Showing papers in "BioScience in 1985"
2,501 citations
TL;DR: I view stress as a syndrome comprising both input and output, and believe that common words in everyday language, such as stress, competition, or community should not be given highly technical meanings, since this only serves to confuse the general reader.
Abstract: The term stress has been widely used for both cause and effect, stimulus and response, or input and output. Although some authors worry about this dual use of the word, I view stress as a syndrome comprising both input and output. One cannot have a response without a stimulus. One can easily identify which part of the syndrome is being singled out by using modifying adjectives, prefixes, or clauses; thus, stress as an input can be designated the stressor as contrasted to stress, the response, or output. (In referring to stress as a syndrome, I do not mean to imply a strict analogy with Selye's [19731 "general stress syndrome," although as recently noted by Rapport et al. 1985, there are interesting parallels between the physiological and community levels.) I believe that common words in everyday language, such as stress, competition, or community should not be given highly technical meanings, since this only serves to confuse the general reader; as already indicated, modifiers can restrict meanings. But we must recognize that these common terms have different meanings, and often different manifestations at different levels of organization. Allen (1984), in discussing hierarchical organization, pointed out that a disturbance detrimental at one level may be beneficial at a higher level. For example, periodic fire in the fire-adapted chaparral is a stress to many organisms
1,024 citations
TL;DR: In this article, conservation biology, a new stage in the application of science to conservation problems, addresses the biology of species, communities, and ecosystems that are perturbed, either directly or indirectly, by human activities or other agents.
Abstract: C onservation biology, a new stage in the application of science to conservation problems, addresses the biology of species, communities, and ecosystems that are perturbed, either directly or indirectly, by human activities or other agents. Its goal is to provide principles and tools for preserving biological diversity. In this article I describe conservation biology, define its fundamental propositions, and note a few of its contributions. I also point out that ethical norms are a genuine part of conservation biology, as they are in all missionor crisis-oriented disciplines.
976 citations
TL;DR: The concept of biological refugia is discussed in this article, and the effect of climatic changes on reserves is discussed, and the types of biological communities particularly at risk due to climatic change are identified.
Abstract: Global warming would diminish biological diversity by causing extinctions among reserve species. Patterns of climatic change are discussed, including global patterns of surface temperature increase, as predicted by the Goddard Institute for Space Studies, and global changes in moisture patterns. The concept of biological reserves (essentially the same concept as biological refugia) is discussed, and the effect of climatic changes on reserves is discussed. The types of biological communities particularly at risk due to climatic changes are identified. 67 references, 3 figures.
522 citations
TL;DR: Researchers have known for decades that many buried seeds need to be brought to the soil surface before they will germinate, and to understand how germination of buried seeds is controlled, plant biologists have studied the re.
Abstract: The classic studies of Brenchley and Warington (1930) and numerous other investigations have demonstrated that large reserves (pools) of weed seeds accumulate in arable soils. Work reviewed by Kropad (1966) and Roberts (1981) shows that the number of seeds per m2 in the upper 15-25 cm of soil in cultivated fields may be as high as 70,000-90,000, and up to 95% of these may be contributed by annuals. Soil samples collected under vegetation of known age and history suggest that buried seeds of some weedy species may remain viable for 50100 years or more (e.g., Livingston and Allessio 1968, Oosting and Humphreys 1940). Seeds of 3 of 21 species buried in 1879 by W. J. Beal were viable after 100 years (Kivilaan and Bandurski 1981). In another experiment started by J. W. T. Duvel in 1902, buried seeds of 36 of 107 species were viable after 39 years (Toole and Brown 1946). Researchers have known for decades that many buried seeds need to be brought to the soil surface before they will germinate. To understand how germination of buried seeds is controlled, plant biologists have studied the re-
419 citations
TL;DR: In its responsibility to evaluate the potential effects of chemical substances proposed for release into the environment, the Environmental Protection Agency (EPA) faces profound challenges.
Abstract: In its responsibility to evaluate the potential effects of chemical substances proposed for release into the environment, the Environmental Protection Agency (EPA) faces profound challenges. The American Chemical Society's Chemical Abstract Service lists some 6 million chemicals, with an estimated 63,000 in common use today (Maugh 1983). Passage during the 1970s of the Toxic Substances Control Act
271 citations
TL;DR: Cryoconite holes are water-filled depressions on the surface of glaciers that contain microbial communities and may contribute to glacial wastage and biological colonization of ice-free areas.
