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Temperate coastal marine communities: biodiversity and threats
210
Selected abstracts
95Z/00007 The process of loss: exploring lime interactions between economic and ecological systems R. B. Norgaard, American Zoologist, 34(1), 1994, pp 145-158. Discusses the interaction of economic systems with the environment, and their policy implications. One of the major problems is that even existing economic understandings of the processes of biodiversity loss are only accepted within a part of the economics profession because these understandings conflict with political ideologies held by most American economists. Thus, processes of biodiversity loss are maintained, not for a lack of knowledge, but for a desire among people to maintain simple views of biological systems. The paper concludes with suggestions of additional ways of modeling the interactions between human activity and biological systems which may provide further insight into how we might better maintain biological diversity. (from Author)
understanding of ecological procesess on reefs combined with concerted conservation efforts has managed to protect some extensive areas of reef. (from Author)
95Z/00008 Temperate coastal marine commoaitles: biodiversity and threats T. H. Suehanek, American Zoologist, 34(1), 1994, pp 100-114. Temperate marine ecosystems are some of the most productive and diverse of all ecosystems, but they are continually subjected to threats from multiple stresses imposed mostly by human activities, particularly: 1) habitat loss and degradation, 2) pollution - including sewage, pesticides, pulp mills, thermal effluents, PCBs, heavy metals, oil and radionuelides, 3) overexploitation, 4) species introductions, 5) global climate change, 6) misguided human perceptions, and 7) legal complexities. Because subtidal and offshore coastal marine communities are not easily observed, their deterioration often goes mostly unnoticed. Impacts from stresses on coastal marine communities are manifested at the individual species level, but magnify in effect throughout the entire ecosystem because of complex inter-connected relationships between species at different trophic levels, including interactions such as predation, competition and mutualism. Therefore, one lost species or group of species may have unpredictable direct or indirect consequences through secondary effects on the ecosystem, possibly leading to the loss of a few to many species. Rather than striving to maintain some specific level of diversity, we should endeavour to understand the basic ecological proceses that control populations, communities and ecosystems so we can best predict what kinds of stresses will cause the most serious alterations to the system and avoid them. We should be conservative about protecting systems even before we understand the procesess fully. (from Author)
95Z/00011 The changing roles of zoological parks in conserving biological diversity G. B. Rabb, American Zoologist, 34(1), 1994, pp 159-164. Education is the primary function in zoo conservation, but zoos have begun to make significant contributions as genetic refuges and reservoirs, especially for large vertebrate species threatened with extinction. In developing this capacity zoos have fostered investigations into several facets of small population biology. These have extended to simulation modelling to help predict the outcome of various combinations of ecological, genetic, and demographic factors on the viability of populations in captivity and in the wild. Because resources of zoos are limited in respect to their enlarged functions in conservation and research, they are encouraging development of criteria to help prioritize actions for conservation ofbiodiversity. North American, European, and Australian zoos are assisting the development of technical capacities among zoo counterparts, government agencies, and protected areas in both developing and developed countries of the world to further the conservation of biodiversity. (from Author) 95Z/00012 Can wildlife pay its way?. S. K. Eltringham, Oryx, 28(3), 1994, pp 163-168. Examines ways in which wildlife can be valuable to local people and made to pay for its own conservation - game viewing, sport hunting, game cropping and ranching. While these uses are possible for some wildlife species, others will never have a direct economic value. (from Author)
95Z/00009 Bindiversity of coral reefs: what are we losing and why? K. P. Sebens, American Zoologist, 34(1), 1994, pp 115-133. Coral reefs are threatened by numerous anthropogenic impacts. These unique tropical environments harbor a high diversity of corals, reef invertebrates, fish and other animals and plants. In most taxa, the species diversity of reef-associated organisms is poorly understood. High coral mortality has been associated with natural events such as hurricanes, predator outbreaks and periods of high temperature, but has also resulted from excess nutrients in sewage and from specific pollutants. Reef corals and associated organisms are also threatened by the possibility of global warming which will result in rising sea levels and periods of increased temperature stress, and which may also bring increased storm frequency and intensity. Although the recent extensive episodes of coral bleaching in the Caribbean and E Pacific cannot be causally related to global warming, the close link between bleaching and temperature suggests that global warming will result in severe changes in coral assemblages. Major reef destruction has followed outbreaks of the predatory crown-of-thorns starfish A canthasterplanciin the Pacific. Although this is part of a natural disturbance cycle, altered land use patterns and reduction of predators on this seastar by human activities may have increased the severity of outbreaks. Recreational and commercial use of reefs has also increased, and has caused extensive damage. A widespread loss to reef biota is the reduction in fish populations from intense overfishing. Improved
