A methodological framework for quantification and valuation of ecosystem services of tree-based intercropping systems

PresentationAlley cropping, also known as tree-based intercropping (TBI), holds a great potential in providing, in agricultural landscapes, a number of ecosystem services such as reduction of nutrient leaching, enhancement of soil nutrient status, increase of soil microbial biomass and diversity, biological pest control and global climate regulation. We developed and tested a framework for biophysical quantification and economic valuation of several such ecosystem services through a case study in southern Québec, Canada. We used a range of mathematical models for quantification of the services and valued them in economic terms. In some instances, we used existing models and equations, but in most instances we developed new ones to meet study objectives. We have found that the economic value of ecosystem services ranged from as low as 24 $ha-1y-1 for pollination to as high as 785$ ha-1y-1 for agricultural products. Water quality regulation ranked highest among the non-market services, followed by air quality regulation and carbon sequestration. The total potential value of TBI ecosystem services was estimated to be 5 billion dollars a year, if the system was implemented in 20 % of Québec’s 1,93 M ha croplands. The study suggests that incentives are needed to interest farmers in adopting TBI systems that benefit society as a whole

The Victorian Newsletter (Spring 1987)

The Victorian Newsletter is sponsored for the Victorian Group of Modern Language Association by the Western Kentucky University and is published twice annually.Arnold among the Contentions of Criticism / Holly Laird -- Closure and the Victorian Novel, 1986 / Marianna Torgovnick -- Victorian Weaving: The Alienation of Work into Text in "The Lady of Shalott" / Gerhard Joseph -- The Tenant of Wildfell Hall: Anne Brontë's Jane Eyre / Margaret Mary Berg -- The Poor Fictionist' s Conscience: Point of View in the Palliser Novels / Patricia A. Vernon -- A New Perspective: Naturalism in George Moore's A Mummer's Wife / Judith Mitchell -- Browning's Testament of His Devisings in The Ring and the Book / Joseph A. Dupras -- Books Receive

Urban Biodiversity and Landscape Ecology: Patterns, Processes and Planning

Effective planning for biodiversity in cities and towns is increasingly important as urban areas and their human populations grow, both to achieve conservation goals and because ecological communities support services on which humans depend. Landscape ecology provides important frameworks for understanding and conserving urban biodiversity both within cities and considering whole cities in their regional context, and has played an important role in the development of a substantial and expanding body of knowledge about urban landscapes and communities. Characteristics of the whole city including size, overall amount of green space, age and regional context are important considerations for understanding and planning for biotic assemblages at the scale of entire cities, but have received relatively little research attention. Studies of biodiversity within cities are more abundant and show that longstanding principles regarding how patch size, configuration and composition influence biodiversity apply to urban areas as they do in other habitats. However, the fine spatial scales at which urban areas are fragmented and the altered temporal dynamics compared to non-urban areas indicate a need to apply hierarchical multi-scalar landscape ecology models to urban environments. Transferring results from landscape-scale urban biodiversity research into planning remains challenging, not least because of the requirements for urban green space to provide multiple functions. An increasing array of tools is available to meet this challenge and increasingly requires ecologists to work with planners to address biodiversity challenges. Biodiversity conservation and enhancement is just one strand in urban planning, but is increasingly important in a rapidly urbanising world

Autoresonant second harmonic generation in a nonuniform LBO crystal

Varying the temperature of a LBO crystal longitudinally has been suggested as a mechanism to improve the SHG conversion efficiency starting from a broadband pulse

Autoresonant harmonic generation in nonuniform crystals

An experiment of second harmonic generation in a nonuniform crystal is presented, and interpreted in terms of an autoresonant wave-mixing theory. A good agreement is found between numerical simulations, analytical solutions and experimental data