Development of a Multimetric Index for Integrated Assessment of Salt Marsh Ecosystem Condition     

Jessica L. Nagel  Hilary A. Neckles  Glenn R. Guntenspergen  Erika N. Rocks  Donald R. SchoolmasterJr  James B. Grace  Dennis Skidds  Sara Stevens 《Estuaries and Coasts》2018,41(2):334-348

Tools for assessing and communicating salt marsh condition are essential to guide decisions aimed at maintaining or restoring ecosystem integrity and services. Multimetric indices (MMIs) are increasingly used to provide integrated assessments of ecosystem condition. We employed a theory-based approach that considers the multivariate relationship of metrics with human disturbance to construct a salt marsh MMI for five National Parks in the northeastern USA. We quantified the degree of human disturbance for each marsh using the first principal component score from a principal components analysis of physical, chemical, and land use stressors. We then applied a metric selection algorithm to different combinations of about 45 vegetation and nekton metrics (e.g., species abundance, species richness, and ecological and functional classifications) derived from multi-year monitoring data. While MMIs derived from nekton or vegetation metrics alone were strongly correlated with human disturbance (r values from ?0.80 to ?0.93), an MMI derived from both vegetation and nekton metrics yielded an exceptionally strong correlation with disturbance (r = ?0.96). Individual MMIs included from one to five metrics. The metric-assembly algorithm yielded parsimonious MMIs that exhibit the greatest possible correlations with disturbance in a way that is objective, efficient, and reproducible.  相似文献   

Slushflows: science and planning considerations for an expanding hazard     

Grace Relf  James M. Kendra  Robert M. Schwartz  Daniel J. Leathers  Delphis F. Levia 《Natural Hazards》2015,78(1):333-354

Slushflows are natural hazards that pose considerable danger to communities across the globe. These events are characterized by the rapid mass movement of water-inundated snow downslope, and they cause economic damage as well as fatalities in many different climates and regions. As the global climate changes and human populations and industries potentially expand to higher latitudes, it will be important to fully understand the slushflow hazard since an anticipated increase in the frequency of rain-on-snow events and an earlier spring thaw would likely increase the probability of slushflows. This article: (1) summarizes the factors that favor the development of slushflows; (2) discusses the hazard management implications of slushflows; (3) examines the policies employed to prevent and mitigate slushflow damage; and (4) sets out the need for modifications in hazard management systems. Conclusions drawn hope to address future research needs in an effort to create policies that better suit the needs of at-risk communities.  相似文献   

Engaging Communities for Success: social impact assessment and social licence to operate at Northparkes Mines,NSW     

Grace Michell 《The Australian geographer》2013,44(4):435-459

Social issues are critical to the mining industry. This study investigates how social issues have been, and are being, assessed and managed within this industry through a case study of Northparkes Mines in central west New South Wales (NSW). The research involved 29 interviews with mining executives, environmental consultants and citizens of Parkes, plus a document analysis of four environmental impact statements prepared between 1990 and 2012. Where appropriate, findings were extrapolated to the wider mining industry. The standard for social impact assessment in NSW and emerging industry guidelines on social responsibility were analysed against internationally accepted good practice. Interviews indicated greater potential to recognise the social impacts of mining in NSW and identified good practice impact assessment as only one component of a successful community engagement strategy. Complementary strategies are essential to extend the benefits of development to local communities and for companies to establish a ‘social licence to operate’. The successful approach taken by Northparkes Mines combined good practice impact assessment with a localised workforce, an integrated management team and context-specific community engagement practices. This study highlights that local communities can be empowered through development, that benefits can extend to both the community and the business and that the ongoing management of social issues will increasingly be critical to the success of the mining industry.  相似文献   

Gradients,Property Templates,and Land Use Change     

Daniel J. Bain  Grace S. Brush 《The Professional geographer》2013,65(2):224-237

The scarcity of historical individual-level data makes understanding historic land use decisions and the influence of physiochemical gradients on these decisions difficult. Here, we present several measures of early property agricultural quality based on commonly available data, including elevation and soil type. These analyses demonstrate the influence of physiochemical gradients on initial land division patterns in the Gywnns Falls watershed (Baltimore, Maryland). Moreover, we examine the influence of the template created by early property decisions on continuing human-driven landscape dynamics. This influence is illustrated by 1900-era forest cover patterns, park locations, and modern transportation networks.  相似文献   

Phenotypic plasticity of floral traits and pollination adaption in an alpine plant <Emphasis Type="Italic">Pedicularis siphonantha</Emphasis> D. Don when transplanted from higher to lower elevation in Eastern Himalaya     

