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David L. Strayer

Bio: David L. Strayer is an academic researcher from University of Utah. The author has contributed to research in topics: Poison control & Dreissena. The author has an hindex of 87, co-authored 363 publications receiving 29105 citations. Previous affiliations of David L. Strayer include Cornell University & Free University of Berlin.


Papers
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Journal ArticleDOI
TL;DR: Progress in conservation of freshwater biodiversity is reviewed, with a focus on the period since 1986, and key challenges for the future are outlined, including bridge the gap between freshwater ecology and conservation biology.
Abstract: Freshwater habitats occupy ,1% of the Earth's surface, yet are hotspots that support ,10% of all known species, and ,M of vertebrate species. Fresh waters also are hotspots for human activities that have led to widespread habitat degradation, pollution, flow regulation and water extraction, fisheries overexploitation, and alien species introductions. These impacts have caused severe declines in the range and abundance of many freshwater species, so that they are now far more imperiled than their marine or terrestrial counterparts. Here, we review progress in conservation of freshwater biodiversity, with a focus on the period since 1986, and outline key challenges for the future. Driven by rising conservation concerns, freshwater ecologists have conducted a great deal of research over the past 25 y on the status, trends, autecology, and propagation of imperiled species, threats to these species, the consequences of biodiversity loss for ecosystem functioning, metapopulation dynamics, biodiversity hotspots, reserve design, habitat restoration, communication with stakeholders, and weaknesses of protective legislation. Nevertheless, existing efforts might be insufficient to stem the ongoing and coming multitude of freshwater extinctions. We briefly discuss 4 important challenges for freshwater conservation. First, climate change will imperil both freshwater species and human uses of fresh water, driving engineering responses that will further threaten the freshwater biota. We need to anticipate both ecological and human responses to climate change, and to encourage rational and deliberate planning of engineering responses to climate change before disasters strike. Second, because freshwater extinctions are already well underway, freshwater conservationists must be prepared to act now to prevent further losses, even if our knowledge is incomplete, and engage more effectively with other stakeholders. Third, we need to bridge the gap between freshwater ecology and conservation biology. Fourth, we suggest that scientific societies and scholarly journals concerned with limnology or freshwater sciences need to improve their historically poor record in publishing important papers and influencing practice in conservation ecology. Failure to meet these challenges will lead to the extinction or impoverishment of the very subjects of our research.

1,369 citations

Journal ArticleDOI
TL;DR: It is suggested that cellular-phone use disrupts performance by diverting attention to an engaging cognitive context other than the one immediately associated with driving.
Abstract: Dual-task studies assessed the effects of cellular-phone conversations on performance of a simulated driving task. Perfor- mance was not disrupted by listening to radio broadcasts or listening to a book on tape. Nor was it disrupted by a continuous shadowing task using a handheld phone, ruling out, in this case, dual-task inter- pretations associated with holding the phone, listening, or speaking. However, significant interference was observed in a word-generation variant of the shadowing task, and this deficit increased with the diffi- culty of driving. Moreover, unconstrained conversations using either a handheld or a hands-free cell phone resulted in a twofold increase in the failure to detect simulated traffic signals and slower reactions to those signals that were detected. We suggest that cellular-phone use disrupts performance by diverting attention to an engaging cognitive context other than the one immediately associated with driving. crease in the likelihood of getting into an accident, and that this increased risk was comparable to that found for driving with a blood alcohol level above the legal limit. In addition, these authors found no reliable safety advantages for those individuals who used a hands-free cellular device. The authors concluded that the interference associated with cell-phone use was due to attentional factors rather than to pe- ripheral factors such as holding the phone. The field studies of Redelmeier and Tibshirani (1997) establish a correlation between cell-phone use and motor-vehicle accidents, but they do not necessarily imply that use of cell phones causes an increase in accident rates. There may be self-selection factors creating an asso- ciation between cell-phone use and accidents. For example, people who drive and use their cell phone may be more likely to engage in risky behavior, and this increase in risk taking may underlie the corre- lation. Similarly, being in a highly emotional state may increase one's likelihood of driving erratically and may also increase one's likelihood of talking on the cell phone. In order to assess the possible causal rela- tionship between cell-phone use and automobile accidents, carefully controlled experiments, such as the ones described in this report, are needed.

