been mainly responsible for providing such data: systematics and community ecology. Simplistically summarized, samples collected by systematists better represent the species richness in an area but are intractable statistically, whereas the analysis of samples collected to answer ecological questions is usually straightforward but often poorly represents the total fauna. The two approaches are complementary and we propose a set of methods that seeks the optimal compromise. We applied these methods to sample and estimate species richness of Araneae in Bolivia, but we present criteria so that the methods can be modified for other broadly similar groups. We describe the methods used, present preliminary analyses of the effect of four variables (site, collecting method, collector, and time of day) on total number of adult individuals taken, and discuss analytical approaches that employ such data to estimate total species richness. We also present data from Peruvian canopy fogging samples to show that estimates of species richness of diverse tropical arthropod taxocenes are obtainable in principle.

Flying Foxes as Strong Interactors in South Pacific Island Ecosystems: A Conservation Hypothesis

Abstract: The dependency of highly endemic island floras on few potential pollinators in depauperate island faunas suggests that pollinators and seed dispersers may be crucial in the preservation of biodiversity in isolated oceanic islands. We discuss the hypothesis that flying foxes are “strong interactors” in South Pacific islands where they serve as the principal pollinators and seed dispersers, This suggests that the ongoing decline and ultimate extinction of flying fox species on Pacific islands may lead to a cascade of linked plant extinctions. We propose an empirical test of this hypothesis: comparisons of plant reproductive success in Guam, which has virtually lost its flying fox populations, and Samoa, where significant populations remain.

An introduction to the ecology of cerrado lizards

Abstract: Nine species of lizards are sympatric in cerrado habitats in the state of Mato Grosso, Brazil, including one polychrid (Anolis meridionalis), three tropidurids (Tropidurus etheridgei, T. cf. montanus, and T. spinulosus), one scincid (Mabuya frenata), two teiids (Ameiva ameiva and Cnemidophorus ocellifer), and two gymnophthalmids (Micrablepharus maximiliani and Pantodactylus schreibersii. Lizard diversity is lower than that reported for caatinga or lowland rainforest. Most striking in the cerrado lizard fauna is the lack of gekkonids, which are common in other Brazilian habitats studied. The Iguania clearly separate by microhabitat, and microhabitat differences are partially reflected in diets. There is little similarity in habitat use by the primarily arboreal Iguania and the strictly terrestrial teiids and gymnophthalmids. Teiids and gymnophthalmids often occur in the same microhabitats, but the large differences in size among species generally result in utilization of different prey types and/or sizes. Ameiva ameiva and Cnemidophorus ocellifer are very similar in habitat use and prey types, but do not overlap in body size and take prey of very different sizes. Electivity analysis of prey volumes suggests sample size bias as well as a bias based on lizard body size differences. The largest species, A. ameiva, accounts for most of the prey taken by the lizard assemblage. Eight of the nine species are oviparous; the other, Mabuya frenata, is viviparous with extended gestation and typical South American Mabuya matrotrophy. As in other Brazilian lizard assemblages studied, a diversity of life history patterns is evident with each species being more similar to closely-related species in distant and different habitats than to unrelated sympatric species. The cerrados represent one of the largest vegetational zones of South America, extending from southern Brazil to the Amazon Basin and totaling about 1,500,000 km2 (Ferri, 1977). In addition, there are isolated patches north of the Amazon Basin. Cerrados consist of a patchwork of at least four macrohabitats: campo, cerrado, cerradao, and gallery forest (Eiten, 1972), which vary in the size, density, and types of trees. Campo (which means "field") contains the lowest density of trees or no trees. Cerrado proper is the most widespread vegetation type in the cerrados, consisting of extensive grasslands covered by varying densities of xeromorphic trees but with an open canopy. The trees appear twisted, have thickened bark usually showing evidence of fire, and the leaves are leathery. Cerradao contains larger trees and the canopy is generally closed or nearly so. Trees may exceed 10 m. Gallery forest (bands of tropical forest along water courses) contains the largest trees and displays a closed canopy. In addition, there are transitional zones between each of these (Eiten, 1975). The most prominent climatological feature of the cerrados is the dry winter (Vanzolini, 1972). Cerrados differ from savannas in containing a permanent deep water table 1 Present Address: Oklahoma Museum of Natural History, University of Oklahoma, Norman, Oklahoma 73019, USA. and deep non-stoney, non-lateritic soils (Eiten, 1972). Considering the extensive distribution of the cerrados in South America, it is surprising that there have been no ecological studies of the liza d assemblages inhabiting them since Vanzolini (1948) first described the squamate assemblage in a cerrado site in the state of Sao Paulo. Indeed, the best available data consist of field observations on individual species (Vanzolini, 1972, 1986), general ecological descriptions in taxonomic studies (e.g., Rodrigues, 1987), comments on the origin and biogeography of cerrado faunas (Vanzolini, 1963, 1976), and more recently, studies of individual species (Colli, 1991). Because of the vast distribution of cerrados, the potential exists to examine the influence of climatic and vegetation gradients on the structure of lizard assemblages. In addition, it should be possible to examine interactions between different lizard assemblages where cerrado contacts lowland Amazonian forest to the north, Atlantic rain forest to the east, the Chaco to the southwest, Andean foothills to the west, and semi-arid caatingas to the northeast. Patterns of alpha, beta, and gamma diversity (Cody, 1975) might be particularly instructive considering these major habitat contacts. Vanzolini (1974), for example, has shown that contact zones provide critical information necessary for understanding the ecology and biogeography of Brazilian lizards. This content downloaded from 207.46.13.131 on Sat, 15 Oct 2016 04:27:20 UTC All use subject to http://about.jstor.org/terms

