To document trends in land use and herbaceous production, 71 field sites sampled among cropped fields, fallow fields and rangelands in the Fakara region (Niger) were monitored from 1994 to 2006. The overall trend in land use confirmed the historical increase of the cropped areas since mid 20th century, at an annual rate of 2% from 1994 to 2006. This trend is the result of changes in the relative extent of fields permanently cropped and fields under shifting cultivation, and for the latter, the relative proportion of short (3 years) and long (10 years) duration fallows. Type of land use together with topography and soil type determine the herbaceous production and the resulting yield measured towards the end of the wet season. The variation in site yields between years is of the same order of magnitude as the variation in yields between sites within a year. There is an overall decreasing trend in site yields by 5% annually from 1994 to 2006 that is not explained by variations in rainfall. The decreasing trend is observed on fields under shifting cultivation, fallowed fields and rangelands, although not all sites are equally affected. Causes are likely to be multiple which might include changes in land use, decline of soil fertility and increased grazing pressure. Indeed, the remaining rangelands on marginal land and the fallows still accessible to livestock are subject to such a heavy grazing during the rainy season that the herbaceous standing mass measured at the end of the season reflects poorly the actual production. After the two first years of cropping, the herbaceous yield in fields under shifting cultivation with no fertilisation is negatively affected by the number of successive years of cropping. Moreover, clearing fallow after a decreasing number of years affects the mean herbaceous yield of fallowed fields by reducing the contribution of more productive old fallows. Changes in land use, grazing pressure and soil fertility also triggered changes in species composition with a strong reduction in diversity from rangelands to fallows, and again from fallows to cropland weeds. No correlations was found however between productivity and species composition. Cumulative rainfall does not explain between site or between year deviations in herbaceous yield even when sites are sorted by land use type or by soil type in the case of fallow and rangelands. Simulated production calculated with the STEP model does not explain herbaceous yields much better even when sites are grouped by land use and soil type. However, relative changes of herbaceous yields are reasonably predicted on sites that remained fallowed and were not heavily grazed for at least four consecutive years

Drought is one of the major climatic hazards impacting on the various sectors including crop and livestock in the West African Sahel. Pastoral and agro-pastoral communities in the region are regularly affected by drought, with vulnerability differing with gender, age, wealth status (access to cropland and livestock endowment), geographic location, social networks, and previous exposure to drought. Effective interventions require regular monitoring of vulnerability to drought, for which various quantitative and qualitative approaches exist. Qualitative assessments of vulnerability rely on participatory approaches with emphasis on involvement of the local communities in the analysis of their vulnerability to climate-induced stresses. In this study, we used a participatory approach to assess the vulnerability of three agro-pastoral communities in Niger to drought. The specific objective of this study was to assess the strength and limitation of a participatory vulnerability approach using a case study. According to the respondents in all the study sites, the incidence of drought has become more frequent in the last three decades compared to previous decades (before 1970). The impacts of drought on livelihoods according to the participants included food shortage, famine, forced sale of livestock to buy grain, decimation of livestock herds, and massive exploitation of woody plant species. The main weakness of participatory vulnerability assessments is the scalability of findings, as they are often location-specific. Therefore, participatory assessment should be complemented with more rigorous quantitative approaches to enhance applicability of the results to other locations with similar contexts.

Changing woody plant density across agricultural landscapes of the Sudano-Sahelian region is a debated issue. This paper reports the results of an investigation on the contribution of field hedges to overall woody plant density. Hedges separating individual cropped parcels were studied within village agropastoral territories in the Dantiandou district in western Niger. In 1992, field hedges were mapped over the study area using aerial photography and in 2016, using high resolution Google Earth imagery. In 1992, field hedge length was equal to 1006 km within 435 km² of croplands, equivalent to 2.3 km km-2. In 2016, 17.5% of these hedges had disappeared, but 1591 km of new hedges were observed resulting in an increased density of hedges to 5.6 km km-2. In 24 years, hedges had increased at a mean annual rate of 3.7% likely associated with the splitting of crop fields by inheritance. The composition and productivity of hedges were also monitored in 1996, 2010 and 2015. All trees (maximum height ≥4m), shrubs (<4m) and tussock perennial grasses were recorded within twelve field hedge samples of 200m each. Field measurements were used to estimate basal area, crown area, foliage mass and wood mass of each woody plant within the sampled hedges. No significant trends were found between 1996 and 2015 in woody plant density, basal area, crown cover, wood and foliage masses across all monitored hedges. However, overall means hide a slight decrease in tree contributions, while shrub contributions first increased and then decreased. They also mask contradictory trends among sites most likely related to different rates of shrub coppicing and tree cutting. The woody species composition of the hedges is poor with an increase of Combretum glutinosum to the detriment of Guiera senegalensis over the study period. Multiplying the hedge sample statistics by the changing lengths of field hedges in the study area provides estimates of the contribution of the hedge woody plants to the woody plant population at a landscape scale. Between 1992 and 2016, field hedges contributed to increases of woody plant density by 3.9%, basal areas by 5.4% , crown cover by 2.7% , leading to 6.1% annual increase in foliage mass and 8.8% increase in wood mass.