Understanding the processes behind Boreal landscape disturbances

点击翻译按钮获取中文摘要

While ecosystems are generally resilient, if pushed beyond a tipping point, a catastrophic shift in ecosystem function will occur as the result of strong positive feedback mechanisms. Within the boreal, this will result not only in a local transformative state shift in the ecosystem, but also a loss of landscape resilience due to the interactions and feedbacks between adjoined ecosystems units. Such a transition could cascade through the mosaic and lead to its large scale landscape failure. The reclamation of the Athabasca Oil Sands requires the construction of such mosaic landscapes of lakes, wetlands and forestlands that characterize the undisturbed Boreal Plains. Such landscapes must develop over time to rapidly develop expansive productive forests, maximizing the economic potential of the landscape, whilst maintaining high water fluxes to flush ecological harmful salts. Mine closure plans must therefore understanding and recognize the risk of such potential failures in mine closure plans, and weigh the desire to minimize risk of failure, and the loss of desired ecosystem services, against the economic costs of initial landscape construction, and the magnitude and diversity of ecosystem services that are targeted by the mine closure plan. Through over decade of ongoing industry funded research within the western Boreal Plain, the Hydrology, Ecology and Disturbance programme (HEAD) has developed a detailed conceptual understanding of the ecohydrological functioning of the landscape through processed based field and modelling research; knowledge that is informing current mine closure plans. This research has demonstrated that the climate cycle, a superposition of varying climate signals of different intensities and phases, provides the overarching driver of the ecohydrology behavior of these landscape systems. This cycle cascades through landscape storage units that vary in configuration, extent and scale of connectivity. The resulting local hydraulic signature provides the primary control on the ecological risk to the different units over time. This project develops on this conceptual foundation, utilizing the legacy of close to two decade of research activities across the HEAD research programme (measurements from ~15000 wells and piezometers in addition to a range of supplementary hydrological, meteorological and ecological data) to provide a top-down statistical analysis of the ecohydrological behavior of the complex mosaic landscape. To test how the hydrology, ecology and biogeochemistry of the diverse array of hydraulic units respond to the climate cycle. To determine the sources of risk for potential conditions that would likely instigate failure of the ecosystem units, their drivers and the impact such local failures within the complex mosaic landscape system. This knowledge will direct future mine closure design plans, in addition to ongoing process based processes based field and modeling studies.