Global climate change and local anthropogenic pressures are among the primary factors leading tot... more Global climate change and local anthropogenic pressures are among the primary factors leading tothe decline of functional biodiversity and critical habitats in coral reefs. Coral bleaching, the poten-tial decreases in dissolved oxygen concentration (deoxygenation) and pH (acidification) in the oceanscan induce severe changes in coral reef ecosystem biodiversity and functionality. The main objective ofthis study was to apply four Ecopath with Ecosim models of a Caribbean coral reef system to individ-ually and collectively model the effects of coral bleaching on the trophic web, deoxygenation on fish,and acidification on calcifying organisms. These three sources of stress were used as forcing functionson several trophic groups depending on the model. The forcing functions were scaled according to thespecies’ responses achieved in previously tested climate change marine models. For the bleaching model,a mediation function was also considered that represents the degree of coral reef protection on smalland intermediate fish groups. The dynamic models were constructed from an extensive database of 171reef fish species (abundance and biomass) and benthic communities from 13 coral reefs that were evenlydistributed parallel to approximately 400 km of the Mexican Caribbean coast as well as fishery landingsin this area. Simulations driven with these different forcing and mediation functions predicted differentchanges in the biomasses of fish and non-fish functional groups as well as the biomass of the func-tional groups of fished species. Coral bleaching and pH reduction caused a phase shift to a decrease incoral biomass and an increase in primary producer biomass. This shift produced a cascading decreasein the biomass of small and intermediate fish groups. Additionally, the fished functional group biomassincreased with coral bleaching but decreased with the effects of decreased oxygen on fish and pH oncalcifying organisms. The biomasses of certain macroinvertebrate functional groups were predicted torespond favourably to the combined effect of the sources of stress. However, when all the sources ofstress were combined, we found a general decrease of biomass in fish, non-fish, and some commerciallyvaluable fish and macroinvertebrate functional groups, suggesting that the combined effects of stressinduced synergistic effects as a result of global climate change and overfishing, which can result in apotential loss of biodiversity and ecosystem services in coral reefs.
Tropical landscape and seascape systems are intimately linked by complex ecological relationships... more Tropical landscape and seascape systems are intimately linked by complex ecological relationships that provide environmental services to human societies located in coastal areas and beyond. Paradoxically, nonsustainable activities from these human societies are threatening the functions and benefits of these systems. Anthropogenic processes that damage tropical seascapes are rapidly increasing as a result of coastal and tourism development, increasing human population, unsustainable economic growth, and extensive transformations of natural landscapes. In addition to this overwhelming trend, tropical coastal seascapes are threatened by global climate change. Thus, to address this problem, it is essential to understand the complex ecological relationships between the components of coastal seascape systems and their links to land ecosystems, including the positive and negative effects of humans. The physical and ecological relationships between tropical landscapes and seascapes often define the energy and matter fluxes through which human activities exert their influence on coastal ecosystems. We illustrate these relationships by presenting a case study and conceptual model of coastal and tourism development in the Yucatan Peninsula, Mexico. Scientific knowledge and proposals for better governance practices are available to guide management actions and to protect the connectivity of seascape systems. Nonetheless, political will, coupled with the implementation of local and regional integrated management schemes of coastal zones, is urgent. More examples are needed of inland and coastal human societies that successfully integrate scientific knowledge of the links among ecosystems and their decision-making processes in order to achieve sustainable development based on the services provided by their surrounding seascapes.
Global climate change and local anthropogenic pressures are among the primary factors leading tot... more Global climate change and local anthropogenic pressures are among the primary factors leading tothe decline of functional biodiversity and critical habitats in coral reefs. Coral bleaching, the poten-tial decreases in dissolved oxygen concentration (deoxygenation) and pH (acidification) in the oceanscan induce severe changes in coral reef ecosystem biodiversity and functionality. The main objective ofthis study was to apply four Ecopath with Ecosim models of a Caribbean coral reef system to individ-ually and collectively model the effects of coral bleaching on the trophic web, deoxygenation on fish,and acidification on calcifying organisms. These three sources of stress were used as forcing functionson several trophic groups depending on the model. The forcing functions were scaled according to thespecies’ responses achieved in previously tested climate change marine models. For the bleaching model,a mediation function was also considered that represents the degree of coral reef protection on smalland intermediate fish groups. The dynamic models were constructed from an extensive database of 171reef fish species (abundance and biomass) and benthic communities from 13 coral reefs that were evenlydistributed parallel to approximately 400 km of the Mexican Caribbean coast as well as fishery landingsin this area. Simulations driven with these different forcing and mediation functions predicted differentchanges in the biomasses of fish and non-fish functional groups as well as the biomass of the func-tional groups of fished species. Coral bleaching and pH reduction caused a phase shift to a decrease incoral biomass and an increase in primary producer biomass. This shift produced a cascading decreasein the biomass of small and intermediate fish groups. Additionally, the fished functional group biomassincreased with coral bleaching but decreased with the effects of decreased oxygen on fish and pH oncalcifying organisms. The biomasses of certain macroinvertebrate functional groups were predicted torespond favourably to the combined effect of the sources of stress. However, when all the sources ofstress were combined, we found a general decrease of biomass in fish, non-fish, and some commerciallyvaluable fish and macroinvertebrate functional groups, suggesting that the combined effects of stressinduced synergistic effects as a result of global climate change and overfishing, which can result in apotential loss of biodiversity and ecosystem services in coral reefs.
Tropical landscape and seascape systems are intimately linked by complex ecological relationships... more Tropical landscape and seascape systems are intimately linked by complex ecological relationships that provide environmental services to human societies located in coastal areas and beyond. Paradoxically, nonsustainable activities from these human societies are threatening the functions and benefits of these systems. Anthropogenic processes that damage tropical seascapes are rapidly increasing as a result of coastal and tourism development, increasing human population, unsustainable economic growth, and extensive transformations of natural landscapes. In addition to this overwhelming trend, tropical coastal seascapes are threatened by global climate change. Thus, to address this problem, it is essential to understand the complex ecological relationships between the components of coastal seascape systems and their links to land ecosystems, including the positive and negative effects of humans. The physical and ecological relationships between tropical landscapes and seascapes often define the energy and matter fluxes through which human activities exert their influence on coastal ecosystems. We illustrate these relationships by presenting a case study and conceptual model of coastal and tourism development in the Yucatan Peninsula, Mexico. Scientific knowledge and proposals for better governance practices are available to guide management actions and to protect the connectivity of seascape systems. Nonetheless, political will, coupled with the implementation of local and regional integrated management schemes of coastal zones, is urgent. More examples are needed of inland and coastal human societies that successfully integrate scientific knowledge of the links among ecosystems and their decision-making processes in order to achieve sustainable development based on the services provided by their surrounding seascapes.
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