Abstract: Cryoconite holes are water-filled depressions on the surface of glaciers. They contain microbial communities and may contribute to glacial wastage and biological colonization of ice-free areas.
210 citations
TL;DR: Since humans first crossed the Bering Strait land bridge, growing human populations and their increased technological impact have degraded water resources in North America, but as population centers developed and urbanization increased, many areas developed chronic water resource problems.
Abstract: Since humans first crossed the Bering Strait land bridge, growing human populations and their increased technological impact have degraded water resources in North America. Initially, this degradation was transitory and local, but as population centers developed and urbanization increased, many areas developed chronic water resource problems. In the Laurentian Great Lakes, for example, sport and commercial fish resources declined following selective overfishing; extensive watershed modifications, including drainage of lake-margin wetlands; introduction of exotics, especially the sea lamprey, alewife, and salmonids; and progressive chemical modification of lake environments (Emery 1981, Francis et al. 1979, Smith 1972, Wagner and Stauffer 1982). Chemical change began with an acceleration of natural processes (e.g., nutrient enrichment and siltation of shallow areas) and was compounded by drainage of wetlands, discharges of synthetic chemicals and chemical wastes, and increased water temperatures stemming from other technological changes. Each lake's fishery was more or less altered, depending on the size, geographic location, and relative influence of these factors on each lake. Watershed modification and chemical contamination, in particular, have severely altered tributary streams
205 citations
TL;DR: Studies of amphibian acid tolerance provide information about the potential effects of acid deposition on amphibian communities, and nonlethal effects, including depression of growth rates and increases in developmental abnormalities, can occur at higher pH.
Abstract: Studies of amphibian acid tolerance provide information about the potential effects of acid deposition on amphibian communities. Amphibians as a group appear to be relatively acid tolerant, with many species suffering increased mortality only below pH 4. However, amphibians exhibit much intraspecific variation in acid tolerance, and some species are sensitive to even low levels of acidity. Furthermore, nonlethal effects, including depression of growth rates and increases in developmental abnormalities, can occur at higher pH.
196 citations
179 citations
TL;DR: This article examines several problems associated with monocultures, particularly those that intercropping can alleviate, and attempts to identify the explicit and implicit assumptions that define the concept of moder agriculture.
Abstract: Intercropping, the practice of growing more than one crop in a field at the same time, was commonly used in the United States before 1940 (Kass 1978). It continues to be widely used in much of the developing world, where farmers have only limited access to the agricultural equipment and products that transformed agriculture in the industrialized world (ASA 1976, Kass 1978, ICRISAT 1981). Modern industrialized agriculture, which typically uses monocultures, has increased yields enormously in the developed countries, but the improvement has not been without its costs. The production and operation of machines and the synthesis of fertilizers and pesticides cost an enormous amount of energy. Other costs can be high as well, ranging from degradation and disruption of the environment to human pesticide poisonings. An increasing number of agricultural scientists are sufficiently concerned about the environmental and health risks of modern agricultural practices that they are reassessing several low-technology alternatives like intercropping for use in developed countries (Schultz et al. 1982, see Environmental Management 7(1) 1983). This article examines several problems associated with monocultures, particularly those that intercropping can alleviate. Intercropping may have been abandoned partly for convenience and not because it is inherently incompatible with modern agricultural techniques. To redefine the potential role of this preindustrial technique in today's world, I attempt to identify the explicit and implicit assumptions that define our concept of moder agriculture. I concentrate on the United States because of its leading role in agricultural modernization, but because the benefits and problems of modern agriculture are global, I have
TL;DR: In Lake Constance, the phytoplankton growth season starts when stratification begins in spring and ends when the mixing depth increases in autumn, algae that can tolerate low light are selected for.
Abstract: In Lake Constance, the phytoplankton growth season starts when stratification begins in spring. Initially, maximum growth rates are favored; later, as the water column stabilizes, zooplankton grazing and competition for nutrients become the dominant selective forces. When the mixing depth increases in autumn, algae that can tolerate low light are selected for. Temperature and sedimentation turn out to be less important in succession than traditionally assumed.
TL;DR: It is concluded that "strange" attractors, the chaotic counterparts to equilibria and limit cycles, may play an important role in ecological systems.
