Population regulation in large northern herbivores: Evolution, thermodynamics, and large predators

Autores
Fluck, Werner Thomas
Año de publicación
2000
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
Understanding population regulation of large northern herbivores like cervids has important practical and theoretical implications. Corrective measures for high densities of cervids must be based on theory and thus necessitate analysis of contradicting views of top-down and bottom-up population control. The former considers cervids incapable of self-regulation and hence that they need external factors like predation to achieve effective population regulation. The latter claims that cervids exhibit the capacity to adjust their numbers to the food supply as shown by physiological responses. However, these phenomena are not an expression of evolutionary adaption, they are a predictable physiological reaction to reduced food. In addition, studies were often done in man-modified environments or without considerations of modulating effects through predators. It is unlikely to study pristine relationships between large herbivores and predators in the future through field work, and insights from other fields need to be heeded. Considerations from evolution, thermodynamics, food webs and nutrient cycling indicate that the development of biological systems is unidirectional due to irreversible processes and leads toward optimal order and optimal accumulation of energy and nutrients. Large predators are thus not just a luxury development of evolution, but a necessary sequel to natural laws and they increase efficiency of the system to capture solar energy. It explains why analogous ecomorphs, like saber-tooth 'cats' (placental and marsupial) have re-evolved independently at least 5 times. As a group, large predators developed traits allowing self-regulation including territoriality, intra- and interspecific killing, prey-switching, and dispersal. However, in man-modified environments, herbivore densities can reach such high levels that even an intact predator community will no longer exert regulation as there is an upper limit of predator density determined by social mechanisms. As kill success rates are very low, predators also affect herbivores by largely determining spacial distribution and behavioral adaptions, all of which modify herbivore-plant interactions. Cervids on the other hand exhibit traits all indicative of absence of a capacity to self-regulate. Predictable physiological responses to reduced food intake thus operate so late that the typical population response is an irruption with subsequent major dieoff and leads to a reduction in system performance including loss of biodiversity. Therefore, the claim that there exists 'natural' regulation in such situations is an erroneous term for what is better called forced starvation. Two conclusions can be drawn: 1. Herbivore densities above a critical level will inevitably cause shifts in community functioning by altering plant and animal species composition, nutrient and energy flow patterns: the system will effectively be forced to a less complex and hence, less productive level, an evolutionary step backwards. 2. By having modified ecological parameters necessary for the welfare of herbivores, we need to take on the responsibility to guarantee their future welfare by actively replacing missing factors. For cervids it may mean implementing harvesting such that population densities permit natural plant rejuvenation and optimal biodiversity. Where the predator community is still intact, it should be protected by all means, and where still possible, predator communities should be restored. A basic tool is to disseminate the best available information, namely that large northern herbivores do not exhibit self regulation.
Fil: Fluck, Werner Thomas. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Materia
Large Predator
Herbivore Density
Predator Community
Behavioral Adaption
Interspecific Killing
Nivel de accesibilidad
acceso abierto
Condiciones de uso
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
Repositorio
CONICET Digital (CONICET)
Institución
Consejo Nacional de Investigaciones Científicas y Técnicas
OAI Identificador
oai:ri.conicet.gov.ar:11336/40115

