182 research outputs found
Spatial dynamics of <I>Fabiana imbricata</I> shrublands in northwestern Patagonia in relation to natural fires
Fire is a critical disturbance in the structuring and functioning of most Mediterranean ecosystems. In northwestern Patagonia, vegetation patterns are strongly influenced by fire and environmental heterogeneity. Dendroecology, together with satellite imagery and GIS, have been demonstrated to be useful tools in studies that relate to fire effects with patches, patterns and species dynamics at landscape scale. Such studies can be approached from landscape ecology, which has evolved in the last years supported by the development of remote sensing and GIS technologies. This study evaluates the spatial dynamic of <I>F. imbricata</I> in response to fire using remote sensing, GIS and dendrochronology techniques, at landscape scale. Two sites were evaluated and one of them was affected by fire in the year 1999. The digital processing images (using the NBR spectral index) and the dendroecological analysis verified this. A fire, occurring in 1978, was also detected by the analysis of <I>F. imbricata</I> growth rings. The relation between <I>F. imbricata</I> shrubland dynamics and spatial configuration with fire, land topography and hydrography was established in the study area
The economic value of wetland conservation and creation: A meta-analysis
The rationale for conservation and creation of wetlands stems from the recognition of both their ecological and economic values. This paper examines the welfare impacts of goods and services provided by wetlands. We collected 385 estimates of the economic value of 181 natural and man-made wetlands from 167 studies worldwide. The resulting database is less biased towards North America than previous reviews of the literature. The relative importance of characteristics of the valuation study, of the wetland site, and of the socio-economic and geographical context is estimated by means of a meta-regression analysis of wetland values. Provision of amenities, flood control and storm buffering, and water quality improvement are the most highly valued wetland services. The relevance of the socio-economic and geographical context clearly emerges from the analysis and, in particular, the proximity to other wetland sites is negatively correlated with valuations. An analysis of the effect of environmental stress on wetland value shows that the latter increases with stress from human development activities and uses. In addition to the basic meta-regression model, the influence of authorship effects and of the geographic regions is examined by means of a multi-level approach. A second extended meta-regression model including cross-effects shows that the valuations of specific services vary according to the type of wetland producing them
Peritoneal carcinomatosis
Several gastrointestinal and gynecological malignancies have the potential to disseminate and grow in the peritoneal cavity. The occurrence of peritoneal carcinomatosis (PC) has been shown to significantly decrease overall survival in patients with liver and/or extraperitoneal metastases from gastrointestinal cancer. During the last three decades, the understanding of the biology and pathways of dissemination of tumors with intraperitoneal spread, and the understanding of the protective function of the peritoneal barrier against tumoral seeding, has prompted the concept that PC is a loco-regional disease: in absence of other systemic metastases, multimodal approaches combining aggressive cytoreductive surgery, intraperitoneal hyperthermic chemotherapy and systemic chemotherapy have been proposed and are actually considered promising methods to improve loco-regional control of the disease, and ultimately to increase survival. The aim of this review article is to present the evidence on treatment of PC in different tumors, in order to provide patients with a proper surgical and multidisciplinary treatment focused on optimal control of their locoregional disease. (C) 2013 Baishideng Publishing Group Co., Limited. All rights reserved
Values of natural and human-made wetlands: A meta-analysis
The values of goods and services provided by wetland ecosystems are examined through a meta-analysis of an expanded database of wetland value estimates and with a focus on human-made wetlands. This study extends and improves upon previous meta-analyses of the wetland valuation literature in terms of the number of observations, geographical coverage, wetland class and integrity, and the measurement of the effects of scarcity and anthropogenic pressure. We find that water quality improvement, nonconsumptive recreation, and provision of natural habitat and biodiversity are highly valued services. Substitution effects are observed through the negative correlation between values and abundance of other wetlands. Wetland values are found to increase with anthropogenic pressure. An extended metaregression model with cross effects shows that the valuation of specific services varies with the type of wetland producing them. Human-made wetlands are highly valued for biodiversity enhancement, water quality improvement, and flood control
Defoliation Effect of \u3cem\u3ePoa ligularis\u3c/em\u3e Nees Ap Steudel on Aerial Biomass Production and Its Components in Northwestern Argentinian Patagonia
Emerging technologies for assessing ecosystem services:A synthesis of opportunities and challenges
Reliability of toxicokinetic modelling for PFAS exposure assessment in contaminated water in northern Italy