95Z/00013 Landscape pattern and population conservation S. Harrison & L. Fahrig, in: Mosaic landscapes and ecological processes, ed L. Hanson & others, (Chapman & Hall; IALE Studies in Landscape Ecology, 2), 1995, pp 293-308. Theory relating population survival to landscape spatial pattern is reviewed. Important generalizations are: 1) as the amount of habitat decreases the probability of regional population survival decreases; 2) for the same total m o u n t of habitat, increased habitat clumping (increasing patch size) increases the probability ofpopulation survival, and this positive effect of increasing patch size outweighs the negative effect of increasing inter-patch distance; 3) increasing interpatch variance in patch size increases the possibility of regional survival; 4) when the landscape pattern is dynamic (patches are ephemeral or disturbance rate is high), landscape spatial pattern is relatively unimportant; and 5) when habitat is ephemeral, regional population survival increases with increasing patch lifespan. Empirical studies cannot be used to rigorously test the theoretical predictions because human activities usually alter several aspects of landscape pattern simultaneously. Important questions for future research are: 1) To what extent can careful planning of landscape pattern compensate for loss of habitat? 2) Under what circumstances (for what kinds ofspeciesin what kinds of landscapes) is spatially explicit modeling necessary for predicting the effects of habitat fragmentation on population survival? 3) How can we make predictions ofeffetets on alteration of landscape pattern on species diversity? (Authors)
95Z/00010 Biodiversity on oceanic islands: its origin and extinction G. Panlay, American Zoologist, 34(1), 1994, pp 134-144. Explores the origin of island biotas through dispersal and in situ diversification, and examines the fate of these biotas since human contact. Island biotas start out depanperate and disharmonic, facilitating survival of relict taxa and stimulating adaptive radiations. The often highly restricted range and small population size of insular species, together with their limited diversity of defenses, make island biotas particularly vulnerable to extinction, largely through habitat loss or interactions with introduced species. (from Author)
Selected abstracts
95Z/00007 The process of loss: exploring lime interactions between economic and ecological systems R. B. Norgaard, American Zoologist, 34(1), 1994, pp 145-158. Discusses the interaction of economic systems with the environment, and their policy implications. One of the major problems is that even existing economic understandings of the processes of biodiversity loss are only accepted within a part of the economics profession because these understandings conflict with political ideologies held by most American economists. Thus, processes of biodiversity loss are maintained, not for a lack of knowledge, but for a desire among people to maintain simple views of biological systems. The paper concludes with suggestions of additional ways of modeling the interactions between human activity and biological systems which may provide further insight into how we might better maintain biological diversity. (from Author)
understanding of ecological procesess on reefs combined with concerted conservation efforts has managed to protect some extensive areas of reef. (from Author)
95Z/00008 Temperate coastal marine commoaitles: biodiversity and threats T. H. Suehanek, American Zoologist, 34(1), 1994, pp 100-114. Temperate marine ecosystems are some of the most productive and diverse of all ecosystems, but they are continually subjected to threats from multiple stresses imposed mostly by human activities, particularly: 1) habitat loss and degradation, 2) pollution - including sewage, pesticides, pulp mills, thermal effluents, PCBs, heavy metals, oil and radionuelides, 3) overexploitation, 4) species introductions, 5) global climate change, 6) misguided human perceptions, and 7) legal complexities. Because subtidal and offshore coastal marine communities are not easily observed, their deterioration often goes mostly unnoticed. Impacts from stresses on coastal marine communities are manifested at the individual species level, but magnify in effect throughout the entire ecosystem because of complex inter-connected relationships between species at different trophic levels, including interactions such as predation, competition and mutualism. Therefore, one lost species or group of species may have unpredictable direct or indirect consequences through secondary effects on the ecosystem, possibly leading to the loss of a few to many species. Rather than striving to maintain some specific level of diversity, we should endeavour to understand the basic ecological proceses that control populations, communities and ecosystems so we can best predict what kinds of stresses will cause the most serious alterations to the system and avoid them. We should be conservative about protecting systems even before we understand the procesess fully. (from Author)
