852 resultados para Antarctic Thresholds - Ecosystem Resilience and Adaptation
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This paper examines two concepts, social vulnerability and social resilience, often used to describe people and their relationship to a disaster. Social vulnerability is the exposure to harm resulting from demographic and socioeconomic factors that heighten the exposure to disaster. Social resilience is the ability to avoid disaster, cope with change and recover from disaster. Vulnerability to a space and social resilience through society is explored through a focus on the elderly, a group sometimes regarded as having low resilience while being particularly vulnerable. Our findings explore the degree to which an elderly group exposed to coastal flood risk exhibits social resilience through both cognitive strategies, such as risk perception and self-perception, as well as through coping mechanisms, such as accepting change and self-organisation. These attenuate and accentuate the resilience of individuals through their own preparations as well as their communities' preparations and also contribute to the delusion of resilience which leads individuals to act as if they are more resilient than they are in reality, which we call negative resilience. Thus, we draw attention to three main areas: the degree to which social vulnerability can disguise its social resilience; the role played by cognitive strategies and coping mechanisms on an individual's social resilience; and the high risk aspects of social resilience. © 2014 Elsevier Ltd. All rights reserved.
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Climate change has become one of the prime challenges the society has to face in the future. As far as businesses are concerned, it also has added one other important issue that they have to consider as part of their business planning. Climate change is of significant importance particularly to the Small and Medium-sized enterprises (SMEs), which are considered as the most vulnerable among the business community to the effects of climate change. This paper presents the findings of a literature review conducted with the aim of identifying the specific importance of climate change to the construction sector SMEs. The objectives of the paper are to identify the vulnerability of construction sector SMEs to the effects of climate change, their consequences and also to identify the importance of improving resilience and implementing adaptive measures to manage these issues. The paper also outlines the directions of a study undertaken to address these issues as part of an EPSRC funded research project titled “Community Resilience to Extreme Weather Events – CREW”. The paper concludes by stressing the importance of improving the resilience of construction sector SMEs to climate change effects and also the importance of collective action in this regard.
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This is the final report of the RICS Education Trust funded “Developing Flood Expert Knowledge in Chartered Surveyors – DEFENCES” research project. The UK has endured a number of major flood events in recent years, and the UK Environment Agency (2009a) identified that about 5.2million properties in England, amounting to one in six, are at risk of flooding. The impacts of flooding include direct and indirect impacts and can be particularly devastating for small and medium-sized enterprises (SMEs) who are generally more vulnerable to such events than larger business organisations. Recent flood events have established how costly flooding can be to the SME sector (Pitt, 2008, ABI, 2010), which has given greater impetus to the need to improve the resilience of at-risk SMEs. A lack of professional advice on flood protection and adaptation measures represents a potential barrier to the uptake of such interventions by SMEs. A recent Royal Institution of Chartered Surveyors (RICS) survey, as quoted in Defra (2008) notes that, although a majority of chartered surveyors would like to work in this area of practice (flood risk assessment and adaptation), they are conscious of gaps in their competency, knowledge and understanding. The research project sought to contextualise this broader issue and investigate how chartered surveyors can bridge the gap in providing professional flood advice to SMEs. Further, a shift in the UK government policy on flood risk management is evident, where at-risk communities are urged to adapt to flooding. This places greater emphasis on property-level flood adaptation, providing further impetus for Chartered Surveyors to be involved. Findings of the research will be of interest to the RICS, the RICS Flood steering Group, practicing surveyors generally, SMEs, business support and policy making organisations.
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Excerpt from EXECUTIVE SUMMARY This report examines the situation of the Haitians in Miami who were formerly incarcerated during 1981 and 1982 in the Immigration and Naturalization Service's Krome Detention Center or other Federal detention centers in the U.S. and Puerto Rico. For convenience, the report refers to all of them as Krome Haitians. This study is based upon a sociological survey of the Krome Haitians and intensive anthropological fieldwork conducted by Dr. Alex Stepick of the Sociology and Anthropology Department of Florida International University with support from the Catholic Services Bureau of Miami. It is the only scientific study of the Krome Haitians and the scientific procedures of the survey complemented by the anthropological fieldwork combine t o produce highly reliable results . To provide context to the conditions of the Krome Haitians, the report compares the characteristics of this population to that of the Haitian Entrants who arrived in 1980 or earlier and provides an update to earlier studies by this author (Stepick 1982) and another by the Behavioral Science Research Institute (1983). The report describes the conditions of the Krome Haitians, including their background in Haiti, experiences in the U.S., past and present employment status , experience with discrimination and social isolation , and adaptation to American society. The report concludes with some specific policy recommendations to state and local agencies and individuals that will assist the Haitians' integration into American society.
