Vulnerability to coastal flooding and response strategies : the case of settlements in Cameroon mangrove forests

Worldwide, millions of people experience coastal flooding each year, with devastating effects especially in rural coastal settlements in tropical developing countries. This paper investigates the vulnerability of local settlements in the Cameroon mangrove forest zone to flooding, and improves understanding of perceptions and responses to past and current coastal flooding. Six communities in the coastal mangrove forest zone of the extreme SouthWest of Cameroon were investigated. A questionnaire was administered to a total of 200 individuals supplemented by other participatory rapid appraisal tools. The ground positions of the sampled sites as well as their altitudes were recorded for subsequent geospatial analysis.Statistical analysis was performed to show trends. The coordinates of the study sites were superimposed on base topographic maps of 1965, to investigate coastal changes over a period of 43 years. Results show that: (1) changes in coastal area have occurred in the past 43 years either through inland retreat or seaward shifts and accordingly, settlements are differentially vulnerable; (2) settlement submergence, house damage, and landscape deformation are the key impacts of flooding; (3) coastal flooding promotes the deforestation of mangrove forest for fuel wood; (4) current adaptive measures include retreat of settlement, abandonment, and house design modifications; and (5) most adaptive strategies are reactive individual actions which are likely inefficient and unsustainable from a longer term perspective given their limited scope of implementation. The paper recommends external support to improve adaptive capacity in mangrove settlements, review and improvement of existing policies, and development of integrated coastal management strategy for the region

SETTING THE SCENE

Chapter published in The IPBES regional assessment report on biodiversity and ecosystem services for Africa, pp. 1-76International audienc

SETTING THE SCENE

Chapter published in The IPBES regional assessment report on biodiversity and ecosystem services for Africa, pp. 1-76International audienc

SETTING THE SCENE

Chapter published in The IPBES regional assessment report on biodiversity and ecosystem services for Africa, pp. 1-76International audienc

SETTING THE SCENE

Chapter published in The IPBES regional assessment report on biodiversity and ecosystem services for Africa, pp. 1-76International audienc

Distribution modeling and lineage diversity of the chytrid fungus <i>Batrachochytrium dendrobatidis</i> (<i>Bd</i>) in a central African amphibian hotspot

<div><p>The amphibian disease chytridiomycosis in amphibians is caused by the chytrid fungus <i>Batrachochytrium dendrobatidis</i> (<i>Bd</i>) and has resulted in dramatic declines and extinctions of amphibian populations worldwide. A hypervirulent, globally-dispersed pandemic lineage (<i>Bd</i>-GPL) is thought to be largely responsible for population declines and extinctions, although numerous endemic lineages have also been found. Recent reports of amphibian declines have been linked to the emergence of <i>Bd</i> in Cameroon, a major hotspot of African amphibian diversity. However, it is not known whether <i>Bd</i>-GPL or other lineages have been found in this region. This study therefore aims to examine <i>Bd</i> lineage diversity in the region and predict the distribution of this pathogen under current and future climate conditions using data from this study and from historical records. Almost 15% (52/360) of individuals tested positive for <i>Bd</i> using a standard quantitative PCR diagnostic. Infected amphibians were found at all eight sites sampled in this study. Species distribution models generated in BIOMOD2 indicate that areas with highest predicted environmental suitability occur in the Cameroon highlands and several protected areas throughout the country. These areas of high environmental suitability for <i>Bd</i> are projected to shift or decrease in size under future climate change. However, montane regions with high amphibian diversity are predicted to remain highly suitable. Phylogenetic analysis of the ITS sequences obtained from a set of positive <i>Bd</i> samples indicate that most fall within the <i>Bd</i>-GPL lineage while the remainder group with isolates from either Brazil or South Korea. Although more in depth phylogenetic analyses are needed, identification of <i>Bd</i>-GPL lineages in areas of high amphibian diversity emphasizes the need to continue to monitor for <i>Bd</i> and develop appropriate conservation strategies to prevent its further spread.</p></div

Map of the study region.

<p>Locations of the study sites, Campo Ma’an National Park (CM), Ebo Forest (EF), Lobéké National Park (LB), Mbam Djerem National Park (MD), Mount Cameroon village (MCV), Mount Cameroon (MC), Ndikiniméki (ND), and Takamanda (TM) are marked with yellow circles. Previously published <i>Bd</i> sample sites are marked with black circles. The sites sampled in this study have all been previously sampled with the exception of Mbam Djerem National Park and Takamanda. This figure was created with Natural Earth vector and raster map data (<a href="http://naturalearthdata.com" target="_blank">naturalearthdata.com</a>).</p

Environmental suitability modeled in BIOMOD2 for <i>Bd</i> under present and future climate projections.

<p>Future models include years 2030, 2050, and 2080 under the 2.6, 4.5, 6.0, and 8.5 RCPs. The scale indicates less suitable environment (cooler colors) and most suitable environment (warmer colors).</p

Phylogenetic tree of ITS rRNA sequences from global <i>Bd</i> samples.

<p>Isolates are color coded according to the country where they were collected. Samples from Cameroon are highlighted in yellow.</p