Exact welfare measurement: theory and application to recreation economics

Although the limitations of consumer surplus have become widely known, there exists a lack of studies which present in a coherent framework recent developments in estimating Hicksian welfare measures. This study attempts to fill partially this gap by analyzing some theoretical and empirical aspects in the estimation of exact welfare measures using market data. Analytical expressions of the "exact" welfare measures, compensating variation (CV) and equivalent variation (EV), for some frequently used single demand equations as well as flexible functional form demand systems are presented. The different magnitudes of benefit estimates generated for the same valuation problem have been a source of important criticism of market related valuation studies. This study compares different functional forms consistent with the restrictions required for the aggregation of consumers and commodities. The results for steelhead rivers in Oregon indicate that the definitional differences in welfare measure (ordinary versus compensated measures) are quite small, which is consistent with the small budget shares that these activities account for a representative household. The results also suggest that the welfare measures may be very sensitive to the formulation of the model. However, the almost ideal demand system (AIDS) and translog indirect utility function demand system (TLOG) produce very close welfare estimates when catch rate, trips and a composite good are considered the commodities yielding utility. The treatment of endogenous quality variables has been a widely discussed issue in the recreation economics and labor economics literatures. In this study, unlike that of Bockstael and McConnell (1981), the demand system is specified as a function of exogenous parameters rather than endogenous implicit prices, avoiding the simultaneity of the demand system and the identification problem. Our empirical results support the comparative static predictions on the price and income elasticities for catch rate per trip and number of trips. A limitation of this study is the restrictive form assumed for the production technology. However, following Strong (1984), our model can be extended to take into account substitution among inputs, non constant returns to scale, and exogenous quality variables. Future research should be directed to study the properties of "exact welfare measures associated with different flexible functional forms. For large economic welfare changes, a global approximation to the underlying utility function as provided by Fourier series might be preferable. The comparisons among different model specifications should be done using rigorous statistical methods including the construction of confidence intervals for the welfare estimates

Incentivos Económicos para una Explotación Eficiente del Bosque

The problem of forest management with noncentralized land property seems of increasing importance, specially for developing countries. There is a need to design mechanisms that allow to obtain both commercial benefits from exploitation and purely social b

Spatio-temporal variability of mid-size pelagic fishes in the Gulf of Cadiz shelf waters in relation to climatic and environmental drivers

Modeling spatio-temporal patterns of mid-size pelagic fish species (MSPFS) distribution and density is of great interest from the standpoint of both their management and conservation. Herein, temporal changes in the spatial patterns of five MSPFS off the Gulf of Cadiz are analyzed from acoustic surveys data (2007-2017). In particular, we evaluated intra-specific variability over time and space and relate such fluctuations to environmental and climatic drivers aimed to provide support to the implementation of a future ecosystem approach to fisheries management in this region

The role of physico-chemical interactions in the seasonality of toxic dinoflagellate cyst assemblages: The case of the NW Patagonian fjords system

Harmful algal blooms (HABs) are recurrent in the NW Patagonia fjords system and their frequency has increased over the last few decades. Outbreaks of HAB species such as Alexandrium catenella, a causal agent of paralytic shellfish poisoning, and Protoceratium reticulatum, a yessotoxins producer, have raised considerable concern due to their adverse socioeconomic consequences. Monitoring programs have mainly focused on their planktonic stages, but since these species produce benthic resting cysts, the factors influencing cyst distributions are increasingly gaining recognition as potentially important to HAB recurrence in some regions. Still, a holistic understanding of the physico-chemical conditions influencing cyst distribution in this region is lacking, especially as it relates to seasonal changes in drivers of cyst distributions as the characteristics that favor cyst preservation in the sediment may change through the seasons. In this study, we analyzed the physico–chemical properties of the sediment (temperature, pH, redox potential) and measured the bottom dissolved oxygen levels in a “hotspot” area of southern Chile, sampling during the spring and summer as well as the fall and winter, to determine the role these factors may play as modulators of dinoflagellate cyst distribution, and specifically for the cysts of A. catenella and P. reticulatum. A permutational analysis of variance (PERMANOVA) showed the significant effect of sediment redox conditions in explaining the differences in the cyst assemblages between spring-summer and fall-winter periods (seasonality). In a generalized linear model (GLM), sediment redox potential and pH were associated with the highest abundances of A. catenella resting cysts in the spring-summer, however it was sediment temperature that most explained the distribution of A. catenella in the fall-winter. For P. reticulatum, only spring-summer sediment redox potential and temperature explained the variation in cyst abundances. The implications of environmental physico-chemical seasonality for the resting cysts dynamics of both species are discussed.Postprint3,74