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spelling Population regulation in large northern herbivores: Evolution, thermodynamics, and large predatorsFluck, Werner ThomasLarge PredatorHerbivore DensityPredator CommunityBehavioral AdaptionInterspecific Killinghttps://purl.org/becyt/ford/1.6https://purl.org/becyt/ford/1Understanding population regulation of large northern herbivores like cervids has important practical and theoretical implications. Corrective measures for high densities of cervids must be based on theory and thus necessitate analysis of contradicting views of top-down and bottom-up population control. The former considers cervids incapable of self-regulation and hence that they need external factors like predation to achieve effective population regulation. The latter claims that cervids exhibit the capacity to adjust their numbers to the food supply as shown by physiological responses. However, these phenomena are not an expression of evolutionary adaption, they are a predictable physiological reaction to reduced food. In addition, studies were often done in man-modified environments or without considerations of modulating effects through predators. It is unlikely to study pristine relationships between large herbivores and predators in the future through field work, and insights from other fields need to be heeded. Considerations from evolution, thermodynamics, food webs and nutrient cycling indicate that the development of biological systems is unidirectional due to irreversible processes and leads toward optimal order and optimal accumulation of energy and nutrients. Large predators are thus not just a luxury development of evolution, but a necessary sequel to natural laws and they increase efficiency of the system to capture solar energy. It explains why analogous ecomorphs, like saber-tooth 'cats' (placental and marsupial) have re-evolved independently at least 5 times. As a group, large predators developed traits allowing self-regulation including territoriality, intra- and interspecific killing, prey-switching, and dispersal. However, in man-modified environments, herbivore densities can reach such high levels that even an intact predator community will no longer exert regulation as there is an upper limit of predator density determined by social mechanisms. As kill success rates are very low, predators also affect herbivores by largely determining spacial distribution and behavioral adaptions, all of which modify herbivore-plant interactions. Cervids on the other hand exhibit traits all indicative of absence of a capacity to self-regulate. Predictable physiological responses to reduced food intake thus operate so late that the typical population response is an irruption with subsequent major dieoff and leads to a reduction in system performance including loss of biodiversity. Therefore, the claim that there exists 'natural' regulation in such situations is an erroneous term for what is better called forced starvation. Two conclusions can be drawn: 1. Herbivore densities above a critical level will inevitably cause shifts in community functioning by altering plant and animal species composition, nutrient and energy flow patterns: the system will effectively be forced to a less complex and hence, less productive level, an evolutionary step backwards. 2. By having modified ecological parameters necessary for the welfare of herbivores, we need to take on the responsibility to guarantee their future welfare by actively replacing missing factors. For cervids it may mean implementing harvesting such that population densities permit natural plant rejuvenation and optimal biodiversity. Where the predator community is still intact, it should be protected by all means, and where still possible, predator communities should be restored. A basic tool is to disseminate the best available information, namely that large northern herbivores do not exhibit self regulation.Fil: Fluck, Werner Thomas. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaBlackwell Verlag GmbH Berlin2000-12info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionhttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfapplication/pdfhttp://hdl.handle.net/11336/40115Fluck, Werner Thomas; Population regulation in large northern herbivores: Evolution, thermodynamics, and large predators; Blackwell Verlag GmbH Berlin; Zeitschrift fur Jagdwissenschaft; 46; 3; 12-2000; 139-1660044-2887CONICET DigitalCONICETenginfo:eu-repo/semantics/altIdentifier/doi/10.1007/BF02241353info:eu-repo/semantics/altIdentifier/url/https://link.springer.com/article/10.1007%2FBF02241353info:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by-nc-sa/2.5/ar/reponame:CONICET Digital (CONICET)instname:Consejo Nacional de Investigaciones Científicas y Técnicas2025-09-29T10:11:47Zoai:ri.conicet.gov.ar:11336/40115instacron:CONICETInstitucionalhttp://ri.conicet.gov.ar/Organismo científico-tecnológicoNo correspondehttp://ri.conicet.gov.ar/oai/requestdasensio@conicet.gov.ar; lcarlino@conicet.gov.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:34982025-09-29 10:11:47.758CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicasfalse
dc.title.none.fl_str_mv Population regulation in large northern herbivores: Evolution, thermodynamics, and large predators
title Population regulation in large northern herbivores: Evolution, thermodynamics, and large predators
