Mixed Nothofagus forest management: a crucial link between regeneration,site and microsite conditions

New Forests - Canopy openings due to harvesting practices constitute a disturbance that changes the environmental conditions of microsites. Its impact on the relative performance of the...     

Effectiveness of amendments to restore metal-arsenic-polluted soil functions using Lactuca sativa L. bioassays

Purpose

Because the success of the stabilisation of contaminants from amendments depends on the pollutants involved and the amendments used, the goals of this study were to assess whether selected amendments are able to restore highly polluted soils and to advance the knowledge of both the most suitable amendments to restore polluted soils and the most appropriate bioassays to estimate soil toxicity.

Materials and methods

An acidic and polluted soil from mining waste was amended with marble sludge, compost and iron in nine different combinations. The soils were placed in plastic pots and bioassays, including the different stages in the development of lettuce (Lactuca sativa L.), were carried out. Pore water was analysed at the different stages of the development of lettuce. At the end of the experiment, pollutant concentrations in lettuce leaf were analysed and the sequential extraction of trace elements was performed.

Results and discussion

The effectiveness of the amendments in reducing the toxicity of contaminated soils varied depending on the bioassay used. Marble sludge was the most effective in increasing pH and in reducing pollutant concentrations in pore water, clearly encouraging germination, root elongation and emergence. Throughout the emergence phase, marble sludge decreased in its effectiveness, probably because the pollutants precipitated as hydroxides and carbonates were taken up by the lettuce. In contrast, the compost began to improve the elongation of the seedling and the growth of lettuce. Although the amendments were effective in reducing the negative impact of pollutants in soils, none of them was able to successfully restore the functions of highly polluted soil.

Conclusions

The development of the plant until the end of the establishment phase is the best index to estimate soil phytotoxicity, although the effect on the health of potential consumers can only be evaluated from the toxic element concentrations in the plant. The uptake of pollutants stabilised by the amendments would explain why the reduction of easily available pollutant concentrations does not necessarily imply the restoration of the normal functioning of the ecosystem.     

Dynamic performance assessment of protected areas

Recognizing the importance of preserving biodiversity and ecosystem services, human society has established extensive protected area networks to conserve these resources in recent decades. Are protected areas working as expected? Empirical coarse-scale assessments of this question across large regions, or even globally, tend to answer “yes”, while fine-scale studies of individual protected areas often and repeatedly answer “no”. We conducted a first fine-scale analysis of Brazil’s extensive Amazonian protected area network (1.8 million km²) and have quantitatively estimated conservation effectiveness in light of changing human development pressures in the surrounding landscape. The overall network maintained intact forest cover for 98.6% of protected forest lands, largely agreeing with previous coarse-scale studies. However, detailed examination of 474 individual protected areas unveils a broad range of efficacy. Many protected areas (544,800 km²) experience default protection simply due to their remoteness. Many others (396,100 km²) have provided highly effective protection in the face of substantial human development pressure. Conversely, 12% (38) of protected areas have failed to protect the 27,300 km² that they encompass, and another 7% (23) provide only marginal protection of 37,500 km². Comprehensive landscape assessments of protected area networks, with frequent monitoring at scales matching the patterns of human-caused disturbances, are necessary to ensure the conservation effectiveness and long term survival of protected areas in rapidly changing landscapes. The methods presented here are globally adaptable to all forested protected areas.     

National Soil Strategy for Sustainable Agriculture (ENASAS): A new systemic approach in Mexico

The National Soil Strategy for Sustainable Agriculture (ENASAS) arises in response to the increasing need to organize, coordinate and strengthen the implementation of actions oriented to the sustainable management of Mexico's agricultural soils. The measures recommended in this paper allow the conservation and maintenance of soils' essential functions for agriculture, food security and population well-being. The health and quality of agricultural soils are under constant pressure from several factors, mainly anthropogenic. One of ENASAS's objectives is to identify and stop the causes involved in land degradation processes using a systemic approach. From this perspective, the participation of various actors in sustainable soil management allows the integration of different systems, practices, techniques and knowledge that promotes awareness among the entire population about the importance of soil resources. On the other hand, given current limitations on the availability of information necessary to support decision-making and evaluate the result of the actions implemented, ENASAS promotes the generation of tools that provide reliable and updated data regarding Mexico's agricultural soils. In the same sense, this strategy encourages the development of scientific and technological research and the transfer of knowledge that meets the needs of farmers, particularly those who carry out their activities on a smaller scale. This perspective describes ENASAS as a multi-institutional initiative that will support sustainable soil management practices across the country's agricultural systems of Mexico and contribute to the adaptation and mitigation of global environmental change.     

