Molecular Genetics of Pre-1940 Red Wolves

Conservation of the endangered red wolf (Canis rufus) has become a controversial issue because its genetic and morphological composition has been altered by hybridization with coyotes (C. latrans) and possibly gray wolves (C. lupus) making its evolutionary origins difficult to ascertain. The evolutionary hypothesis based on morphological data is that the red wolf had an Early Pleistocene origin and was the predecessor of both modern coyotes and gray wolves. After 1940 red wolves hybridized with coyotes as the species vanished from the wild. In contrast to this ancient origin-recent introgression hypothesis, molecular data are more consistent with an origin through hybridization between gray wolves and coyotes. Interspecific hybridization may have occurred repeatedly over time prior to European settlement in the southcentral United States or may have been induced recently by anthropogenic changes. We review recent molecular evidence and present new results from the analysis of mitochondrial and nuclear DNA markers in pre-1940 populations of red wolves. Our results are inconsistent with an ancient origin of the red wolf and support the hybridization model. We discuss possible hybridization scenarios and reasons for the red wolf reintroduction program to be concerned with the effects of genetic introgression from coyotes.     

Euro Chlor Risk Assessment for the Marine Environment Osparcom Region: North Sea - 1,2-Dichloroethane

This risk assessment on 1,2-dichloroethane (EDC) was carried out specifically for the marine environment, according to the methodology laid down in the EU risk assessment Regulation (1488/94) and the Guidance Document of the EU New and Existing Substances Regulation (TGD, 1997). The study consists of the collection and evaluation of data on effects and environmental concentrations from analytical monitoring programs in large rivers and estuaries in the North Sea area. The risk is indicated by the ratio of the "predicted environmental concentrations" (PEC) and the "predicted no effect concentrations" (PNEC) for the marine aquatic environment. In total, 21 studies for fish, 17 studies for invertebrates and 7 studies for algae have been evaluated. Both acute and chronic toxicity studies have been taken into account and the appropriate assessment factors have been used to define a PNEC value of 1100 µg/l. Most of the available monitoring data apply to rivers and estuaries and were used to calculate PECs. The most recent data (1991-1995) support a typical PEC of 0.5 µg EDC/l and a worst case PEC of 6.4 µg EDC/l. The calculated PEC/PNEC ratios give a safety margin of 170 to 2200 between the predicted no effect concentration and the exposure concentration. Additional evaluation of environmental fate and bioaccumulation characteristics showed that no concern is expected for food chain accumulation.     

Removal of color from real textile dyeing effluent utilizing tannin immobilized jute fiber as biosorbent: optimization with response surface methodology

Environmental Science and Pollution Research - The present study explored an efficient technoeconomic method for treating intensely colored dyeing effluents from a commercial source. Firstly, the...     

Governing intensification: the influence of state institutions on smallholder farming strategies in Calakmul,Mexico

ABSTRACT

In forest frontiers, smallholder agrarian livelihoods remain uneasily juxtaposed with conservation interests. Agricultural intensification is often considered a viable means of reconciling competing environmental and livelihood objectives given its potential to concentrate production on less land. However, intensification may have unintended consequences, including loss of resilient agricultural systems. The risks of smallholder agricultural intensification warrant a better understanding of its drivers. This study uses the case of Calakmul, Mexico, to examine the critical role of the state in intensification processes. Drawing on household surveys and key-informant interviews, it traces the linkages between state institutions and local farming practices. Statistical and qualitative analyses reveal how intensification is both incentivized and imposed by prevailing policies, the former via subsidies and the latter via regulations against field rotations. The outcome – increased external inputs and longer cultivation periods between fallows – may undermine the sustainability of smallholders’ agroecosystems, an undesirable consequence amid limited livelihood alternatives.     

Artifact evidence in carbonyl compound sampling using the enclosure technique with cuvette system

Biogenic hydrocarbon emission rates from individual plant species have been estimated experimentally placing small plants or branches in enclosures and measuring the emission rates of the compounds. All-Teflon chambers (cuvettes) where air samples are drawn through tubes packed with adsorbents, have been commonly used for plant enclosure. Sampling of carbonyl compounds emitted from plants has been done using 2,4-dinitrophenylhydrazine coated particles and the derivative carbonyl compounds have been analyzed by HPLC-UV. In this work, the enclosure technique using a cuvette for measurements of carbonyl compound emissions from plants was evaluated. Blank measurements in an empty cuvette have revealed quite different results for experiments performed under laboratory and field conditions. Rigorous univariate statistical analysis of the data obtained indicate that the analytical procedure to determine carbonyl compounds at trace levels in emission samples using the cuvette may lead to positive artifacts during field sampling. This analysis applied to laboratory measurements showed no difference in the results for the cuvette and external lines. Multivariate statistical calculations point out that solar light intensity accounts for the high carbonyl compound levels, especially for acetaldehyde, in the empty cuvette.     