1,122 citations

Journal ArticleDOI
TL;DR: The data suggest that the impairment of driving performance produced by cell phone conversations is mediated, at least in part, by reduced attention to visual inputs.
Abstract: This research examined the effects of hands-free cell phone conversations on simulated driving. The authors found that these conversations impaired driver’s reactions to vehicles braking in front of them. The authors assessed whether this impairment could be attributed to a withdrawal of attention from the visual scene, yielding a form of inattention blindness. Cell phone conversations impaired explicit recognition memory for roadside billboards. Eye-tracking data indicated that this was due to reduced attention to foveal information. This interpretation was bolstered by data showing that cell phone conversations impaired implicit perceptual memory for items presented at fixation. The data suggest that the impairment of driving performance produced by cell phone conversations is mediated, at least in part, by reduced attention to visual inputs.

1,040 citations

Journal ArticleDOI
TL;DR: The ecological and evolutionary processes that modulate the effects of invasive species over time are described, and it is argued that such processes are so widespread and important that ecologists should adopt a long-term perspective.
Abstract: We describe here the ecological and evolutionary processes that modulate the effects of invasive species over time, and argue that such processes are so widespread and important that ecologists should adopt a long-term perspective on the effects of invasive species. These processes (including evolution, shifts in species composition, accumulation of materials and interactions with abiotic variables) can increase, decrease, or qualitatively change the impacts of an invader through time. However, most studies of the effects of invasive species have been brief and lack a temporal context; 40% of recent studies did not even state the amount of time that had passed since the invasion. Ecologists need theory and empirical data to enable prediction, understanding and management of the acute and chronic effects of species invasions.

926 citations

Journal ArticleDOI
TL;DR: Biological invasions are numerous in fresh waters around the world and the number of alien species in freshwater ecosystems will increase in the future as new aliens are moved outside of their native ranges by humans, and as established aliens fill their potential ranges.
Abstract: Summary 1. Biological invasions are numerous in fresh waters around the world. At least hundreds of freshwater species have been moved outside of their native ranges by vectors such as ballast water, canals, deliberate introductions, and releases from aquaria, gardens, and bait buckets. As a result, many bodies of fresh water now contain dozens of alien species. 2. Invasions are highly nonrandom with respect to the taxonomic identity and biological traits of the invaders, the ecological characteristics of the ecosystems that are invaded, and the geographical location of the ecosystems that supply and receive the invaders. 3. Some invaders have had deep and pervasive effects on the ecosystems that they invade. Classes of ecologically important invaders in fresh waters include molluscs that are primary consumers and disrupt the food web from its base, fishes that disrupt the food web from its apex or centre, decapods that act as powerful omnivores, aquatic plants that have strong engineering effects and affect the quality and quantity of primary production, and diseases, which probably have been underestimated as an ecological force. 4. The number of alien species in freshwater ecosystems will increase in the future as new aliens are moved outside of their native ranges by humans, and as established aliens fill their potential ranges. Alien species create “no-analogue” ecosystems that will be difficult to manage in the future. We may be able to reduce future impacts of invaders by making more serious efforts to prevent new invasions and manage existing invaders. 5. Thematic implications: interactions between alien species and other contemporary stressors of freshwater ecosystems are strong and varied. Because disturbance is generally thought to favour invasions, stressed ecosystems may be especially susceptible to invasions, as are highly artificial ecosystems. In turn, alien species can strongly alter the hydrology, biogeochemical cycling, and biotic composition of invaded ecosystems, and thus modulate the effects of other stressors. In general, interactions between alien species and other stressors are poorly studied.