Abstract: One of the fundamental problems in ecology is understanding the ragged ups and downs in abundance that characterize many natural populations. Recent advances in nonlinear dynamics suggest that even the "noisiest" variation may have its origin in simple deterministic mechanisms. Here we review both the theory and the evidence and conclude that "strange" attractors, the chaotic counterparts to equilibria and limit cycles, may play an important role in ecological systems.
TL;DR: Methanogenic bacteria make up a unique group of strictly anaerobic organisms that derive their energy for growth from the reduction of CO2 or other simple compounds to CH4; they are members of the Archaebacteriae, a third kingdom and line of evolutionary descent only distantly related to either the Eubacteria or Eukaryota
Abstract: Methanogenic bacteria make up a unique group of strictly anaerobic organisms that derive their energy for growth from the reduction of CO2 or other simple compounds (like acetate, formate, methanol, and alkylamines) to CH4 (Taylor 1982). Along with the extreme halophiles and certain thermoacidophiles, they are members of the Archaebacteriae, a third kingdom and line of evolutionary descent only distantly related to either the Eubacteria or Eukaryota (Fox et al. 1980). Methanogens play an important role in many ecological systems, the rumen, for instance (Wuhrmann 1982), and in recycling carbon fixed by photosynthesis (Vogels 1979). Methanogens also produce methane gas, the major component of natural gas; at water treatment plants and landfill sites, it is economically feasible to trap and use this gas (Klass 1984). In addition, methanogens play a major role in anaerobic digestion, where they direct electron flow to a more efficient degradation of waste (Zeikus 1983). Finally, methanogens have several unusual properties, including unusual coenzymes; cell walls that lack peptidoglycan; and ether-linked, rather than ester-linked, lipids in their membranes. Initially, progress in understanding the physiology and biochemistry of methanogens was slow because the organisms are difficult to culture; they have long generation times and are extremely sensitive to 02. Recent developments in methanogen culture have, however, circumvented most of the problems.
TL;DR: A large number of new contraceptive agents, designed primarily for use in humans, can be administered remotely by injection to large mammals or orally to smaller animals.
Abstract: Chemical fertility control is a neglected yet potentially powerful wildlife management tool that represents an effective, inexpensive, and humane alternative to current control methods. A large number of new contraceptive agents, designed primarily for use in humans, can be administered remotely by injection to large mammals or orally to smaller animals. These compounds will not cause death, do not disturb social order, and can be manipulated to protect nontarget species.
TL;DR: Several mechanisms enable leaf stomata to optimize water loss with respect to carbon gain and changes in the concentrations of endogenous growth regulations and their influence onStomata may well be important to both defense strategies.
Abstract: Several mechanisms enable leaf stomata to optimize water loss with respect to carbon gain. Stomatal responses to environmental variation constitute a plant's first and second lines of defense against damaging water deficits. Changes in the concentrations of endogenous growth regulations and their influence on stomata may well be important to both defense strategies.
TL;DR: In this article, the authors look at the problem from the view of the ecosystem as a whole and quantitatively relate forest damage to emissions of air pollutants, and what role can ecological scientists play in establishing air quality standards.
Abstract: tree species and the processes by which they may be damaged by specific air pollutants (Lindhurst 1984, Tamm 1984, Ulrich and Pankrath 1983). This paper looks at the problem from the view of the ecosystem as a whole. Questions that arise from this analysis are: Is it possible to quantify ecosystem damage resulting from specific air pollutants? Can we quantitatively relate forest damage to emissions of air pollutants? Can we wait for quantification of the relationship between emissions and damage to write air quality standards? Finally, what role can ecological scientists play? What is their responsibility in establishing air quality standards?
TL;DR: In ecology, as in other scientific disciplines, there are times when certain conceptual and experimental approaches appear to hold special promise for solving specific problems or stimulating great leaps forward in understanding as discussed by the authors.