Measuring biodiversity taxonomic relatedness for conservation priorities

Abstract: A definition of biodiversity is adopted that takes account not only of numbers of species, but also of the degrees of difference among them. The most appropriate measure of species differences is likely to be made in terms of genealogical relationships, as embodied in taxonomic classifications. Five new measures of taxonomic diversity are compared with existing measures of species richness and taxonomic root weighting for prioritising areas for the conservation of biodiversity, using as an example some data for 43 bumble bee species of the sibiricus-group. Although certain of the new measures can be shown to perform better than any existing methods, more extensive trials are needed, and further refinements can be anticipated. We conclude that combining species richness with taxonomic diversity to give a single measure inevitably involves compromise, as either component could be maximised in its own right. Nonetheless, the new prioritisation methods are already capable of giving practical results.

Application of Ecological Principles to the Management of Endangered Species: The Case of the Red-Cockaded Woodpecker

Abstract: A major development in the biological sciences in the 1980s was the emergence of the discipline known as conservation biology. The rise of conservation biology was triggered by growing concern about environmental problems such as tropical deforestation and the loss of biodiversity (50). Historically, conservation biology may be viewed as a union between parts of the fields of wildlife biology and ecology (50) that reflects the maturation of both. Wildlife biology has always focused on conservation and management of natural resources. Attention was originally concentrated on those few species that were hunted (45, p. 2) and, as in all disciplines, research was mostly descriptive. Management techniques developed largely through trial and error. As the field developed, its focus broadened to include nongame species, particularly endangered species. Interest in the basic biology of the species and ecosystems of concern grew, and management increasingly was based on deductions derived from fundamental understanding of the systems involved rather than from trial and error. Within ecology, the relevant changes have been in theory. The theory developed in the 1950s, 1960s, and early 1970s (e.g. 37) can be characterized

Landscape linkages and biodiversity

Abstract: In Landscape Linkages and Biodiversity experts explain biological diversity conservation, focusing on the need for protecting large areas of the most diverse ecosystems, and connecting those ecosystems with land corridors to allow species to move among them more easily.

How Best Can We Use Biodiversity in Agroecosystems

Abstract: Agriculture affects biodiversity by replacing nature's diversity with a smaller number of cultivated plants and domesticated animals. Agricultural systems are often artificial ecosystems of genetic...

Coastal-Zone Biodiversity Patterns

Abstract: iodiversity occurs at all levels of biological organization from molecules to entire biotas and ecosystems. The investigation of biodiversity thus requires the formulation of a wide range of hypotheses (Solbrig 1991). Measuring biodiversity and assessing its role in ecosystem function is important because human perturbations are relentlessly altering biodiversity just as society is recognizing its significance. Many approaches to coastal-zone biological diversity are possible. In this article, I emphasize how biogeography is related to coastal structure. Understanding pattern is essential because biodiversity is hierarchical, that is, a function of time and space at varying levels of scale. Nelson and Ladiges (1990) state forcefully, "Indeed, what beyond biogeography is 'biodiversity' about?" An understanding of how biodiversity has risen and how it can be conserved is best

Approaches to the Conservation of Coastal Wetlands in the Western Hemisphere

Abstract: Coastal wetlands rank among the most productive and ecologically valuable natural ecosystems on Earth. Unfortunately, they are also some of the most disturbed. Because they are productive and can serve as transportation arteries, coastal wetlands have long attracted human settlement. More than half of the U.S. population currently lives within 80 km of its coasts, and one estimate places 70% of all humanity in the coastal zone. Human impacts to coastal wetlands include physical alteration of hydrological processes; the introduction of toxic materials, nutrients, heat, and exotic species; and the unsustainable harvest ofnative species. Between 1950 and 1970, coastal wetland losses in the U.S. averaged 8 100 ha/year. In Central and South America, development pressures along the coastal zone rank among the most serious natural resource problems in the region. Here, we (1) briefly describe coastal wetland avifauna, (2) discuss the threat of global warming on coastal wetlands, (3) use several Western Hemisphere wetlands as site-specific examples of development pressures facing these habitats, and (4) provide synopses of non- governmental and governmental approaches to wetland conservation. Overall, we provide a socio-economic context for conservation of coastal wetlands in the Western Hemisphere. We suggest that efforts aimed at conserving sites of particular importance for their biological diversity should be pursued within a framework of wise use that addresses the broader issues of human population growth and economic development.

