La photogénie de l’artiste en action : six exemples de l’acte créateur photographié au xxe siècle

La photographie et l’acte créateur sont de natures incompatibles : l’une fige l’instant dans un fragment de temps infinitésimal, l’autre est un processus qui s’étend dans le temps et dans l’espace. Dès lors, que peut-on attendre de leur association, surtout au xxe siècle qui a vu éclore les formes les plus subjectives et les plus immatérielles de l’art ? Certains clichés cependant, par la qualité de l’empreinte qu’ils nous donnent à voir, mais aussi par le contexte matériel dans lequel ils nous apparaissent, réussissent à dépasser ce clivage. La solution semble se trouver dans le concept de « photogénie », qualité par essence insaisissable, que certains artistes et photographes, usant de stratégies diverses, parviennent à s’approprier.Photography and the creative act are incompatible by nature: one freezes the moment in an infinitesimal fragment of time, the other is a process that extends into time and space. What therefore can we expect from their association, especially in the twentieth century, which saw the birth of the most subjective and immaterial forms of art? Certain photographs, however, through the quality of the impression they show us, as well as by the material context in which they appear to us, have managed to overcome this divide. The solution seems to be in the concept of “photogenicness”, an essentially elusive quality that certain artists and photographers, using different strategies, succeed in appropriating

Madagascar's grasses and grasslands:anthropogenic or natural?

Grasses, by their high productivity even under very low pCO2, their ability to survive repeated burning and to tolerate long dry seasons, have transformed the terrestrial biomes in the Neogene and Quaternary. The expansion of grasslands at the cost of biodiverse forest biomes in Madagascar is often postulated as a consequence of the Holocene settlement of the island by humans. However, we show that the Malagasy grass flora has many indications of being ancient with a long local evolutionary history, much predating the Holocene arrival of humans. First, the level of endemism in the Madagascar grass flora is well above the global average for large islands. Second, a survey of many of the more diverse areas indicates that there is a very high spatial and ecological turnover in the grass flora, indicating a high degree of niche specialization. We also find some evidence that there are both recently disturbed and natural stable grasslands: phylogenetic community assembly indicates that recently severely disturbed grasslands are phylogenetically clustered, whereas more undisturbed grasslands tend to be phylogenetically more evenly distributed. From this evidence, it is likely that grass communities existed in Madagascar long before human arrival and so were determined by climate, natural grazing and other natural factors. Humans introduced zebu cattle farming and increased fire frequency, and may have triggered an expansion of the grasslands. Grasses probably played the same role in the modification of the Malagasy environments as elsewhere in the tropics

Phylogeny of the plant genus Pachypodium (Apocynaceae)

Background. The genus Pachypodium contains 21 species of succulent, generally spinescent shrubs and trees found in southern Africa and Madagascar. Pachypodium has diversified mostly into arid and semi-arid habitats of Madagascar, and has been cited as an example of a plant group that links the highly diverse arid-adapted floras of Africa and Madagascar. However, a lack of knowledge about phylogenetic relationships within the genus has prevented testing of this and other hypotheses about the group.Methodology/Principal Findings. We use DNA sequence data from the nuclear ribosomal ITS and chloroplast trnL-F region for all 21 Pachypodium species to reconstruct evolutionary relationships within the genus. We compare phylogenetic results to previous taxonomic classifications and geography. Results support three infrageneric taxa from the most recent classification of Pachypodium, and suggest that a group of African species (P. namaquanum, P. succulentum and P. bispinosum) may deserve taxonomic recognition as an infrageneric taxon. However, our results do not resolve relationships among major African and Malagasy lineages of the genus.Conclusions/Significance. We present the first molecular phylogenetic analysis of Pachypodium. Our work has revealed five distinct lineages, most of which correspond to groups recognized in past taxonomic classifications. Our work also suggests that there is a complex biogeographic relationship between Pachypodium of Africa and Madagascar

Extinction vulnerability of tropical montane endemism from warming and upslope displacement: a preliminary appraisal for the highest massif in Madagascar

