Identifying pathways to visions of future land use in Europe

Regional Environmental Change - Plausible scenarios of future land use derived from model projections may differ substantially from what is actually desired by society, and identifying such...     

Compartmentation of metals in foliage of Populus tremula grown on soils with mixed contamination. II. Zinc binding inside leaf cell organelles

The phytoextraction potential of plants for removing heavy metals from polluted soils is determined by their capacity to store contaminants in aboveground organs and complex them safely. In this study, the metal compartmentation, elemental composition of zinc deposits and zinc complexation within leaves from poplars grown on soil with mixed metal contamination was analysed combining several histochemical and microanalytical approaches. Zinc was the only heavy metal detected and was stored in several organelles in the form of globoid deposits showing β-metachromasy. It was associated to oxygen anions and different cations, noteworthy phosphorous. The deposit structure, elemental composition and element ratios indicated that zinc was chelated by phytic acid ligands. Maturation processes in vacuolar vs. cytoplasmic deposits were suggested by differences in size and amounts of complexed zinc. Hence, zinc complexation by phytate contributed to metal detoxification and accumulation in foliage but could not prevent toxicity reactions therein.     

Evaluating long-term urban resilience through an examination of the history of green spaces in Tokyo

Long-term urban resilience requires urban systems with the capacity to respond to change and disturbance and to enhance the conditions for lasting wellbeing. Over the past century Tokyo has demonstrated impressive resilience, especially a capacity to reorganise and rebuild in response to successive major disturbances. Throughout these recoveries, the city-region maintained a focus on re-establishing, improving and maintaining international competitiveness through industrial development. Green spaces in Tokyo provided a flexible, but gradually disappearing resource. Today, to meet the needs of its ageing and minimally expanding population for enhanced wellbeing, Tokyo requires active transition planning covering many intertwined factors, but the adaptive capacity provided by the green space resource is no longer available. The Tokyo case underscores the risk inherent in the depletion of non-renewable resources (in this instance, green space) to secure immediate recovery and accommodate growth and short-term resilience at the expense of long-term resilience.     

Adaptation potential of ecosystem-based management to climate change in the eastern Canadian boreal forest

Ecosystem-based management (EBM) of forests is gaining acceptance for its focus on the maintenance of the long-term integrity of ecosystem processes, but climate change challenges this view because of its impacts on these very processes. We have therefore evaluated the robustness of EBM to projected climate change, considering the role of climate on forest growth and fire regime in a boreal forest of eastern Canada. A climate sensitive growth index model was calibrated for three commercial species and used to project the evolution of merchantable volume for two climate scenarios (B1 and A2) under conventional and EBM strategies. Current burn rate and burn rates under future climate scenarios were also considered. Under the most extreme projected climate scenario, the periodic timber supply could be reduced by up to 79% through direct (growth reduction) and indirect (fire) effects. However, ecological indicators show that EBM is a more robust forest management strategy than conventional one demonstrating its adaptation potential to climate change at least in the short term.     

Differential responses of eubacterial, Mycobacterium, and Sphingomonas communities in polycyclic aromatic hydrocarbon (PAH)-contaminated soil to artificially induced changes in PAH profile

Recent reports suggest that Mycobacterium is better adapted to soils containing poorly bioavailable polycyclic aromatic hydrocarbons (PAHs) compared to Sphingomonas. To study this hypothesis, artificial conditions regarding PAH profile and PAH bioavailability were induced in two PAH-contaminated soils and the response of the eubacterial, Mycobacterium, and Sphingomonas communities to these changed conditions was monitored during laboratory incubation. Soil K3663 with a relatively high proportion of high molecular weight PAHs was amended with phenanthrene or pyrene to artificially change the soil into a soil with a relatively increased bioavailable PAH contamination. Soil AndE with a relatively high proportion of bioavailable low molecular weight PAHs was treated by a single-step Tenax extraction to remove the largest part of the easily bioavailable PAH contamination. In soil K3663, the added phenanthrene or pyrene compounds were rapidly degraded, concomitant with a significant increase in the number of phenanthrene and pyrene degraders, and minor and no changes in the Mycobacterium community and Sphingomonas community, respectively. However, a transient change in the eubacterial community related to the proliferation of several gamma-proteobacteria was noted in the phenanthrene-amended soil. In the extracted AndE soil, the Sphingomonas community initially developed into a more diverse community but finally decreased in size below the detection limit. Mycobacterium in that soil never increased to a detectable size, while the eubacterial community became dominated by a gamma-proteobacterial population. The results suggest that the relative bioavailability of PAH contamination in soil affects bacterial community structure but that the behavior of Mycobacterium and Sphingomonas in soil is more complex than prospected from studies on their ecology and physiology.     

Variation partitioning of species data matrices: estimation and comparison of fractions

Establishing relationships between species distributions and environmental characteristics is a major goal in the search for forces driving species distributions. Canonical ordinations such as redundancy analysis and canonical correspondence analysis are invaluable tools for modeling communities through environmental predictors. They provide the means for conducting direct explanatory analysis in which the association among species can be studied according to their common and unique relationships with the environmental variables and other sets of predictors of interest, such as spatial variables. Variation partitioning can then be used to test and determine the likelihood of these sets of predictors in explaining patterns in community structure. Although variation partitioning in canonical analysis is routinely used in ecological analysis, no effort has been reported in the literature to consider appropriate estimators so that comparisons between fractions or, eventually, between different canonical models are meaningful. In this paper, we show that variation partitioning as currently applied in canonical analysis is biased. We present appropriate unbiased estimators. In addition, we outline a statistical test to compare fractions in canonical analysis. The question addressed by the test is whether two fractions of variation are significantly different from each other. Such assessment provides an important step toward attaining an understanding of the factors patterning community structure. The test is shown to have correct Type I. error rates and good power for both redundancy analysis and canonical correspondence analysis.