Richard C. Tinsley
- Published in print:
- 2005
- Published Online:
- September 2007
- ISBN:
- 9780198529873
- eISBN:
- 9780191712777
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198529873.003.0007
- Subject:
- Biology, Disease Ecology / Epidemiology
There is good physiological documentation of the survival of parasites (generally the ‘off-host’ stages) in environments that would be considered hostile to life and characterized by freezing, ...
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There is good physiological documentation of the survival of parasites (generally the ‘off-host’ stages) in environments that would be considered hostile to life and characterized by freezing, extreme desiccation, and so on. Equivalent adaptations may occur in free-living organisms, and are not therefore a feature of parasitism. However, these mechanisms are relevant to the ability of some parasites to persist in ecosystems at the margins of survival of life (as in hot and cold deserts). It is a feature of many such severe environments that constraints are relaxed periodically, even if very briefly, creating a ‘window of opportunity’ when transfer from host to host may occur. It is of even greater interest that, in some cases, transmission may continue even when external conditions appear to be most extreme and when it might be predicted that transmission should be arrested. In these situations, the host is typically regarded as the ‘safe’ environment while the external environment is viewed as hostile. In contrast, there is now abundant evidence that the host actually represents the most hostile environment in the parasite’s life cycle, constituting a finely tuned ‘killing machine’. The mechanisms of the various lethal factors are well documented, together with the reciprocal parasite adaptations for evasion and suppression of attack. This review takes an ecological perspective. Variations in parasite infectivity for particular host types and in host susceptibility to infection determine that some ‘environments’ (hosts) are more hostile than others. The shifting balance between prevailing host and parasite types determines the ability of parasites to persist in the spectrum of environments within the ecosystem. Even the ‘favourable’ environments (in which surviving infections reproduce) may be responsible for major mortality within parasite populations and this contributes to the regulation of the interactions.Less
There is good physiological documentation of the survival of parasites (generally the ‘off-host’ stages) in environments that would be considered hostile to life and characterized by freezing, extreme desiccation, and so on. Equivalent adaptations may occur in free-living organisms, and are not therefore a feature of parasitism. However, these mechanisms are relevant to the ability of some parasites to persist in ecosystems at the margins of survival of life (as in hot and cold deserts). It is a feature of many such severe environments that constraints are relaxed periodically, even if very briefly, creating a ‘window of opportunity’ when transfer from host to host may occur. It is of even greater interest that, in some cases, transmission may continue even when external conditions appear to be most extreme and when it might be predicted that transmission should be arrested. In these situations, the host is typically regarded as the ‘safe’ environment while the external environment is viewed as hostile. In contrast, there is now abundant evidence that the host actually represents the most hostile environment in the parasite’s life cycle, constituting a finely tuned ‘killing machine’. The mechanisms of the various lethal factors are well documented, together with the reciprocal parasite adaptations for evasion and suppression of attack. This review takes an ecological perspective. Variations in parasite infectivity for particular host types and in host susceptibility to infection determine that some ‘environments’ (hosts) are more hostile than others. The shifting balance between prevailing host and parasite types determines the ability of parasites to persist in the spectrum of environments within the ecosystem. Even the ‘favourable’ environments (in which surviving infections reproduce) may be responsible for major mortality within parasite populations and this contributes to the regulation of the interactions.
Amy Lauren Lovecraft
- Published in print:
- 2008
- Published Online:
- August 2013
- ISBN:
- 9780262220842
- eISBN:
- 9780262285445
- Item type:
- chapter
- Publisher:
- The MIT Press
- DOI:
- 10.7551/mitpress/9780262220842.003.0005
- Subject:
- Environmental Science, Climate
This chapter examines the effect of climate change on Arctic ecosystems using social-ecological systems (SES) analysis. It also considers the effect of global climate change on the social dynamics of ...
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This chapter examines the effect of climate change on Arctic ecosystems using social-ecological systems (SES) analysis. It also considers the effect of global climate change on the social dynamics of people living in the Arctic and how it might continue to do so. The chapter examines the effects of rapid climate change on Arctic SESs by focusing on two examples of ecological processes: wildfire disturbance and sea-ice coverage.Less
This chapter examines the effect of climate change on Arctic ecosystems using social-ecological systems (SES) analysis. It also considers the effect of global climate change on the social dynamics of people living in the Arctic and how it might continue to do so. The chapter examines the effects of rapid climate change on Arctic SESs by focusing on two examples of ecological processes: wildfire disturbance and sea-ice coverage.