Influence of elevated carbon dioxide and temperature on belowground carbon allocation and enzyme activities in tropical flooded soil planted with rice

Changes in the soil labile carbon fractions and soil biochemical properties to elevated carbon dioxide (CO₂) and temperature reflect the changes in the functional capacity of soil ecosystems. The belowground root system and root-derived carbon products are the key factors for the rhizospheric carbon dynamics under elevated CO₂ condition. However, the relationship between interactive effects of elevated CO₂ and temperature on belowground soil carbon accrual is not very clear. To address this issue, a field experiment was laid out to study the changes of carbon allocation in tropical rice soil (Aeric Endoaquept) under elevated CO₂ and elevated CO₂ + elevated temperature conditions in open top chambers (OTCs). There were significant increase of root biomass by 39 and 44 % under elevated CO₂ and elevated CO₂ + temperature compared to ambient condition, respectively. A significant increase (55 %) of total organic carbon in the root exudates under elevated CO₂ + temperature was noticed. Carbon dioxide enrichment associated with elevated temperature significantly increased soil labile carbon, microbial biomass carbon, and activities of carbon-transforming enzyme like β-glucosidase. Highly significant correlations were noticed among the different soil enzymes and soil labile carbon fractions.     

1,1,1-Trichloroethane Marine Risk Assessment with Special Reference to the Osparcom Region: North Sea

This risk assessment on 1,1,1-trichloroethane was carried out specifically for the marine environment, accordingly to the methodology laid down in the EU risk assessment Regulation (1488/94) and the Guidance Document of the EU New and Existing Substances Regulation (TGD, 1996). 1,1,1-trichloroethane is being phased out of most uses because of its ozone depletion potential (ODP) under the Montreal Protocol. Production for emissive uses has already been phased out end 1995 in Europe and 1996 in the United States, Japan and other industrial countries. The risk assessment study consists of the collection and evaluation of data on effects and environmental concentrations from analytical monitoring programmes in large rivers and estuaries in the North Sea area. The risk is indicated by the ratio of the Predicted Environmental Concentration (PEC) and the Predicted No-Effect Concentration (PNEC) for the marine aquatic environment. In total 14 studies for fish, 7 studies for invertebrates and 9 studies for algae have been evaluated. Both acute and chronic studies have been taken into account and the appropriate assessment factors have been used to calculate a PNEC value of 21 microg/l based on long term exposure. The PEC was derived from monitoring data. The PEC was set at 0.206 microg/l (worst case) and 0.024 microg/l (typical case) for coastal waters and estuaries and 0.6 microg/l (worst case) and <0.1 microg/l (typical case) for river waters. The calculated PEC/PNEC ratios, which do not take into account any dilution factor within the sea, correspond to a safety margin of 35 to 1000 between the aquatic effect and the exposure concentration. 1,1,1-trichloroethane is not a 'toxic, persistent and liable to bioaccumulate' substance according to the criteria as mentioned by the Oslo and Paris Conventions for the Prevention of Marine Pollution (OSPAR-DYNAMEC). It can be concluded that the present use of 1,1,1-trichloroethane does not present a risk to the marine aquatic environment.     

Decreasing reliance on mineral nitrogen--yet more food

Higher crop production normally demands higher nutrient application rates and consequently increased mineral nitrogen use. With food demand for 2030 estimated around 2800 mill. tonnes (t) yr-1, the corresponding mineral N consumption figure is 96 mill. t (78 mill. t yr-1 in 1995/1997). Global-level mineral N losses to the environment from mineral fertilizer use are currently 36 mill. t yr-1, worth USD 11,700 mill. and with adverse environmental impacts. However, innovative fertilizer-use efficiency (FUE) technologies enable increased production with a less than a proportionate increase in mineral-N use. Moreover, nitrogen-nutrient supplies can be augmented through improvements in agricultural production systems and in the exploitation of alternative sources such as biological nitrogen fixation (BNF). By 2030, with adequate policy, technology transfer, research and investment support, the on-farm adoption of BNF and FUE technologies could generate savings of 10 mill. t yr-1 of mineral N, worth USD 3300 mill.     

Assessing Landscape Functions with Broad-Scale Environmental Data: Insights Gained from a Prototype Development for Europe

We examine the advantages and disadvantages of a methodological framework designed to analyze the poorly understood relationships between the ecosystem properties of large portions of land, and their capacities (stocks) to provide goods and services (flows). These capacities (stocks) are referred to as landscape functions. The core of our assessment is a set of expert- and literature-driven binary links, expressing whether specific land uses or other environmental properties have a supportive or neutral role for given landscape functions. The binary links were applied to the environmental properties of 581 administrative units of Europe with widely differing environmental conditions and this resulted in a spatially explicit landscape function assessment. To check under what circumstances the binary links are able to replace complex interrelations, we compared the landscape function maps with independently generated continent-wide assessments (maps of ecosystem services or environmental parameters/indicators). This rigorous testing revealed that for 9 out of 15 functions the straightforward binary links work satisfactorily and generate plausible geographical patterns. This conclusion holds primarily for production functions. The sensitivity of the nine landscape functions to changes in land use was assessed with four land use scenarios (IPCC SRES). It was found that most European regions maintain their capacity to provide the selected services under any of the four scenarios, although in some cases at other locations within the region. At the proposed continental scale, the selected input parameters are thus valid proxies which can be used to assess the mid-term potential of landscapes to provide goods and services.