Change agents: sea urchin regulation and state shifts in Mediterranean macrophyte systems = Agents de canvi: el control de les garotes i els canvis d'estat en els ecosistemes de macròfits de la Mediterrània
[eng] Macrophyte systems are globally vulnerable to overgrazing, often shifting precipitously to functionally poorer alternative stable states triggered by herbivore population outbreaks. Sea urchin herbivory can cause shifts in shallow macrophyte systems in the Mediterranean (i.e. macroalgal commun...
| Autor: | |
|---|---|
| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2016 |
| País: | España |
| Institución: | Universidad de Barcelona |
| Repositorio: | Dipòsit Digital de la UB |
| OAI Identifier: | oai:diposit.ub.edu:2445/104085 |
| Acceso en línea: | https://hdl.handle.net/2445/104085 http://hdl.handle.net/10803/397785 |
| Access Level: | acceso abierto |
| Palabra clave: | Macròfits Hàbitat (Ecologia) Eriçons de mar Macrophytes Habitat (Ecology) Sea urchins |
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España |
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Change agents: sea urchin regulation and state shifts in Mediterranean macrophyte systems = Agents de canvi: el control de les garotes i els canvis d'estat en els ecosistemes de macròfits de la Mediterrània |
| title |
Change agents: sea urchin regulation and state shifts in Mediterranean macrophyte systems = Agents de canvi: el control de les garotes i els canvis d'estat en els ecosistemes de macròfits de la Mediterrània |
| spellingShingle |
Change agents: sea urchin regulation and state shifts in Mediterranean macrophyte systems = Agents de canvi: el control de les garotes i els canvis d'estat en els ecosistemes de macròfits de la Mediterrània Boada García, Jordi Macròfits Hàbitat (Ecologia) Eriçons de mar Macrophytes Habitat (Ecology) Sea urchins |
| title_short |
Change agents: sea urchin regulation and state shifts in Mediterranean macrophyte systems = Agents de canvi: el control de les garotes i els canvis d'estat en els ecosistemes de macròfits de la Mediterrània |
| title_full |
Change agents: sea urchin regulation and state shifts in Mediterranean macrophyte systems = Agents de canvi: el control de les garotes i els canvis d'estat en els ecosistemes de macròfits de la Mediterrània |
| title_fullStr |
Change agents: sea urchin regulation and state shifts in Mediterranean macrophyte systems = Agents de canvi: el control de les garotes i els canvis d'estat en els ecosistemes de macròfits de la Mediterrània |
| title_full_unstemmed |
Change agents: sea urchin regulation and state shifts in Mediterranean macrophyte systems = Agents de canvi: el control de les garotes i els canvis d'estat en els ecosistemes de macròfits de la Mediterrània |
| title_sort |
Change agents: sea urchin regulation and state shifts in Mediterranean macrophyte systems = Agents de canvi: el control de les garotes i els canvis d'estat en els ecosistemes de macròfits de la Mediterrània |
| dc.creator.none.fl_str_mv |
Boada García, Jordi |
| author |
Boada García, Jordi |
| author_facet |
Boada García, Jordi |
| author_role |
author |
| dc.contributor.none.fl_str_mv |
Alcoverro i Pedrola, Teresa Romero, Javier (Romero Martinengo) Universitat de Barcelona. Facultat de Biologia |
| dc.subject.none.fl_str_mv |
Macròfits Hàbitat (Ecologia) Eriçons de mar Macrophytes Habitat (Ecology) Sea urchins |
| topic |
Macròfits Hàbitat (Ecologia) Eriçons de mar Macrophytes Habitat (Ecology) Sea urchins |
| description |
[eng] Macrophyte systems are globally vulnerable to overgrazing, often shifting precipitously to functionally poorer alternative stable states triggered by herbivore population outbreaks. Sea urchin herbivory can cause shifts in shallow macrophyte systems in the Mediterranean (i.e. macroalgal communities and seagrass meadows) changing the structure of these communities to completely bare extensions; rocky macroalgal systems are particularly prone to barren formation. These sudden transitions are inherently surprising making it very difficult to manage the rich diversity and productivity these ecosystems support. This thesis attempts to address the uncertainty underlying these regime transitions by first identifying the location of critical thresholds in response to sea urchin stressors and then predicting how these thresholds vary under different environmental conditions. Specifically, it describes how inherently poor nutrient regions are more prone to catastrophic shifts related