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431.
There is a growing assumption that payments for environmental services including carbon sequestration and greenhouse gas emission reduction provide an opportunity for poverty reduction and the enhancement of sustainable development within integrated natural resource management approaches. Yet in experiential terms, community-based natural resource management implementation falls short of expectations in many cases. In this paper, we investigate the asymmetry between community capacity and the Land Use Land Use Change Forestry (LULUCF) provisions of the Clean Development Mechanism within community forests in Cameroon. We use relevant aspects of the Clean Development Mechanism criteria and notions of “community capacity” to elucidate determinants of community capacity needed for CDM implementation within community forests. The main requirements are for community capacity to handle issues of additionality, acceptability, externalities, certification, and community organisation. These community capacity requirements are further used to interpret empirically derived insights on two community forestry cases in Cameroon. While local variations were observed for capacity requirements in each case, community capacity was generally found to be insufficient for meaningful uptake and implementation of Clean Development Mechanism projects. Implications for understanding factors that could inhibit or enhance community capacity for project development are discussed. We also include recommendations for the wider Clean Development Mechanism/Kyoto capacity building framework.  相似文献   
432.

Goal and Scope

Products based on fatty acids (including acetic acid) are known in plant protection since more than 100 years to control several harmful organisms. In the following decades, however, they lost their importance due to the rapid development of ‘modern’ chemical pesticides. In the meantime some trials were run to control weeds with relatively high doses. The knowledge on its ecotoxic effects on soil microorganisms as a part of the soil fertility, however, is still incomplete.

Methods

Under laboratory conditions two agricultural soils were treated with different dosages of two products based on acetic acid and pelargonic acid (=nonanoic acid) as well as with a biocidal reference compound (e.g. dinitrophenol herbicide). The applied dosages were related to the concentrations in soil reached after simulated penetration of practical field amounts into upper soil layers. In some cases green manuring was simulated by adding lucerne meal to the soil. During the incubation for several weeks biomass-related microbial activities (dehydrogenase activity, substrate-induced shortterm respiration) as well as the mineralization of carbon and nitrogen (including nitrification) were measured.

Results and Conclusion

As compared to ‘normal’ pesticides (e.g. the reference compound) the effects of both test substances on soil microorganisms showed different behaviour. Nearly none of the effects typical for strongly biocidal compounds, namely a dose-related inhibition of microbial biomass combined with a stimulated mineralization (especially of nitrogen), occurred with the fatty acid products. Depending on the marked input of organic carbon by the higher dosages of fatty acid products and their rapid decomposition, especially of acetic acid, an increase of biomass-related parameters and of carbon mineralization combined with a reduction of the available nitrate content (e.g biological nitrogen immobilization) occurred for several weeks. By combining the results of the soil with that of lucerne meal-amended soil ‘real effects’ can be distinguished from those depending on the decomposition of the introduced carbon. In comparison with the strongly biocidal reference compound the two fatty acid products not only caused little microbiological-ecotoxicological impacts on the soil, but often stimulated important microbiological parameters for some time.

