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Extensive 14C dating and botanical identification of charcoal fragments located in the organic surface soil layer and buried in the mineral podzolic solum were used to reconstruct the successional pathways of a balsam fir forest site. The studied forest site developed in a context of continuous fire disturbance over the last 9000 years with at least 26 fires occurring at a mean interval of 330 years. Tree vegetation of the site followed a four-step trajectory consisting of an early-Holocene spruce forest and a late-Holocene mixedwood balsam fir forest. Boreal-like spruce-birch and temperate-like white pine-birch forests dominated the site between 7900 and 5900 cal. B.P. and 5600 and 1275 cal. B.P., respectively. Because all forest types developed repeatedly after fire since early deglaciation, changes in forest composition, in particular the shift of white pine forest to balsam fir forest, and concurrent decline of birch (yellow birch and/or paper birch) and pine populations were most likely related to progressive cooler and wetter conditions from mid- to late Holocene. Fire disturbance on this part of the southern boreal biome has been a continuous, positive regenerative process over the Holocene, allowing the successional turnover of boreal and temperate trees under the influence of climatic change. [ABSTRACT FROM AUTHOR]

Reported from marine, freshwater, and terrestrial habitats, trichomycetes are an ecological group of both fungi and protists that colonize the guts of insects, crustaceans, and millipedes. Lotic sites (streams, rivers) are a rich source of hosts and their trichomycetes. As part of a larger study of trichomycetes from different aquatic habitats within the Halifax Regional Municipality in Nova Scotia, Canada, one stream from each of three separate watersheds was sampled for aquatic insects, and their guts were dissected and examined for microscopic trichomycetes. Over the course of 17 months, 24 species of trichomycetes were collected including the following four new species: Glotzia gemina sp. nov. R.T. William and Strongman from a mayfly (Baetidae); Stachylina tanysoma sp. nov. R.T. William and Strongman; Smittium ampliboja sp. nov. R.T. William and Strongman; and Smittium insolitum sp. nov. R.T. William and Strongman, all recovered from dipteran (Chironomidae) hosts. New continental records were established for three species including Smittium pusillum Manier & Coste and Stachylina euthena Manier & Coste, both originally described from France, and Smittium nodifixum Strongman & Shengquan Xu previously known only from China. A new regional geographical record for Pennella arctica Lichtw. & M.C. Williams is reported and 17 other species previously known from eastern Canada were recorded. Pteromaktron timberleaense R.T. William & Strongman was described by us from Timberlea, Nova Scotia, but at the time no sexual spores (zygospores) were seen. In the collections reported in this paper, zygospores were found so the original description is emended to include the zygospore features for this species. This report adds to the published data on trichomycetes from Nova Scotia that have appeared over the last 10 years and highlights the significance of long-term sampling in cataloguing the diversity of this group of insect associated microorganisms. We also present some data on seasonal variation in trichomycete occurrence and comment on site specificity in the trichomycetes we collected. [ABSTRACT FROM AUTHOR]

This paper discusses local understanding of plants and habitats, based on the linguistic evidence [terms for plants and (or) habitats] gathered from ethnobotanical and ethnoecological field work conducted with several Dene Nations of the Canadian northwestern boreal forest and adjacent regions. Nations involved in the study include Gwich’in (Mackenzie Delta Region), Sahtú’otine’ (Great Bear Lake), Kaska Dena (southern Yukon), and Witsuwit’en (northwest British Columbia). Key plant-related habitats include meadow, “swamp”, forest, “willows”, and “brush”. The ethnobotanical classification of willows is explored in conjunction with the explanation of the Dene habitat concept. In local classifications, ‘willow’ is not co-extensive with the genus Salix, but includes a variety of medium to tall woody shrubs that lack either conspicuous flowers, ‘berries’, or thorns; these may include shrubby species of Salix, Alnus, Cornus, and Betula. Shoreline and alpine environments are also discussed as plant habitats. Dene use of alpine environments and resources is ancient, according to the results of recent alpine ice patch research in the Yukon region. The Human dimensions of habitat knowledge are presented. Indigenous concepts of plant taxa and of landscape associations or habitats may differ substantially from those of scientific botany and ecology, and are based in a holistic and interactive ethnoecology. [ABSTRACT FROM AUTHOR]