spellingShingle Population regulation in large northern herbivores: Evolution, thermodynamics, and large predators
Fluck, Werner Thomas
Large Predator
Herbivore Density
Predator Community
Behavioral Adaption
Interspecific Killing
title_short Population regulation in large northern herbivores: Evolution, thermodynamics, and large predators
title_full Population regulation in large northern herbivores: Evolution, thermodynamics, and large predators
title_fullStr Population regulation in large northern herbivores: Evolution, thermodynamics, and large predators
title_full_unstemmed Population regulation in large northern herbivores: Evolution, thermodynamics, and large predators
title_sort Population regulation in large northern herbivores: Evolution, thermodynamics, and large predators
dc.creator.none.fl_str_mv Fluck, Werner Thomas
author Fluck, Werner Thomas
author_facet Fluck, Werner Thomas
author_role author
dc.subject.none.fl_str_mv Large Predator
Herbivore Density
Predator Community
Behavioral Adaption
Interspecific Killing
topic Large Predator
Herbivore Density
Predator Community
Behavioral Adaption
Interspecific Killing
purl_subject.fl_str_mv https://purl.org/becyt/ford/1.6
https://purl.org/becyt/ford/1
dc.description.none.fl_txt_mv Understanding population regulation of large northern herbivores like cervids has important practical and theoretical implications. Corrective measures for high densities of cervids must be based on theory and thus necessitate analysis of contradicting views of top-down and bottom-up population control. The former considers cervids incapable of self-regulation and hence that they need external factors like predation to achieve effective population regulation. The latter claims that cervids exhibit the capacity to adjust their numbers to the food supply as shown by physiological responses. However, these phenomena are not an expression of evolutionary adaption, they are a predictable physiological reaction to reduced food. In addition, studies were often done in man-modified environments or without considerations of modulating effects through predators. It is unlikely to study pristine relationships between large herbivores and predators in the future through field work, and insights from other fields need to be heeded. Considerations from evolution, thermodynamics, food webs and nutrient cycling indicate that the development of biological systems is unidirectional due to irreversible processes and leads toward optimal order and optimal accumulation of energy and nutrients. Large predators are thus not just a luxury development of evolution, but a necessary sequel to natural laws and they increase efficiency of the system to capture solar energy. It explains why analogous ecomorphs, like saber-tooth 'cats' (placental and marsupial) have re-evolved independently at least 5 times. As a group, large predators developed traits allowing self-regulation including territoriality, intra- and interspecific killing, prey-switching, and dispersal. However, in man-modified environments, herbivore densities can reach such high levels that even an intact predator community will no longer exert regulation as there is an upper limit of predator density determined by social mechanisms. As kill success rates are very low, predators also affect herbivores by largely determining spacial distribution and behavioral adaptions, all of which modify herbivore-plant interactions. Cervids on the other hand exhibit traits all indicative of absence of a capacity to self-regulate. Predictable physiological responses to reduced food intake thus operate so late that the typical population response is an irruption with subsequent major dieoff and leads to a reduction in system performance including loss of biodiversity. Therefore, the claim that there exists 'natural' regulation in such situations is an erroneous term for what is better called forced starvation. Two conclusions can be drawn: 1. Herbivore densities above a critical level will inevitably cause shifts in community functioning by altering plant and animal species composition, nutrient and energy flow patterns: the system will effectively be forced to a less complex and hence, less productive level, an evolutionary step backwards. 2. By having modified ecological parameters necessary for the welfare of herbivores, we need to take on the responsibility to guarantee their future welfare by actively replacing missing factors. For cervids it may mean implementing harvesting such that population densities permit natural plant rejuvenation and optimal biodiversity. Where the predator community is still intact, it should be protected by all means, and where still possible, predator communities should be restored. A basic tool is to disseminate the best available information, namely that large northern herbivores do not exhibit self regulation.