Recommendation and Perspective

As result of the trials we recommend an extended microbiological-ecotoxicological test spectrum especially for those plant protection products (pesticides) which should be applied at high dosages or if they contain higher amounts of well decomposable organic substances. This is necessary to distinguish dose-related enhanced biocidal activities induced by biocidal effects (including the subsequent mineralization of the killed microorganisms) from ‘real’ stimulations directly produced by the substrate.  相似文献   
433.
Xue N  Seip HM  Guo J  Liao B  Zeng Q 《Chemosphere》2006,65(11):2468-2476
Distribution of Al-, Fe- and Mn-pools was investigated in five forest soil profiles (consisting of four horizons) in each of two Hunan catchments (BLT and LKS) where acid deposition has been considered critical. Al- and Fe-pools were higher in BLT than those in LKS, but Mn-pools much lower in BLT. Mn-pools vary from topsoils to bottom soils, but there are different trends for different Mn speciation. Al- and Fe-pools, except amorphous Feox, were positively correlated to contents of soil organic matter (OM) showed by the loss on ignition in the two catchments. Accumulation of Al- and Fe-pools may occur in the area where soil organic matter was enriched (e.g. in top soil and rhizosphere soil). However, no direct correlation is observed between Mn and OM. Acidic atmospheric deposition may affect transforming among speciations of Al-, Fe- and Mn-pools and leaching of soil Al, Fe and Mn through formation of soluble organo-metal dissolved Al which was potentially toxic, increased. There were significant correlations between Al-pools complexes or change of oxidation–reduction conditions. Mnex (exchangeable Mn) and Mnox (amorphous and organic Mn) were highly linearly correlation with soil pH values at LKS but at BLT. Under acid deposition, the availability of the nutrient Fe increased with the amount of dissolved Al, which was potentially toxic, in the two catchments. There are no significant correlations between Alex (exchangeable Al) and Mnex, Feex (exchangeable Fe) and Mnex in this work, indicating potentially toxic Mn increase seldom accompanying with Al increase in the two catchments.  相似文献   
434.
Summary. Queens in colonies of the small myrmicine ant, Leptothorax gredleri Mayr 1855 (Hymenoptera, Formicidae) engage in dominance interactions and form social hierarchies, in which typically only the top-ranking queen lays eggs. Occasionally, queen antagonism escalates to violent mandible fighting, during which the sting is used to apply Dufour gland secretions onto the cuticle of the opponent. Contaminated queens often are attacked by nestmate workers. Here we show that the chemical composition of the Dufour gland is colony-specific and that workers can discriminate between secretions from their own and other colonies. Our findings suggest that Dufour gland secretions are involved in the establishment of hierarchies within a colony. When invading an alien colony the queen presumably employs the secretions during the expulsion of the resident queen. Apparently, Dufour gland secretions play a role in intraspecific queen competition similar to that in slave-making and inquiline formicoxenine ants, where they function as "propaganda substances" in an interspecific context. Received 7 July 1998; accepted 15 September 1998.  相似文献   
435.
Summary People have been living on the Australian continent for at least 40 000 years, possibly longer. Many significant environmental changes in climate, flora and fauna have occurred during that period of human occupation. Availability of water has been a constant concern. It was sought after, of necessity, due to the fairly consistent low precipitation rate throughout the continent, both along the coast, as well as inland to the very arid, dry desert area. From earliest times, ingenious methods of water resources exploitation were practised. There are significant examples of fish and eel trap systems in western Victoria. Another important fish trap exists at Brewarrina, in New South Wales. Coastal fish traps are in existence along many suitable seaboard locations, from the east coast to the west. Water, retained in naturally occurring rock pools, was extensively exploited. An important source of water, particularly in the arid inland was from the so called native wells. These wells sustained a great number of the white explorers in the 1840s to 1880s, amongst them Ludwig Leichhardt and Ernest Giles. Some interesting native wells, in former Aboriginal occupation sites, have even been traced in the Simpson Desert. The construction of the hydraulic structures which have remained in existence were carried out using simple tools and limited materials. A culture existed with the technical sophistication, ingenuity and skills to satisfy the water needs of the people in the environment of an arid continent over several thousand years.Hans Bandler is both an Editorial Board member and a Civil and Environmental Engineering consultant.  相似文献   
436.
