Cause, conseguenze e strategie di mitigazione Proponiamo il primo di una serie di articoli in cui affronteremo l’attuale problema dei mutamenti climatici. Presentiamo il documento redatto, votato e pubblicato dall’Ipcc - Comitato intergovernativo sui cambiamenti climatici - che illustra la sintesi delle ricerche svolte su questo tema rilevante.

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Climate Change 2007: The Physical Science Basis.

Nature And Properties Of Soils

Many ecosystems are rapidly being transformed into new, non-historical configurations owing to a variety of local and global changes. We discuss how new systems can arise in the face of primarily biotic change (extinction and/or invasion), primarily abiotic change (e.g. land use or climate change) and a combination of both. Some changes will result in hybrid systems retaining some original characteristics as well as novel elements, whereas larger changes will result in novel systems, which comprise different species, interactions and functions. We suggest that these novel systems will require significant revision of conservation and restoration norms and practices away from the traditional place-based focus on existing or historical assemblages.

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Novel ecosystems: implications for conservation and restoration

Much as Rachel Carson's \"Silent Spring\" was a call to action against the pesticides that were devastating bird populations, Charles S. Elton's classic \"The Ecology of Invasions by Animals and Plants\" sounded an early warning about an environmental catastrophe that has become all too familiar today-the invasion of nonnative species. From kudzu to zebra mussels to Asian long-horned beetles, nonnative species are colonizing new habitats around the world at an alarming rate thanks to accidental and intentional human intervention. One of the leading causes of extinctions of native animals and plants, invasive species also wreak severe economic havoc, causing $79 billion worth of damage in the United States alone. Elton explains the devastating effects that invasive species can have on local ecosystems in clear, concise language and with numerous examples. The first book on invasion biology, and still the most cited, Elton's masterpiece provides an accessible, engaging introduction to one of the most important environmental crises of our time. Charles S. Elton was one of the founders of ecology, who also established and led Oxford University's Bureau of Animal Population. His work has influenced generations of ecologists and zoologists, and his publications remain central to the literature in modern biology. \"History has caught up with Charles Elton's foresight, and \"The Ecology of Invasions\" can now be seen as one of the central scientific books of our century.\"-David Quammen, from the Foreword to \"Killer Algae: The True Tale of a Biological Invasion\

The Ecology of Invasions by Animals and Plants

Positive ions that are available in soils absorb on grain surfaces. The total sum of cations that can be absorbed bij a soil/sediment at a certain PH is defined by the cation-exchange capacity (CEC, in meq g-1: mol equivalents per gram). The uptake of cations is an important parameter in agriculture and the larger the CEC, the more cations can be absorbed to the soil. The CEC depends highly on the pH of soil and sediments, where the CEC decreases with decreasing PH (increasing acidity). The exchange of ions on sediments occurs commonly fast on geological time scales, but the kinetics of adsorption in natural environments is still poorly understood. The strength of the bonding between the cations and the sediments varies from weak Van der Waals bondings (physical adsorption) to strong chemical bonds. The CEC is widely used for agricultural assessment because it is a measure of general soil fertility as well as an indicator of structural stability because CED is capabel of enhancing development of shrinkage cracks. The list below shows the CEC for different types of minerals. The data indicate that the CEC can vary over 2 orders of magnitude for various types of , minerals and can vary one order of magnitude within one soil type. Cation exchange capacity for different types of sediment (Eisma, 1992; Locher and de Bakker, 1990):

Cation exchange capacity.