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Arctic soils store close to 14% of the global soil carbon. Most of arctic carbon is stored below ground in the permafrost. With climate warming the decomposition of the soil carbon could represent a significant positive feedback to global greenhouse warming. Recent evidence has shown that the temperature of the Arctic is already increasing, and this change is associated mostly with anthropogenic activities. Warmer soils will contribute to permafrost degradation and accelerate organic matter decay and thus increase the flux of carbon dioxide and methane into the atmosphere. Temperature and water availability are also important drivers of ecosystem performance, but effects can be complex and in opposition. Temperature and moisture changes can affect ecosystem respiration (ER) and gross primary productivity (GPP) independently; an increase in the net ecosystem exchange can be a result of either a decrease in ER or an increase in GPP. Therefore, understanding the effects of changes in ecosystem water and temperature on the carbon flux components becomes key to predicting the responses of the Arctic to climate change. The overall goal of this work was to determine the response of arctic systems to simulated climate change scenarios with simultaneous changes in temperature and moisture. A temperature and hydrological manipulation in a naturally-drained lakebed was used to assess the short-term effect of changes in water and temperature on the carbon cycle. Also, as part of International Tundra Experiment Network (ITEX), I determined the long-term effect of warming on the carbon cycle in a natural hydrological gradient established in the mid 90's. I found that the carbon balance is highly sensitive to short-term changes in water table and warming. However, over longer time periods, hydrological and temperature changed soil biophysical properties, nutrient cycles, and other ecosystem structural and functional components that down regulated GPP and ER, especially in wet areas.
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Top predators can have large effects on community and population dynamics but we still know relatively little about their roles in ecosystems and which biotic and abiotic factors potentially affect their behavioral patterns. Understanding the roles played by top predators is a pressing issue because many top predator populations around the world are declining rapidly yet we do not fully understand what the consequences of their potential extirpation could be for ecosystem structure and function. In addition, individual behavioral specialization is commonplace across many taxa, but studies of its prevalence, causes, and consequences in top predator populations are lacking. In this dissertation I investigated the movement, feeding patterns, and drivers and implications of individual specialization in an American alligator (Alligator mississippiensis ) population inhabiting a dynamic subtropical estuary. I found that alligator movement and feeding behaviors in this population were largely regulated by a combination of biotic and abiotic factors that varied seasonally. I also found that the population consisted of individuals that displayed an extremely wide range of movement and feeding behaviors, indicating that individual specialization is potentially an important determinant of the varied roles of alligators in ecosystems. Ultimately, I found that assuming top predator populations consist of individuals that all behave in similar ways in terms of their feeding, movements, and potential roles in ecosystems is likely incorrect. As climate change and ecosystem restoration and conservation activities continue to affect top predator populations worldwide, individuals will likely respond in different and possibly unexpected ways.
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We developed diatom-based prediction models of hydrology and periphyton abundance to inform assessment tools for a hydrologically managed wetland. Because hydrology is an important driver of ecosystem change, hydrologic alterations by restoration efforts could modify biological responses, such as periphyton characteristics. In karstic wetlands, diatoms are particularly important components of mat-forming calcareous periphyton assemblages that both respond and contribute to the structural organization and function of the periphyton matrix. We examined the distribution of diatoms across the Florida Everglades landscape and found hydroperiod and periphyton biovolume were strongly correlated with assemblage composition. We present species optima and tolerances for hydroperiod and periphyton biovolume, for use in interpreting the directionality of change in these important variables. Predictions of these variables were mapped to visualize landscape-scale spatial patterns in a dominant driver of change in this ecosystem (hydroperiod) and an ecosystem-level response metric of hydrologic change (periphyton biovolume). Specific diatom assemblages inhabiting periphyton mats of differing abundance can be used to infer past conditions and inform management decisions based on how assemblages are changing. This study captures diatom responses to wide gradients of hydrology and periphyton characteristics to inform ecosystem-scale bioassessment efforts in a large wetland.
