Assessing strategies to reconcile agriculture and bird conservation in the temperate grasslands of South America

Globally, agriculture is the greatest source of threat to biodiversity, through both ongoing conversion of natural habitat and intensification of existing farmland. Land sparing and land sharing have been suggested as alternative approaches to reconcile this threat with the need for land to produce food. To examine which approach holds most promise for grassland species, we examined how bird population densities changed with farm yield (production per unit area) in the Campos of Brazil and Uruguay. We obtained information on biodiversity and crop yields from 24 sites that differed in agricultural yield. Density–yield functions were fitted for 121 bird species to describe the response of population densities to increasing farm yield, measured in terms of both food energy and profit. We categorized individual species according to how their population changed across the yield gradient as being positively or negatively affected by farming and according to whether the species’ total population size was greater under land‐sparing, land‐sharing, or an intermediate strategy. Irrespective of the yield, most species were negatively affected by farming. Increasing yields reduced densities of approximately 80% of bird species. We estimated land sparing would result in larger populations than other sorts of strategies for 67% to 70% of negatively affected species, given current production levels, including three threatened species. This suggests that increasing yields in some areas while reducing grazing to low levels elsewhere may be the best option for bird conservation in these grasslands. Implementing such an approach would require conservation and production policies to be explicitly linked to support yield increases in farmed areas and concurrently guarantee that larger areas of lightly grazed natural grasslands are set aside for conservation.     

Farmers' perceptions of constraints to plantain production in Ghana

SUMMARY

Plantain (Musa AAB), a primary food crop in Ghana, is a key component in sustainable agricultural systems in high rainfall zones. Recently, there has been a substantial yield decline and reduction in plantation life. To elucidate the context in which intervention strategies should be developed, a Participatory Rural Appraisal (PRA) was conducted at five villages in the major plantain-producing belt of Ghana. The importance of plantain as a preferred food was confirmed, although farmers tended to sell plantain for cash income, using cheaper, less preferred alternatives for home consumption. Farmers identified decreasing soil fertility, the high cost of labour for weeding, pests and diseases, lack of good quality planting material and marketing-related issues as the major production constraints. Due to declining productivity in less fertile regions, plantain has been replaced with other food crops such as cassava and maize. Farmers overestimated the importance of insect pests but were unaware of the extensive damage that could be caused by nematodes and the foliar disease, black sigatoka. They observed, however, that pest damage is more severe when soil fertility is poor. Clearly, integrated pest management is likely to be most effective when practiced within the context of cropping systems management; sustainable strategies that are being developed for resource-limited plantain farmers in Ghana are discussed.     

GIS and remote sensing as tools for conducting geo-hazards risk assessment along Gulf of Aqaba coastal zone,Egypt

Satellite remote sensing data, in addition to Geographic Information Systems (GIS), offers an excellent alternative to conventional mapping techniques in monitoring and mapping of geo-hazards areas. One of the most sustainable development projects in Egypt has been accomplished in Sinai, especially along and around the Gulf of Aqaba and the Gulf of Suez. Variations along the coastal zone of the Gulf of Aqaba have been identified through the analysis of multi-temporal satellite images with the aid of GIS analysis. The study area is subject to rapid and increasing changes in land-use/land-cover that resulting from natural and human activities such as flash flooding, seismic activity, landslides, and tourist and urban activities. This is in addition to the construction projects of roads, ports, PowerStation stations, mineral exploration, beaches, and tourist villages resulting from major environmental impacts. The current study aims to use Remote Sensing and GIS tools to investigate, monitor, and assess geo-hazards through the building of a geographical database. Several techniques have been developed over the last decade mostly to study the geological and geomorphologic characteristics of the terrain; land-use and land-cover changes. These are based on satellite imagery and Digital Elevation Models (DEM) to determine the topographic features, and geo-hazards maps. It is concluded that integrated approaches to monitoring can successfully be used to assess the environmental impacts along the Gulf of Aqaba coastal zone.     

Terrestrial vertebrates alter seedling composition and richness but not diversity in an Australian tropical rain forest

Although birds and mammals play important roles in several mechanisms hypothesized to maintain plant diversity in species-rich habitats, there have been few long-term, community-level tests of their importance. We excluded terrestrial birds and mammals from fourteen 6 x 7.5 m plots in Australian primary tropical rain forest and compared recruitment and survival of tree seedlings annually over the subsequent seven years to that on nearby open plots. We re-censused a subset of the plots after 13 years of vertebrate exclusion to test for longer-term effects. After two years of exclusion, seedling abundance was significantly higher (74%) on exclosure plots and remained so at each subsequent census. Richness was significantly higher on exclosure plots from 1998 to 2003, but in 2009 richness no longer differed, and rarefied species richness was higher in the presence of vertebrates. Shannon's diversity and Pielou's evenness did not differ in any year. Vertebrates marginally increased density-dependent mortality and recruitment limitation, but neither effect was great enough to increase richness or diversity on open plots relative to exclosure plots. Terrestrial vertebrates significantly altered seedling community composition, having particularly strong impacts on members of the Lauraceae. Overall, our results highlight that interactions between terrestrial vertebrates and tropical tree recruitment may not translate into strong community-level effects on diversity, especially over the short-term, despite significant impacts on individual species that result in altered species composition.     