Wen-Kui Dai  Grace Mercy Amboka  Edwin Luguba Kadiori  Qing-Feng Wang  Chun-Feng Yang 《山地科学学报》2017,14(10):1995-2002

Phenotypic plasticity and/or pollinator-mediated selection may be responsible for the changes in floral traits of plants when they are forced to live in new conditions. Although the two events could be independent, we hypothesized that phenotypic plasticity in floral traits might help to coordinate plant-pollinator interactions and enhance plant reproductive success in changing habitats. To test this hypothesis, we investigated floral traits and pollination on three natural populations of a lousewort (Pedicularis siphonantha) ranging at different elevations, as well as two downward transplanted populations in Shangeri-La County and Deqin County, northwest Yunnan, China. The results indicated that floral traits, i.e. phenology, longevity, display size, corolla tube length and pollen production differed significantly among populations. Moreover, or the two transplanted populations, floral traits diverged from their original populations, but converged to their host populations. Although the phenotypic plasticity in floral traits might be a rapid response to abiotic factor such as warmer environment, the changes in floral traits were found to be well adapted to pollination environment of the host population. Compared with plants of their original habitats in higher elevation, the transplanted individuals advanced flowering time, shortened flower longevity, reduced floral display size and pollen production, received higher visiting frequency and yielded more seeds. These findings suggested that phenotypic plasticity of floral traits might help plants adjust their resource allocation strategy between preand post-pollination stages in response to harsh or temperate conditions, which might correspondingly meet a pollinator-poor or hyphen rich environment. This would be beneficial for the widely-distributed species to adapt to various environmental changes.  相似文献   

Sub-kilometer length scales in coastal waters     

Shelley M. Blackwell  Mark A. Moline  Andrew Schaffner  Thomas Garrison  Grace Chang 《Continental Shelf Research》2008

Patchiness or spatial variability is ubiquitous in marine systems. With increasing anthropogenic impacts to coastal resources and coastal systems being disproportionately large contributors to ocean productivity, identifying the spatial scales of this patchiness, particularly in coastal waters, is of critical importance to understand coastal ecosystem dynamics. The current work focuses on fine scale structure in three coastal regions. More specifically, we utilize variogram analyses to identify sub-kilometer scales of variability in biological and physical parameters measured by an autonomous underwater vehicle (AUV) in the Mid-Atlantic Bight, Monterey Bay, and in San Luis Obispo Bay between 2001 and 2004. Critical scales of variability in density, turbidity, fluorescence, and bioluminescence are examined as a function of depth and distance offshore. Furthermore, the effects of undersampling are assessed using predictive error analysis. Results indicate the presence of scales of variability ranging from 10s to 100s of meters and provide valuable insight for sampling design and resource allocation for future studies.  相似文献   

Controls on salt marsh accretion: A test in salt marshes of Eastern Canada     

Gail?L.?ChmuraEmail author  Grace?A.?Hung 《Estuaries and Coasts》2004,27(1):70-81

We used¹³⁷Cs-dating to determine vertical accretion rates of 15 salt marshes on the Bay of Fundy, the Gulf of St. Lawrence, and the Atlantic coast of Nova Scotia. Accretion rates are compared to a number of factors assumed to influence vertical marsh accretion: rates of relative sea-level rise, climatic parameters (average daily temperatures and degree days) and latitude (related to insolation and day length), sediment characteristics (organic matter inventory, bulk, mineral, and organic matter density), distance of the core site from the nearest source of tidal waters, and the tidal range. Uniques to our study is a consideration of climatic parameters and latitude, which should influence organic matter production, and thus vertical accretion rates. Significant predictors of accretion rates (in order of importance) were found to be organic matter inventory, distance from a creek, and range of mean tides. Contrary to conclusions from previous studies, we found that accretion rates decreased with increasing tidal range, probably because we considered a wider span of tidal ranges, from micro- to macrotidal. Although four marshes with low organic matter inventories also show a deficit in accretion with respect to relative sea-level rise, organic matter is not limiting in two-thirds of the marshes studied, despite shorter growing seasons.  相似文献   

Excursion to the lower carboniferous rocks of Westmorland: July 26th–August 2nd, 1916     

E.J. Garwood  Grace M. Bauer 《Proceedings of the Geologists' Association. Geologists' Association》1917,28(1):44-45

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The Semi-diurnal Lunar Tidal Motion of the Red Sea.     

S. F. Grace  D. Sc.   《Geophysical Journal International》1930,2(S6):273-296

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The Influence of Friction on the Tidal Motion of the Gulf of Suez.     

S. F. Grace  D. Sc.   《Geophysical Journal International》1931,2(S7):309-318

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