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Halifax, Canada

John J.,Dalhousie University | Kernaghan G.,Mount St Vincent University | Lundholm J.,Saint Marys University, Halifax
Urban Ecosystems | Year: 2016

The selection of plant species for use on green roofs has been based primarily on their ability to cope with the harsh climatic conditions of the urban rooftop environment. However, green roof plants must also survive in engineered substrates that often lack organic material and beneficial soil microorganisms such as mycorrhizal fungi. We review the literature on mycorrhizae in the context of green roof ecosystems, identifying aspects of green roof functioning that could be enhanced through the integration of mycorrhizal fungi. Although relatively few studies have addressed the influence of mycorrhizal symbiosis on green roof plants specifically, we include information from a variety of naturally occurring habitats with analogous growing conditions. The available literature suggests that the incorporation of mycorrhizal fungi can improve a number of green roof functional attributes, including plant diversity, drought resilience, leachate quality, nutrient use efficiency and carbon sequestration, all while reducing the need for external nutrient inputs. We present evidence that mycorrhizal fungi are of general benefit to green roof ecosystems, and can be effectively integrated into green roof design. We recommend methods for this integration and propose future research directions. © 2016 Springer Science+Business Media New York

John J.,Dalhousie University | Lundholm J.,Saint Marys University, Halifax | Kernaghan G.,Mount St Vincent University
Ecological Engineering | Year: 2014

Green roof plants must survive hot and dry conditions in low nutrient artificial growing media. Although soil microorganisms such as arbuscular mycorrhizal fungi (AMF) can ameliorate these constraints by increasing water and mineral uptake, virtually nothing is known about the microbes associated with the roots of green roof plants. We determined levels of AMF and dark septate endophyte (DSE) colonization of plants grown for four years on an experimental green roof in Halifax, Nova Scotia. Green roof plant species included the forb Solidago bicolor, the grasses Danthonia spicata and Poa compressa and the succulent Sedum acre. We also assessed root colonization of these same species, as well as three additional succulents (Sedum spurium, Rhodiola rosea and Hylotelephium telephium), collected from their natural habitats. We further assessed the inoculum potential of a commercial green roof substrate before and after the introduction of host plants. Levels of AMF colonization were similar within plant species, regardless of collecting location (roof or field). All plant species were colonized except for the succulent S. acre, which is commonly utilized as a green roof plant. The commercial growing medium contained extremely low levels of viable AMF propagules, but this increased significantly after planting with Solidago. Conversely, all species (from roof, field and bioassay) were well colonized by DSE, which appear to differ from the AMF with respect to their pattern of dispersal onto the green roof. Although the widespread use of non-mycorrhizal succulent species such as S. acre precludes the ecosystem services provided by the AMF symbiosis, the benefits of both succulent tissue and AMF could be obtained simultaneously with careful green roof plant selection. © 2014 Elsevier B.V.

Pottie I.R.,Memorial University of Newfoundland | Pottie I.R.,Mount St Vincent University | Nandaluru P.R.,Memorial University of Newfoundland | Bodwell G.J.,Memorial University of Newfoundland
Synlett | Year: 2011

Urolithin M7 was synthesized from 2-hydroxy-4-methoxybenzaldehyde in 8 steps and 48% overall yield. The key step was an inverse electron demand Diels-Alder (IEDDA) reaction between diene 10 and the enamine (7) derived from dimethoxyacetaldehyde and pyrrolidine, which generated the 6H-dibenzo[b,d]pyran- 6-one skeleton. © Georg Thieme Verlag Stuttgart - New York.

Kebli H.,University of Quebec | Drouin P.,University of Quebec | Brais S.,University of Quebec | Kernaghan G.,Mount St Vincent University
Microbial Ecology | Year: 2011

Coarse woody debris supports large numbers of saproxylic fungal species. However, most of the current knowledge comes from Scandinavia and studies relating the effect of stand or log characteristics on the diversity and composition of decomposer fungi have not been conducted in Northeastern Canada. Logs from five tree species were sampled along a decomposition gradient in nine stands representing three successional stages of the boreal mixed forest of Northwestern Quebec, Canada. Using a molecular fingerprinting technique, we assessed fungal community Shannon-Weaver diversity index, richness, and composition. We used linear mixed models and multivariate analyses to link changes in fungal communities to log and stand characteristics. We found a total of 33 operational taxonomic units (OTUs) including an indicator species for balsam fir (similar to Athelia sp.) and one found only in aspen stands (similar to Calocera cornea). Spruce logs supported the highest fungal Shannon-Weaver diversity index and OTU number. Our results support the hypothesis that log species influences fungal richness and diversity. However, log decay class does not. Stand composition, volume of coarse woody debris, and log chemical composition were all involved in structuring fungal communities. Maintaining the diversity of wood-decomposing communities therefore requires the presence of dead wood from diverse log species. © 2011 Springer Science+Business Media, LLC.

Tharamangalam J.,Mount St Vincent University
Economic and Political Weekly | Year: 2011

While agreeing with K P Kannan's remarks on the neglected agricultural scenario of Kerala ("Agricultural Development in an Emerging Non-Agrarian Regional Economy: Kerala's Challenges", 26 February 2011), this comment challenges the author's dismissal of food insecurity in Kerala as a myth.

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