Spatially explicit multi-threat assessment of food tree species in Burkina Faso: A fine-scale approach

Abstract

Over the last decades agroforestry parklands in Burkina Faso have come under increasing demographic as well as climatic pressures, which are threatening indigenous tree species that contribute substantially to income generation and nutrition in rural households. Analyzing the threats as well as the species vulnerability to them is fundamental for priority setting in conservation planning. Guided by literature and local experts we selected 16 important food tree species (Acacia macrostachya, Acacia senegal, Adansonia digitata, Annona senegalensis, Balanites aegyptiaca, Bombax costatum, Boscia senegalensis, Detarium microcarpum, Lannea microcarpa, Parkia biglobosa, Sclerocarya birrea, Strychnos spinosa, Tamarindus indica, Vitellaria paradoxa, Ximenia americana, Ziziphus mauritiana) and six key threats to them (overexploitation, overgrazing, fire, cotton production, mining and climate change). We developed a species-specific and spatially explicit approach combining freely accessible datasets, species distribution models (SDMs), climate models and expert survey results to predict, at fine scale, where these threats are likely to have the greatest impact. We find that all species face serious threats throughout much of their distribution in Burkina Faso and that climate change is predicted to be the most prevalent threat in the long term, whereas overexploitation and cotton production are the most important short-term threats. Tree populations growing in areas designated as ‘highly threatened’ due to climate change should be used as seed sources for ex situ conservation and planting in areas where future climate is predicting suitable habitats. Assisted regeneration is suggested for populations in areas where suitable habitat under future climate conditions coincides with high threat levels due to short-term threats. In the case of Vitellaria paradoxa, we suggest collecting seed along the northern margins of its distribution and considering assisted regeneration in the central part where the current threat level is high due to overexploitation. In the same way, population-specific recommendations can be derived from the individual and combined threat maps of the other 15 food tree species. The approach can be easily transferred to other countries and can be used to analyze general and species specific threats at finer and more local as well as at broader (continental) scales in order to plan more selective and efficient conservation actions in time. The concept can be applied anywhere as long as appropriate spatial data are available as well as knowledgeable experts.

Tree genetic resources at risk in South America: A spatial threat assessment to prioritize populations for conservation

“…We chose 1.2 as the threshold value, which is 2/5 of the maximum value of 3, distinguishing low threat values from medium and high threat values (>2/5 of the maximum value). For choosing this threshold, we followed a 5-point threat scale after IUCN-CMP (2007) and modified by Gaisberger et al (2017).…”

“…The threat maps used in this study were made with freely available data. It is straightforward to develop your own threat maps with this freely available data (Gaisberger et al, 2017;Samuel, Drucker, Andersen, Simianer, & Zonneveld, 2013). We used historical species location records, freely available through online portals such as the Global Biodiversity Information Facility (GBIF), which facilitates repeatability of spatial threat assessments for other species.…”

“…Expert feedback is an alternative approach to indicate species-specific threat sensitivity, and social science methods can be used to formalize the feedback from experts (Gaisberger et al, 2017;Metcalf & Wallace, 2013).…”

Impact of environmental conditions on fruit production patterns of shea tree (Vitellaria paradoxa C.F.Gaertn) in West Africa

“…The decrease in shea tree parklands increased during the past few decades due to climate change and high human pressure such as overexploitation and agropastoral activities (Boffa, ; Gaisberger et al, ). The reduction of tree density, the predominance of old trees and lack of regeneration in shea tree populations are an evidence of the degradation of these parklands (Okullo, Hall, & Masters, ; Teklehaimanot, ).…”

Climate Change and Fading Genetic Resources of <em>Parkia biglobosa</em> (Jacq.) in Nigeria Based on SSR Markers

“…Genetic resources are fading away, and improved tree management practices are lacking while genetic improvement are not sufficiently promoted. The species is threatened by over-exploitation, bush fires, and a progressive habitat degradation leading to fragmentation of tree populations [18]. In addition, overgrazing by domestic animals causes a lack of regeneration and an over-aging of tree individuals in savanna parklands; additional potential threats are also envisaged as a result of the absence or declining number of pollinators [5,6,17].…”