Hair lichens are distinctive for their capillary growth and typically arboreal occurrence, especially in temperate and boreal forests. They consist of two morphogroups based on cortical pigments: a brown-black group with fungal melanin and a pale yellow-green group with usnic acid. Here we test the hypothesis that these morphogroups are ecologically distinct and thus appropriately regarded as functional groups. We examine their respective horizontal occurrence in the lower canopy of 60-year-old conifer forests on a 250 m tall volcanic cone in south-central British Columbia. Trees on open south-facing slopes and near the summit were found to support mainly melanic hair lichens (Bryoria and Nodobryoria), whereas more densely spaced trees on north-facing slopes and at the base had higher cover values of usnic lichens (especially Alectoria sarmentosa and Ramalina thrausta). The cover of melanic hair lichens was strongly correlated with canopy openness but not for their usnic counterparts. We suggest that investment in light-absorbing melanic pigments is an extreme form of specialization for high light, favouring persistence in dry, sun-exposed canopies of otherwise cool forests. By contrast, the cortex of pendent usnic hair lichens appears to facilitate optimum light transmission to underlying photobionts in shaded sites, though at the cost of sensitivity to light in open habitats, especially in rather dry regions.

Sedimentary charcoal particles from lakes are commonly used to investigate fire history. Fire-history reconstructions are based on measuring the surface area or counting the number of charcoal fragments in adjacent samples. Recently, the volume of charcoal particles was advised as a more accurate method for quantifying past charcoal production. Large charcoal datasets, used to synthesize global fire history, include these different types of charcoal measurements and implicitly assume that they provide comparable fire-history information. However, no study has demonstrated that this assumption is valid. Here we compare fire-frequency reconstructions based on measurements of charcoal area and number, and estimates of charcoal volume from two lake sediment records from the eastern Canadian boreal forest. Results indicate that the three proxies provide comparable fire-history interpretations when using a locally defined threshold to identify fire events.

The Ratcliff Site in southwestern Virginia lies in a small second-order stream valley filled with approximately 3.5 m of organic-rich deposits that contain bones of mammoth, mastodon, deer (or antelope), logs, and plant macrofossils. Radiocarbon analyses indicate the age of the organic-rich sediment ranges from > 44,000 to 29,100 14C yr BP, a time period with no fossil remains reported in this region of the Appalachians. Analyses of field observations, textural data, organic carbon content, and plant macrofossils indicate that the organic-rich sediments contain interbedded standing-water and debris-flow deposits. Up to 6 m of oxidized debris-flow sediments bury the organic-rich sediments. The presence of Rubus parviflorus (Thimble Berry) throughout the deposit indicates the site had a boreal environment from > 44,000 to 29,100 14C yr BP. Plant macrofossil evidence indicates the uplands had stands of spruce/jack-pine forests while the valley contained ponds and associated wetlands. Three debris flows occurred at the site between approximately 38,000 and 29,000 14C yr BP, suggesting a recurrence interval for major storms of approximately 3000 yr, even though the apparent stability of the boreal environment implies a climate not conducive to catastrophic rainstorms. This conflicting combination of features suggests that during the middle Wisconsinan this area experienced generally cool climates, dominated by polar air masses, but was punctuated by relatively brief warm periods marked by incursions of tropical air masses.

Land snails have been investigated isotopically in tropical islands and mid-latitude continental settings, while high-latitude locales, where snails grow only during the summer, have been overlooked. This study presents the first isotopic baseline of live snails from Fairbanks, Alaska (64°51’N), a proxy calibration necessary prior to paleoenvironmental inferences using fossils. δ13C values of the shell (– 10.4 ± 0.4‰) and the body (– 25.5 ± 1.0‰) indicate that snails consumed fresh and decayed C 3-plants and fungi. A flux-balance mixing model suggests that specimens differed in metabolic rates, which may complicate paleovegetation inferences. Shell δ18O values (– 10.8 ± 0.4‰) were ~ 4‰ higher than local summer rain δ18O. If calcification occurred during summer, a flux-balance mixing model suggests that snails grew at temperatures of ~ 13°C, rainwater δ18O values of ~– 15‰ and relative humidity of ~ 93%. Results from Fairbanks were compared to shells from San Salvador (Bahamas), at 24°51’N. Average (annual) δ18O values of shells and rainwater samples from The Bahamas were both ~ 10‰ 18O-enriched with respect to seasonal (summer) Alaskan samples. At a coarse latitudinal scale, shell δ18O values overwhelmingly record the signature of the rainfall during snail active periods. While tropical snails record annual average environmental information, high-latitude specimens only trace summer season climatic data.