Selection of native trees for intercropping with coffee in the Atlantic Rainforest biome

A challenge in establishing agroforestry systems is ensuring that farmers are interested in the tree species, and are aware of how to adequately manage these species. This challenge was tackled in the Atlantic Rainforest biome (Brazil), where a participatory trial with agroforestry coffee systems was carried out, followed by a participatory systematisation of the farmers experiences. Our objective was to identify the main tree species used by farmers as well as their criteria for selecting or rejecting tree species. Furthermore, we aimed to present a specific inventory of trees of the Leguminosae family. In order to collect the data, we reviewed the bibliography of the participatory trial, visited and interviewed the farmers and organised workshops with them. The main farmers’ criteria for selecting tree species were compatibility with coffee, amount of biomass, production and the labour needed for tree management. The farmers listed 85 tree species; we recorded 28 tree species of the Leguminosae family. Most trees were either native to the biome or exotic fruit trees. In order to design and manage complex agroforestry systems, family farmers need sufficient knowledge and autonomy, which can be reinforced when a participatory methodology is used for developing on-farm agroforestry systems. In the case presented, the farmers learned how to manage, reclaim and conserve their land. The diversification of production, especially with fruit, contributes to food security and to a low cost/benefit ratio of agroforestry systems. The investigated agroforestry systems showed potential to restore the degraded landscape of the Atlantic Rainforest biome.     

Antimicrobial activity of coupled hydroxyanthracenones isolated from plants of the genus Karwinskia

The in vitro activity of some isolated hydroxyanthracenones belonging to the genus Karwinskia against four bacteria, six filamentous fungi and four yeast are reported. These hydroxyanthracenones were found to possess antimicrobial activity, particularly against Streptococcus pyogenes, Candida albicans, C. boidinii, C. glabrata and Cryptococcus neoformans; minimal inhibitory concentrations range between 16 and 2 microg/ml.     

Cardiopulmonary and analgesic effects of caudal epidurally administered ropivacaine in cattle

ObjectiveTo assess cardiopulmonary and analgesic effects after administration of ropivacaine into the caudal epidural space of cattle.Study designProspective, single-dose trial.AnimalsEight healthy mixed breed cows aged 8 ± 5 years and weighing 507 ± 112 kg.MethodsCaudal epidural anesthesia was produced in cows with 0.75% ropivacaine (0.11 mg kg^?1). Onset time, duration and cranial spread of analgesia were recorded. Heart rate (HR), respiratory rate (f_R), rectal temperature (RT), and mean arterial blood pressure (MAP) were measured prior to epidural administration (T₀) and at 15, 30, 60, 120, 180 and 240 minutes after epidural administration (T₁₅, T₃₀, T₆₀, T₁₂₀, T₁₈₀ and T₂₄₀). Arterial blood acid-base balance (pH, standard bicarbonate and base excess), gas tension (PaO₂, PaCO₂, SaO₂) and electrolytes (Na⁺, K⁺, iCa²⁺,Cl^?) were recorded at T₀, T₃₀, T₆₀, T₁₂₀, T₁₈₀ and T_240. Ataxia was evaluated at T₀, T₃₀, T₆₀, T₁₂₀, T₁₈₀ and T₂₄₀ and at 1 hour intervals thereafter until analgesia was no longer present in each animal.ResultsEpidurally administered ropivacaine induced variable analgesia extending bilaterally from the coccyx to S3. Time to onset of analgesia and mean duration in the perineal area were 15 ± 4 and 359 ± 90 minutes, respectively. Respiratory rate and RT increased from T₁₂₀ to T₂₄₀ when compared to the value at T₀. Ionized calcium and chloride concentrations increased at T₁₈₀ and T₂₄₀ when compared to T₀. The other variables were not significantly different from baseline values (p> 0.05). Four animals were mildly ataxic.Conclusion and clinical relevanceRopivacaine (0.75%, 0.11 mg kg^?1) can be administered by caudal epidural injection to produce prolonged bilateral perineal analgesia with minimal ataxia and cardiopulmonary changes in standing cattle.     

