Forest Management Patterns in the Floodplain of the Amazon Estuary

In the Amazon basin, few studies have focused on environmentally sound land-use alternatives that are linked to markets. This paper analyzes land uses carried out by traditional inhabitants ( ribeirinhos ) on three islands in the Amazon estuary. Management of the native floodplain forest is the most extensive form of land use on these islands. Such management varies in response to local economic and ecological conditions but invariably targets key nontimber forest resources destined for local markets, requires minimal input of labor and capital, and maintains a considerable stock of biotic resources. While restricted to a specific forest type, this form of land use is associated with relatively high population densities and, if supported by appropriate development policies, could provide an environmentally sound land-use alternative for hundreds of thousands of rural inhabitants of Amazonia.     

Direct-push geochemical profiling for assessment of inorganic chemical heterogeneity in aquifers

Discrete-depth sampling of inorganic groundwater chemistry is essential for a variety of site characterization activities. Although the mobility and rapid sampling capabilities of direct-push techniques have led to their widespread use for evaluating the distribution of organic contaminants, complementary methods for the characterization of spatial variations in geochemical conditions have not been developed. In this study, a direct-push-based approach for high-resolution inorganic chemical profiling was developed at a site where sharp chemical contrasts and iron-reducing conditions had previously been observed. Existing multilevel samplers (MLSs) that span a fining-upward alluvial sequence were used for comparison with the direct-push profiling. Chemical profiles obtained with a conventional direct-push exposed-screen sampler differed from those obtained with an adjacent MLS because of sampler reactivity and mixing with water from previous sampling levels. The sampler was modified by replacing steel sampling components with stainless-steel and heat-treated parts, and adding an adapter that prevents mixing. Profiles obtained with the modified approach were in excellent agreement with those obtained from an adjacent MLS for all constituents and parameters monitored (Cl, NO(3), Fe, Mn, DO, ORP, specific conductance and pH). Interpretations of site redox conditions based on field-measured parameters were supported by laboratory analysis of dissolved Fe. The discrete-depth capability of this approach allows inorganic chemical variations to be described at a level of detail that has rarely been possible. When combined with the mobility afforded by direct-push rigs and on-site methods of chemical analysis, the new approach is well suited for a variety of interactive site-characterization endeavors.     

Fruit traits and temporal abundance shape plant-frugivore interaction networks in a seasonal tropical forest

Interactions between fleshy fruited plants and frugivores are crucial for the structuring and functioning of biotic communities, particularly in tropical forests where both groups are diverse and play different roles in network organization. However, it remains poorly understood how different groups of frugivore species and fruit traits contribute to network structure. We recorded interactions among 28 plant species and three groups of frugivores (birds, bats, and non-flying mammals) in a seasonal forest in Mexico to determine which species contribute more to network structure and evaluate the importance of each species. We also determined whether fruit abundance, water content, morphology traits, and fruiting phenology are related to network parameters: the number of interactions, species contribution to nestedness, and species strength. We found that plants did not depend on a single group of frugivores, but rather on one species of each group: the bird Pitangus sulphuratus, the bat Sturnira parvidens, and the non-flying mammal Procyon lotor. The abundance, size, and water content of the fruits were significantly related to the contribution to nestedness, number of interactions, and species strength index of plant species. Tree species and birds contributed mainly to the nested structure of the network. We show that the structure of plant-frugivore networks in this seasonal forest is non-random and that fruit traits (i.e., abundance, phenology, size, and water content) are important factors shaping plant-frugivore networks. Identification of the key species and their traits that maintain the complex structure of species interactions is therefore fundamental for the integral conservation of tropical forests.     

Malodors–A Basis for Regulations

Of the four major categories of objectionable air pollution effects, the sensory offenses are considered to be of dominant importance, and should receive much higher priority in governmental policy than has been accorded to them. This applies with particular force to the malodors. This deficiency may be partially due to the pre-eminent emphasis on the search for health effects and partly to the problems of measurement of malodors which is of prime importance in the framing of odor control ordinances in objective terms. The author shows that malodors can be measured at the source with quite satisfactory precision, contrary to commonly-held opinion. Ambient air quality with respect to malodors likewise can be evaluated by a quite simple technique and with nontechnical personnel. A compatible system of an ambient air quality standard and allowable emission rates from sources is demonstrated, and the essential elements of an odor control regulation are described.     

