Knowledge Resource Center for Ecological Environment in Arid Area
| Understanding aspen in the James Bay area of Québec at multiple scales | |
| Whitbeck;Kristen | |
| 出版年 | 2014 |
| 学位授予单位 | McGill University |
| 英文摘要 | Understanding tree species distributions and dynamics in northern boreal forests is necessary for appropriate societal action and response to critical issues such as climate change, increased economic development of northern natural resources, and the collateral damage to cultures of indigenous communities. Northern tree species are expected to be sensitive to ongoing and anticipated climate change. Due to their remoteness and lack of a history of management-oriented research, information that is available for temperate areas, such as species distribution maps, soils, and climatology is often poorly quantified in the North. Consequently, our understanding of the factors controlling tree species northern distributional limits (NDL) and our ability to predict how future environmental change will affect their range distributions is limited. Moreover, very little attention has been devoted to understanding the dynamics of the few broadleaf tree species, such as trembling aspen, which are important components of northern boreal forest systems, from both an ecological and an economical perspective.This thesis was inspired by observations of aspen growing in uncharacteristic abundance near the extremes of its NDL in Quebec in conjunction with the pressing need to answer questions regarding how individual boreal tree species may respond to current and future environmental change. Here, I investigate the factors driving the variation in observable patterns of aspen distribution and abundance at regional and landscape scales in the James Bay area of northwestern Quebec, as well as the influence of a range of ecological conditions on aspen growth. The four specific objectives of this research were: (i) to map aspen's regional distribution and abundance using a combination of field, GIS, and remote sensing techniques, (ii) to determine how aspen height growth responds to change in environmental conditions across a broad latitudinal gradient from 46° to 54°N latitude, (iii) to determine the factors organizing vegetation community composition in and around aspen-dominated communities at the landscape scale, and (iv) to explore the influence of specific environmental factors on aspen abundance at the landscape scale near aspen's NDL.The key scientific merits of this thesis are: (i) creation of baseline data characterizing aspen's geographic range and associated land cover in northwestern Quebec to allow for more accurate comparative and quantitative studies now and in the future, (ii) development and application of a new method for rapid extraction of land cover classification data in remote areas, (iii) demonstration that the regional scale pattern of aspen occupancy in the James Bay area of QC appears influenced by anthropogenic driven disturbance, (iv) demonstration that aspen's NDL in QC is not predominately governed by harsh climate, thus highlighting the need for more in depth species specific research on determinants of range limits, and the subsequent factors most appropriate for use in predictive modelling of future tree species' distributions, and (v) demonstration that gradients related to soil moisture and soil fertility best characterize forest composition and structure at the landscape scale in the study area, while aspen abundance, in particular, is associated with soils high in K, and inland areas where fire events are more frequent than those on the coast. Together these tools and findings suggest that identifying and understanding species' distribution and abundance patterns is complex and a further grasp of change in species specific patterns across their entire ranges is necessary to make informed forest management decisions and predict future outcomes. Une meilleure compréhension de la dynamique et de la répartition des espèces d'arbres en forêt boréale permettra d'intervenir socialement de façon plus appropriée face aux pressions exercées par les changements climatiques et par le développement accru du Nord, en plus |
| 英文关键词 | Agriculture - Forestry and Wildlife |
| 语种 | 法语 |
| URL | http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=121316 |
| 来源机构 | McGill University |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/248227 |
| 推荐引用方式 GB/T 7714 | Whitbeck;Kristen. Understanding aspen in the James Bay area of Québec at multiple scales[D]. McGill University,2014. |
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