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1.
Models of natural and human dynamics in forest landscapes: Cross-site and cross-cultural synthesis 总被引:1,自引:0,他引:1
Miguel F. Acevedo J. Baird Callicott Donald Lyons Judith Rosales Magdiel Ablan Giorgio Tonella Emilio Vilanova 《Geoforum》2008,39(2):846-866
We synthesize the study of coupled natural and human systems across sites and cultures through a process of simplification and abstraction based on multiple dimensions of human-nature connectedness: satisfaction of basic needs, psycho-cultural connectedness and regulation of use of natural resources. We thus provide both a place-based and general understanding of value-driven anthropogenic environmental change and response. Two questions guide this research: what are the crucial stakeholder values that drive land use decisions and thus land cover change? And how can knowledge of these values be used to make decisions and policies that sustain both the human and natural systems in a place? To explore these questions we build simulation models of four study sites, two in the State of Texas, United States, and two in Venezuela. All include protected areas, though they differ in the specifics of vegetation and land use. In the Texas sites, relatively affluent individuals are legally converting forests to residential, commercial, and industrial uses, while in Venezuela landless settlers are extra-legally converting forests for purposes of subsistence agriculture. Contemporary modeling techniques now facilitate simulations of stakeholder and ecosystem dynamics revealing emergent patterns. Such coupled human and natural systems are currently recognized as a form of biocomplexity. Our modeling framework is flexible enough to allow adaptation to each of the study sites, capturing the essential features of the respective natural and anthropogenic land use changes and stakeholder reactions. The interactions between human stakeholders are simulated using multi-agent models that act on forest landscape models, and receive feedback of the effects of these actions on ecological habitats and hydrological response. The multi-agent models employ a formal logic-based method for the Venezuelan sites and a decision analysis approach using multi-attribute utility functions for the Texas sites, differing more in style and emphasis than in substance. Our natural-systems models are generic and can be tailored according to site-specific conditions. Similar models of tree growth and patch transitions are used for all the study sites and the differing responses to environmental variables are specified for each local species and terrain conditions. 相似文献
2.
Histopathological biomarkers in estuarine fish species for the assessment of biological effects of contaminants 总被引:1,自引:0,他引:1
Stentiford GD Longshaw M Lyons BP Jones G Green M Feist SW 《Marine environmental research》2003,55(2):137-159
The increasing emphasis on the assessment and monitoring of estuarine ecosystems has highlighted the need to deploy appropriate biological indices for these locations. Fish diseases and histopathology, with a broad range of causes, are increasingly being used as indicators of environmental stress since they provide a definite biological end-point of historical exposure. This study reports on the histopathological alterations observed in selected organs and tissues of three species of estuarine fish (Platichthys flesus, Pomatoschistus minutus and Zoarces viviparus), captured from four British estuaries (the Tyne, Tees, Mersey and Alde), differently impacted by contaminants, including PAHs. A biannual sampling regime was used to identify the important seasonal variations that occur in terms of the observed biological effects. Inflammatory lesions and hepatocellular fibrillar inclusions attained their highest prevalence in P. flesus captured from the Tyne, Tees and Mersey. The presence of pre-neoplastic and neoplastic toxicopathic lesions was highest in P. flesus captured from these sites, when compared to fish from the Aide reference site. In particular, the prevalence of hepatic foci of cellular alteration (up to 43.3%) and hepatocellular adenoma (up to 10%) were highest in P. flesus captured from the Mersey estuary. Intersex (ovotestis) was only recorded in male P.flesus captured from the Mersey estuary (up to 8.3%) and from male Z. viviparous captured from the Tyne estuary (25%). Pathologies associated with the gill and the kidney were also most prevalent in fish captured from the Tyne, Tees and Mersey estuaries. This study has successfully applied histopathology to an estuarine monitoring program, both for the recording of toxicopathic lesions in the liver and other organs, and for the detection of the endpoint of endocrine disruption, intersex. As such, it provides a powerful integrative tool for the assessment of biological effects of contaminants in these environments. 相似文献
3.
There is a growing body of evidence to suggest that certain polycyclic aromatic hydrocarbons (PAHs) pose a greater hazard to aquatic organisms than previously demonstrated, due to their potential to cause photo-induced toxicity when exposed to ultraviolet (UV) radiation. The consequences of photo-induced toxicity are reported here for embryo-larval stages of the pacific oyster Crassostrea gigas, following exposure to pyrene and benzo[a]pyrene. During laboratory investigations, significant increases in toxicity were observed in the presence of environmentally attainable levels of UV-radiation, compared with embryos exposed to PAH alone, at levels previously deemed to have little acute biological effect. The phototoxicity of pyrene and benzo[a]pyrene completely inhibited the development to the D-shell larval stage when embryos were simultaneously exposed to 5 microg l(-1) PAH and ultraviolet light (UVB = 6.3 +/- 0.1 microW/cm2 and UVA = 456.2 +/- 55 microW/cm2). A linear relationship was also demonstrated for benzo[a]pyrene phototoxicity with decreasing UV light intensity. 相似文献
4.
Zhangxin Chen Richard E. Ewing Hao Lu Stephen L. Lyons Serguei Maliassov Michael B. Ray Tong Sun 《Computational Geosciences》2002,6(3-4):545-564
In this paper we employ mixed finite elements and numerically study an integrated two-dimensional model of fluid flow and compaction in a sedimentary basin. This model describes a single phase incompressible flow in a two-dimensional section of a sedimentary basin with vertical compaction. At each time step, an iterative algorithm is used to solve this model. The determination of the grid movement is based on the mass conservation and movement of sediments in the basin, while the mixed method is utilized to solve the fluid flow over the moving grid. Numerical experiments are presented to verify this iterative algorithm and show representative solutions for the model under consideration. 相似文献
5.
