Mangroves supply essential ecosystem services to tropical informal economies. In the Cameroon coastal region, the impacts of various projections on change in temperatures and precipitations sound low compared to the pressure of human activities. This survey evaluated the sensitivity of local population on the impact of climate change and the vulnerability of coastal ecosystems. An investigation carried out on 425 individuals was based on the major income and development activities, the knowledge of the subject, the information sources, the origin of changes, perceptible effects, risks and consequences. More than 90% of interviewees have heard about climate change essentially from radio (20%). Industries (47.53%) are perceived to have major responsibility for temperature (78%) and precipitation (67%) changes and increased inundation (39.07%) was perceived as the highest risk. Compared with Cartesian predictions in the area, the results have shown the sensitivity of population to local variation of climate factors. No efficient endogenous measure has been recorded. Forest and specially mangroves are the most affected ecosystems by local activities. Expected extension of the dry season could affect the natural regeneration and the structure of mangrove forests. Considering the importance of woody species in the local economies, the lack of appropriate actions and adaptation measures will lead to the total degradation of mangroves.
Several studies indicate that climate change is already taking place, and that the climate system is likely to experience some amount of change, regardless of whether emission reductions are successfully undertaken [
The fast increase in the gas issue rate for purpose of greenhouse, since the industrial revolution of the 19th century, has led to a constant increase of their concentration in the atmosphere, with serious potential consequences on the climate of our planet. The possible future modifications of the climate on a regional or local scale must be evaluated as of now, according to the precautionary principle. However this taking into account cannot be effective and requires that one has the clearest possible vision of disturbances. That requires estimating the climatic emissions, and future concentrations and modifications which would result from it.
As in certain areas of Africa, Cameroon is characterized by a strong climatic variation since 1960. The rise of pluviometry is palpable on annual, seasonal and monthly scales. The issue here is to bring out an analysis of the evolution of the climate parameters in Cameroon since 1961 to 2000 in order to establish the bond between the climatic disturbances and their impacts in certain development sectors such as agriculture, fishing, water and energy, etc. Significant studies on variability and the climatic fluctuations in relation to the development and the environment showed rainfall deficits of about 20%. These values might be sometimes higher than 25% on the Atlantic coast and in the forest areas that confirms that “wet” Tropical Africa is regularly under the effect of climatic variability [
Mangroves in Africa cover over 3.2 million ha, corresponding to about 20% of its global coastline coverage, with approximately 1.5 million ha located along the Atlantic coast [
Rapid population growth has affected resources, including arable land, food supplies, water and energy, especially in developing countries where government policy-makers still pay little attention to protect these coastal ecosystems [
In spite of their biological, economic and ecological values, mangroves continue to be greatly degraded because of sea level rise [
Cameroon is located on the Gulf of Guinea in Central Africa. It lies between latitude 1˚40'N and 13˚05'N and between longitude 8˚30'E and 16˚10'E. With a surface area of 475,412 km2, it has an extremely diversified landscape, including a variety of climatic and geomorphologic zones. The four major ecological zones of Cameroon include a tropical forest zone, a coastal and maritime zone, a savannah zone and a sudano-sahelian zone. Mangroves area cover about 1961.84 km2 grouped into three blocks [
Heavy annual rainfall totals are observed from more than 5000 mm in the Limbe area and decreased to about 3000 mm in the Kribi area. During the spring tide, the tidal regime reaches 3 m in the Cameroon Estuary, 1.2 m in the mouth of Nyong and 1.5 m in Kribi [
The flora consists essentially of tree species. The herbaceous stratum represents <1% of the entire vegetation. However, the flora remains poor with Rhizophora racemosa GF Meyer being largely the dominant vegetation in all sites. The faunal component includes vertebrates, such as birds, reptiles and fishes, and a wide range of invertebrates, mainly crabs and molluscs which constitute the bulk of benthic diversity in the region [
Local perception of climate change and adaptations were assessed using a wide range of methodologies. The methodology of evaluation used two generally known methods. A participative process based on specific investigations with the populations, to express their perception of the phenomenon associated with an analysis with the data of the climatic parameters.
