As climatic changes and human uses intensify,resource managers and other decision makers are taking actions to either avoid or respond to ecosystem tipping points,or dramatic shifts in structure and function that are ...As climatic changes and human uses intensify,resource managers and other decision makers are taking actions to either avoid or respond to ecosystem tipping points,or dramatic shifts in structure and function that are often costly and hard to reverse.Evidence indicates that explicitly addressing tipping points leads to improved management outcomes.Drawing on theory and examples from marine systems,we distill a set of seven principles to guide effective management in ecosystems with tipping points,derived from the best available science.These principles are based on observations that tipping points(1)are possible everywhere,(2)are associated with intense and/or multifaceted human use,(3)may be preceded by changes in earlywarning indicators,(4)may redistribute benefits among stakeholders,(5)affect the relative costs of action and inaction,(6)suggest biologically informed management targets,and(7)often require an adaptive response to monitoring.We suggest that early action to preserve system resilience is likely more practical,affordable,and effective than late action to halt or reverse a tipping point.We articulate a conceptual approach to management focused on linking management targets to thresholds,tracking early-warning signals of ecosystem instability,and stepping up investment in monitoring and mitigation as the likelihood of dramatic ecosystem change increases.This approach can simplify and economize management by allowing decision makers to capitalize on the increasing value of precise information about threshold relationships when a system is closer to tipping or by ensuring that restoration effort is sufficient to tip a system into the desired regime.展开更多
GeoLink has leveraged linked data principles to create a dataset that allows users to seamlessly query and reason over some of the most prominent geoscience metadata repositories in the United States.The GeoLink datas...GeoLink has leveraged linked data principles to create a dataset that allows users to seamlessly query and reason over some of the most prominent geoscience metadata repositories in the United States.The GeoLink dataset includes such diverse information as port calls made by oceanographic cruises,physical sample meta-data,research project funding and staffing,and authorship of technical reports.The data has been published according to best practices for linked data and is publicly available via a SPARQL Protocol and RDF Query Language(SPARQL)end point that at present contains more than 45 million Resource Description Framework(RDF)triples together with a collection of ontologies and geo-visualization tools.This article describes the geoscience datasets,the modeling and publication process,and current uses of the dataset.The focus is on providing enough detail to enable researchers,application developers and others who wish to lever-age the GeoLink data in their own work to do so.展开更多
Aims We present an improved model for the growth of individuals in plant populations experiencing competition.Methods Individuals grow sigmoidally according to the Birch model,which is similar to the more commonly use...Aims We present an improved model for the growth of individuals in plant populations experiencing competition.Methods Individuals grow sigmoidally according to the Birch model,which is similar to the more commonly used Richards model,but has the advantage that initial plant growth is always exponential.The individual plant growth models are coupled so that there is a maximum total biomass for the population.The effects of size-asymmetric competition are modeled with a parameter that reflects the size advantage that larger individual have over smaller individuals.We fit the model to data on individual growth in crowded populations of Chenopodium album.Important Findings When individual plant growth curves were not coupled,there was a negative or no correlation between initial growth rate and final size,suggesting that competitive interactions were more important in determining final plant size than were plants’initial growth rates.The coupled growth equations fit the data better than individual,uncoupled growth models,even though the number of estimated parameters in the coupled competitive growth model was far fewer,indicating the importance of modeling competition and the degree of size-asymmetric growth explicitly.A quantitative understanding of stand development in terms of the growth of individuals,as altered by competition,is within reach.展开更多
Introduction:Human impacts on Arctic marine ecosystems are increasing in extent and intensity as sea ice shrinks and utilization of marine resources expands.The effects of climate change are being felt across the arct...Introduction:Human impacts on Arctic marine ecosystems are increasing in extent and intensity as sea ice shrinks and utilization of marine resources expands.The effects of climate change are being felt across the arctic while stressors such as commercial fishing and shipping continue to grow as the Arctic becomes more accessible.Given these emerging changes,there is need for an assessment of the current cumulative impact of human activities to better anticipate and manage for a changing Arctic.Cumulative human impacts(CHI)assessments have been widely applied around the world in a variety of ecosystem types but have yet to incorporate temporal dynamics of individual stressors.Such dynamics are funda-mental to Arctic ecosystems.Outcomes:Here,we present the first CHI assessment of an Arctic ecosystem to incorporate sea ice as a habitat and assess impact seasonality,using the Bering Strait Region(BSR)as a case study.We find that cumulative impacts differ seasonally,with lower impacts in winter and higher impacts in summer months.Large portions of the BSR have significantly different impacts within each season when compared to a mean annual cumulative impact map.Cumulative impacts also have great spatial variability,with Russian waters between 2.38 and 3.63 times as impacted as US waters.Conclusion:This assessment of seasonal and spatial cumulative impacts provides an under-standing of the current reality in the BSR and can be used to support development and evaluation of future management scenarios that address expected impacts from climate change and increasing interest in the Arctic.展开更多
基金Primary funding was provided by the Gordon and Betty Moore Foundation,with additional support to K.A.Selkoe from National Science Founda-tion(BioOCE Award 1260169).