To conserve biodiversity on forest landscapes, it is necessary to understand how incentives in an offset market affect the dynamics of habitat loss and restoration. In this study, a model of firm behaviour in a temporary biodiversity offset market is developed to understand the impact of offset rules on the dynamics of land use and offset policy costs and benefits for Alberta's boreal forest. Policy treatments include eligibility rules for restoration versus avoided loss; time lags for crediting restoration benefits; and geographic trading restrictions. The analysis highlights the assumptions and trade-offs embedded in offset principles such as additionality. Restoration-based policies, which require biodiversity benefits to be established prior to development, are over 200 times more costly than policies that include avoided loss. Geographic trading restrictions result in a significant redistribution of policy costs and ecological risks between regions, with little impact on aggregate policy costs and benefits. Including avoided loss results in a decline in biodiversity intactness by 2% to 2.2% compared to a decline of 3.6% under a no-offset policy. Increasing time lags for crediting restoration to match ecological recovery trajectories reduces restoration effort when policies include both restoration and avoided loss.

In 2009, a haplotype closely related to European strains of Echinococcus multilocularis was detected in a dog from the Quesnel region of British Columbia, Canada. We now report the establishment of this same haplotype in 7 coyotes (Canis latrans) trapped within 40 km of Quesnel, BC. In addition, 3 coyotes and 1 red fox (Vulpes vulpes) harboured adult cestodes morphologically compatible with that of E. multilocularis (overall prevalence 33% in 33 carnivores). None of 156 potential intermediate hosts, including 131 representatives of two highly suitable rodent species, Peromyscus maniculatus and Microtus pennsylvanicus, trapped from a region 120–210 km south of Quesnel were infected. This report confirms the establishment and local transmission of a European-type strain of E. multilocularis (the causative agent of human alveolar hydatid disease), in wildlife in a forested region of North America where this cestode had not been previously detected, with significance for public and animal health.

Alectorioid and foliose lichens were weighed from full-size branches of Picea abies cut at two canopy heights in 100 trees in an old subalpine forested area in eastern Norway. The mean lichen biomass per branch decreased from 46 to 37 g moving upwards from 2–3 to 5–6 m canopy height. The lichen biomass correlated strongly with branch size variables, branch diameter alone explaining 48 of the variation in lichen biomass per branch (n=200). The alectorioid/foliose biomass ratio increased from 0·149 at 2–3 m to 0·316 at 5–6 m. Site factors reflecting openness of the canopy were computed for the branch at 2–3 m in all trees. The alectorioid/foliose biomass ratio increased significantly with the indirect site factors, suggesting that light, or factors associated with light, determine the balance between these two growth forms in tree canopies. Within the alectorioid biomass component, genera with usnic acid (Alectoria, Usnea) decreased with height, whereas the genus Bryoria with melanic pigments increased. According to the literature, dark melanic pigments have higher visible light screening efficiency than the yellowish usnic acid. Such patterns suggest a functional role for cortical pigments in the niche differentiation of alectorioid lichens.

The effects of two logging strategies and edge effects on cover and abundance of the epiphytic chlorolichens Cavernularia hultenii, Platismatia glauca and P. norvegica were studied in an experimentally logged boreal spruce forest. Whether lichen size distribution within the three species was affected by logging regimes was also tested. One hundred and ten branches were sampled at random within: (1) fine-grained clearcuts consisting of 23 cutblocks 0·25 ha each; (2) coarse-grained clearcuts consisting of 3 clearcuts 2·25 ha each; and (3) a control area.