The participatory process data were generated by conducting semi-structured interviews with local residents (living in the immediate vicinity of the mangroves) and our field based observations. The results of the investigations have been supplemented by the traditional methods used in the evaluation of the mangroves risks and the vulnerability to the climatic changes [
Interviews were conducted in French, English and local languages, sometimes with the help of translators. The households were sampled opportunistically (i.e., interviewing people in their homes as well as those out of their homes). To avoid recurrent information, only one person (>20 years of age) per house was questioned. The preference was given to (local) elderly people who have been living in the site for more than a generation and therefore could relate changes that had occurred in adjacent mangroves to certain events or conditions. Interviewees were asked if the surrounding mangrove forest coverage had increased, decreased or remained unchanged. Likewise, an attempt was made to distinguish whether local informants perceived mangrove forests as less or more degraded over time. They were urged to provide the causes of the reported changes and the derived consequences on their livelihood. They were also asked questions about any observed changes in the mangrove ecosystem.
A total of 425 persons were questioned. More than 55% of interviewees have heard about climate change essentially
from radio (20%), followed by television (17.7%) and newspapers (15%). The effects of the climatic changes felt are the rise of the temperatures (78%) and the rise of precipitations (67%). These effects have been felt for more than 10 years (72.7%). Contrary to scientific predictions, populations observed an increase of precipitations accompanied with the rise of floods frequency. Temperature increases are likely to result on faster growth, reproduction, photosynthesis and respiration, changes in community composition, diversity and an expansion of latitudinal limits [
The most practiced activities are trade of wood (24.5%), fishing (20.5%) and agriculture (19%). The degree of land utilization exploitable is raised and profits from the favorable climatic conditions. Industries through gas emissions, followed by transport and deforestation are responsible of the changes according to the interviewees (
The major risks of the climate change according to the interviewees are inundation, soil erosion and salt water intrusion (
associated increases in frequency of extreme sea level, waves and the storm surges, resulting in higher intensity and frequency of flooding and erosion of vulnerable coastal areas [
In Cameroon estuary, the effects of inundation will be more important than erosion, since the zone is largely dominated by muddy coasts. Consequently, the few sandy beaches in the mangrove area could be destroyed (
As the trees recede, more rapid erosion would occur, resulting in the formation of small cliffs in the seaward front. The salinity of mangrove creeks is relatively low, but varies with time and location. It has been reported that salinity on the same day varied between 17.5‰ and 19.5‰ at Mabeta, and between 12‰ and 17.5‰ at Tiko [
Intense human development within mangrove ecosystems, coupled with the rapid urbanization of adjacent towns and the excessive utilization of trees for the production of firewood, charcoal, and clearing for agricultural purposes, has led to the gradual degradation of these ecosystems. This degradation is expected to become worse in the future, largely as a result of a climate change that would induce sea level rise and salt water intrusion.
Only, 17.8% of women noted that the climate of their area has changed against 82.2% of men. The most widespread channel of information is radio (women, 35.6% and men, 41.6%). This change has been felt since 5 years for 69.3% of women, and since 10 years for 52.3% of men. The ages of the individuals were gathered into three classes of amplitude 20 with a base of 20 years. The first class was the most represented, while the class of 60 - 80 years was the least (
The channel of information more used is television for the young people, the press for the medium (40 - 60 years) and the radio for the old people (
In the operations of adaptation, it is necessary to have permanently in mind relevant questions as what or who must adapt before thinking on efficient mechanisms of adaptation. It is therefore important to establish solid relationships with the major targets in order to elaborate a list of scientific assumptions likely to improve knowledge when they are linked especially to the functioning of other parameters of the natural systems. In addition to this, a measure of adaptation will be better when the populations in charge of its implementation understand and appreciate the paramount necessity.
