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Montréal, Canada

Tremblay S.,University of Quebec at Montreal | Lucotte M.,University of Quebec at Montreal | Reveret J.-P.,University of Quebec at Montreal | Davidson R.,Biodome de Montreal | And 3 more authors.
Agroforestry Systems

Agroforestry systems are widely recognized as an important way to address numerous environmental challenges in tropical areas. They represent a sustainable alternative form of land-use for small-scale agriculture, responding to the economic development needs of communities and offering a number of ecosystem services. This article presents an evaluation of the short- and medium-term profitability of two experimental agroforestry systems where fruit trees are predominant, which were established in 2009 in the Tapajós region of the Brazilian Amazon, state of Pará. An analysis of net present value (NPV) confirms that the two experimental systems studied recover their total implementation and operating costs within a 20 years time horizon. These results underlie that prices of inputs are stable and farmers have access to markets, credit, and agricultural knowledge. The two experimental systems are compared to plots under traditional slash-and-burn cultivation, and Bragantino system. The results support changes to public policies in order to facilitate alternatives to slash-and-burn cultivation by supporting access to credit, knowledge of alternative agricultural practices, transportation systems, and industries that transform agricultural products. The consideration of ecosystem services should add a supplementary argument in favour of policies that promote agroforestry systems and thus limit the practice of slash-and-burn subsistence agriculture. © 2014, Springer Science+Business Media Dordrecht. Source

Comte I.,University of Quebec at Montreal | Lucotte M.,University of Quebec at Montreal | Davidson R.,Biodome de Montreal | Davidson R.,University of Quebec at Montreal | And 3 more authors.
Water, Air, and Soil Pollution

Many studies have shown the relationship between fire clearing and mercury contamination of aquatic ecosystems in the Brazilian Amazon. This study aimed at quantifying mercury content in long-time cultivated soils and at assessing the potential of a fire-free alternative clearing technique on mercury retention for long-time cultivated soils compared to traditional slash-and-burn. This case study included five land uses: one crop plot and one pasture plot cleared using slash-and-burn, one crop plot and one pasture plot cleared using chop-and-mulch, and one 40-year-old forest as a control. Low mercury concentrations were recorded in the surface horizon (24.83 to 49.48 ng g-1, 0-5 cm depth). The long-time cultivation (repeated burnings) of these soils triggered large mercury losses in the surface horizon, highlighted by high enrichment factors from surface to deeper horizons. The predominant effect of repeated burnings before the experimental implementation did not let us to distinguish a positive effect of the chop-and-mulch clearing method on soil mercury retention for crops and pastures. Moreover, some processes related to the presence of the mulch may favor mercury retention (Hg volatilization decrease, cationic sites increase), while others may contribute to mercury losses (cationic competition and dislocation, mobilization by the dissolved organic matter). © 2013 Springer Science+Business Media Dordrecht. Source

Auclair J.,INRS Institute Armand Frappier | Parent S.,Biodome de Montreal | Villemur R.,INRS Institute Armand Frappier
Microbial Ecology

