991 research outputs found
Biodiversity loss threatens human well-being.
The diversity of life on Earth is dramatically affected by Human alterations of ecosystems. Compelling evidence now shows that the reverse is also true: biodiversity in the broad snsse affects the properties of ecosystem and, therefore, the benefits that humans obtain from them. In this article, we provide a synthesis of the most crucial messages emerging from the latest scientific literature and international assessments of the role of biodiversity in ecosystem services and human well- being. Human societies have beeb built on biodiversity. Many activities indispensable for human subsistence lead to biodiversity loss, and this trend is ikely to continue in the future. We clearly benefit from the diversity of organisms that we have learned to use for medicines, food, fibers, and other renwable resources. In addition, biodiversity has always been an integral part of the human experience and there are many moral reasons to preserve it for its own sake. What has been less recognized is that biodiversity also influences human well- being, including the access to water and basic materials for a satifactory life, and security in the face of environmental change, through its effects on the ecosystem processes that lie at the core of the EarthÂŽs most vital life support system.Fil: DĂaz, Sandra Myrna. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - CĂłrdoba. Instituto Multidisciplinario de BiologĂa Vegetal. Universidad Nacional de CĂłrdoba. Facultad de Ciencias Exactas FĂsicas y Naturales. Instituto Multidisciplinario de BiologĂa Vegetal; ArgentinaFil: Fargione, Joseph. Universidad Nacional de CĂłrdoba; Argentina. University Of New Mexico; Estados UnidosFil: Chapin III, Francis Stuart. University Of Alaska; Estados UnidosFil: Tilman, David. University of Minnesota; Estados Unido
Going beyond 'it depends:' the role of context in shaping participation in natural resource management
Public participation is increasingly advocated in natural resource management to meet a spectrum of instrumental to normative goals. However, the success of participation in achieving these goals is highly variable, depending on both societal and institutional contexts. Whether participation realises its benefits or succumbs to its pitfalls is shaped by dynamic interactions operating among three contextual dimensions: participatory rationales (instrumental to normative), institutional fit of different levels (types) of participation (information delivery to partnership to delegation), and social structures (such as cultural context, social capital and power distribution). Some levels of participation may support the existing power hierarchy, others benefit organized stakeholder groups and special interests, and still others foster deliberative democratic outcomes. We argue that wise choice of levels of participation in particular contexts shapes the balance of participationâs benefits and pitfalls
Interactions between changing climate and biodiversity: Shaping humanity's future
Scientists have known for more than a century aboutpotential human impacts on climate (1). In the last 30 y,estimates of these impacts have been confirmed andrefined through increasingly precise climate assess-ments (2). Other global-scale human impacts, includingland use change, overharvesting, air and water pollu-tion, and increased disease risk from antibiotic resis-tance, have risen to critical levels, seriously jeopardizingthe prospects that future generations can thrive (3â5).Earth has entered a stage characterized by humandomination of critical Earth system processes (6â8).Although the basic trajectories of these changes arewell known, many of the likely consequences areshrouded in uncertainty because of poorly understoodinteractions among these drivers of change and there-fore their effects on ecosystems and societies.Fil: Stuart Chapin III, F.. University of Alaska; Estados UnidosFil: DĂaz, Sandra Myrna. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - CĂłrdoba. Instituto Multidisciplinario de BiologĂa Vegetal. Universidad Nacional de CĂłrdoba. Facultad de Ciencias Exactas FĂsicas y Naturales. Instituto Multidisciplinario de BiologĂa Vegetal; Argentin
Land-Atmosphere-Ice Interactions (LAII): An Interdisciplinary Study of Change in the Terrestrial Climate System (Extended Abstract)
Changes in the surface energy budget after fire in boreal ecosystems of interior Alaska: An annual perspective
Understanding links between the disturbance regime and regional climate in boreal regions requires observations of the surface energy budget from ecosystems in various stages of secondary succession. While several studies have characterized fireâinduced differences in surface energy fluxes from boreal ecosystems during summer months, much less is known about these differences over the full annual cycle. Here we measured components of the surface energy budget (including both radiative and turbulent fluxes) at three sites from a fire chronosequence in interior Alaska for a 1âyear period. Our sites consisted of large burn scars resulting from fires in 1999, 1987, and âŒ1920 (hereinafter referred to as the 3â, 15â, and 80âyear sites, respectively). Vegetation cover consisted primarily of bunch grasses at the 3âyear site, aspen and willow at the 15âyear site, and black spruce at the 80âyear site. Annual net radiation declined by 31% (17 W m^(â2)) for both the 3â and the 15âyear sites as compared with the 80âyear site (which had an annual mean of 55 W m^(â2)). Annual sensible heat fluxes were reduced by an even greater amount, by 55% at the 3âyear site and by 52% at the 15âyear site as compared with the 80âyear site (which had an annual mean of 21 W m^(â2)). Absolute differences between the postfire ecosystems and the mature black spruce forest for both net radiation and sensible heat fluxes were greatest during spring (because of differences in snow cover and surface albedo), substantial during summer and winter, and relatively small during fall. Fireâinduced disturbance also initially reduced annual evapotranspiration (ET). Annual ET decreased by 33% (99 mm yr^(â1)) at the 3âyear site as compared with the 80âyear site (which had an annual flux of 301 mm yr^(â1)). Annual ET at the 15âyear site (283 mm yr^(â1)) was approximately the same as that from the 80âyear site, even though the 15âyear site had substantially higher ET during July. Our study suggests that differences in annual ET between deciduous and conifer stands may be smaller than that inferred solely from summer observations. This study provides a direct means to validate land surface processes in global climate models attempting to capture vegetationâclimate feedbacks in northern terrestrial regions
Changing Forests in a Warming World
Severe fires can dramatically alter the future growth of a spruce forest. A severe fire is likely to change the forest to one dominated by broadleaf deciduous trees, especially in drier places.York's Knowledge Mobilization Unit provides services and funding for faculty, graduate students, and community organizations seeking to maximize the impact of academic research and expertise on public policy, social programming, and professional practice. It is supported by SSHRC and CIHR grants, and by the Office of the Vice-President Research & Innovation.