Passive samplers were used to monitor ammonia concentrations at rural inner alpine and pre-alpine, as well as urban, sites in Austria and Bavaria. Elevated concentrations were measured both at farms (up to 36 microg NH3 m(-3)) and at urban locations (up to 28 microg NH3 m(-3)). At urban locations a linear relationship between the traffic density and the NH3 concentration was found, but there was no marked seasonal trend. The highest ammonia concentrations were measured in a traffic tunnel (up to 78 microg NH3 m(-3)). The presence of livestock breeding or small scale alpine pastures resulted in elevated concentrations at the rural sites (8.1-12 and 2.5-4.6 microg NH3 m(-3), respectively), compared to the surrounding areas (3.1 and 0.9 microg NH3 m(-3)). Agriculture related sources are usually limited either spatially or seasonally. As the emissions were moderate in our case, a rapid removal and dilution of ammonia was possible and therefore the NH3 burden was only local. Sources related to traffic are more evenly distributed both geographically and seasonally. The WHO guideline, annual average concentration of 8 microg m(-3) for the protection of vegetation, was only exceeded at farms, at the urban station with the heaviest traffic and in the Tauerntunnel.  相似文献   
437.
438.
An increasing number of studies indicate that marine mammals and some seabirds are exposed to organotins. However, results from northern and Arctic areas are few. Here results from analysis of tributyltin (TBT), dibutyltin (DBT), monobutyltin (MBT), triphenyltin (TPhT), diphenyltin (DPhT) and monophenyltin (MPhT) in harbour porpoise (Phocoena phocoena), common seal (Phoca vitulina), ringed seal (Phoca hispida) and glaucous gull (Larus hyperboreus) from Norwegian territory are presented. Relatively high concentrations of DBT, TBT and MBT were observed in muscle, kidney and liver from harbour porpoises caught in northern Norway in 1988, just before restrictions on the use of tributyltin (TBT)(mainly on small boats) were introduced in several European countries. The concentrations in harbour porpoise muscle tissue were reduced significantly 11 years later, possibly as a result of the introduced restrictions. Considerably lower concentrations of butyltins were observed in the seals compared to porpoises. The lowest levels of organotins were found in ringed seals from Spitsbergen, where only traces of dibutyltin (DBT) and monobutyltin (MBT) were observed. Traces of DBT and MBT were also found in some individual glaucous gulls from Bear Island. The sum of the degradation products MBT and DBT in liver samples from all analysed species were generally higher than TBT itself. Triphenyltin (TPhT) was observed in all porpoise samples and in livers of common seals. Also the sum of the degradation products MPhT and DPhT in liver samples from porpoise and common seals were higher than TPhT. No traces of phenyltins were found in ringed seals from Spitsbergen or in glaucous gulls from Bear Island. The limited data available indicate low to moderate exposure to organotins in northern areas (Spitsbergen and Bear Island). Marine mammals are however more exposed further south along the Norwegian Coast.  相似文献   
439.
Two test methods are presented to assess the cytotoxicity of chemicals. On one hand the protozoonTetrahymena pyriformis and on the other the bacteriumPseudomonas aeruginosa is cultured in defined media containing the test chemicals. Test parameter is the quantity of living cells surviving exposure. The conversion of the tetrazolium salt MTT into formazan is equivalent to cell viability. A mixture of detergent and isopropanol is used to dissolve the blue formazan which is not soluble in water, prior to photometric measurement. For cetyltrimethylammonium bromide, benzyldimethyldodecylammonium chloride, dodecylbenzenesulfonic acid sodium salt, potassium dichromate, 4-toluenesulfonic acid sodium salt, and 4-nitrophenol the EC50-values (mol/l) in theTetrahymena pyriformis- (Pseudomonas aeruginosa) test system were: 10?5,81 (10?5,08); 10?4,68) (10?3,80; 10?4,50 (10?4,14); 10?3,97 (10?5,11); 10?2,71 (10?2,50) and 10?4,00 (10?3,64). — With the assays described here it is possible to measure a large number of samples by quick and simple means.  相似文献   
440.
We developed logistic regression models from data on biotic and abiotic variables for 172 sites on Banks Peninsula, New Zealand, to predict the probability of occurrence of two diadromous fish, banded kokopu (Galaxias fasciatus) and koaro (G. brevipinnis). Banded kokopu occurrence was positively associated with small streams and low-intensity land uses (e.g., sheep grazing or forested), whereas intensive land uses (e.g., mixed sheep and cattle farming) and lack of riparian forest cover impacted negatively on occurrence at sampled sites. Also, if forests were positioned predominantly in lowland areas, banded kokopu occurrence declined with increasing distance to stream mouth. Koaro occurrence was positively influenced by catchment forest cover, high stream altitudes, and areas of no farming activity or mixed land uses. Intensive land uses, distance to stream mouth, and presence of banded kokopu negatively influenced koaro occupancy of stream reaches. Banded kokopu and koaro presence was predicted in 86.0% and 83.7% agreement, respectively, with field observations. We used the models to quantify the amount of stream reaches that would be of good, moderate, and poor quality, based on the probability of occurrences of the fish being greater than 0.75, between 0.75 and 0.5, or less than 0.5, respectively. Hindcasting using historical data on vegetation cover undertaken for one catchment, Pigeon Bay, showed they would have occupied most of the waterway before anthropogenic modification. We also modeled potential future scenarios to project potential fish distribution.  相似文献   
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