Of the three species studied, C. hultenii was the most vulnerable to logging, with an abundance much lower in logged areas than in the control area. By contrast, P. glauca was equally abundant in the fine-grained area and in the control area, but significantly less abundant in the coarse-grained area where it seems to have been adversely affected by a pronounced edge effect. No such edge effect, however, was noted in the fine-grained area. Juvenile thalli of C. hultenii and P. glauca were less frequent in the coarse-grained area than in the fine-grained and control areas, suggesting that the juvenile stage might be more sensitive to logging than mature thalli. These results indicate that creation of large clearcuts (2·25 ha) may not be in accordance with the goal of maintaining population size in either C. hultenii or P. glauca. However, P. glauca does not seem to be negatively influenced by a fine-grained logging pattern. No effect of logging strategy or distance from the forest edge was observed on P. norvegica. It follows from the above that any management plans aimed at maintaining population size should be based on an understanding of ecology and life history gleaned from the area in question.

Les changements du zooplancton lacustre à la suite des feux et des coupes à blanc dans la forêt boréale ont été évalués en 1996 en comparant trois groupes de lacs du Québec méridional : 20 lacs de référence aux bassins versants non perturbés, 9 lacs ayant subi en 1995 des feux de forêt sur la majorité de leur bassin versant et 9 lacs ayant eu en 1995 une coupe à blanc sur une partie de leur bassin versant. Les communautés zooplanctoniques ont été caractérisées par différentes variables : 1) la composition, la richesse spécifique et la densité du zooplancton, 2) la masse organique du limnoplancton (seston > 53 µm) et 3) le biovolume du méso- et macrozooplancton (> 250 µm). La richesse spécifique et les assemblages d'espèces en juillet 1996 ne différaient pas entre les groupes de lacs ; la variation inter-réplicats dans les assemblages d'espèces de chaque lac était très faible en comparaison de la variation inter-lacs. Par contre, la densité du zooplancton et la masse organique du limnoplancton étaient en moyenne significativement plus élevées dans les lacs de feux que dans les lacs de coupes et les lacs de référence. Le biovolume du méso et macrozooplancton suivait les mêmes tendances. L'effet des traitements (groupes de lacs : référence, feu, coupe) expliquait moins de 15 % de la variance totale de la masse organique du limnoplancton et du biovolume du méso et macrozooplancton tandis que les différences inter-lacs expliquaient la majorité (> 70 %) de la variance totale dans ces indicateurs. Les 15 % de variance résiduelle étaient attribuables à la variation inter-réplicats dans chaque lac. Notre étude préliminaire indique que les feux de forêts provoquent une poussée trophique du zooplancton et du limnoplancton mais n'ont pas d'effet sur la biodiversité et les assemblages d'espèces de zooplancton. Par contre, les coupes de forêt n'accroissent pas la biomasse du zooplancton en dépit d'une légère augmentation des nutriments, car les apports plus importants en carbone organique dissous après la coupe limitent la production biologique. Les changements limnologiques d'un lac à l'autre ont beaucoup plus d'importance que les feux et les coupes de forêts dans le contrôle environnemental du zooplancton des lacs de la forêt boréale.

The 15N natural abundance and N concentrations of fruit bodies from 70 species (23 genera) of ectomycorrhizal fungi found in boreal forests are presented. Large intraspecific and intrageneric differences were found, e.g. 8·3‰ 15N in the species Dermocybe crocea and 12·6‰ in the genus Cortinarius. In addition, significant differences in both δ15N and %N were found between different parts of fruit bodies, with cap material giving consistently higher values. Proteins and amino acids were enriched by 9·7±0·4‰ (mean±1 SE) relative to chitin, irrespective of the part of the fruit body examined. Chitin had δ15N values similar to that of plant hosts. The higher δ15N and %N values of the caps than of the stipes probably reflect a higher portion of proteins and amino acids in the caps. The δ15N of mycorrhizal fungi can be a function of the N species used (organic N, NH4+, NO3−), the depth of soil at which the mycelium occurs, and metabolic fractionations. The metabolic fractionations, e.g. potential transaminations during the flux of N from the soil through the fungus to the plant, make it difficult, at present, to make inferences about sources of N based on δ15N values alone. No effect of sample drying temperature on δ15N values of fungal material was detected.