Estimating urban population patterns from stereo-satellite imagery

With more than half of the world’s population living in towns and cities, urban areas get more and more into the focus of humanitarian relief organisations such as ICRC, Médecins sans Frontières (MSF), or SOS Children’s Villages. A key information required for almost any intervention is an estimation of the population numbers for the towns and cities where these organisations operate in. As census data are usually not available or outdated, population numbers have to be estimated by alternative methods such as remote sensing. To do that built-up densities are estimated from high-resolution image data and population numbers are disaggregated proportional to the densities in a top-down approach. Alternatively, population counts per density unit can be aggregated following a bottom-up approach. Both approaches were tested applying normalised Digital Surface Models (nDSM) derived from tri-stereo Pléiade images for Salzburg, Austria and Port-au-Prince, Haiti; the former for testing the quality and stability of the approach in a well-known setting, the latter for testing the approach in a critical environment. Key findings are that satellite-derived nDSMs provide sufficient accuracy for estimating population distributions, as long as reliable information is available for the separation of residential and non-residential urban areas

Landscape analysis and tsunami damage in Aceh: comment on Iverson and Prasad (2007)

Data presented in Iverson and Prasad (2007), Using landscape analysis to assess and model tsunami damage in Aceh province, Sumatra. Landscape Ecology 22: 323–331 do not justify their conclusion that tree belts provided an effective defence against the Indian Ocean tsunami in Aceh, Indonesia. The mitigation hypothesis is not explicitly tested, and their modelling approach to predict areas susceptible to tsunami damage ignores many variables known to be important in the area studied

The Global Risk Analysis for the 2009 Global Assessment Report on Disaster Risk Reduction

In May 2009, the UNISDR system published the 2009 Global Assessment Report on Disaster Risk Reduction (GAR 2009). One component of this report consisted in a global risk analysis. This task was performed by several institutions which join their efforts during two years to achieve a global modelling of hazards. This includes new hazard models for floods, tropical cyclones, landslides, drought and tsunamis as well as re-interpretation of earthquakes hazard. It allowed for the computation of human and economical exposure. A totally new methodology was used to calibrate vulnerability by using a so- called "event per event" analysis. This allowed determining what are the socio-economical and contextual parameters that are associated with human and economical vulnerability. This new methodology allows considering the intensity of each event as well as contextual parameters in order to compute the risk for different natural hazards. Risk maps were produced for four natural hazards (i.e. floods, earthquakes, landslides and tropical cyclones). This was provided at a resolution of 1 x 1 km. This also allow for the computation of an index for comparing the risk level of different countries. Trend in risk were also studied

Wetlands, livelihoods and human health

In developing countries millions of people live a life of subsistence agriculture, mired in poverty, with limited access to basic human needs, such as food and water. Under such circumstances wetlands, through the provision of a range of direct and indirect ecosystem services, play a vital role in supporting and sustaining peoples’ livelihoods and hence, their health. This chapter discusses the role of wetlands in the context of the sustainable livelihoods framework in which wetlands are viewed as an asset for the rural poor in the form of “natural capital”. The framework is used to illustrate how ecosystem services, livelihoods and health are entwined and how the ecosystem services provided by wetlands can be converted to human health either directly or via other livelihood assets. It highlights the contributions that wetlands make to basic human needs and, either directly or through transformations to other forms of livelihood capital, the support they provide to livelihoods and overall well-being

A brief history of mangrove distribution and coastline development in soc Trang Province, Vietnam, to address coastal management strategies

Coastlines and their mangrove forests change over time under the influence of human and natural drivers. To design appropriate mangrove reforestation interventions, we use the Vietnamese province of Soc Trang, at the Bassac River mouth, as a case study to understand coastal zone changes. Our research, covering 1904–2007, is based on historical material from the French colonial period (topographic maps, reports), satellite images, and onsite interviews with key informants. Since 1904, the coastline and mangrove forests have changed significantly, including a sequence of deforestation and reforestation in some areas, changes in tree species composition, transformation of the coastline landscape from sand dunes to mangrove forests, and large-scale accretion at the river mouth. The natural processes of accretion and erosion have changed over time for the same area in Vin Chau District, thus influencing mangrove cover and reforestation programs. Damage to the mangrove forest during the Vietnam War due to defoliants was localised to specific areas along the coastline, and damaged trees were later cut for local use. Deforestation for fuelwood, expansion of farming areas, access rights, and usage of the mud flats during the French colonial period, followed by reforestation that modified the original species composition, are the main drivers of coastline changes. These drivers influence the coastline and mangrove cover dynamics in different ways. The knowledge of historical processes and coastal dynamics is important in developing climate change adaptation strategies, which combine such site-specific measures as effective mangrove protection and management, mangrove rehabilitation, and engineering measures.</p

From bathymetry to bioshields: a review of post-tsunami ecological research in India and its implications for policy

More than half a decade has passed since the December 26th 2004 tsunami hit the Indian coast leaving a trail of ecological, economic and human destruction in its wake. We reviewed the coastal ecological research carried out in India in the light of the tsunami. In addition, we also briefly reviewed the ecological research in other tsunami affected countries in Asia namely Sri Lanka, Indonesia, Thailand and Maldives in order to provide a broader perspective of ecological research after tsunami. A basic search in ISI Web of Knowledge using keywords "tsunami" and "India" resulted in 127 peer reviewed journal articles, of which 39 articles were pertaining to ecological sciences. In comparison, Sri Lanka, Indonesia, Thailand and Maldives had, respectively, eight, four, 21 and two articles pertaining to ecology. In India, bioshields received the major share of scientific interest (14 out of 39) while only one study (each) was dedicated to corals, seagrasses, seaweeds and meiofauna, pointing to the paucity of research attention dedicated to these critical ecosystems. We noted that very few interdisciplinary studies looked at linkages between pure/applied sciences and the social sciences in India. In addition, there appears to be little correlation between the limited research that was done and its influence on policy in India. This review points to gap areas in ecological research in India and highlights the lessons learnt from research in other tsunami-affected countries. It also provides guidance on the links between science and policy that are required for effective coastal zone management. © 2010 Springer Science+Business Media, LLC.(IF52009 = 1.895; IF2009 = 1.503; CHL = 8.2).SCOPUS: re.jinfo:eu-repo/semantics/publishe