In accordance with the past and present climatic risks usually observed in the locality, the populations have adopted various types of behaviors to fit one’s surroundings. According to recorded events, the reactions achieved ranged from common panic to the abandonment of site. The relevant endogenous measures of adaptation from the survey and which can be used as a base of discussion in the determination of the potential options of adaptation are recorded in
The impacts of climate change are anticipated to be greatest in low and lower-middle-income countries where most of the world’s poor live [
It is widely recognized that judicious measures of adaptation can reduce the vulnerability. However, it is only very recently that research is deeply interested in the capacity of the populations to react to the environmental constraints and the extreme climatic events. We noted that, the term local endogenous measures is analogous to
Major climatic Risks | Consequences | Endogenous adaptation measures |
---|---|---|
Inundations | Loss of ecosystems | Migration of the population |
Diversification of activities | ||
Disturbance of agricultural and fishery activities | Rotation of crops | |
Development of truck farming | ||
Modification of fishing calendar | ||
Destruction of the infrastructures | Construction of pile houses | |
Raising of house foundation levels | ||
Drowning | Displacement of children and livestock | |
Fasten the craft on the nearest tree | ||
Soil erosion | Sandbanks of rivers | Exploitation of sandpits |
Opening of the streams | ||
Loss of the biodiversity | Avoid tree cuttings around houses | |
Learning of stock farming | ||
Destruction of the infrastructures | Construction of embankments | |
Building small dams on the tributaries | ||
Conflicts from the access and management of resources | Severe distribution of tasks in the community | |
Appointment and vote of leaders | ||
Reinforcement of local vigilance committees | ||
Salt water intrusion | Absence of drinkable water | Non usage of drinkable water for cooking |
Draw water early in the morning | ||
Duration of water in clay pots | ||
Destruction of the infrastructures | Non destruction of trees around houses | |
Violent winds | Hedges around plantations | |
Support crops with poles | ||
Drowning | Avoid fishing in full moon periods | |
Devote to new activities |
terms such as local and indigenous knowledge (LINK), local knowledge, traditional ecological knowledge, indigenous technical knowledge, endogenous knowledge [
- perceptions and understandings of climatic changes and related natural phenomena (prediction of storms based on observations of the sky, sea and wind);
- livelihood sustainability practices (livelihood diversification);
- survival, coping and mitigation strategies (migration to higher ground, construction of houses using local materials);
- cultural belief systems (traditional rituals and ceremonies).
All these categories have been encountered in the investigation. The third group seems to be the most frequent situation which is normal in the context of poverty. On the other hand, the migrations found in this survey area must be considered as a temporary measure of adaptation since populations always tend to return to their land after the end of the manifestations from an extreme climatic event.
Perception on climate change and sea level rise is already felt by local populations except the appreciation on rainfall. Observations varied significantly by age and sex. The increase in frequency of floods and their impacts are the relevant indicators for populations to refuse predicted rainfall deficits in the area. Expected extension of the dry season could affect the natural regeneration and the structure of mangrove forests. No efficient and continuous endogenous measure of adaptation has been recorded. Considering the importance of woody species in the local economies, the urban demographic pressure, the lack of appropriate actions and adaptation measures will lead to the total degradation of mangrove ecosystems around cities. In Cameroon, mangroves are only found in the Atlantic front and tributaries. The various mechanisms of adaptation could produce best results when they are integrated into other policies such as the fight against natural disasters and regional planning. Adaptation measures will therefore play a basic role in the reduction of the width and the stretch from the real impacts and from the vulnerability of coastal zones to the climatic change.
Ndongo Din,Vanessa Maxemilie Ngo-Massou,Guillaume Léopold Essomè-Koum,Ernest Kottè-Mapoko,Jean Michel Emane,Akusa Dorice Akongnwi,Richelieu Tchoffo, (2016) Local Perception of Climate Change and Adaptation in Mangrove Areas of the Cameroon Coast. Journal of Water Resource and Protection,08,608-618. doi: 10.4236/jwarp.2016.85050