COMBINING PHOTOGRAPHY AND A GEOGRAPHIC INFORMATION SYSTEM TO MEASURE WINTER BROWSE USE

Browse use surveys such as the twig-length method typically used to assess browsing by ungulates are time-consuming and costly. Here, we describe a modification of the twig-length method that utilizes digital photography and a Geographic Information System (GIS) technique to quantify browse shoot removal. Linear regression analysis indicated that the cumulative shoot length (cm) and biomass removal (g) estimated with our indirect method was similar to direct measurements on Scouler’s willows (Salix scouleriana). Our results suggest that this indirect browse assessment procedure could reduce field time, presumably increase sample size and efficiency, and create a photographic record of each plant for long-term assessment of moose (Alces alces) browsing

Mini-review: Fostering comprehension and integration in mycorrhiza biology: conceptual scaffolding as an aid in teaching and exploration

The last decade has witnessed extraordinary progress in understanding molecular dialogues between partners of plant root mutualisms and, as such, a considerable amount of new information now needs to be integrated into an already significant body of literature. The topic of symbiosis has become difficult to explore in a teaching venue, as there is seemingly so much to discuss, and yet students are truly interested in the discipline because of its potential applications in conservation, sustainable agriculture and forestry. In this review targeted to instructors, senior students and scientists, we offer a means of teaching the symbioses between mycorrhizal fungi and vascular plants, whereby we propose a conceptual staircase with three levels of incremental learning difficulty. At the first level, we describe the fundamentals of mycorrhizas with special emphasis on the plant-fungus interface. At the second level, we focus on the pre-communication between the two partners. At the third level, we discuss the physiology of the interface in terms of agriculture and forestry. At the end of each level, we provide a short summary where the most important concepts have been outlined for an instructor. As well, throughout the text, we raise questions of interest to the field at large.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Combining leaf gas-exchange and stable carbon isotopes to assess mycoheterotrophy in three Pyroleae species.

The determination of extent of mycoheterotrophy (MH) in plants, primarily made through the use of stable isotope methods, has gained considerable attention in the last decade. The aim of this study was to characterize the photosynthetic rates (PS) and several gas-exchange parameters, as well as stable carbon isotope composition (δThe accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Calcium and pH co-restrict abundance of Drosera rotundifolia (Droseraceae) in a Central BC Sphagnum bog

The genus Drosera is represented in BC, Canada, by Drosera rotundifolia, Drosera anglica and their hybrid Drosera x obovata. All three can be found in Sphagnum bogs of central BC, including those within the Aleza Lake Research Forest (ALRF) located 60 km east of Prince George. Vegetation patterns in bogs are known to be correlated with light, water and nutrient gradients, and despite information being available on the influence of light and water on Drosera occurrence, little information is known about the role of nutrients. Here, we focused on a bog containing all three Drosera species to determine if nutrient levels are related to the abundance of the widespread species, D. rotundifolia. Univariate regression tree analysis between soil water chemistry and D. rotundifolia numbers indicates that D. rotundifolia is a calcifuge, preferring moderately-acidic soil pH (> 5.5) and relatively low calcium levels (The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Community structure of ericoid mycorrhizas and root-associated fungi of Vaccinium membranaceum across an elevation gradient in the Canadian Rocky Mountains

individuals were examined using culture-dependent sequencing and ARISA (automated ribosomal intergenic spacer analysis). Our results demonstrated that high elevation fungal communities, characterised by Rhizoscyphus ericae, differ from lower elevation communities, where Phialocephala fortinii was the most frequently isolated fungus. Co-occurrence analysis indicated that, overall, fungi tended to occur together more often than would be expected by chance. At the scale of the individual host plant, facilitation may play a more important role than competition in shaping fungal communities in these ecosystems.