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Youth homelessness is defined within the literature as youth who have left their homes and are living independent of parental figures and/or caregivers, have no stable residence or source of income, and lack access to the supports needed to make the challenging transition into adulthood (Canadian Observatory on Homelessness, 2015). Previous research studying homeless (or street-involved) youth has primarily focused on risk factors hindering the development of this population, and has largely ignored resilience, coping, and help-seeking behaviours. The current study examined the attachment styles (both categorically and dimensionally), psychological functioning, resilience, and help-seeking behaviours in street-involved youth of St. John’s, Newfoundland. Face-to face interviews were completed over a four-month period with 63 youth (42 males, 21 females) aged 15-29 (Mage = 20.00), recruited from a local community organization providing outreach services to street-involved youth. Results revealed the disproportionate struggles of the street-involved youth population, and highlighted higher levels of attachment insecurity, psychological distress and lower resilience compared to normative peers. Findings also showed a significant difference in psychological functioning, overall resilience, and emotional reactivity based on individual attachment style. In an exploratory model of help-seeking, a positive relationship was found between overall resilience (defined as a sense of mastery and sense of relatedness) and frequency of community service access. However, contrary to predictions, no relationships were found between frequency of community service access and attachment, psychological functioning, or emotional reactivity. Implications of the present findings in development of interventions for street-involved youth are discussed, in addition to strengths and limitations of the present research, and suggested areas of future inquiry.
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We present new d13C measurements of atmospheric CO2 covering the last glacial/interglacial cycle, complementing previous records covering Terminations I and II. Most prominent in the new record is a significant depletion in d13C(atm) of 0.5 permil occurring during marine isotope stage (MIS) 4, followed by an enrichment of the same magnitude at the beginning of MIS 3. Such a significant excursion in the record is otherwise only observed at glacial terminations, suggesting that similar processes were at play, such as changing sea surface temperatures, changes in marine biological export in the Southern Ocean (SO) due to variations in aeolian iron fluxes, changes in the Atlantic meridional overturning circulation, upwelling of deep water in the SO, and long-term trends in terrestrial carbon storage. Based on previous modeling studies, we propose constraints on some of these processes during specific time intervals. The decrease in d13C(atm) at the end of MIS 4 starting approximately 64 kyr B.P. was accompanied by increasing [CO2]. This period is also marked by a decrease in aeolian iron flux to the SO, followed by an increase in SO upwelling during Heinrich event 6, indicating that it is likely that a large amount of d13C-depleted carbon was transferred to the deep oceans previously, i.e., at the onset of MIS 4. Apart from the upwelling event at the end of MIS 4 (and potentially smaller events during Heinrich events in MIS 3), upwelling of deep water in the SO remained reduced until the last glacial termination, whereupon a second pulse of isotopically light carbon was released into the atmosphere.
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The Arctic Ocean and Western Antarctic Peninsula (WAP) are the fastest warming regions on the planet and are undergoing rapid climate and ecosystem changes. Until we can fully resolve the coupling between biological and physical processes we cannot predict how warming will influence carbon cycling and ecosystem function and structure in these sensitive and climactically important regions. My dissertation centers on the use of high-resolution measurements of surface dissolved gases, primarily O2 and Ar, as tracers or physical and biological functioning that we measure underway using an optode and Equilibrator Inlet Mass Spectrometry (EIMS). Total O2 measurements are common throughout the historical and autonomous record but are influenced by biological (net metabolic balance) and physical (temperature, salinity, pressure changes, ice melt/freeze, mixing, bubbles and diffusive gas exchange) processes. We use Ar, an inert gas with similar solubility properties to O2, to devolve distinct records of biological (O2/Ar) and physical (Ar) oxygen. These high-resolution measurements that expose intersystem coupling and submesoscale variability were central to studies in the Arctic Ocean, WAP and open Southern Ocean that make up this dissertation.
Key findings of this work include the documentation of under ice and ice-edge blooms and basin scale net sea ice freeze/melt processes in the Arctic Ocean. In the WAP O2 and pCO2 are both biologically driven and net community production (NCP) variability is controlled by Fe and light availability tied to glacial and sea ice meltwater input. Further, we present a feasibility study that shows the ability to use modeled Ar to derive NCP from total O2 records. This approach has the potential to unlock critical carbon flux estimates from historical and autonomous O2 measurements in the global oceans.