Structural comparison of tropical montane rain forests along latitudinal and altitudinal gradients in south and east Asia

Abstract: Geographical patterns of altitudinal zonation, floristic composition, and structural features of tropical montane rain forests were examined along latitudinal gradients in south and east Asia. On equatorial mountains, the tropical montane rain forests occur above 1000 m. Toward middle latitudes, they come farther down and reach sea level at c. 35° N. Thus, the forests are equivalent to the subtropical rain forests of the latitudinal, horizontal zonation series. They exhibit gradual changes in floristic composition and structure along both altitudinal and latitudinal gradients. On equatorial mountains, they are divided into three types, i.e. tropical lower montane, upper montane, and subalpine forests. The three tree regeneration types, having emergent, sporadic and inverse-J type stem-diameter class frequency distributions, coexist in the lower montane forests, but the upper and subalpine forests display only the inverse-J type species with a few species of the sporadic type. Toward the northern latitudinal limit, the distinction between the three tropical montane forest zones in equatorial mountains becomes less clear. This can be explained by temperature conditions: on equatorial mountains, a temperature sum of 85° C months which controls the upper limit of the lower montane forests, and a coldest month mean temperature of-1° C which controls the evergreen broad-leaved trees, appear at c. 2500 and c. 4000 m respectively. The altitudinal range between 2500 m and 3800 m, which is the upper forest limit, is covered by upper montane and subalpine forests. On the other hand, at the latitudinal northern limit, the tropical upper montane and subalpine forests cannot exist because the above mentioned two temperature conditions occur at nearly the same point. Thus, at the northern latitudinal limit of the tropical montane forests, the three zones of equatorial mountains amalgamate into a single subtropical lowland forest community. This is due to the seasonal temperature climate in middle latitudes in, e.g., central Japan and central China.

Deep-sea benthic biodiversity.

Abstract: The life that inhabits ocean depths beyond the continental shelves is unfamiliar even to most biologists. Samples of deep-ocean sediments typically contain representatives of a dozen phyla but most deep-sea animals are small and live below the sediment surface. In contrast to the graphs showing the perceived species population presented before the 1960s the new sampling method demonstrated the existence of large numbers of species in the deep sea. In the context of regional species diversity no single theory can account for the high diversity in the deep sea. Several major features of the deep sea contribute to its relatively high diversity. These include the following: 1) absence of widespread disruption of habitat; 2) patchy food resources; 3) disturbance; and 4) large area. But deep-sea floor vastness and remoteness makes it appear attractive as a waste disposal area. Moreover the potential effect of toxic compounds that have been found to accumulate in deep-sea sediments is a serious cause for concern. The establishment of long-term stations to better understand the interactions of deep-sea organisms with their natural environment and to monitor the potential effects of pollution are necessary to provide the information required for wise management of ocean resources.

The Bird Fauna of a Deciduous Woodland in the Wet-Dry Tropics of Northern Australia.

Abstract: Censuses of birds were made monthly from October 1986 to October 1987 in a deciduous woodland in the Australian Northern Territory. Additional limited counts of granivorous birds were made in March and April 1988. The woodland was selected for the study because it contains a population of the endangered Gouldian finch (Erythrua gouldiae). The species composition of birds was temporally unstable; this was associated with the marked wet-dry seasonality. For some foraging groups (e.g. nectarivores, foliage-gleaners), diversity was correlated with resource availability. Although the species composition of birds of this site is not very similar to that of any other surveyed area, it falls within the range encompassed by that of woodlands across tropical Australia, and is distinct from that of open and closed forests in the same region. Tropical savanna woodlands and open forests differ in composition of their foraging groups compared with their temperate counterparts. The species richness of granivores, hawking insectivores, nectarivores and terrestrial omnivores at this site is unusually high. The changing composition of bird species in this tropical woodland site suggests that many birds in this environment undergo substantial regional movements. The conservation of such species demands large and heterogeneous reserves, a strategically located reserve system and/or sympathetic management of land outside reserves.