Turbulence and hypoxia contribute to dense biological scattering layers in a Patagonian fjord system

The aggregation of plankton species along fjords can be linked to physical properties and processes such as stratification, turbulence and oxygen concentration. The goal of this study is to determine how water column properties and turbulent mixing affect the horizontal and vertical distributions of macrozooplankton along the only northern Patagonian fjord known to date, where hypoxic conditions occur in the water column. Acoustic Doppler current profiler moorings, scientific echo-sounder transects and in situ plankton abundance measurements were used to study macrozooplankton assemblages and migration patterns along Puyuhuapi Fjord and Jacaf Channel in Chilean Patagonia. The dissipation of turbulent kinetic energy was quantified through vertical microstructure profiles collected throughout time in areas with high macrozooplankton concentrations. The acoustic records and in situ macrozooplankton data revealed diel vertical migrations (DVM) of siphonophores, chaetognaths and euphausiids. In particular, a dense biological backscattering layer was observed along Puyuhuapi Fjord between the surface and the top of the hypoxic boundary layer ( ∼ 100&thinsp;m), which limited the vertical distribution of most macrozooplankton and their DVM, generating a significant reduction of habitat. Aggregations of macrozooplankton and fishes were most abundant around a submarine sill in Jacaf Channel. In this location macrozooplankton were distributed throughout the water column (0 to  ∼ 200&thinsp;m), with no evidence of a hypoxic boundary due to the intense mixing near the sill. In particular, turbulence measurements taken near the sill indicated high dissipation rates of turbulent kinetic energy (ε ∼ 10−5&thinsp;W&thinsp;kg−1) and vertical diapycnal eddy diffusivity (Kρ ∼ 10−3&thinsp;m2&thinsp;s−1). The elevated vertical mixing ensures that the water column is well oxygenated (3–6&thinsp;mL&thinsp;L−1, 60&thinsp;%–80&thinsp;% saturation), creating a suitable environment for macrozooplankton and fish aggregations. Turbulence induced by tidal flow over the sill apparently enhances the interchange of nutrients and oxygen concentrations with the surface layer, creating a productive environment for many marine species, where the prey–predator relationship might be favored.</p

Science Priorities for Seamounts: Research Links to Conservation and Management

Seamounts shape the topography of all ocean basins and can be hotspots of biological activity in the deep sea. The Census of Marine Life on Seamounts (CenSeam) was a field program that examined seamounts as part of the global Census of Marine Life (CoML) initiative from 2005 to 2010. CenSeam progressed seamount science by collating historical data, collecting new data, undertaking regional and global analyses of seamount biodiversity, mapping species and habitat distributions, challenging established paradigms of seamount ecology, developing new hypotheses, and documenting the impacts of human activities on seamounts. However, because of the large number of seamounts globally, much about the structure, function and connectivity of seamount ecosystems remains unexplored and unknown. Continual, and potentially increasing, threats to seamount resources from fishing and seabed mining are creating a pressing demand for research to inform conservation and management strategies. To meet this need, intensive science effort in the following areas will be needed: 1) Improved physical and biological data; of particular importance is information on seamount location, physical characteristics (e.g. habitat heterogeneity and complexity), more complete and intensive biodiversity inventories, and increased understanding of seamount connectivity and faunal dispersal; 2) New human impact data; these shall encompass better studies on the effects of human activities on seamount ecosystems, as well as monitoring long-term changes in seamount assemblages following impacts (e.g. recovery); 3) Global data repositories; there is a pressing need for more comprehensive fisheries catch and effort data, especially on the high seas, and compilation or maintenance of geological and biodiversity databases that underpin regional and global analyses; 4) Application of support tools in a data-poor environment; conservation and management will have to increasingly rely on predictive modelling techniques, critical evaluation of environmental surrogates as faunal “proxies”, and ecological risk assessment

