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Fabronia ciliaris (Fabroniaceae, Bryophyta) was recently discovered in the Great Lakes-St. Lawrence forest region in southeastern Manitoba. This collection represents the first record of the species in Canada and the northernmost extent of the species in North America. [ABSTRACT FROM AUTHOR]

Highlights: [•] Biological traits of bryophytes may indicate species’ responses to partial harvesting. [•] We used fourth-corner analysis to relate species’ traits to the forest environment. [•] Species’ traits were closely related to retention level and pre-harvest forest canopy. [•] Moisture loss after harvest was a strong environmental filter of species’ responses. [•] Sensitivity of species to harvesting may be informed by the traits they exhibit. [ABSTRACT FROM AUTHOR]

Abstract: Forest harvesting practices designed to conserve biodiversity require further insight into the relationship between species habitat requirements and how these are preserved after harvest. We examined the effects of different levels (10%, 50%, and 75%) of dispersed green-tree retention (unharvested stands as controls) on the diversity and composition of bryophytes 5–6years after partial harvesting. Bryophytes were sampled in six large (20m radius) plots in 24 forest stands (each 10ha) using a factorial experimental design with replication at the stand level. Sampled stands represented two mixedwood forest canopy types with contrasting abundances of broadleaf and coniferous trees before harvesting. Mosses and liverworts both responded to retention level and forest type but liverwort response was more pronounced. Liverwort richness and diversity were reduced at low (10% and 50%) retention, and composition differed between all harvested levels and the control. In comparison, mosses did not differ in richness or diversity among retention levels but at low retention composition differed from that of intact forest. Bryophyte responses to harvesting were partly explained by species substrate preferences: epixylics on decayed wood and epiphytes on bark experienced declines in richness with any level of harvesting, whereas responses for species on other substrates were not as apparent. Furthermore, partial harvesting influenced regional patterns of species diversity, as revealed by additive partitioning of diversity into within-plot (alpha) and among-plot and among-stand (beta) components. For both mosses and liverworts, total beta diversity explained the greatest proportion of total diversity for each retention level, indicating that species representation in boreal mixedwood landscapes after harvesting needs to be considered at multiple hierarchical levels. Total beta diversity of liverworts but not mosses increased substantially at low retention, reflecting greater among-plot and among-stand differentiation of liverwort assemblages with increasing disturbance. Results highlight the importance of canopy retention and composition for maintaining bryophytes in managed forests. Although several species persisted at low retention, intact forest is required for the conservation of numerous species that are sensitive to any degree of harvest. Implementation of conservation strategies for bryophytes in managed boreal forests should consider species diversity not only at local scales but also differences among entire forest stands. [Copyright &y& Elsevier]

An assessment of bryophyte species growing on an Ordovician dolomite escarpment in the Interlake region of Manitoba known as Marble Ridge revealed a diverse flora composed mostly of circumboreal floristic elements. Two liverwort families (including three species) and four moss species are reported for Manitoba for the first time: the liverworts Alhalamia hyalina (Sommert.) Hatt. (Cleveaceae), Mannia fragrans (Balbis) Frye et Clark (Aytoniaceae), and Mannia sibirica (K. Müll.) Frye et Clark (Aytoniaceae) and the mosses Brachythecium collinum (Schleich, ex C. Müll.) Schimp. in B.S.G., Grimmia teretinervis Limpr., Schistidium frigidum H. H. Blom, and Seligeria donniana (Sm.) C. Müll. An annotated summary of these and other bryophyte species documented at the site is provided. The diversity of encountered bryophytes can mostly be attributed to the moist and shaded microclimatic conditions on the escarpment and the large number of microhabitats the escarpment supports. This study represents one of few accounts of bryophytes in the region and highlights the importance of this particular geologic formation in supporting a number of species that are expected to be regionally uncommon. [ABSTRACT FROM AUTHOR]

Epiphytic mosses and liverworts contribute substantially to the bryophyte diversity of circumpolar boreal forests but are susceptible to altered growing conditions after forest harvesting. Management practices that retain some trees after harvest may enhance epiphyte survival; however, the effectiveness of this emerging method needs to be assessed. We examined the survival, composition, and nearest neighbour relationships of epiphytic bryophytes on trembling aspen (Populus tremuloides Michx.) across a range (10%–100%) of dispersed green-tree retention 5 years after harvest in boreal mixed-wood forest. Growth of the forest floor moss Hylocomium splendens (Hedw.) Schimp. in B.S.G. was used as an indicator of changes in moisture availability for epiphytes following harvesting. Epiphyte richness and abundance increased with canopy retention and were positively correlated with local abundance of coniferous trees. Positive associations among neighbouring species in intact forest demonstrated that interspecies relationships form naturally. However, there was a shift in species composition after harvesting and fewer interspecific associations with declining retention. These trends were accompanied by reduced Hylocomium splendens growth, which implies that moisture may be an important driver of epiphyte response. Although different levels of canopy retention were similarly capable of maintaining some epiphytes, the loss of species associated with intact forest will require consideration of alternative management practices for their conservation. Les mousses et les hépatiques épiphytes contribuent substantiellement à la diversité des bryophytes des forêts boréales circumpolaires, mais sont sensibles aux modifications des conditions de croissance, suite aux opérations forestières. Les méthodes d’aménagement qui conservent certains arbres après la récolte peuvent améliorer la survie des épiphytes; cependant, on doit évaluer l’efficacité de ces méthodes en émergence. Les auteurs ont examiné la survie, la composition et les relations avec les voisins les plus rapprochés des bryophytes épiphytes sur le peuplier faux-tremble (Populus tremuloides Michx.) pour l’ensemble d’une aire (10 % à 100 %) comportant des arbres vivants conservés et dispersés, 5 ans après la récolte dans une forêt boréale mixte. Ils ont utilisé la croissance d’une mousse du parterre forestier, l’Hylocomium splendens (Hedw.) Schimp. in B.S.G., comme indicatrice des modifications de la disponibilité de l’humidité pour les épiphytes, suite à la récolte des arbres. La richesse et l’abondance des épiphytes augmentent avec la rétention de la canopée et montrent des corrélations positives avec l’abondance localisée de conifères. Les associations positives avec les espèces avoisinantes dans la forêt intacte démontrent que des relations interspécifiques se forment naturellement. Cependant, on observe un déplacement de la composition en espèces après la récolte et moins d’associations interspécifiques avec une diminution de la rétention. Ces tendances s’accompagnent d’une réduction de la croissance de l’ Hylocomium splendens, ce qui implique que l’humidité pourrait être un agent causal important de la réaction des épiphytes. Bien que différents degrés de conservation de la canopée peuvent être également aptes à maintenir certaines épiphytes, la perte d’espèces associées aux forêts intactes nécessitera la définition de méthodes alternatives d’aménagement pour leur conservation. [ABSTRACT FROM AUTHOR]