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Changing Daily Wind Speeds on Alaskaâs North Slope: Implications for Rural Hunting Opportunities
Because of their reliance on the harvest of fish and game, Alaskan rural communities have experienced a variety of impacts from climate change, the effects of which are amplified at high latitudes. We collaborated with hunters from the coastal community of Wainwright, Alaska, to document their observations of environmental change (e.g., sea ice, wind, temperature) and the implications of those changes for opportunities to hunt bowhead whale (Balaena mysticetus) during spring and caribou (Rangifer tarandus) during summer. We integrated hunter observations on wind with statistical analysis of daily wind speed data collected in the nearby community of Barrow, Alaska, between 1971 and 2010 to characterize changes in the number of days with suitable hunting conditions. Hunters in Wainwright currently observe fewer days than in previous decades with wind conditions suitable for safely hunting bowhead whales and caribou. The statistical analysis of wind speed data supported these conclusions and suggested that the annual windows of opportunity for hunting each species have decreased by up to seven days since 1971. This study demonstrates the potential power of collaboration between local communities and researchers to characterize the societal impacts of climate change. Continued collaborative research with residents of rural northern Alaskan communities could produce knowledge and develop tools to help rural Alaskans adapt to novel social-ecological conditions.Les collectivitĂ©s rurales de lâAlaska dĂ©pendent de la rĂ©colte du poisson et du gibier et Ă ce titre, elles sont assujetties Ă une panoplie dâincidences dĂ©coulant du changement climatique, dont les effets sont amplifiĂ©s en haute altitude. GrĂące Ă lâaide des chasseurs de la collectivitĂ© cĂŽtiĂšre de Wainwright, en Alaska, nous avons consignĂ© les observations de ces chasseurs relativement Ă lâĂ©volution de lâenvironnement (en ce qui a trait, par exemple, Ă la glace de mer, au vent et aux tempĂ©ratures) de mĂȘme que les incidences de cette Ă©volution sur les possibilitĂ©s de chasse de la baleine borĂ©ale (Balaena mysticetus) au printemps, et du caribou (Rangifer tarandus) Ă lâĂ©tĂ©. Nous avons intĂ©grĂ© les observations des chasseurs au sujet du vent Ă lâanalyse statistique des donnĂ©es de la vitesse quotidienne du vent, donnĂ©es recueillies dans la localitĂ© avoisinante de Barrow, en Alaska, entre 1971 et 2010, afin de caractĂ©riser les changements quant au nombre de jours oĂč les conditions de chasse sont convenables. Comparativement aux dĂ©cennies prĂ©cĂ©dentes, les chasseurs de Wainwright observent un moins grand nombre de jours, Ă lâheure actuelle, quâau cours des dĂ©cennies prĂ©cĂ©dentes pendant lesquels le rĂ©gime des vents se prĂȘte Ă la chasse sĂ©curitaire de la baleine borĂ©ale et du caribou. Lâanalyse statistique des donnĂ©es de la vitesse du vent permet de soutenir ces conclusions et suggĂšre quâannuellement, la pĂ©riode pendant laquelle chacune de ces espĂšces peut faire lâobjet de la chasse a diminuĂ© dans une mesure allant jusquâĂ sept jours depuis 1971. Cette Ă©tude tĂ©moigne du pouvoir de collaboration qui pourrait exister entre les collectivitĂ©s de la rĂ©gion et les chercheurs dans le but de caractĂ©riser les incidences du changement climatique sur la sociĂ©tĂ©. Les travaux de recherche en collaboration continue avec les habitants des collectivitĂ©s rurales du nord de lâAlaska pourraient permettre de produire des connaissances et dâĂ©laborer des outils qui aideraient les Alaskiens Ă sâadapter aux nouvelles conditions socioĂ©cologiques
Role of Boreal Vegetation in Controlling Ecosystem Processes and Feedbacks to Climate
In the field, dark respiration rates are greatest in cores from more northerly locations. This is due in part to greater amounts of dwarf shrub biomass in the more northerly cores, but also to differences in soil organic matter quality. Laboratory incubations of these soils under common conditions show some evidence for greater pools of available carbon in soils from more northerly tundra sites, although the most northerly site does not fit this pattern for reasons which are unclear at this time. While field measurements of cores transplanted among different vegetation types at the same location (Toolik Lake) show relatively small differences in whole ecosystem carbon flux, laboratory incubation of these same soils shows that there are large differences in soil respiration rates under common conditions. This is presumably due to differences in organic matter quality. Microenvironmental site factors (temperature, soil moisture, degree of anaerobiosis, etc.) may be responsible for evening out these differences in the field. These site factors, which differ with slope, aspect, and drainage within a given location along the latitudinal gradient, appear to exert at least as strong a control over carbon fluxes as do macroclimatic factors among sites across the latitudinal gradient. While our field measurements indicate that, in the short term, warming will tend to increase ecosystem losses Of CO2 via respiration more than they will increase plant gross assimilation, the degree to which different topographically-defined plant communities will respond is likely to vary