Unlike temperate and polythermal proglacial streams, the proglacial streams in Taylor Valley (TV), Antarctica, are derived primarily from glacier surface melt with no subglacial or groundwater additions. Solute responses to flow reflect only the interaction of glacial meltwater with the valley floor surrounding the stream channel. We have investigated the major, minor and trace element 24‐h variations of two proglacial melt streams, Andersen Creek and Canada Stream, originating from the Canada Glacier in TV, Antarctica. Both streams exhibited diel mid‐austral summer diurnal flow variation, with maximum flow being more than 50 times the minimum flow. Dissolved (< 0.4 µm) major, minor and trace solute behaviors through diel periods were strongly controlled by the availability of readily solubilized material on the valley floor and hyporheic‐biological exchanges. Anderson Creek had generally greater solute concentrations than Canada Stream because of its greater receipt of eolian sediment. Andersen Creek also acquired greater solute concentrations in the rising limb of the hydrograph than the falling limb because of dissolution of eolian material at the surface of the stream channel coupled with minimal hyporheic‐biological exchange. Conversely, Canada Stream had less available eolian sediment, but a greater hyporheic‐biological exchange, which preferentially removed trace and major solutes in the rising limb and released them in the falling limb. Given the dynamic nature of discharge, eolian, and hyporheic‐biological processes, solute loads in TV streams are difficult to predict. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
6.
Kirby MF Smith AJ Barry J Katsiadaki I Lyons B Scott AP 《Marine environmental research》2006,62(4):315-325
This study was conducted as an initial investigation of 'differential response' in one of the main sentinel organisms used for monitoring programmes in United Kingdom estuaries, the flounder Platichthys flesus. It has been hypothesised that monitoring using species with a wide geographical spread and limited migration, such as flounder, might result in the comparison of different genetic stocks and certainly of populations with differing early life stage contaminant exposure histories. Furthermore, it is probable that these pre-exposure and genetic differences could manifest themselves in an ability to respond differently to contaminant exposure, so-called 'differential response'. It is important that the extent and nature of this response is understood, if we want to be able to fully interpret the monitoring data from such programmes. During this study, flounder were collected from four separate sources; wild caught fish from the estuaries of the Rivers Alde, Mersey and Tyne, and farmed flounder from Port Erin Farm, Isle of Man. Under controlled laboratory conditions, groups of fish from each source were exposed to water-borne concentrations of the synthetic oestrogen ethynylestradiol (EE2) at a nominal concentration of 50 ng/l. Plasma was taken from each male fish after 6 and 10 days exposure and analysed for the presence of vitellogenin (VTG) using an ELISA technique. Significant levels of VTG induction were evident in fish from all sources after both 6 and 10 days exposure. Flounder from the Mersey were the only fish with significantly elevated initial background levels of VTG (day 0) and this appeared to be reflected in that these specimens showed the highest induction response after day 6. However, after day 10, fish from all other sites had a slightly higher mean VTG than those from the Mersey which showed significantly (p < 0.05) lower mean plasma VTG. It is suggested that other differential responses may have been masked by the use of a high dose of EE2 which produced maximum induction in nearly all fish. The findings of the study are discussed in terms of implications for further research into the differential response issue and how the initial plasma VTG figures contribute to a time-series from the Mersey, Tyne and Alde estuaries. 相似文献
7.
Summary A simple surface energy budget model is developed and validated for an aboriginal rock art site in Western Australia. The thermal regime of the rock face is strongly dependent on the sky view factor for a vertical surface element and the sensible and latent heat fluxes are shown to be relatively unimportant. Using climatological data, the model is extended to form the basis for appropriate environmental management and conservation of the rock art.
With 4 Figures 相似文献
Zusammenfassung Es wird ein einfaches Oberflächenenergiebilanzmodell für eine Höhle mit Felszeichnungen der Eingeborenen in Westaustralien entwickelt und überprüft. Das thermische Regime der Felsoberfläche wird vom Bildwinkel des Himmels für ein vertikales Oberflächenelement dominiert, während sich die Flüsse fühlbarer und latenter Wärme als unbedeutend erwiesen. Die Berücksichtigung von klimatologischen Daten ermöglicht es, damit die Grundlagen für geeignete Umweltund Konservierungsmaßnahmen für das Kunstwerk zu schaffen.
With 4 Figures 相似文献
8.
9.
Benthic fluxes of C, N, P and Si have been measured at two sites in Great Bay Estuary, New Hampshire. Higher fluxes of reactive phosphate, nitrate and reactive silicate were observed at the site where bioturbation is known to occur and the fluxes of NH4 +, PO4 ?3 and reactive silicate at this location were from 3 to 6 times higher than that calculated by simple pore water diffusion models. *** DIRECT SUPPORT *** A01BY019 00010 相似文献
10.
Concentrations and calculated fluxes of trace metals into Bermuda nearshore marine and lake sediments are presented. In areas affected by anthropogenic activity, metal profiles show surface sediment enrichments similar to those observed in North American and European lacustrine and estuarine sediments. Atmospheric fluxes of Cu, Zn and Pb into the lake sediments are higher than those of rural areas in North America. These high fluxes are assumed to be due to jet-fuel combustion. Sediment profiles in the Hamilton City area indicate increased anthropogenic input of Cu and Pb compared to other marine locations. 相似文献