Marine Biological DiversityA scientific program to help conserve marine biological diversity is urgently required

Abstract: arine systems are extraordinarily diverse in all aspects, from genetic to taxonomic to ecological. As diversity is becoming widely recognized, the scientific literature and the public press are reporting that many marine systems, particularly coastal ones, are severely depleted, drastically altered, overfished, and polluted. The United Nations Environment Programme (UNEP 1990) has documented pathogens, toxic substances, eutrophication, and disruption of ecological habitats in the marine environment. UNEP also reported that biological diversity has been decreased. Such reports lead scientists to the suspicion that many marine ecosystems are in states of ecological collapse. Biological diversity in time and space has long been a major ingredient in the development of what we now term ecology. There is now an extensive literature on biological diversity, although the number of species on Earth and how species are distributed in time and space remain largely unknown. E. 0. Wilson of Harvard University estimates that species numbers fall "somewhere between 5 and 30 million" (Wilson 1988). Because many species are threatened by extinction, the Na-

Biodiversity and sustainability of wetland rice production: role and potential of microorganisms and invertebrates.

Abstract: Some of the ecological foundations of sustainable wetland rice production related to microorganisms and invertebrates and their biodiversity are considered including: (i) aspects of sustainability of rice-producing environments involving microbial and invertebrate populations, the maintenance of soil fertility, effects and control of rice pests and vector-borne diseases; (ii) how crop intensification affects these populations and their biodiversity; (iii) agricultural practices that use microbial and invertebrate populations and their biodiversity; and (iv) the status of germplasm collections and the potential of biotechnology to use them to improve the sustainability of rice-producing environments. The beneficial and detrimental roles of microorganisms and invertebrates in sustainable rice production have been identified and, sometimes, quantified. However, less is known about the possible long-term effects of crop intensification on these populations and their biodiversity. Numerous methods using microorganisms and invertebrates to increase soil fertility and control pests and diseases have been tested. But the success of these methods is limited and their adoption almost negligible. This will probably continue while the methods are still based on a very restricted knowledge of biodiversity, community structure, and trophic relationships at the ecosystem level. Recent data on arthropods confirm that high biodiversity does not imply stability and low pest populations. Increases in pest and vector densities depend more on predator diversity, species resilience to perturbations, and biological attributes. Thus, increasing or preserving diversity per se does not necessarily contribute to pest stability, but developing effective trophic linkages might. This approach might also be valid for maintaining soil fertility through microbial management, the Present address: Laboratoire de Microbiologie ORSTOM, Universite de Provence, Case 87, 3 Place Victor Hugo, F-13331 Marseille Cedex, France. The Biodiversity of Microorganisms and Invertebrates: Its Role in Sustainable A riculture. Edited by D.L. Hawksworth. 0 CAB international 1991. ORSTO& Fonds Documentaire 11s P.A. Roger et al. optimization of primary production in floodwater, and the optimization of nutrient recycling by invertebrate populations. v

Protecting biodiversity in coastal environments: Introduction and overview

Abstract: Much less attention has been paid in recent years to the threats to coastal and marine biodiversity, compared to biodiversity in more terrestrial habitats. The tremendous biodiversity at risk and the severity and magnitude of the pressures being exerted on coastal habitats suggest the need for much greater attention to be focused here by both the policy and scientific communities. The threats to coastal biodiversity are numerous and include air and water pollution; over exploitation and harvesting; the introduction of exotic species; the dramatic loss of habitat due to urbanization, agricultural expansion, and other land use changes; and the potentially serious effects of global climate change. These threats suggest the need for swift action at a number of jurisdictional and governmental levels. Major components of such an effort are identified and described. These include the need for comprehensive management approaches, the expansion of parks and protected areas, restoration and mitigation, mul...

Beekeeping in Integrated Mountain Development: Economic and Scientific Perspectives

Abstract: Honeybees are social insects with which man has established a harmonious coexistence. These insects have provided humanity with the very basis of civilization because of their highly evolved social behaviour and being the source of the earliest sweet food and trade commodity. Besides, honeybees provide free ecosystem services in the form of cross-pollination and propagation of several cultivated and wild plant species, thereby maintaining biological diversity. They, therefore, not only boost crop productivity but also help in the conservation of forests and grassland ecosystems and save several botanical sources from extinction.

Marine Functional DiversityOcean and land ecosystems may have different time scales for their responses to change

Abstract: he term biological diversity has the virtue of containing many different interpretations, scientifically and emotionally. A recent report (OTA 1987) suggested three technical meanings: genetic, species, and ecological diversity. I suggest a fourth category that needs to be considered, which I term functional diversity-the variety of different responses to environmental change, especially the diverse space and time scales with which organisms react to each other and to the envi-