Climate and species affect fine root production with long-term fertilization in acidic tussock tundra near Toolik Lake, Alaska
Author Posting. © The Author(s), 2007. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Oecologia 153 (2007): 643-652, doi:10.1007/s00442-007-0753-8.Long-term fertilization of acidic tussock tundra has led to changes in plant species
composition, increases in aboveground production and biomass and substantial losses of soil
organic carbon (SOC). Root litter is an important input to SOC pools, though little is known
about fine root demography in tussock tundra. In this study, we examined the response of fine
root production and live standing fine root biomass to short- and long-term fertilization, as
changes in fine root demography may contribute to observed declines in SOC. Live standing
fine root biomass increased with long-term fertilization, while fine root production declined,
reflecting replacement of the annual fine root system of Eriophorum vaginatum, with the long-lived
fine roots of Betula nana. Fine root production increased in fertilized plots during an
unusually warm growing season, but remained unchanged in control plots, consistent with
observations that B. nana shows a positive response to climate warming. Calculations based on
a few simple assumptions suggest changes in fine root demography with long-term fertilization
and species replacement could account for between 20 and 39% of observed declines in SOC
stocks.This project was supported by National Science Foundation research grants 9810222,
9911681, 0221606 and 0528748
Changes in the surface energy budget after fire in boreal ecosystems of interior Alaska: An annual perspective
Understanding links between the disturbance regime and regional climate in boreal regions requires observations of the surface energy budget from ecosystems in various stages of secondary succession. While several studies have characterized fireâinduced differences in surface energy fluxes from boreal ecosystems during summer months, much less is known about these differences over the full annual cycle. Here we measured components of the surface energy budget (including both radiative and turbulent fluxes) at three sites from a fire chronosequence in interior Alaska for a 1âyear period. Our sites consisted of large burn scars resulting from fires in 1999, 1987, and âŒ1920 (hereinafter referred to as the 3â, 15â, and 80âyear sites, respectively). Vegetation cover consisted primarily of bunch grasses at the 3âyear site, aspen and willow at the 15âyear site, and black spruce at the 80âyear site. Annual net radiation declined by 31% (17 W m^(â2)) for both the 3â and the 15âyear sites as compared with the 80âyear site (which had an annual mean of 55 W m^(â2)). Annual sensible heat fluxes were reduced by an even greater amount, by 55% at the 3âyear site and by 52% at the 15âyear site as compared with the 80âyear site (which had an annual mean of 21 W m^(â2)). Absolute differences between the postfire ecosystems and the mature black spruce forest for both net radiation and sensible heat fluxes were greatest during spring (because of differences in snow cover and surface albedo), substantial during summer and winter, and relatively small during fall. Fireâinduced disturbance also initially reduced annual evapotranspiration (ET). Annual ET decreased by 33% (99 mm yr^(â1)) at the 3âyear site as compared with the 80âyear site (which had an annual flux of 301 mm yr^(â1)). Annual ET at the 15âyear site (283 mm yr^(â1)) was approximately the same as that from the 80âyear site, even though the 15âyear site had substantially higher ET during July. Our study suggests that differences in annual ET between deciduous and conifer stands may be smaller than that inferred solely from summer observations. This study provides a direct means to validate land surface processes in global climate models attempting to capture vegetationâclimate feedbacks in northern terrestrial regions
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