906 citations


Cited by
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Journal ArticleDOI
TL;DR: The results suggest that it is important to recognize both the unity and diversity ofExecutive functions and that latent variable analysis is a useful approach to studying the organization and roles of executive functions.

12,182 citations

Journal ArticleDOI
TL;DR: This article explores the special features of freshwater habitats and the biodiversity they support that makes them especially vulnerable to human activities and advocates continuing attempts to check species loss but urges adoption of a compromise position of management for biodiversity conservation, ecosystem functioning and resilience, and human livelihoods.
Abstract: Freshwater biodiversity is the over-riding conservation priority during the International Decade for Action - 'Water for Life' - 2005 to 2015. Fresh water makes up only 0.01% of the World's water and approximately 0.8% of the Earth's surface, yet this tiny fraction of global water supports at least 100000 species out of approximately 1.8 million - almost 6% of all described species. Inland waters and freshwater biodiversity constitute a valuable natural resource, in economic, cultural, aesthetic, scientific and educational terms. Their conservation and management are critical to the interests of all humans, nations and governments. Yet this precious heritage is in crisis. Fresh waters are experiencing declines in biodiversity far greater than those in the most affected terrestrial ecosystems, and if trends in human demands for water remain unaltered and species losses continue at current rates, the opportunity to conserve much of the remaining biodiversity in fresh water will vanish before the 'Water for Life' decade ends in 2015. Why is this so, and what is being done about it? This article explores the special features of freshwater habitats and the biodiversity they support that makes them especially vulnerable to human activities. We document threats to global freshwater biodiversity under five headings: overexploitation; water pollution; flow modification; destruction or degradation of habitat; and invasion by exotic species. Their combined and interacting influences have resulted in population declines and range reduction of freshwater biodiversity worldwide. Conservation of biodiversity is complicated by the landscape position of rivers and wetlands as 'receivers' of land-use effluents, and the problems posed by endemism and thus non-substitutability. In addition, in many parts of the world, fresh water is subject to severe competition among multiple human stakeholders. Protection of freshwater biodiversity is perhaps the ultimate conservation challenge because it is influenced by the upstream drainage network, the surrounding land, the riparian zone, and - in the case of migrating aquatic fauna - downstream reaches. Such prerequisites are hardly ever met. Immediate action is needed where opportunities exist to set aside intact lake and river ecosystems within large protected areas. For most of the global land surface, trade-offs between conservation of freshwater biodiversity and human use of ecosystem goods and services are necessary. We advocate continuing attempts to check species loss but, in many situations, urge adoption of a compromise position of management for biodiversity conservation, ecosystem functioning and resilience, and human livelihoods in order to provide a viable long-term basis for freshwater conservation. Recognition of this need will require adoption of a new paradigm for biodiversity protection and freshwater ecosystem management - one that has been appropriately termed 'reconciliation ecology'.

5,857 citations

01 Jan 1964
TL;DR: In this paper, the notion of a collective unconscious was introduced as a theory of remembering in social psychology, and a study of remembering as a study in Social Psychology was carried out.
Abstract: Part I. Experimental Studies: 2. Experiment in psychology 3. Experiments on perceiving III Experiments on imaging 4-8. Experiments on remembering: (a) The method of description (b) The method of repeated reproduction (c) The method of picture writing (d) The method of serial reproduction (e) The method of serial reproduction picture material 9. Perceiving, recognizing, remembering 10. A theory of remembering 11. Images and their functions 12. Meaning Part II. Remembering as a Study in Social Psychology: 13. Social psychology 14. Social psychology and the matter of recall 15. Social psychology and the manner of recall 16. Conventionalism 17. The notion of a collective unconscious 18. The basis of social recall 19. A summary and some conclusions.

5,690 citations

Journal ArticleDOI
TL;DR: In this article, it is suggested to adjust the frequency windows of alpha and theta for each subject by using individual alpha frequency as an anchor point, based on this procedure, a consistent interpretation of a variety of findings is made possible.

5,613 citations