Structure and functions of bryophyte communities in temperate and boreal ecosystems

点击翻译按钮获取中文摘要

In boreal coniferous forests, forest-floor bryophytes (mosses, liverworts, and hornworts) carry out key ecosystem processes and plant-soil feedbacks that maintain ecosystem resilience. Whether this holds true at the boreal-temperate ecotone that comprises a mosaic of broadleaf deciduous, mixed wood, and coniferous forests remains unclear. Our knowledge of the functional traits of bryophytes, i.e. the characteristics of species that define their roles in ecosystems, is still scant, especially along canopy or climate driven gradients. Deciphering the effects of canopy composition, climate, and species interactions on bryophytes is critical for conservation and sustainable forest management, especially in areas like the Acadian forest. My long-term objective is to provide a comprehensive understanding of the structures and functions of bryophyte communities in temperate and boreal ecosystems, particularly in transition zones, such as the Acadian forest. My recent research in boreal and subarctic ecosystems has shown that interactions between canopy composition and age of forests, natural and anthropic disturbances, leaf microbial communities, and climate have major impacts on bryophyte community assembly and ecosystem functions related to carbon and nitrogen (N) cycling and vascular plant recruitment. My short-term objective is to understand the mechanisms affecting the composition and functions of bryophyte communities at the boreal-temperate ecotone at different spatial scales by combining field-based observational and experimental work using botanical, biogeochemical, and molecular tools. With the proposed research we will: (1) characterize bryophyte functional traits and ecosystem function in Acadian forests, (2) determine how bryophytes and their microbiome interact and affect N-fixation, and (3) test the adaptation potential and phenotypic plasticity of bryophytes to novel environmental conditions at the boreal-temperate ecotone. Our work will be conducted along three natural gradients at the southern edge of the boreal forest: coastal to inland gradient in moisture availability, deciduous to coniferous gradient, and a latitudinal gradient in temperature. Ecotones are particularly sensitive to environmental change and species range shifts are likely at the southern edge of the boreal forest in response to climate change. We will provide key field- and experimental-based evidence on the ecology, structure, and functions of understory bryophyte communities in the boreal-temperate ecotone. Acadian forests have been designated as a critically endangered ecosystem by the World Wildlife Fund. Our research will improve our understanding of forest resilience in response to climate change and to increasing anthropogenic pressures, as about 50% of forests in New Brunswick will be actively managed in the next 50 years.