Abstract: In ecology, as in other scientific disciplines, there are times when certain conceptual and experimental approaches appear to hold special promise for solving specific problems or stimulating great leaps forward in understanding. The ultimate consequences of these quasi-concerted approaches vary. Some scientific fads arise from the ephemeral reclothing of old ideas; they generate interest but little actual improvement in understanding. Other instances clearly represent breakthroughs that change the ways the scientific enterprise is conducted or provide fundamental new understanding. Most popular trends eventually fall between these extremes, producing some new information, perhaps a novel experimental technique, and an incremental increase in our understanding. Indeed, the history of science has only infrequently been punctuated by bursts of real insight or conspicuous episodes of chasing elusive notions up scientific blind alleys. Today, there are several approaches to studying ecosystems under stress, and it remains to be seen which, if any, will produce powerful problem-solving results. For 15 years or more, ecologists have been espousing a "holistic" approach to
TL;DR: This work has constructed an evolutionary sequence to account for the diversity of ion pumps found today and concludes that ion pumps were the first solution to swelling and lysis.
Abstract: The earliest problem faced by living cells was an unavoidable trend to swelling and lysis, as extracellular salts and water leaked through a semipermeable plasma membrane enclosing impermeant macromolecules. Two solutions countered this ever-present threat-a rigid cell wall to resist expansion and ion pumps to offset the passive influx with an active efflux. On the premise that ion pumps were the first solution, we have constructed an evolutionary sequence to account for the diversity of ion pumps found today.
TL;DR: Despite their extraordinarily long evolutionary history, bacteria appear to have retained certain fundamental elements of design, and it is assumed that bacterial architecture represents an early and highly successful adaptation to selective environmental pressures that still exist.
Abstract: About 3 to 4 billion years ago, all the various syntheses that constitute a living entity managed to become enclosed within a thermodynamically stable membranous sac (Woese and Fox 1977). This hypothetical cell, or progenote, as it has been called (Woese et al. 1978), presumably evolved into more familiar cell types, including archaebacteria and eubacteria. Much of our visible evidence for the existence of microorganisms during this early epoch comes from microfossils in ancient shales and cherts (Banghoorn and Tyler 1965, Pflug and Jaeschke-Boyer 1979, Pierce and Cloud 1979), which bear a striking similarity to contemporary bacteria that have been artificially aged and fossilized in the laboratory (Beveridge et al. 1983; Figure 1). Despite their extraordinarily long evolutionary history, bacteria appear to have retained certain fundamental elements of design. We can therefore assume that bacterial architecture represents an early and highly successful adaptation to selective environmental pressures that still exist. To understand bacterial form and function, we must consider the nature of the world they live in. Their success and vigor are determined primarily by solute diffusion. Sometimes different design strategies can circumvent diffusion problems; for example, the diffusion distance in a rod is less than that in a sphere of equal volume, so large bacterial cells are rarely ovoid. It is clearly advantageous for bacteria to control their shape as well as their local environments, and they
TL;DR: A series of guidelines for testing perturbations at the ecosystem level are outlined, defining stability as the ability of a system to retain or return to some ground state after being perturbed.
Abstract: Ecological systems are frequently exposed to a wide array of ubiquitous perturbations (e.g., acid rain, increased C02, and pesticides). The response of these systems to stress has become a fertile field of investigation. For example, Darnell (1970) noted that an ecosystem's response to stress usually reflects the intensity and duration of the stress agents imposed and the ability of a particular system to respond. Hurd and Wolf (1974) proposed a model of ecosystem stability in response to stress, defining stability as the ability of a system to retain or return to some ground state after being perturbed. They pointed out that one can design experiments to test stability in terms of a system's response to an external perturbation measured as a deflection from ground state. My colleagues and I (Barrett et al. 1976) outlined a series of guidelines for testing perturbations at the ecosystem level.
TL;DR: In a study of the humid tropical ecosystems and especially lowland forests, the National Research Council (1982) concluded that these ecosystems "represent a very important, underexploited resource for tropical countries and that, as population pressures increase in these countries, rapid and extensive development will and must take place if even the currently inadequate standard of living in most countries is to be maintained.
Abstract: In a study of the humid tropical ecosystems and especially lowland forests, the National Research Council (1982) concluded that these ecosystems "represent a very important, underexploited resource for tropical countries and that, as population pressures increase in these countries, rapid and extensive development will and must take place if even the currently inadequate standard of living in most countries is to be maintained." Approximately one-third of the world's 1489 million hectares in the humid tropics lies within the Amazon Basin. Most of the basin devoted to annual crops is subjected to shifting cultivation, i.e., the land is cleared, one or two crops are grown on it, and the soil then lies fallow for several years. Primarily two groups are responsible for clearing much of the Amazon Basin. Shifting cultivators do most of it in the tropical rainforests of the upper portion, and ranchers attempting to create pasture clear the seasonal semievergreen forest in most of the Brazilian or eastern portions (Hecht 1983, Myers 1980). Those areas now subjected to shifting cultivation need continuous cropping systems that provide "permanent field cultivation without first going through a
TL;DR: It is maintained that natural selection is an inevitable process, given the known characteristics of life; that scientists may base scientific explanations and predictions on an understanding of its workings; and that they need not invoke novel mechanisms in the speciation process.