One of the predicted biological responses to climate warming is the upslope displacement of species distributions. In the tropics, because montane assemblages frequently include local endemics that are distributed close to summits, these species may be especially vulnerable to experiencing complete habitat loss from warming. However, there is currently a dearth of information available for tropical regions. Here, we present a preliminary appraisal of this extinction threat using the herpetological assemblage of the Tsaratanana Massif in northern Madagascar (the island's highest massif), which is rich with montane endemism. We present meteorological evidence (individual and combined regional weather station data and reanalysis forecast data) for recent warming in Madagascar, and show that this trend is consistent with recent climate model simulations. Using standard moist adiabatic lapse rates, these observed meteorological warming trends in northern Madagascar predict upslope species displacement of 17–74 m per decade between 1993 and 2003. Over this same period, we also report preliminary data supporting a trend for upslope distribution movements, based on two surveys we completed at Tsaratanana. For 30 species, representing five families of reptiles and amphibians, we found overall mean shifts in elevational midpoint of 19–51 m upslope (mean lower elevation limit 29–114 m; mean upper elevation limit −8 to 53 m). We also found upslope trends in mean and median elevational observations in seven and six of nine species analysed. Phenological differences between these surveys do not appear to be substantial, but these upslope shifts are consistent with the predictions based on meteorological warming. An elevational range displacement analysis projects complete habitat loss for three species below the 2 °C ‘dangerous’ warming threshold. One of these species is not contracting its distribution, but the other two were not resampled in 2003. A preliminary review of the other massifs in Madagascar indicates potential similar vulnerability to habitat loss and upslope extinction. Consequently, we urgently recommend additional elevational surveys for these and other tropical montane assemblages, which should also include, when possible, the monitoring of local meteorological conditions and habitat change.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74789/1/j.1365-2486.2008.01596.x.pd

Grass Functional Traits Differentiate Forest and Savanna in the Madagascar Central Highlands

<p>Grassland, woodland, and forest are three key vegetation types that co-occur across the central highlands of Madagascar, where the woodland has historically been considered as degraded forest. Here, we use grass functional traits to inform our understanding of the biogeography of Malagasy vegetation and the differentiation of vegetation types in the region. We sampled grass community composition at 56 sites across the central highlands of Madagascar spanning grassland, woodland, and forest. We selected seven functional traits known to correlate with different aspects of life history collated via GrassBase (habit, culm type, physiology, leaf consistency, plant height, leaf width, and leaf length) for the 71 constituent species. Via analyses of the beta diversity, rank abundance, functional dispersion, functional group richness, and community phylogenetic structure of grassland communities, we differentiate these vegetation types using plant functional traits. Grassland and woodland are highly similar in grass species composition and dominated by the same species (Loudetia simplex, Trachypogon spicatus, and Schizachyrium sanguineum). In contrast, forest grass species composition significantly differs from both grassland and woodland. Consistent with these species composition patterns, the vegetation types can be distinguished based on physiology, culm type, and leaf consistency. Forests harbor primarily C₃ grasses, which are almost invariably laterally spreading with herbaceous leaves. In contrast, both grassland and woodland species are predominantly tall, caespitose C₄ grasses with coriaceous leaves. Forest grasses are phylogenetically clustered and less diverse than the grassland and woodland communities. Further, we sampled bark thickness of the common woody species occurring in the woodland and forest of the region and found that the relative bark thickness of the woodland tree species was significantly greater than that of forest species from the same genus. We found that the functional traits and architecture of grasses diverge strongly between forest and the grassland-woodland mosaic. We conclude that the woodlands, primarily dominated by Uapaca bojeri Baill., are a form of savanna and not forest as has been previously suggested.</p

Resource Warfare, Pacification and the Spectacle of ‘Green’ Development: Logics of Violence in Engineering Extraction in Southern Madagascar

Bringing political ecology's concern with the critical politics of nature and resource violence into dialogue with key debates in political geography, critical security studies and research on the geographies and phenomenology of violence and warfare, this paper explores strategies ‘from above’ in relation to the establishment and operation of the Rio Tinto QIT-Madagascar Minerals (QMM) ilmenite mine in southeast Madagascar. While QMM claims to be a responsible ‘green’ self-regulator and sustainable development actor, it has triggered serious social, environmental and legal conflicts since its inception, including allegations of a ‘double land grab’ to accommodate mining activities and compensatory biodiversity offsetting. We argue that ‘pacification’, theorised as a productive form of violence that works through the re-ordering of socio-nature, underwrites the forms of ‘security’, ‘stability’ and even ‘sustainability’ that facilitate multiple and overlapping strategies of value extraction in the territorial and extra-territorial spaces occupied by the QMM mine partnership. By situating these dynamics historically, we identify ways in which pacification draws upon sedimented and evolving logics of racialised violence to facilitate operations and silence opposition