Sample Chapter - United Nations University

12 RENAUD, SUDMEIER-RIEUX AND ESTRELLA
based on an original paper by Kathiresan and Rajendran in 2005 that was
subsequently debated by Kathiresan and Rajendran, 2006; Kerr et al.,
2006; Vermaat and Thampanya, 2006, 2007; as well as further results and
discussions by Cochard et al., 2008; Danielsen et al., 2005; Kaplan et al.,
2009; Kerr and Baird, 2007; Renaud 2013; Chapters 3 and 4 in this volume).
Nonetheless, in the interval between the Indian Ocean tsunami disaster
and the systematic and scientific collection of evidence on the role
of coastal vegetation in protecting populations against tsunami waves,
millions of dollars were spent in replanting mangroves in various affected
countries, sometimes with disappointing results (see Cochard, 2011).
Even in areas where mangroves were successfully established, further research
is required to ascertain whether populations are more protected
from tsunami waves.
Another example where further scientific analysis is required relates to
determining linkages between vegetation/forest cover and flooding. It is
often perceived that the greater the forest cover the less the likelihood of
floods. However, this is a subject that is still scientifically debated (Bradshaw
et al., 2007; van Dijk et al., 2009; WWF, 2008). For example, the
Food and Agriculture Organization and the Center for International
Forestry Research (FAO and CIFOR, 2005) showed that the cause–effect
relationship will vary depending on the scale of the flood-generating
weather event and of the catchment considered. This was confirmed further
by Bathurst et al. (2011a, 2011b) through rigorous empirical and
modelling catchment-scale studies in Latin America.
The two examples above point to areas where more research is required
to establish the role of ecosystems in DRR. As mentioned in the
previous section, there are, however, many examples where greater certainties
exist and where ecosystems have been integrated in risk prevention
actions. In order for the role of ecosystems to be considered seriously
by decision-makers at various governance scales, research gaps need to
be addressed by the science community and implementation experiences
upscaled and better communicated by practitioners in terms of what
works and what does not work (see Chapter 18 in this volume).
Another potential pitfall is to overemphasize the role of ecosystems in
DRR. That ecosystems and society are intertwined goes without saying
but, in order to reduce future disaster risks, we need to analyse complex
vulnerability, risk and environmental factors in a more systematic manner.
As an example we can consider the situation on the island of Hispaniola,
which is divided between Haiti and the Dominican Republic. In
2004 both countries were affected by intense rainfall brought about by a
low pressure system, which generated flooding in the south-central, crossborder
region of the island on 24–25 May (Gubbels and Brakenridge,
2004), and by Hurricane/Tropical Storm Jeanne, which affected the island