Optimization of Physical Conditions for the Aqueous Extraction of Antioxidant Compounds from Ginger (<Emphasis Type="Italic">Zingiber officinale</Emphasis>) Applying a Box-Behnken Design

Since ancient times, ginger (Zingiber officinale) has been widely used for culinary and medicinal purposes. This rhizome possesses several chemical constituents; most of them present antioxidant capacity due mainly to the presence of phenolic compounds. Thus, the physical conditions for the optimal extraction of antioxidant components of ginger were investigated by applying a Box-Behnken experimental design. Extracts of ginger were prepared using water as solvent in a conventional solid–liquid extraction. The analyzed variables were time (5, 15 and 25 min), temperature (20, 55 and 90 °C) and sample concentration (2, 6 and 10 %). The antioxidant activity was measured using the 2,2-diphenyl-1-picrylhydrazyl method and a modified ferric reducing antioxidant power assay while total phenolics were measured by Folin & Ciocalteu’s method. The suggested experimental design allowed the acquisition of aqueous extracts of ginger with diverse antioxidant activity (100–555 mg Trolox/100 g, 147–1237 mg Fe²⁺/100 g and 50–332 mg gallic acid/100 g). Temperature was the determining factor in the extraction of components with antioxidant activity, regardless of time and sample quantity. The optimal physical conditions that allowed the highest antioxidant activity were: 90 °C, 15 min and 2 % of the sample. The correlation value between the antioxidant activity by ferric reducing antioxidant power assay and the content of total phenolics was R²?=?0.83. The experimental design applied allowed the determination of the physical conditions under which ginger aqueous extracts liberate compounds with antioxidant activity. Most of them are of the phenolic type as it was demonstrated through the correlation established between different methods used to measure antioxidant capacity.     

Gender, rural households, and biodiversity in native Mexico

Knowledge about maize varieties is the key to rural households' survival in native Mexico. Native peoples relate to nature in particular ways and they play a crucial role in maintaining biodiversity. This paper discusses the relationship between native women's accumulated knowledge on maize varieties and the laboratory analysis of the species that they manage. Fieldwork was conducted in an Otomí community, San Pablo Arriba, located in the state of Mexico. This revised version was published online in June 2006 with corrections to the Cover Date.     

Sorption Behavior of 4-Chlorophenol from Aqueous Solutions By a Surfactant-modified Mexican Zeolitic Rock in Batch and Fixed Bed Systems

The removal of 4-chlorophenol from aqueous solutions by both a Mexican clinoptilolite-heulandite zeolitic rock and the modified zeolitic material with the surfactant hexadecyltrimethylammonium bromide (HDTMABr), using batch and packed-bed (column) configurations, was investigated. The unmodified zeolitic rock did not show any adsorption of 4-chlorophenol. The effects of pH, contact time and concentration of 4-chlorophenol on the adsorption process by the surfactant modified material were examined. The sorption of 4-chlorophenol was not affected by the pH range from 4 to 9.5. 4-chlorophenol retention reached equilibrium in about 18 h and the rate of 4-chorophenol adsorption by the modified material was faster in the first 10 h than later. The experimental data were treated with the models: pseudo-first order, pseudo-second order, fractional power and Elovich models. Although, the last three gave correlation coefficients higher than 0.96, the pseudo-second order model was the best to describe the reaction rate. The experimental data follow a linear isotherm which is characteristic for sorption of organic solutes by the partition mechanism. The Bed Depth-Service Time Model was applied to the sorption results in order to model the column operation. The results showed that the surfactant modified zeolitic rock could be considered as a potential adsorbent for 4-chlorophenol removal from aqueous solutions.