Fil: Fluck, Werner Thomas. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
description Understanding population regulation of large northern herbivores like cervids has important practical and theoretical implications. Corrective measures for high densities of cervids must be based on theory and thus necessitate analysis of contradicting views of top-down and bottom-up population control. The former considers cervids incapable of self-regulation and hence that they need external factors like predation to achieve effective population regulation. The latter claims that cervids exhibit the capacity to adjust their numbers to the food supply as shown by physiological responses. However, these phenomena are not an expression of evolutionary adaption, they are a predictable physiological reaction to reduced food. In addition, studies were often done in man-modified environments or without considerations of modulating effects through predators. It is unlikely to study pristine relationships between large herbivores and predators in the future through field work, and insights from other fields need to be heeded. Considerations from evolution, thermodynamics, food webs and nutrient cycling indicate that the development of biological systems is unidirectional due to irreversible processes and leads toward optimal order and optimal accumulation of energy and nutrients. Large predators are thus not just a luxury development of evolution, but a necessary sequel to natural laws and they increase efficiency of the system to capture solar energy. It explains why analogous ecomorphs, like saber-tooth 'cats' (placental and marsupial) have re-evolved independently at least 5 times. As a group, large predators developed traits allowing self-regulation including territoriality, intra- and interspecific killing, prey-switching, and dispersal. However, in man-modified environments, herbivore densities can reach such high levels that even an intact predator community will no longer exert regulation as there is an upper limit of predator density determined by social mechanisms. As kill success rates are very low, predators also affect herbivores by largely determining spacial distribution and behavioral adaptions, all of which modify herbivore-plant interactions. Cervids on the other hand exhibit traits all indicative of absence of a capacity to self-regulate. Predictable physiological responses to reduced food intake thus operate so late that the typical population response is an irruption with subsequent major dieoff and leads to a reduction in system performance including loss of biodiversity. Therefore, the claim that there exists 'natural' regulation in such situations is an erroneous term for what is better called forced starvation. Two conclusions can be drawn: 1. Herbivore densities above a critical level will inevitably cause shifts in community functioning by altering plant and animal species composition, nutrient and energy flow patterns: the system will effectively be forced to a less complex and hence, less productive level, an evolutionary step backwards. 2. By having modified ecological parameters necessary for the welfare of herbivores, we need to take on the responsibility to guarantee their future welfare by actively replacing missing factors. For cervids it may mean implementing harvesting such that population densities permit natural plant rejuvenation and optimal biodiversity. Where the predator community is still intact, it should be protected by all means, and where still possible, predator communities should be restored. A basic tool is to disseminate the best available information, namely that large northern herbivores do not exhibit self regulation.
publishDate 2000
dc.date.none.fl_str_mv 2000-12
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
http://purl.org/coar/resource_type/c_6501
info:ar-repo/semantics/articulo
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/11336/40115
Fluck, Werner Thomas; Population regulation in large northern herbivores: Evolution, thermodynamics, and large predators; Blackwell Verlag GmbH Berlin; Zeitschrift fur Jagdwissenschaft; 46; 3; 12-2000; 139-166
0044-2887
CONICET Digital
CONICET
url http://hdl.handle.net/11336/40115
identifier_str_mv Fluck, Werner Thomas; Population regulation in large northern herbivores: Evolution, thermodynamics, and large predators; Blackwell Verlag GmbH Berlin; Zeitschrift fur Jagdwissenschaft; 46; 3; 12-2000; 139-166
0044-2887
CONICET Digital
CONICET
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/doi/10.1007/BF02241353
info:eu-repo/semantics/altIdentifier/url/https://link.springer.com/article/10.1007%2FBF02241353
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
eu_rights_str_mv openAccess
rights_invalid_str_mv https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
dc.format.none.fl_str_mv application/pdf
application/pdf
dc.publisher.none.fl_str_mv Blackwell Verlag GmbH Berlin
publisher.none.fl_str_mv Blackwell Verlag GmbH Berlin
dc.source.none.fl_str_mv reponame:CONICET Digital (CONICET)
instname:Consejo Nacional de Investigaciones Científicas y Técnicas
reponame_str CONICET Digital (CONICET)
collection CONICET Digital (CONICET)
instname_str Consejo Nacional de Investigaciones Científicas y Técnicas
repository.name.fl_str_mv CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicas
repository.mail.fl_str_mv dasensio@conicet.gov.ar; lcarlino@conicet.gov.ar
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