to two synergistic mechanisms, i) compensatory feeding by urchins in low nutrient regions and ii) higher rates of algal growth in high nutrient areas. Additionally, it identifies the principal regulatory processes determining variations in sea urchin numbers (main stressor) in the complex seascapes of mixed macroalgal communities and seagrass meadows that dominate shallow Mediterranean shores. Particularly, this thesis shows that habitat can determine when in the sea urchin’s life history this regulation occurs. While predation is the most important agent of regulation in both macroalgal and seagrass meadows, populations are also highly influenced by migration and settlement processes. Finally, it describes the importance of identifying hotspots of functional predation (main regulating agent) across a wide stretch of coastline to implement management actions and preserve the sustainability of macrophyte ecosystems. In parallel, this thesis also tests the effectiveness of a widely-employed but rarely tested assay to measure rates of predation that was central to this work. The results of this assessment show that marking sea urchins in the field by piercing is a very reliable tool to measure predation rates, neither affecting the mortality of the marked organism nor enhancing its detectability by predators. Overall, the results presented here will enhance the predictability of catastrophic transitions in Mediterranean macrophyte systems and could potentially be extrapolated to other ecosystems in temperate seas. |
| publishDate |
2016 |
| dc.date.none.fl_str_mv |
2016 |
| dc.type.none.fl_str_mv |
info:eu-repo/semantics/doctoralThesis info:eu-repo/semantics/publishedVersion |
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doctoralThesis |
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publishedVersion |
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https://hdl.handle.net/2445/104085 http://hdl.handle.net/10803/397785 |
| url |
https://hdl.handle.net/2445/104085 http://hdl.handle.net/10803/397785 |
| dc.language.none.fl_str_mv |
Inglés |
| language_invalid_str_mv |
Inglés |
| dc.rights.none.fl_str_mv |
cc-by (c) Boada, 2016 http://creativecommons.org/licenses/by/3.0/ info:eu-repo/semantics/openAccess |
| rights_invalid_str_mv |
cc-by (c) Boada, 2016 http://creativecommons.org/licenses/by/3.0/ |
| eu_rights_str_mv |
openAccess |
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application/pdf |
| dc.publisher.none.fl_str_mv |
Universitat de Barcelona |
| publisher.none.fl_str_mv |
Universitat de Barcelona |
| dc.source.none.fl_str_mv |
Tesis Doctorals - Facultat - Biologia reponame:Dipòsit Digital de la UB instname:Universidad de Barcelona |
| instname_str |
Universidad de Barcelona |
| reponame_str |
Dipòsit Digital de la UB |
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Dipòsit Digital de la UB |
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| _version_ |
1869403249237295104 |
| spelling |
Change agents: sea urchin regulation and state shifts in Mediterranean macrophyte systems = Agents de canvi: el control de les garotes i els canvis d'estat en els ecosistemes de macròfits de la MediterràniaBoada García, JordiMacròfitsHàbitat (Ecologia)Eriçons de marMacrophytesHabitat (Ecology)Sea urchins[eng] Macrophyte systems are globally vulnerable to overgrazing, often shifting precipitously to functionally poorer alternative stable states triggered by herbivore population outbreaks. Sea urchin herbivory can cause shifts in shallow macrophyte systems in the Mediterranean (i.e. macroalgal communities and seagrass meadows) changing the structure of these communities to completely bare extensions; rocky macroalgal systems are particularly prone to barren formation. These sudden transitions are inherently surprising making it very difficult to manage the rich diversity and productivity these ecosystems support. This thesis attempts to address the uncertainty underlying these regime transitions by first identifying the location of critical thresholds in response to sea urchin stressors and then predicting how these thresholds vary under different environmental conditions. Specifically, it describes how inherently poor nutrient regions are more prone to catastrophic shifts related to two synergistic mechanisms, i) compensatory feeding by urchins in low nutrient regions and ii) higher rates of algal growth in high nutrient areas. Additionally, it identifies the principal regulatory processes determining variations in