Julie Pierson

Genetic data suggest a natural prehuman origin of open habitats in northern Madagascar and question the deforestation narrative in this region

The impact of climate change and anthropogenic deforestation on biodiversity is of growing concern worldwide. Disentangling how past anthropogenic and natural factors contributed to current biome distribution is thus a crucial issue to understand their complex interactions on wider time scales and to improve predictions and conservation strategies. This is particularly important in biodiversity hotspots, such as Madagascar, dominated by large open habitats whose origins are increasingly debated. Although a dominant narrative argues that Madagascar was originally entirely covered by woodlands, which were destroyed by humans, a number of recent studies have suggested that past climatic fluctuations played a major role in shaping current biome distributions well before humans arrived. Here, we address the question of the origin of open habitats in the Daraina region in northern Madagascar, using a multiproxy approach combining population genetics modeling and remote-sensing analyses. We show that (i) contrary to most regions of Madagascar, the forest cover in Daraina remained remarkably stable over the past 60 y, and (ii) the golden-crowned sifaka (Propithecus tattersalli), a forest-dwelling lemur, underwent a strong population contraction before the arrival of the first humans, hence excluding an anthropogenic cause. Prehuman Holocene droughts may have led to a significant increase of grasslands and a reduction in the species’ habitat. This contradicts the prevailing narrative that land cover changes are necessarily anthropogenic in Madagascar but does not preclude the later role played by humans in other regions in which recent lemur bottlenecks have been observed.

Spatial Data Sharing: A Pilot Study of French SDIs

Since the appearance of Spatial Data Infrastructure several years ago, there has been a tremendous increase in spatial data available on the Internet. This situation raises several research issues, in terms of identifying the content actually accessible via this medium and its impact on governance and local authority management. Our study proposes a mixed methodology applied to 45 French institutional infrastructures, to compare the objectives stated by their promoters, their content, and the actual services provided. The methodology, based on an analysis of interviews with Spatial Data Infrastructure (SDI) coordinators and their answers to questionnaires, as well as a study of their websites and an exploration of over 160,000 metadata in their metadata catalogues, produced varied results concerning data accessibility, stakeholder networks, the interoperability of tools, and informational equality in different regions. Despite the proactive stance of SDI promoters, only 15.7% of data are open-access. Their interoperability remains restricted to specific types of actors and themes. Although geocollaboration organised by SDIs is very active, it only concerns the public sector. These disparities also concern their informational dimension, as some regions have considerable resources at their disposal, but others do not.