RESUMO
The design of appropriate adaptation strategies to the impacts of climate change requires a contextual study of local perceptions due to the non-homogeneity of climate in a given agro-ecological area. The research objective of the current study aims to examine the evolution of climate parameters from 1983 to 2019 linked to the perceptions of local populations and appropriate adaptation measures in the Belabo-Diang Communal Forest of Cameroon. The methodological approach includes collecting and analyze climate data from 1983 to 2019; and surveying existing local perceptions and adaptive strategies among 540 households using semi-structured questionnaires. A significant increase in temperature of about 1 °C over 36 years (1983-2019) and a non-significant decrease in precipitation (95.36 mm) over the same period were observed. Local perceptions related to climate change vary according to the sector of activity and are mainly associated with more heat in the dry season (90%), late onset of rains (84%), drought recurrence (82%), less rainfall during the year (80%), and increase in the duration of drought (80%). For 82-100% of households, according to the activity sector, no appropriate adaptation measures to climate change were applied depending on activities. The adaptation measures used by less than 0-20% of respondents, include mainly the abandonment or change of activity, and modification of the agricultural calendar. With the lack of appropriate and adequate adaptation measures by the riparian populations, this study appears necessary to inform policy-makers of the need to develop and implement more appropriate strategies to enable the riparian people living in forest area of Cameroon to better adapt to these effects of climate changes.
RESUMO
Hydro-geochemical data are required for understanding of water quality, provenance, and chemical composition for the 2,117,700 km2 Niger River Basin. This study presents hydro-geochemical analysis of the Benue River Basin, a major tributary of the Niger River. The distribution of major ions, Si, δD, and δ18O, trace and rare-earth elements (TE and REEs, respectively) composition in 86 random water samples, revealed mixing of groundwater with surface water to recharge shallow aquifers by July and September rains. Equilibration of groundwater with kaolinite and montmorillonites, by incongruent dissolution, imprints hydro-chemical signatures that vary from Ca + Mg - NO3 in shallow wells to Na + K - HCO3 in boreholes and surface waters, with undesirable concentrations of fluoride identified as major source of fluorosis in the local population. Our results further indicate non-isochemical dissolution of local rocks by water, with springs, wells and borehole waters exhibiting surface water-gaining, weakest water-rock interaction, and strongest water-rock interaction processes, respectively. Poorly mobile elements (Al, Th and Fe) are preferentially retained in the solid residue of incongruent dissolution, while alkalis, alkaline earth and oxo-anion-forming elements (U, Mo, Na, K, Rb, Ca, Li, Sr, Ba, Zn, Pb) are more mobile and enriched in the aqueous phase, whereas transition metals display an intermediate behavior. Trace elements vary in the order of Ba > Sr > Zn > Li > V > Cu > Ni > Co > As > Cr > Sc > Ti > Be > Pb > Cd, with potentially harmful elements such as Cd, As, and Pb mobilized in acidic media attaining near-undesirable levels in populated localities. With the exception of Y, REEs distribution in groundwater in the order of Eu > Sm > Ce > Nd > La > Gd > Pr > Dy > Er > Yb > Ho > Tb > Tm differs slightly with surface water composition. Post-Archean Average Australian Shale-normalized REEs patterns ranging from 1.08 to 199 point to the dissolution of silicates as key sources of trace elements to groundwater, coupled to deposition by eolian dust.