Introduction: Long-term contamination of tap water and groundwater by perfluoroalkyl and polyfluoroalkyl substances (PFASs) has been documented in the Veneto region of northern Italy. This study aimed to assess the exposure of individuals residing in the contaminated area and to test several toxicokinetic (TK) models of varying complexities to identify an efficient method for predicting perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) concentrations in human serum using observed data. The ultimate goal is to provide public health officials with guidance on selecting the appropriate TK model for specific contexts, a reliable and rapid tool to support human bio-monitoring (HBM) studies. Methods: Two simpler empirical TK models and a more complex multi-compartment physiologically based toxicokinetic (PBTK) model were compared with individual and aggregate data from an HBM study. In addition, the PBPK model was modified by adjusting input parameters and introducing new terms into the equations within the original model code. These modifications aimed to optimize the results compared to the original model, with some versions incorporating adjustments to account for the influence of menstruation in women. All models were evaluated to understand their strengths and weaknesses, providing guidance on the appropriate model to use according to specific scenarios. Results: The results obtained from the tested models were quite similar, with significant improvements observed only in the modified models. Simpler models also provided satisfactory results in scenarios involving low PFOS serum concentrations and recent exposure cessation. In many cases, predictions demonstrated high accuracy, particularly at the aggregate level and for women. Conclusions: These findings suggest that environmental protection agencies and health authorities may benefit from employing the tested models at the aggregate level as an initial step in HBM studies, rather than conducting more invasive and expensive screening campaigns
Economic values for ecosystem services:A global synthesis and way forward
This paper presents a global synthesis of economic values for ecosystem services provided by 15 terrestrial and marine biomes. Information from over 1,300 studies, yielding over 9,400 value estimates in monetary units, has been collected and organised in the Ecosystem Services Valuation Database (ESVD). This is a substantial expansion of data since the de Groot et al. (2012) description of the ESVD and provides an important juncture to explore developments in the use of valuation methods and the contexts in which valuations are conducted. In this paper we provide summary values for 23 ecosystem services from 15 biomes to represent the magnitude, variation and gaps in economic values. To enable the comparison and synthesis of values, estimates in the ESVD are standardised to a common set of units (Int$/ha/year at 2020 price levels). This data provides a basis for value transfers to inform decision-making in current policy contexts but requires due consideration and adjustment for context specific determinants of value. Although the coverage of the ESVD is global, the geographic distribution of data is not even. There is a particularly high representation of European ecosystems and relatively little information for Russia, Central Asia and North Africa. Therefore, the data are not globally representative of biophysical and socio-economic contexts. The distribution of data across ecosystem services is also far from even, with some services very well represented (e.g. recreation, wild fish and wild animals, ecosystem and species appreciation, air filtration and global climate regulation) and others with almost no value estimates (e.g. disease control, water baseflow maintenance, rainfall pattern regulation). In the past decade, there has been a notable increase in demand for information on the economic value of ecosystem services from both public and private institutions to improve the conservation and management of natural capital. The literature is developing to meet this demand but there is a need for targeted and refined valuation research to ensure sufficient certainty, comparability, and representativeness of the data, and to enable transferability and fill knowledge gaps. This paper concludes by identifying avenues for future development to further increase the amount, quality, representativeness and application of data on economic values for ecosystem services.</p
Economic values for ecosystem services: A global synthesis and way forward
This paper presents a global synthesis of economic values for ecosystem services provided by 15 terrestrial and marine biomes. Information from over 1,300 studies, yielding over 9,400 value estimates in monetary units, has been collected and organised in the Ecosystem Services Valuation Database (ESVD). This is a substantial expansion of data since the de Groot et al. (2012) description of the ESVD and provides an important juncture to explore developments in the use of valuation methods and the contexts in which valuations are conducted. In this paper we provide summary values for 23 ecosystem services from 15 biomes to represent the magnitude, variation and gaps in economic values. To enable the comparison and synthesis of values, estimates in the ESVD are standardised to a common set of units (Int$/ha/year at 2020 price levels). This data provides a basis for value transfers to inform decision-making in current policy contexts but requires due consideration and adjustment for context specific determinants of value. Although the coverage of the ESVD is global, the geographic distribution of data is not even. There is a particularly high representation of European ecosystems and relatively little information for Russia, Central Asia and North Africa. Therefore, the data are not globally representative of biophysical and socio-economic contexts. The distribution of data across ecosystem services is also far from even, with some services very well represented (e.g. recreation, wild fish and wild animals, ecosystem and species appreciation, air filtration and global climate regulation) and others with almost no value estimates (e.g. disease control, water baseflow maintenance, rainfall pattern regulation). In the past decade, there has been a notable increase in demand for information on the economic value of ecosystem services from both public and private institutions to improve the conservation and management of natural capital. The literature is developing to meet this demand but there is a need for targeted and refined valuation research to ensure sufficient certainty, comparability, and representativeness of the data, and to enable transferability and fill knowledge gaps. This paper concludes by identifying avenues for future development to further increase the amount, quality, representativeness and application of data on economic values for ecosystem services
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