sea urchin numbers (main stressor) in the complex seascapes of mixed macroalgal communities and seagrass meadows that dominate shallow Mediterranean shores. Particularly, this thesis shows that habitat can determine when in the sea urchin’s life history this regulation occurs. While predation is the most important agent of regulation in both macroalgal and seagrass meadows, populations are also highly influenced by migration and settlement processes. Finally, it describes the importance of identifying hotspots of functional predation (main regulating agent) across a wide stretch of coastline to implement management actions and preserve the sustainability of macrophyte ecosystems. In parallel, this thesis also tests the effectiveness of a widely-employed but rarely tested assay to measure rates of predation that was central to this work. The results of this assessment show that marking sea urchins in the field by piercing is a very reliable tool to measure predation rates, neither affecting the mortality of the marked organism nor enhancing its detectability by predators. Overall, the results presented here will enhance the predictability of catastrophic transitions in Mediterranean macrophyte systems and could potentially be extrapolated to other ecosystems in temperate seas.[spa] Los ecosistemas de macrófitos son sistemas especialmente vulnerables al herbivorismo sobredimensionado. Estos, pueden sufrir cambios funcionales bruscos cuando las poblaciones de herbívoros crecen de manera descontrolada, precipitando hacia estados alternativos estables poco productivos. El herbivorismo de los erizos de mar puede ser causa de estos cambios de fase en los sistemas de macrófitos marinos costeros en el Mediterráneo (comunidades de macroalgas y praderas de fanerógamas marinas). Las comunidades de macroalgas son particularmente susceptibles a la presión de los erizos, que provoca importantes cambios estructurales en los sistemas rocosos dejando a su paso extensas zonas desérticas conocidas como blanquizales. Estos cambios de fase son difícilmente predecibles y como consecuencia, la diversidad y productividad de estos ecosistemas es muy difícil de gestionar. La presente tesis pretende reducir la incertidumbre asociada dichos cambios de fase, identificando primero, la posición del umbral crítico (presión de herbivorismo) que provoca la perdida de estructura y segundo, cómo este umbral puede variar en función de las condiciones ambientales específicas de una región. En particular, se describe como las zonas pobres en nutrientes son más susceptibles a los cambios de fase debido a i) compensación alimentaria en las zonas de bajos nutrientes y ii) aumento en las tasas de crecimiento de las algas en zonas de altos nutrientes. Adicionalmente, se identifican los principales procesos que determinan variaciones en las poblaciones de erizos de mar (estresor principal) en los ecosistemas costeros de macroalgas y fanerógamas marinas del Mediterráneo. En particular, se demuestra como el hábitat puede determinar el momento y los procesos en qué la regulación de las poblaciones tiene lugar. Finalmente, esta tesis describe la importancia de identificar los puntos calientes de depredación (principal agente regulador de las poblaciones de erizos) para la gestión sostenible de los ecosistemas de macrófitos costeros. En paralelo, se prueba la fiabilidad de una metodología extensamente utilizada en el marcaje de erizos de mar para el análisis de depredación, observando cómo esta técnica es perfectamente fiable en el análisis de depredación de erizos de mar, no afectando a la mortalidad de los individuos marcados ni a su detectabilidad por parte de depredadores. En global, los resultados presentados mejoraran la capacidad para predecir los cambios entre estados alternativos de los ecosistemas de macrófitos en el Mediterráneo y potencialmente de otros ecosistemas similares en los mares templados a nivel global.Universitat de BarcelonaAlcoverro i Pedrola, TeresaRomero, Javier (Romero Martinengo)Universitat de Barcelona. Facultat de Biologia2016info:eu-repo/semantics/doctoralThesisinfo:eu-repo/semantics/publishedVersionapplication/pdfhttps://hdl.handle.net/2445/104085http://hdl.handle.net/10803/397785Tesis Doctorals - Facultat - Biologiareponame:Dipòsit Digital de la UBinstname:Universidad de BarcelonaIngléscc-by (c) Boada, 2016http://creativecommons.org/licenses/by/3.0/info:eu-repo/semantics/openAccessoai:diposit.ub.edu:2445/1040852026-05-27T06:46:51Z |
| score |
15,300719 |