Vulnerability of wild indigenous agroforestry species to climate change in Niger State, Nigeria: A proxy analysis

摘要

This study assessed the vulnerability of five indigenous agroforestry trees to climate change: Adansonia. digitata, Vitellaria paradoxa, Parkia biglobosa, Tamarindus indica, and Vitex doniana, using the vulnerability of rural communities that rely on these species as a proxy. An integrated assessment approach, encompassing exposure, sensitivity, and adaptive capacity was adopted. Individual questionnaires were administered to 340 farmers, across seven Local Government Areas (LGA): Bosso, Rafi, Lavun, Lapai, Mashegu, Kontagora, and Borgu in Niger State. Data were collected on farmers' perceptions about species vulnerability to climate change. The vulnerability index was computed based on nineteen indicators. Trend analysis of rainfall and temperature dataset over 40 years, indicated on one side no trend of annual rainfall, but a significant increase of annual temperature on the other side, supported by high intra-annual variability. Although observed variabilities in the climate were confined within the known tolerance limits of these species, reduction in productivity was the most reported impact (58.21 of the respondents). A change in species' distribution, progressive extirpation, premature fructification, and tree mortality were also mentioned among the impacts of climate change. V. doniana was perceived to be the most vulnerable by 68.75 of the respondents followed by A. digitata, while V. paradoxa and T. indica seemed not to be vulnerable to climate change according to 48.65 and 27.00 of the respondents, respectively. There was a spatial variability of species vulnerability. The study concluded that the cultural importance of the species influences the extent to which the species are perceived to be vulnerable to climate change. This conclusion draws more attention toward the promotion of sustainable use and conservation of indigenous tree species to reduce their vulnerability to future climate conditions.