文摘As climatic changes and human uses intensify,resource managers and other decision makers are taking actions to either avoid or respond to ecosystem tipping points,or dramatic shifts in structure and function that are often costly and hard to reverse.Evidence indicates that explicitly addressing tipping points leads to improved management outcomes.Drawing on theory and examples from marine systems,we distill a set of seven principles to guide effective management in ecosystems with tipping points,derived from the best available science.These principles are based on observations that tipping points(1)are possible everywhere,(2)are associated with intense and/or multifaceted human use,(3)may be preceded by changes in earlywarning indicators,(4)may redistribute benefits among stakeholders,(5)affect the relative costs of action and inaction,(6)suggest biologically informed management targets,and(7)often require an adaptive response to monitoring.We suggest that early action to preserve system resilience is likely more practical,affordable,and effective than late action to halt or reverse a tipping point.We articulate a conceptual approach to management focused on linking management targets to thresholds,tracking early-warning signals of ecosystem instability,and stepping up investment in monitoring and mitigation as the likelihood of dramatic ecosystem change increases.This approach can simplify and economize management by allowing decision makers to capitalize on the increasing value of precise information about threshold relationships when a system is closer to tipping or by ensuring that restoration effort is sufficient to tip a system into the desired regime.
基金This work was supported by the National Science Foundation[1440202].
文摘GeoLink has leveraged linked data principles to create a dataset that allows users to seamlessly query and reason over some of the most prominent geoscience metadata repositories in the United States.The GeoLink dataset includes such diverse information as port calls made by oceanographic cruises,physical sample meta-data,research project funding and staffing,and authorship of technical reports.The data has been published according to best practices for linked data and is publicly available via a SPARQL Protocol and RDF Query Language(SPARQL)end point that at present contains more than 45 million Resource Description Framework(RDF)triples together with a collection of ontologies and geo-visualization tools.This article describes the geoscience datasets,the modeling and publication process,and current uses of the dataset.The focus is on providing enough detail to enable researchers,application developers and others who wish to lever-age the GeoLink data in their own work to do so.
基金supported,in part,by a Sabbatical Fellowship to J.W.from the National Center for Ecological Analysis and Synthesis,a Center funded by NSF(Grant#DEB-0553768)the University of California,Santa Barbara,and the State of California.
文摘Aims We present an improved model for the growth of individuals in plant populations experiencing competition.Methods Individuals grow sigmoidally according to the Birch model,which is similar to the more commonly used Richards model,but has the advantage that initial plant growth is always exponential.The individual plant growth models are coupled so that there is a maximum total biomass for the population.The effects of size-asymmetric competition are modeled with a parameter that reflects the size advantage that larger individual have over smaller individuals.We fit the model to data on individual growth in crowded populations of Chenopodium album.Important Findings When individual plant growth curves were not coupled,there was a negative or no correlation between initial growth rate and final size,suggesting that competitive interactions were more important in determining final plant size than were plants’initial growth rates.The coupled growth equations fit the data better than individual,uncoupled growth models,even though the number of estimated parameters in the coupled competitive growth model was far fewer,indicating the importance of modeling competition and the degree of size-asymmetric growth explicitly.A quantitative understanding of stand development in terms of the growth of individuals,as altered by competition,is within reach.
基金the United States National Science Foundation under award no.[NSF-PLR 1263819].
文摘Introduction:Human impacts on Arctic marine ecosystems are increasing in extent and intensity as sea ice shrinks and utilization of marine resources expands.The effects of climate change are being felt across the arctic while stressors such as commercial fishing and shipping continue to grow as the Arctic becomes more accessible.Given these emerging changes,there is need for an assessment of the current cumulative impact of human activities to better anticipate and manage for a changing Arctic.Cumulative human impacts(CHI)assessments have been widely applied around the world in a variety of ecosystem types but have yet to incorporate temporal dynamics of individual stressors.Such dynamics are funda-mental to Arctic ecosystems.Outcomes:Here,we present the first CHI assessment of an Arctic ecosystem to incorporate sea ice as a habitat and assess impact seasonality,using the Bering Strait Region(BSR)as a case study.We find that cumulative impacts differ seasonally,with lower impacts in winter and higher impacts in summer months.Large portions of the BSR have significantly different impacts within each season when compared to a mean annual cumulative impact map.Cumulative impacts also have great spatial variability,with Russian waters between 2.38 and 3.63 times as impacted as US waters.Conclusion:This assessment of seasonal and spatial cumulative impacts provides an under-standing of the current reality in the BSR and can be used to support development and evaluation of future management scenarios that address expected impacts from climate change and increasing interest in the Arctic.