Ectomycorrhizas and climate change

Climate changes have important consequences for plant communities and their root symbionts. The distribution of tree species within temperate, boreal and tropical biomes will be altered, as palaeoecological studies have demonstrated for previous climate change events. Predicted effects on ectomycorrhizal (ECM) associations include migration of host and symbiont, modification of interactions between plant and fungal species, and changes in the contribution of both partners to the global carbon cycle. Anthropogenic factors introduce new variables, affecting the ability of tree species and their fungal associates to disperse in response to climate change. Here we focus on how ECM fungi and their hosts respond to atmospheric CO2 enrichment, increasing temperatures, nutrient addition, species invasions, loss of biodiversity and anthropogenic land-use changes, particularly silviculture. All of these factors are key to understanding the impacts of climate change on the ECM symbiosis, and relevant future topics of research are presented

Enhanced biodegradation of petroleum hydrocarbons in the mycorrhizosphere of sub-boreal forest soils

Petroleum hydrocarbon (PHC) contamination is becoming more common in boreal forest soils. However, linkages between PHC biodegradation and microbial community dynamics in the mycorrhizosphere of boreal forest soils are poorly understood. Seedlings (lodgepole pine, paper birch, lingonberry) were established in reconstructed soil systems, consisting of an organic layer (mor humus, coarse woody debris, or previously oil-contaminated mor humus) overlying mineral (Ae, Bf) horizons. Light crude oil was applied to the soil surface after 4 months; systems were destructively sampled at 1 and 16 weeks following treatment. Soil concentrations of four PHC fractions were determined using acetone– hexane extraction followed by gas chromatography – flame ionization detection analysis. Genotypic profiles of root-associated bacterial communities were generated using length heterogeneity-PCR of 16S rDNA. Most plant–soil treatments showed significant loss in the smaller fraction PHCs indicating an inherent capacity for biodegradation. Concentrations of total PHCs declined significantly only in planted (pine-woody debris and birch-humus) systems (averaging 59% and 82% loss between 1 and 16 weeks respectively), reinforcing the importance of the mycorrhizosphere for enhancing microbial catabolism. Bacterial community structure was correlated more with mycorrhizosphere type and complexity than with PHC contamination. However, results suggest that communities in PHC-contaminated and pristine soils may become distinct over time

Host and habitat filtering in seedling root-associated fungal communities: taxonomic and functional diversity are altered in ‘novel’ soils

Climatic and land use changes have significant consequences for the distribution of tree species, both through natural dispersal processes and following management prescriptions. Responses to these changes will be expressed most strongly in seedlings near current species range boundaries. In northern temperate forest ecosystems, where changes are already being observed, ectomycorrhizal fungi contribute significantly to successful tree establishment. We hypothesised that communities of fungal symbionts might therefore play a role in facilitating, or limiting, host seedling range expansion. To test this hypothesis, ectomycorrhizal communities of interior Douglas-fir and interior lodgepole pine seedlings were analysed in a common greenhouse environment following growth in five soils collected along an ecosystem gradient. Currently, Douglas-fir’s natural distribution encompasses three of the five soils, whereas lodgepole pine’s extends much further north. Host filtering was evident amongst the 29 fungal species encountered: 7 were shared, 9 exclusive to Douglas-fir and 13 exclusive to lodgepole pine. Seedlings of both host species formed symbioses with each soil fungal community, thus Douglas-fir did so even where those soils came from outside its current distribution. However, these latter communities displayed significant taxonomic and functional differences to those found within the host distribution, indicative of habitat filtering. In contrast, lodgepole pine fungal communities displayed high functional similarity across the soil gradient. Taxonomic and/or functional shifts in Douglas-fir fungal communities may prove ecologically significant during the predicted northward migration of this species; especially in combination with changes in climate and management operations, such as seed transfer across geographical regions for forestry purposes

Short-term changes in spruce foliar nutrients and soil properties in response to wood ash application in the sub-boreal climate zone of British Columbia

Utilization of wood ash as a forest soil amendment in British Columbia could have numerous benefits, including potentially increasing tree growth. Two wood-derived bottom ashes (low carbon gasifier ash and high carbon boiler ash) were applied at 5000 kg ha-1 (dry weight equivalent) with urea (100 kg N ha-1), in a two-way factorial randomized block design across two (18- and 24-year-old) hybrid spruce (Picea glauca X engelmannii Parry x Engelm.) plantations in interior British Columbia. Changes in spruce foliar nutrients and selected soil properties were evaluated. After one growing-season, foliar Ca and S significantly increased in plots treated with ash, and foliar N significantly increased while foliar Mg and P significantly decreased in spruce treated with urea. In LFH horizons, soil pH, exchangeable base cations (Ca, Mg, K), strong acid extractable B and Ca significantly increased (pThe accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author