Characterizing the complexity of landscape boundaries by remote sensing

This paper presents a method for characterizing the complexity of landscape boundaries by remote sensing. This characterization is supported by a new boundary typology, that takes into account points where three or more landcovers converge (i.e., convergency points or coverts). Landscape boundary richness and diversity indices were proposed and calculated over 19 landscapes in South-East Brazil. Results showed that landscape boundaries, especially convergency points, provided an enrichment in landscape pattern analysis. Landcover boundary diversities were significantly related to landcover shape: elongated riparian units had the highest values for boundary diversity and coverts proportion indices. On the other hand, landscape analysis showed that indices of shape, richness, diversity and coverts proportion provided an additional evaluation of landcover spatial distribution within the landscape

Temps dans le cycle de vie du document numérique (Le)

Intervention au colloque "Le numérique : impact sur le cycle de vie du document", organisé à l\u27université de Montréal par l\u27EBSI et l\u27ENSSIB du 13 au 15 octobre 2004. Cet article propose une modélisation capable de rendre compte des différentes dimensions temporelles portées par un document. Après la définition de la notion de document, nous introduisons trois univers : l\u27univers sociohistorique, l\u27espace documentaire et l\u27univers du discours. Chacun d\u27eux contient sa propre dimension temporelle

Climate change and sugarcane expansion increase Hantavirus infection risk

Hantavirus Cardiopulmonary Syndrome (HCPS) is a disease caused by Hantavirus, which is highly virulent for humans. High temperatures and conversion of native vegetation to agriculture, particularly sugarcane cultivation can alter abundance of rodent generalist species that serve as the principal reservoir host for HCPS, but our understanding of the compound effects of land use and climate on HCPS incidence remains limited, particularly in tropical regions. Here we rely on a Bayesian model to fill this research gap and to predict the effects of sugarcane expansion and expected changes in temperature on Hantavirus infection risk in the state of São Paulo, Brazil. The sugarcane expansion scenario was based on historical data between 2000 and 2010 combined with an agro-environment zoning guideline for the sugar and ethanol industry. Future evolution of temperature anomalies was derived using 32 general circulation models from scenarios RCP4.5 and RCP8.5 (Representative greenhouse gases Concentration Pathways adopted by IPCC). Currently, the state of São Paulo has an average Hantavirus risk of 1.3%, with 6% of the 645 municipalities of the state being classified as high risk (HCPS risk ≥ 5%). Our results indicate that sugarcane expansion alone will increase average HCPS risk to 1.5%, placing 20% more people at HCPS risk. Temperature anomalies alone increase HCPS risk even more (1.6% for RCP4.5 and 1.7%, for RCP8.5), and place 31% and 34% more people at risk. Combined sugarcane and temperature increases led to the same predictions as scenarios that only included temperature. Our results demonstrate that climate change effects are likely to be more severe than those from sugarcane expansion. Forecasting disease is critical for the timely and efficient planning of operational control programs that can address the expected effects of sugarcane expansion and climate change on HCPS infection risk. The predicted spatial location of HCPS infection risks obtained here can be used to prioritize management actions and develop educational campaigns

Le trésor de Vaise à Lyon (Rhône)

Un trésor parle toujours à l’imaginaire : outre sa valeur intrinsèque, la noblesse des matériaux et l’esthétique des objets qui le composent ne manquent pas de frapper l’esprit qui ne peut s’empêcher d’évoquer le destin du propriétaire, disparu sans récupérer ses biens cachés en prévision de jours meilleurs... Au-delà de la part du mystère, la découverte du trésor de Vaise dans le cadre d’une fouille archéologique préventive - celle qui a précédé la réalisation de la ZAC Charavay - et sa com..

Experiences from the Brazilian Atlantic Forest:\ud ecological findings and conservation initiatives

The Brazilian Atlantic Forest hosts one of the world’s most diverse and threatened tropical forest\ud biota. In many ways, its history of degradation describes the fate experienced by tropical forests\ud around the world. After five centuries of human expansion, most Atlantic Forest landscapes are\ud archipelagos of small forest fragments surrounded by open-habitat matrices. This ‘natural\ud laboratory’ has contributed to a better understanding of the evolutionary history and ecology of\ud tropical forests and to determining the extent to which this irreplaceable biota is susceptible to\ud major human disturbances.We share some of the major findings with respect to the responses of\ud tropical forests to human disturbances across multiple biological levels and spatial scales and\ud discuss some of the conservation initiatives adopted in the past decade. First, we provide a short\ud description of the Atlantic Forest biota and its historical degradation. Secondly, we offer\ud conceptual models describing major shifts experienced by tree assemblages at local scales and\ud discuss landscape ecological processes that can help to maintain this biota at larger scales. We\ud also examine potential plant responses to climate change. Finally, we propose a research agenda\ud to improve the conservation value of human-modified landscapes and safeguard the biological\ud heritage of tropical forests.C.A.J. was supported by grants from the BIOTA/FAPESP Program (FAPESP 03/12595-7, 10/50811-7, 12/51872-5) and CNPq (403710/2012-0). J.P.M. (307934/2011-0) and M.T. (304598/2011-9) thank the Brazilian Science Council (Conselho Nacional de Desenvolvimento Cientıfico) for their research fellowships. We thank Leandro Reverberi Tambosi for providing Fig. 1, and the three ad hoc reviewers for their constructive critical evaluation of the manuscript which resulted in a much improved final version

Beyond the Fragmentation Threshold Hypothesis: Regime Shifts in Biodiversity Across Fragmented Landscapes

Ecological systems are vulnerable to irreversible change when key system properties are pushed over thresholds, resulting in the loss of resilience and the precipitation of a regime shift. Perhaps the most important of such properties in human-modified landscapes is the total amount of remnant native vegetation. In a seminal study Andrén proposed the existence of a fragmentation threshold in the total amount of remnant vegetation, below which landscape-scale connectivity is eroded and local species richness and abundance become dependent on patch size. Despite the fact that species patch-area effects have been a mainstay of conservation science there has yet to be a robust empirical evaluation of this hypothesis. Here we present and test a new conceptual model describing the mechanisms and consequences of biodiversity change in fragmented landscapes, identifying the fragmentation threshold as a first step in a positive feedback mechanism that has the capacity to impair ecological resilience, and drive a regime shift in biodiversity. The model considers that local extinction risk is defined by patch size, and immigration rates by landscape vegetation cover, and that the recovery from local species losses depends upon the landscape species pool. Using a unique dataset on the distribution of non-volant small mammals across replicate landscapes in the Atlantic forest of Brazil, we found strong evidence for our model predictions - that patch-area effects are evident only at intermediate levels of total forest cover, where landscape diversity is still high and opportunities for enhancing biodiversity through local management are greatest. Furthermore, high levels of forest loss can push native biota through an extinction filter, and result in the abrupt, landscape-wide loss of forest-specialist taxa, ecological resilience and management effectiveness. The proposed model links hitherto distinct theoretical approaches within a single framework, providing a powerful tool for analysing the potential effectiveness of management interventions