Interactions between Climate and Land Cover Change over West Africa

Abstract

Climate–land interaction over West Africa has often been assessed using climate simulations, although the model-based approach suffers from the limitations of climate models for the region. In this paper, an alternative method based on the analysis of historical land cover data and standardized climatic indices is used to investigate climate–land interactions, in order to establish climatic conditions and their corresponding land cover area changes. The annual variation in land cover area changes and climatic changes are first estimated separately and then linked using various spatiotemporal scales. The results show that incidences of land cover change result from abrupt changes in climatic conditions. Interannual changes of −1.0–1.0 °C, 0–1.5 °C, and −0.5–0.5 °C, and up to ±50 mm changes in precipitation and climatic water balance, lead to 45,039–52,133 km2, 20,935–22,127 km2, and approximately 32,000 km2 changes, respectively, while a ±0.5 °C and ±20 mm change represents normal climate conditions with changes below 20,000 km2. Conversely, conversions of cropland, forest, grassland, and shrubland are the main land cover change types affecting the climate. The results offer a basis for the re-evaluation of land cover change and climate information used in regional climate models simulating land–climate interactions over West Africa.

Potential impact of climate change on spatial distribution of two savannah amphibian species in West Africa

“…Furthermore, an increase in the number of extreme rainfall days in West Africa has been projected especially in its Sahelian part (Vizy & Cook, 2012), with more intense and frequent occurrences of extreme rainfall over the Guinea highlands and Cameroon mountains (Haensler et al, 2013; Sylla et al, 2012). However, from 1975 to 2019, the natural landscape of the West African biogeographic region has been progressively replaced by an anthropogenic landscape dominated by agriculture (Barnieh et al, 2020; Dimobé et al, 2015; Gansaonré, 2018; Mortey et al, 2023). Thus, due to the predicted increase in humidity, the loss of the large part of the Sudanian and Guinean forests which are replaced by savannah zones (Mortey et al, 2023), and the results shown by Figure 5b–e, the future climate is likely to become more suitable for P. bibroni .…”

“…However, from 1975 to 2019, the natural landscape of the West African biogeographic region has been progressively replaced by an anthropogenic landscape dominated by agriculture (Barnieh et al, 2020; Dimobé et al, 2015; Gansaonré, 2018; Mortey et al, 2023). Thus, due to the predicted increase in humidity, the loss of the large part of the Sudanian and Guinean forests which are replaced by savannah zones (Mortey et al, 2023), and the results shown by Figure 5b–e, the future climate is likely to become more suitable for P. bibroni . The increasing favourable habitats of P. bibroni in the future could also be explained by the fact that this species prefers savannah shrub‐land and grassland to forest habitats (Amphibiaweb, 2023; Rödel, 2000).…”

“…This should be an important signal to conservationists. Several studies have shown that in West Africa, some natural zones (savannah‐protected areas and forest zones) will decrease in area under climate change and anthropogenic impacts (Barnieh et al, 2020; Dimobé et al, 2015; Gansaonré, 2018; Mortey et al, 2023), leading sometimes to the disappearance of small forest groups in Niger, or conversely expected to remain stable in Burkina Faso and Côte dʼIvoire in the future (Niasse et al, 2004). Yet, it is in these natural areas that amphibians could find refuge!…”

“…We would like to draw the attention of decision‐makers in natural resource conservation programmes to strengthen and emphasise the management and protection of currently available natural habitats and also to reframe the size of agricultural land holdings in West Africa. This will help mitigate the loss of natural areas in which amphibians live today, as anthropogenic action induces climate change (Barnieh et al, 2020; Mortey et al, 2023). We also recommend that amphibian conservation actions focus more on areas with high biodiversity conservation potential located in the Sudanian and Guinean bioclimatic zones, which will be greatly affected by climate variation and land cover change in West Africa in the future.…”

“…Previous studies have shown that the distribution of amphibian species in different areas across West Africa is linked to the availability of various habitats, and species diversity is highest in dense or non‐degraded forest areas (Ernst & Rödel, 2005; Ernst et al, 2006; Hillers et al, 2008). It is thus concerning that in recent decades, West African countries have lost and continue to lose large areas of natural habitat (Barnieh et al, 2020; Mortey et al, 2023). In addition to the anthropogenic threats, it has been observed that this region will face a temperature increase of between 3 and 6°C by 2100, combined with severe changes in precipitation, in the non‐sustainable use of savannah vegetation, and in a higher variability of the rainfall events (Fields et al, 2014).…”