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The boron isotope systematics has been determined for azooxanthellate scleractinian corals from a wide range of both deep-sea and shallow-water environments. The aragonitic coral species, Caryophyllia smithii, Desmophyllum dianthus, Enallopsammia rostrata, Lophelia pertusa, and Madrepora oculata, are all found to have relatively high d11B compositions ranging from 23.2 per mil to 28.7 per mil. These values lie substantially above the pH-dependent inorganic seawater borate equilibrium curve, indicative of strong up-regulation of pH of the internal calcifying fluid (pH(cf)), being elevated by ~0.6-0.8 units (Delta pH) relative to ambient seawater. In contrast, the deep-sea calcitic coral Corallium sp. has a significantly lower d11B composition of 15.5 per mil, with a corresponding lower Delta pH value of ~0.3 units, reflecting the importance of mineralogical control on biological pH up-regulation. The solitary coral D. dianthus was sampled over a wide range of seawater pH(T) and shows an approximate linear correlation with Delta pH(Desmo) = 6.43 - 0.71 pH(T) (r**2 = 0.79). An improved correlation is however found with the closely related parameter of seawater aragonite saturation state, where Delta pH(Desmo) = 1.09 - 0.14 Omega(arag) (r**2 = 0.95), indicating the important control that carbonate saturation state has on calcification. The ability to up-regulate internal pH(cf), and consequently Omega(cf), of the calcifying fluid is therefore a process present in both azooxanthellate and zooxanthellate aragonitic corals, and is attributed to the action of Ca2+ -ATPase in modulating the proton gradient between seawater and the site of calcification. These findings also show that the boron isotopic compositions (d11Bcarb) of aragonitic corals are highly systematic and consistent with direct uptake of the borate species within the biologically controlled extracellular calcifying medium.
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The last few decades have seen rapid proliferation of hard artificial structures (e.g., energy infra-structure, aquaculture, coastal defences) in the marine environment: ocean sprawl. The replacement of natural, often sedimentary, substrata with hard substrata has altered the distribution of species, particularly non-indigenous species, and can facilitate the assisted migration of native species at risk from climate change. This has been likened to urbanization as a driver of global biotic homogenization in the marine environment—the process by which species invasions and extinctions increase the genetic, taxonomic, or functional similarity of communities at local, regional, and global scales. Ecological engineering research showed that small-scale engineering interventions can have a significant positive effect on the biodiversity of artificial structures, promoting more diverse and resilient communities on local scales. This knowledge can be applied to the design of multifunctional structures that provide a range of ecosystem services. In coastal regions, hybrid designs can work with nature to combine hard and soft approaches to coastal defence in a more environmentally sensitive manner. The challenge now is to manage ocean sprawl with the dual goal of supporting human populations and activities, simultaneously strengthening ecosystem resilience using an ecosystem- based approach.
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Parasites are not typically considered to be important components of polar marine ecosystems. It was therefore surprising when 18S rDNA surveys of protists in the West Antarctic Peninsula in winter revealed high abundances of parasite sequences. Parasite sequences made up, on average, over half (52%) of sequence reads in samples from deep water in winter. Winter surface water and sediment samples contained relatively fewer, but still strikingly high, parasite sequence reads (13 and 9%, respectively), while surface water samples in summer contained fewer parasite sequences (1.8%). A total of 1028 distinct parasite Operational Taxonomic Units were observed in winter, with the largest abundances and diversities within Syndiniales groups I and II, including Amoebophrya. Less abundant parasite sequence groups included Apicomplexa, Blastodinium, Chytriodinium, Cryptocaryon, Paradinium, Perkinsidae, Pirsonia and Ichthyophonae. Parasite sequence distributions suggested interactions with known hosts, such as diatom parasites which were mainly in the sediments, where resting spores of Chaetoceros spp. diatoms were abundant. Syndiniales sequences were correlated with radiolarian sequences, suggesting parasite–host interactions. The abundant proportions of parasite sequences indicate a potentially important role for parasites in the Antarctic marine ecosystem, with implications for plankton population dynamics, the role of the microbial loop, carbon flows and ecosystem responses to ongoing anthropogenic climate change.
Resumo:
Parasites are not typically considered to be important components of polar marine ecosystems. It was therefore surprising when 18S rDNA surveys of protists in the West Antarctic Peninsula in winter revealed high abundances of parasite sequences. Parasite sequences made up, on average, over half (52%) of sequence reads in samples from deep water in winter. Winter surface water and sediment samples contained relatively fewer, but still strikingly high, parasite sequence reads (13 and 9%, respectively), while surface water samples in summer contained fewer parasite sequences (1.8%). A total of 1028 distinct parasite Operational Taxonomic Units were observed in winter, with the largest abundances and diversities within Syndiniales groups I and II, including Amoebophrya. Less abundant parasite sequence groups included Apicomplexa, Blastodinium, Chytriodinium, Cryptocaryon, Paradinium, Perkinsidae, Pirsonia and Ichthyophonae. Parasite sequence distributions suggested interactions with known hosts, such as diatom parasites which were mainly in the sediments, where resting spores of Chaetoceros spp. diatoms were abundant. Syndiniales sequences were correlated with radiolarian sequences, suggesting parasite–host interactions. The abundant proportions of parasite sequences indicate a potentially important role for parasites in the Antarctic marine ecosystem, with implications for plankton population dynamics, the role of the microbial loop, carbon flows and ecosystem responses to ongoing anthropogenic climate change.