John E. Hobbie and George W. Kling (eds)
- Published in print:
- 2014
- Published Online:
- May 2015
- ISBN:
- 9780199860401
- eISBN:
- 9780190267889
- Item type:
- book
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:osobl/9780199860401.001.0001
- Subject:
- Biology, Ecology
This book synthesizes the findings from the NSF-funded Arctic LTER project based in Toolik Lake, Alaska, a site that has been active since the mid-1970s. The book presents research concerning the ...
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This book synthesizes the findings from the NSF-funded Arctic LTER project based in Toolik Lake, Alaska, a site that has been active since the mid-1970s. The book presents research concerning the core issues of climate-change science, and addresses the treeless regions of arctic Alaska, as well as the adjoining boreal forests. The book examines both terrestrial and freshwater-aquatic ecosystems, and their three typical habitats: tundra, streams and lakes. The book provides a history of the Toolik Lake LTER site, and discusses its present condition and future outlook. The chapters create a multidisciplinary survey of the Alaskan arctic ecosystem. Topics include glacial history, climatology, land-water interactions, mercury found in the Alaskan arctic, and the response of lakes to environmental change. The final chapter brings together these findings in order to make predictions regarding the consequences that arctic Alaska faces due to global warming and climate change, and discusses the future of the LTER site in the region.Less
This book synthesizes the findings from the NSF-funded Arctic LTER project based in Toolik Lake, Alaska, a site that has been active since the mid-1970s. The book presents research concerning the core issues of climate-change science, and addresses the treeless regions of arctic Alaska, as well as the adjoining boreal forests. The book examines both terrestrial and freshwater-aquatic ecosystems, and their three typical habitats: tundra, streams and lakes. The book provides a history of the Toolik Lake LTER site, and discusses its present condition and future outlook. The chapters create a multidisciplinary survey of the Alaskan arctic ecosystem. Topics include glacial history, climatology, land-water interactions, mercury found in the Alaskan arctic, and the response of lakes to environmental change. The final chapter brings together these findings in order to make predictions regarding the consequences that arctic Alaska faces due to global warming and climate change, and discusses the future of the LTER site in the region.
RAYMOND C. HIGHSMITH, KENNETH O COYLE, BODIL A BLUHM, and BRENDA KONAR
- Published in print:
- 2007
- Published Online:
- March 2012
- ISBN:
- 9780520248847
- eISBN:
- 9780520933200
- Item type:
- chapter
- Publisher:
- University of California Press
- DOI:
- 10.1525/california/9780520248847.003.0023
- Subject:
- Biology, Aquatic Biology
Among the large cetaceans, gray whales (Eschrichtius robustus) are unique in three important ways: They are benthic feeders; they undertake one of the longest migrations of any mammal; and they may ...
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Among the large cetaceans, gray whales (Eschrichtius robustus) are unique in three important ways: They are benthic feeders; they undertake one of the longest migrations of any mammal; and they may be fully recovered from overharvesting by commercial whaling. The eastern gray whales migrate annually between the mating regions and calving lagoons on the west coast of Baja California, Mexico, to summer feeding grounds in the northern Bering Sea and the Chukchi Sea. This chapter explores the arctic ecosystem dynamics that justify such a migration and the impacts of the whales upon the system. It concludes with an oceanographic production model that both explains the current location of major gray whale feeding sites and can be used for predictive purposes.Less
Among the large cetaceans, gray whales (Eschrichtius robustus) are unique in three important ways: They are benthic feeders; they undertake one of the longest migrations of any mammal; and they may be fully recovered from overharvesting by commercial whaling. The eastern gray whales migrate annually between the mating regions and calving lagoons on the west coast of Baja California, Mexico, to summer feeding grounds in the northern Bering Sea and the Chukchi Sea. This chapter explores the arctic ecosystem dynamics that justify such a migration and the impacts of the whales upon the system. It concludes with an oceanographic production model that both explains the current location of major gray whale feeding sites and can be used for predictive purposes.