Abstract: Biologists continue to discuss the neo-Darwinian theory of evolution through natural selection. Some question its respectability as a scientific construct, while others doubt its ability to explain adequately the evolution of organic diversity. We maintain that natural selection is an inevitable process, given the known characteristics of life; that we may base scientific explanations and predictions on an understanding of its workings; and that we need not invoke novel mechanisms in the speciation process.
TL;DR: In this article, the authors consider both what we predict and what we cannot predict in managing stressed systems, and propose a model that combines both natural and anthropogenic sources of stress to produce unanticipated and unprecedented ecosystem responses such as a new equilibrium with long-term effects.
Abstract: Both natural and anthropogenic sources of stress can produce unanticipated and unprecedented ecosystem responses, such as a new equilibrium with long-term effects. Ecosystem models that simulate the prospective outcomes of management help to analyze responses to stress mitigation but cannot usually anticipate surprises-the emergence of new stable states. In managing stressed systems, we should therefore consider both what we predict and what we cannot predict.
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TL;DR: As Szostak examines magnified images of spheres, he can't help but notice a striking resemblance to bacterial ecosystems, pulsing with that fetid, yet undeniable quality that has eluded definition for generations life.
Abstract: BY JACK LUCENTINI HORDES OF GREEN, SUB-MICROSCOPIC BALLOONS FLOAT in a watery mixture in Jack Szostak's laboratory at Harvard Medical School. They come in a variety of shapes: spheres, blimps, worms. And as Szostak examines magnified images of them, he can't help but notice a striking resemblance to bacterial ecosystems, pulsing with that fetid, yet undeniable quality that has eluded definition for generations life.
TL;DR: T the presence of parasites and hosts, predators and prey, herbivores and plants, territorial and other competition creates important selective pressures on interacting populations and influences their genetic composition.
Abstract: T the presence of parasites and hosts, predators and prey, herbivores and plants, territorial and other competition creates important selective pressures on interacting populations and influences their genetic composition. Competitive interactions may lead to the extinction of a denizen in a given community. One may thus view today's communities and ecosystems as assemblages of species that have survived extinction (Fowler and MacMahon 1982). Laboratory studies on the effect of infectious diseases on host populations have been reviewed by Anderson and May (1981); Pimentel et al. (1963) researched the survival of parasite-host systems. Disease as an agent of natural selection has been discussed by various authors (Allison 1954, Armelagos and Dewey 1970, Boyd 1961, Haldane 1957, Lederberg 1959, Motulsky 1960). Allison linked the sickle-cell trait, an aberration of the hemoglobin molecule, with protection of the heterozygous carrier against malaria. Haldane suggested that a specific gene for disease resistance may be linked to other genetic expressions. Lederberg discussed ge-
TL;DR: The problem stems principally from budgetary and organizational restrictions as mentioned in this paper, which makes rice fields an ideal habitat for breeding mosquitos, including the vectors of encephalitis and malaria in California's Central Valley, where 90% of California's rice acreage is located.
Abstract: Rice production poses a particularly knotty problem for mosquito control in California's Central Valley. Rice is a profitable crop; its ability to grow well on relatively poor land makes it especially valuable. But economical cultivation methods make rice fields an ideal habitat for breeding mosquitos, including the vectors of encephalitis and malaria. Mosquito control is the principal means of preventing these diseases and is thus important to public health as well as environmental quality. Stringent mosquito control is both technically feasible and socially desirable, yet many organized mosquito abatement districts (MADs) in California have been unable to achieve high enough levels of mosquito control. The problem stems principally from budgetary and organizational restrictions. Many MADs in the Sacramento Valley (northern California Central Valley), where 90% of California's rice acreage is located, cannot afford the required control measures. Moreover, in some Sacramento Valley counties a substantial proportion of the rice acreage lies outside the boundaries of organized abatement districts, which are thereby rendered legally and financially incapable of applying the appropriate controls.