Posterior reversible encephalopathy syndrome – Case report

Introduction. Posterior reversible encephalopathy syndrome (PRES) is a group of clinical disorders typically manifested by the presence of seizures, headache, impaired consciousness, nausea and focal neurological deficits. It is stated that PRES is a result of high blood pressure which leads to impaired self-regulation and hyperperfusion causing endothelial damage and vasogenic oedema or that excessive arteriolar vasoconstriction causes reduced blood flow, thus causing ischemia and cytotoxic oedema. Case Report. A 21-year-old woman was admitted to obstetrics & gynaecology department with symptoms of eclampsia. CT of the head revelaed a holohemispheric watershed pattern. MRI confirmed the presence of vasogenicoedema in the affected regions, typical for PRES. C-section was performed. Ten days after administering treatment, MRI showed complete withdrawal of the lesions. The diagnosis of PRES was based on clinical symptoms and MRI, with typical cortical and subcortical oedema without infarction

The use of fishing vessels to provide acoustic data on the distribution and abundance of Antarctic krill and other pelagic species

A fishery for Antarctic krill (Euphausia superba) has existed for over 3 decades and the Commission for Conservation of Antarctic Marine Living Resources (CCAMLR) manages this fishery using precautionary catch limits, fishery data collection and a scientific observer programme operating on the fishing vessels. A recent increase in the number of vessels fishing and the rising costs of undertaking scientific research cruises have focussed attention on being able to use fishing vessels to collect more extensive scientific data sets. In 2011, CCAMLR’s Subgroup on Acoustic Survey and Analysis Methods (SG-ASAM) was tasked with assessing the use of acoustic data collected from fishing vessels to provide qualitative and quantitative information on the distribution and relative abundance of Antarctic krill and other pelagic species. SG-ASAM conceived a proof of concept programme and implemented the first stage in 2013 to determine the current setup of acoustic equipment on participating fishing vessels and to establish whether these vessels could collect geo- and time-referenced acoustic data. To date data have been received from 7 krill fishing vessels and SG-ASAM has now focussed on the development of data collection protocols to enable fishing vessels to collect quantitative acoustic data along prescribed transects. While this development work continues, the willingness of fishing industry to participate in such studies has already been demonstrated by several fishing companies, and Norwegian- and Chinese-flagged fishing vessels are undertaking krill biomass surveys in two key fishery areas in the South Atlantic sector of the Southern Ocean

What is a land grab? Exploring green grabs, conservation, and private protected areas in southern Chile

Discussions of land grabs for various purposes, including environmental ends, have expanded in recent years, yet land grabbing remains inconsistently defined and poorly understood. Our ability to assess the extent to which land grabs are occurring, and to identify the mixture of factors driving land and resource acquisition, is limited. This paper assesses whether a land grab for conservation is happening in southern Chile, and identifies the various driving forces that combine to drive land acquisitions in the region, based on a detailed exploration of the recent massive growth in privately owned protected areas in the region. This paper finds that the various dominant definitions of land grabs each apply only partially to southern Chile, that land grabs for conservation need to be understood as the latest stage in a longer process by which the region's natural resources are incorporated into the Chilean and the global economy, and that green grabs interact in various ways with broader resource grabs, particularly for forestry and hydroelectricity. This case study demonstrates the limitations of some definitions of land grabs, particularly their focus on capitalist accumulation within land grabs, their international nature and their emphasis on legal processes