Since its emergence in the past decades, restoration ecology has demonstrated an astounding growth as a new discipline of applied science. At the same time, this young discipline has been criticized for its retrospective goals largely based on the past, its fragmented approach, and its idealistic goals, which do not relate to the real world context. Restoration with past-focused, idealistic, and/or ad hoc goals may not work in the future because an ecosystem that is restored for the past environment is not likely to be sustainable in the changing environment of the future, simple recomposition of isolated and fragmented naturalistic patches is not likely to restore ecosystem functions, and unrealistic goals and work plans are not likely to gain public support. We advocate directing the principles and practice of ecological restoration to the future. Future- aimed restoration should acknowledge the changing and unpredictable environment of the future, assume the dynamic nature of ecological communities with multiple trajectories, and connect landscape elements for improving ecosystem functions and structures. In this paper, we discuss the predictability of restoration trajectories under changing environmental conditions, the application of ecological theories to restoration practice, the importance of interdisciplinary approaches and human inter- ventions in ecosystem recovery, and the social context of ecological restoration. Keywords: ecology, environment, future, restoration, sustainability. Resume : Depuis son emergence dans les dernieres decennies, la restauration ecologique a demontre une croissance phenomenale en tant que nouvelle discipline scientifique appliquee. En meme temps, cette jeune discipline a ete critiquee pour ses objectifs retrospectifs, son approche fragmentaire et ses ideaux qui ne sont pas toujours realistes. Il est fort possible qu'une restauration orientee vers le passe, avec des objectifs idealistes et/ou ad hoc ne sera pas fonctionnelle dans l'avenir. En effet, un ecosysteme restaure en fonction d'un environnement passe ne sera peut etre pas viable dans un futur en changement, la rehabilitation vers un aspect naturel de parcelles isolees et fragmentees ne restaurera probablement pas les fonctions de l'ecosysteme et des objectifs et plans de travail irrealistes ont peu de chance d'obtenir la faveur du public. Nous recommandons d'orienter les principes et la pratique de la restauration ecologique vers le futur. Cette restauration tournee vers l'avenir devrait prendre en compte que les environnements futurs seront changeants et imprevisibles, considerer la nature dynamique des communautes ecologiques ayant des trajectoires multiples et assurer la connectivite des elements du paysage pour ameliorer les fonctions et structures des ecosystemes. Dans cet article, nous discutons de la previsibilite des trajectoires de restauration dans des conditions environnementales changeantes, de l'application des theories ecologiques a la pratique de la restauration, de l'importance de l'approche multidisciplinaire et des interventions humaines pour la rehabilitation des ecosystemes et finalement, du contexte social de la restauration ecologique. Mots-cles : ecologie, environnement, futur, restauration, viabilite.

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Ecological restoration for future sustainability in a changing environment

Biochar properties and lead(II) adsorption capacity depend on feedstock type, pyrolysis temperature, and steam activation.

This study was undertaken to determine if use of stratified organic layers of intact litter, fragmented litter, and humus on the forest floor (LFH) improves establishment of upland native boreal plant species during oil sands reclamation in Alberta, Canada. The abundance and composition of vascular plant species in the soil propagule bank were determined for LFH and peat materials before salvage from donor sites and 18 months after application on the receiver site. Applications of 10 and 20 cm were evaluated. Various soil properties were assessed to determine impacts of donor materials. In the growth chamber, LFH donor material had significantly more plant species emerge (37) from the propagule bank than did peat donor material (19). In the field, LFH treatments had significantly higher species richness (49, 47, 24, and 25 species for LFH 10 cm, LFH 20 cm, peat 10 cm, and peat 20 cm treatments, respectively), plant abundance, and soil nutrients than peat treatments. Application thickness of peat had little effect, but 20 cm of LFH was more beneficial for plant community establishment than 10 cm. LFH treatments had narrower C:N ratios and higher soluble potassium and available phosphorus than peat. Applying 10 versus 20 cm of donor material increased admixing of fine-textured subsoil, reducing organic carbon, nitrogen, and potassium; these effects were greater for LFH than peat treatments. Thus, addition of LFH aids in creating diverse ecosystems on reclaimed upland landscapes by providing a source of propagules for revegetating upland boreal forest communities and improving nutrient availability for plants.

The role of the forest soil propagule bank in assisted natural recovery after oil sands mining.

Biochar surface complexation and Ni(II), Cu(II), and Cd(II) adsorption in aqueous solutions depend on feedstock type.

Most of North America’s northern Great Plains have been cultivated for crop production, leaving remnants of natural mixed-grass prairie fragmented and threatened by alien plant invasions. The region’s most widespread alien perennial forage crop, crested wheatgrass (Agropyron cristatum sensu amplo), has invaded native grassland and raised concerns regarding its ecological impact. To evaluate impacts at multiple scales of organization, adjacent invaded and uninvaded mixed-grass prairie were sampled at eight widely separated locations. At the population level, native C3 mid-grasses and forbs were less abundant in invaded grasslands, while native C3 and C4 short-grass abundance was not different. At community and landscape levels, diversity was lower in invaded grasslands largely because of lower forb species richness and cover, and crested wheatgrass dominance of both cover (14% basal cover) and seedbank (404 seeds m−2). At the ecosystem level, both vegetation and litter biomass were greater in invaded grasslands, however, below ground organic matter (roots and litter), soil organic carbon, total nitrogen and phosphorus were not different. Crested wheatgrass invasion of mixed-grass prairie was associated with lower diversity within and among plant communities, and appears to simplify the composition of mixed-grass prairie landscapes. Hypotheses for crested wheatgrass dominance and persistence following invasion are suggested.

M. Anne Naeth

Papers

Ecological restoration for future sustainability in a changing environment

Biochar properties and lead(II) adsorption capacity depend on feedstock type, pyrolysis temperature, and steam activation.

The role of the forest soil propagule bank in assisted natural recovery after oil sands mining.

Biochar surface complexation and Ni(II), Cu(II), and Cd(II) adsorption in aqueous solutions depend on feedstock type.

Multi-scale impacts of crested wheatgrass invasion in mixed-grass prairie.