95Z/00011 The changing roles of zoological parks in conserving biological diversity G. B. Rabb, American Zoologist, 34(1), 1994, pp 159-164. Education is the primary function in zoo conservation, but zoos have begun to make significant contributions as genetic refuges and reservoirs, especially for large vertebrate species threatened with extinction. In developing this capacity zoos have fostered investigations into several facets of small population biology. These have extended to simulation modelling to help predict the outcome of various combinations of ecological, genetic, and demographic factors on the viability of populations in captivity and in the wild. Because resources of zoos are limited in respect to their enlarged functions in conservation and research, they are encouraging development of criteria to help prioritize actions for conservation ofbiodiversity. North American, European, and Australian zoos are assisting the development of technical capacities among zoo counterparts, government agencies, and protected areas in both developing and developed countries of the world to further the conservation of biodiversity. (from Author) 95Z/00012 Can wildlife pay its way?. S. K. Eltringham, Oryx, 28(3), 1994, pp 163-168. Examines ways in which wildlife can be valuable to local people and made to pay for its own conservation - game viewing, sport hunting, game cropping and ranching. While these uses are possible for some wildlife species, others will never have a direct economic value. (from Author)
95Z/00009 Bindiversity of coral reefs: what are we losing and why? K. P. Sebens, American Zoologist, 34(1), 1994, pp 115-133. Coral reefs are threatened by numerous anthropogenic impacts. These unique tropical environments harbor a high diversity of corals, reef invertebrates, fish and other animals and plants. In most taxa, the species diversity of reef-associated organisms is poorly understood. High coral mortality has been associated with natural events such as hurricanes, predator outbreaks and periods of high temperature, but has also resulted from excess nutrients in sewage and from specific pollutants. Reef corals and associated organisms are also threatened by the possibility of global warming which will result in rising sea levels and periods of increased temperature stress, and which may also bring increased storm frequency and intensity. Although the recent extensive episodes of coral bleaching in the Caribbean and E Pacific cannot be causally related to global warming, the close link between bleaching and temperature suggests that global warming will result in severe changes in coral assemblages. Major reef destruction has followed outbreaks of the predatory crown-of-thorns starfish A canthasterplanciin the Pacific. Although this is part of a natural disturbance cycle, altered land use patterns and reduction of predators on this seastar by human activities may have increased the severity of outbreaks. Recreational and commercial use of reefs has also increased, and has caused extensive damage. A widespread loss to reef biota is the reduction in fish populations from intense overfishing. Improved
95Z/00013 Landscape pattern and population conservation S. Harrison & L. Fahrig, in: Mosaic landscapes and ecological processes, ed L. Hanson & others, (Chapman & Hall; IALE Studies in Landscape Ecology, 2), 1995, pp 293-308. Theory relating population survival to landscape spatial pattern is reviewed. Important generalizations are: 1) as the amount of habitat decreases the probability of regional population survival decreases; 2) for the same total m o u n t of habitat, increased habitat clumping (increasing patch size) increases the probability ofpopulation survival, and this positive effect of increasing patch size outweighs the negative effect of increasing inter-patch distance; 3) increasing interpatch variance in patch size increases the possibility of regional survival; 4) when the landscape pattern is dynamic (patches are ephemeral or disturbance rate is high), landscape spatial pattern is relatively unimportant; and 5) when habitat is ephemeral, regional population survival increases with increasing patch lifespan. Empirical studies cannot be used to rigorously test the theoretical predictions because human activities usually alter several aspects of landscape pattern simultaneously. Important questions for future research are: 1) To what extent can careful planning of landscape pattern compensate for loss of habitat? 2) Under what circumstances (for what kinds ofspeciesin what kinds of landscapes) is spatially explicit modeling necessary for predicting the effects of habitat fragmentation on population survival? 3) How can we make predictions ofeffetets on alteration of landscape pattern on species diversity? (Authors)
95Z/00010 Biodiversity on oceanic islands: its origin and extinction G. Panlay, American Zoologist, 34(1), 1994, pp 134-144. Explores the origin of island biotas through dispersal and in situ diversification, and examines the fate of these biotas since human contact. Island biotas start out depanperate and disharmonic, facilitating survival of relict taxa and stimulating adaptive radiations. The often highly restricted range and small population size of insular species, together with their limited diversity of defenses, make island biotas particularly vulnerable to extinction, largely through habitat loss or interactions with introduced species. (from Author)