Nitrate is a serious problem in closed-circuit public aquariums because its accumulation rapidly becomes toxic to many lifeforms. A moving bed biofilm denitrification reactor was installed at the Montreal Biodome to treat its 3,250-m3 seawater system. Naturally occurring microorganisms from the seawater affluent colonized the reactor carriers to form a denitrifying biofilm. Here, we investigated the functional diversity of this biofilm by retrieving gene sequences related to narG, napA, nirK, nirS, cnorB, and nosZ. A total of 25 sequences related to these genes were retrieved from the biofilm. Among them, the corresponding napA1, nirK1, cnorB9, and nosZ3 sequences were identical to the corresponding genes found in Hyphomicrobium sp. NL23 while the narG1 and narG2 sequences were identical to the two corresponding narG genes found in Methylophaga sp. JAM1. These two bacterial strains were previously isolated from the denitrifying biofilm. To assess the abundance of denitrifiers and nitrate respirers in the biofilm, the gene copy number of all the narG, napA, nirS, and nirK sequences found in biofilm was determined by quantitative PCR. napA1, nirK1, narG1, and narG2, which were all associated with either Methylophaga sp. JAM1 or Hyphomicrobium sp. NL23, were the most abundant genes. The other genes were 10 to 10,000 times less abundant. nirK, cnorB, and nosZ but not napA transcripts from Hyphomicrobium sp. NL23 were detected in the biofilm, and only the narG1 transcripts from Methylophaga sp. JAM1 were detected in the biofilm. Among the 19 other genes, the transcripts of only two genes were detected in the biofilm. Our results show the predominance of Methylophaga sp. JAM1 and Hyphomicrobium sp. NL23 among the denitrifiers detected in the biofilm. The results suggest that Hyphomicrobium sp. NL23 could use the nitrite present in the biofilm generated by nitrate respirers such as Methylophaga sp. JAM1. © 2011 Springer Science+Business Media, LLC. Source

Fabianek F.,University of Quebec at Montreal | Gagnon D.,University of Quebec at Montreal | Delorme M.,Biodome de Montreal

In Quebec, Canada, 5 out of the 8 species of bats are considered potentially threatened or vulnerable. Measuring the impact on bat species of environmental changes brought about by urban development is crucial for bat species conservation. At which spatial scale does a gradient of increasing urbanization have the most significant effect on the distribution and activity of bats? To address this question, 3 sampling points in each of 24 green spaces (of different sizes, degree of naturalness, and presence or not of water) across Montréal Island were sampled over 3 separate nights in June and July 2006. Echolocation calls of bats were recorded with Anabat detectors. Bat activity was determined by species or group of species for each green space. Various habitat factors associated with the urban gradient were acquired using GIS along a range of spatial scales, from local to landscape scales (areas of 0.1 km to 2 km radius around sampling points). Results show that patterns of distribution and bat activity differ according to species. Bats of the Myotis genus and Perimyotis subflavus were found mostly in areas with a high percentage of forest cover and near running water. Eptesicus fuscus and Lasiurus cinereus appeared to be less selective, as they were distributed much more uniformly across the study area. The more local spatial scales (from 0.1 km to 0.5 km radius) seem to have had a predominant influence on habitat requirements of bats, particularly for forest-dwelling species. Source

Auclair J.,INRS Institute Armand Frappier | Lepine F.,INRS Institute Armand Frappier | Parent S.,Biodome de Montreal | Villemur R.,INRS Institute Armand Frappier
ISME Journal

Methylophaga spp. are methylotrophs commonly associated with marine environments and have been defined as strict aerobic methylotrophs. They have been shown previously to represent 50-70% of the bacterial population in the biofilm of the methanol-fed denitrification reactor treating a large seawater aquarium at the Montreal Biodome. It was therefore surprising to find such a high concentration of Methylophaga spp. in anoxic conditions. In this study, we showed by cultivation-independent and -dependent approaches that one Methylophaga strain present in the anoxic biofilm is involved in the denitrification process. DNA stable-isotope probing (SIP) experiments in which the biofilm was cultured under denitrifying conditions with 13C- methanol have revealed the enrichment of one particular taxon. By screening a 16S ribosomal RNA gene library derived from a 13C-DNA fraction of the SIP gradients, 62% of the library was composed of one sequence affiliated with the genus Methylophaga. One strain, named JAM1, representing this Methylophaga species was isolated. It grows aerobically but also under denitrifying conditions by reducing nitrate into nitrite. The nitrate-reducing activity was correlated with the presence and the expression of two highly divergent narG genes (narG1 and narG2). narG1 showed a high percentage of identity with the corresponding part of narG found in Thiobacillus denitrificans, which suggests a recent acquisition of narG in strain JAM1 by horizontal gene transfer. This study provides the first direct evidence of the adaptation of a Methylophaga species to an oxygen-limited environment. © 2010 International Society for Microbial Ecology. All rights reserved. Source

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