Corrections for measurements of tritium in subterranean vapor using silica gel

Hazardous contaminants buried within vadose zones can accumulate in soil gas. The concentrations and spatial extent of these contaminants are measured to evaluate potential transport to groundwater for public risk evaluation. Tritium is an important contaminant found and monitored for in vadose zones across numerous sites within the US nuclear weapons complex, including Los Alamos National Laboratory. The extraction, collection, and laboratory analysis of tritium from subterranean soil gas presents numerous technical challenges that have not been fully studied. Particularly, the lack of moisture in the soil gas in the vadose zone makes it difficult to obtain enough sample (e.g., >5 g) to provide for the required measurement sensitivity, and often, only small amounts of moisture can be collected. Further, although silica gel has high affinity for water vapor and is prebaked prior to sampling, there is still sufficient residual moisture in the prebaked gel to dilute the relatively small amount of sampled moisture; thereby, significantly lowering the ??true?? tritium concentration in the soil gas. This paper provides an evaluation of the magnitude of the bias from dilution, provides methods to correct past measurements by applying a correction factor (CF), and evaluates the uncertainty of the CF values. For this, 10,000 Monte Carlo calculations were performed, and distribution parameters of CF values were determined and evaluated. The mean and standard deviation of the distribution of CF values were 1.53 ± 0.36, and the minimum, median, and maximum values were 1.14, 1.43, and 5.27, respectively.     

Exploring the influence of outdoor recreation participation on pro-environmental behaviour in a demographically diverse population

This study used structural equation modelling to examine the effects of socio-demographic variables and outdoor recreation participation on pro-environmental behaviour (PEB) among an ethnically diverse population of adult state-park visitors near Atlanta, Georgia, USA (N?=?319). Data collected through intercept surveys at three state parks were used to examine interactions among potential predictors of PEB, including socio-demographics (ethnicity, gender, education, and income), outdoor recreation participation (during childhood and adulthood), and environmental value orientations (biocentric and anthropocentric). The best fitting model accounted for 40% of the variance in self-reported PEB and indicated the strongest positive relationship between adult outdoor recreation participation and PEB (β?=?0.54, t?=?5.70). Biocentric and anthropocentric value orientation scores were also significant antecedents of PEB (β?=?0.17, t?=?1.99, and β?=?0.19, t?=?2.56, respectively), and both were influenced by socio-demographic variables. Overall, results suggest that a diverse public's environmental ethos and propensity to engage in PEBs could be influenced by outdoor recreation opportunities.     

A critical evaluation of combustible/explosible dust testing methods – Part 1

Tests were conducted by the Center for Agricultural Air Quality Engineering and Science (CAAQES) and by Safety Consulting Engineers Inc. (SCE) to determine if dust found in cotton gins (gin dust) would serve as fuel for dust explosions. In other words, is gin dust explosible? The laboratory tests used by CAAQES and SCE are very different. SCE used a totally enclosed 20 liter (L) chamber, flame from a 10,000 J (10 kJ) ignition source, reported that gin dust was a class ‘A’ explosible dust. CAAQES used a 28.3-L (1 ft³) chamber with diaphragm, a stationary coil as the igniter, video and pressure recordings of each test and concluded that gin dust was not explosible. SCE followed the protocols specified by ASTM E1226 and E1515. The only indicator used to determine whether a deflagration occurred during a test was pressure. If the pressure rise exceeded one bar gage (g) in a 20-L chamber test with a flame from a 10 kJ energy source as the igniter, it was assumed that a deflagration occurred in the chamber and the dust was classified as explosible (ASTM E1226-05, 2005). The CAAQES criterion for determining if a dust was explosible consisted of determining the minimum explosive concentration (MEC). If the MEC existed using the CAAQES test system, it was explosible! The criteria used with the CAAQES method for determining the MEC was to test concentrations starting at concentrations above the MEC and lowering the concentrations until at least one of the three tests at that concentration failed to result in a deflagration. The indicators of a deflagration were (1) bursting of a diaphragm, (2) flame front leaving the chamber and (3) characteristic pressure vs. time curve.It was concluded that the ASTM method of using only pressure as the indicator of a deflagration in a totally enclosed chamber would likely result of an “over-driven” test and an incorrect finding that gin dust was explosible. The result of CAAQES testing was that gin dust was not explosible.