Use of multitracers for the study of water mixing in the Paraíba do Sul River estuary

Multitracers were used to study water mixing in the Paraíba do Sul River estuary region in August 2007 (dry season) and March 2008 (rainy season) and to evaluate the reach of the river plume in the direction of the open ocean. Two sampling campaigns were carried out, each in a different season. Based on these results, it was possible to conclude that the multitracers used in this study (salinity, Si, Ba and U, as well as the radium isotopes ²²³Ra, ²²⁴Ra, ²²⁶Ra and ²²⁸Ra) presented satisfactory results toward defining the plume reach and determining the residence time and water-mixing processes in the estuary. A strong correlation was observed between tracers and the distance to the coast. During the low river water discharge period, the riverine water took about 10 days to reach open ocean waters (salinity ∼ 35). During the rainy period this value decreased to 6 days. Based on the radium results, it was possible to calculate diffusion coefficients (K_h) of 23 km² d⁻¹ and 38 km² d⁻¹ for ²²⁴Ra and ²²³Ra, respectively, during the dry season (winter). Values of 65 km² d⁻¹ and 68 km² d⁻¹ for ²²³Ra and ²²⁴Ra, respectively, were found for the rainy period (summer).     

Two methods to assess vulnerability to climate change in the Mexican agricultural sector

We applied two methods to assess vulnerability to climate change in Mexico’s agricultural sector. The first one was a principal component analysis (PCA) that weighted each variable separately. For the second one, we integrated the variables in a linear array in which all variables were weighted equally, and then, we used the arithmetic sum of the sub-indices of exposure and sensitivity minus the adaptive capacity to obtain the vulnerability index. We discuss the similarities and differences between two methods with respect to municipal-level maps as the outputs. The application of the method for the agricultural sector in Mexico gave us the spatial distribution of the high- and very-high vulnerability categories, which we propose as a tool for policy. The methods agreed that the very-high vulnerability category is present in 39 municipalities. Also we found that 16 % of the total population in the country is located in high-exposure areas. In addition, 41 % lives in municipalities identified as highly-sensitive. In terms of adaptive capacity, 20 % of the population lives in 1273 municipalities with low-adaptive capacity. Finally, we discuss the need for information regarding vulnerability at the national level to guide policies aimed at reducing exposure and sensitivity and increasing adaptive capacity.     

137Cs in marine samples from the Brazilian southeastern coastal region

The present work presents the results of ¹³⁷Cs concentration in seawater, fish and sediments samples collect in 11 sampling points, crossing the Brazilian Southeastern coastal region, from Vitória (ES) to Santos (SP), on a routine basis from 1997 to 2002. This monitoring program was carried out by the Instituto de Radioproteção e Dosimetria (IRD/CNEN/MCT), in cooperation with the Instituto de Estudos do Mar Almirante Paulo Moreira (IEAPM/Brazilian Navy), aiming at determining artificial radionuclides in marine samples. Additionally to the ¹³⁷Cs results, ⁹⁰Sr concentrations in fish samples from 1998 to 2002 are also reported.The ¹³⁷Cs in seawater follows a lognormal distribution, with a geometric mean of 1.8 Bq m^-3 and a geometric standard deviation of 1.4 (n=54), decay corrected to June/2002. For ¹³⁷Cs levels in fish samples a geometric mean of 0.19 Bq kg⁻¹ and a geometric standard deviation of 2.9 (n=39), decay corrected to June/2002, with a range of 0.03 to 1.7 Bq kg⁻¹, were obtained. Based on the ¹³⁷Cs mean concentration in fish as well as in seawater, a transfer factor of 1 × 10² was calculated, which is quite in agreement with the recommended value found in the Safety Report Serie 19.     

Pollution control and technological advance: A dynamic model of the firm

The paper extends the static comparison of effluent taxes and effluent standards to a dynamic world in which firms invest resources in improving their abatement technology as well as their production technology. The analysis shows that the two pollution control policies lead to a distinctly different allocation of research and development (R & D) funds between improvement in abatement technology and improvement in production technology. The model also shows that a temporally constant effluent tax leads to an increasing effluent discharge rate for “typical” firms. Other results concern the pattern of output growth and the rate of technological advance.