Pastoralists use resource spatial heterogeneity during drought to prevent livestock from climatic disaster in semi-arid rangelands. Although resource spatial heterogeneity occurred at different scales: rainfall spatial variations generate large-scale and geographic variation generates small-scale of resource spatial heterogeneity, how pastoralists select these different scales of resource heterogeneity is not clear. Here we examined that the economic conditions of pastoralists may affect selection of the scale of resources heterogeneity during droughts.

We interviewed to 77 pastoralists in Mandalgobi, Mongolia and asked them what they base their pasture selections on during droughts and the number of livestock they have as an indicator of economic condition.

Poor pastoralists selected small-scale of resource heterogeneity that are cause by geographic variation whereas rich pastoralists selected large-scale of resource heterogeneity that are caused by rainfall spatial variation. These different selections may affect the distribution of grazing impact and thus we suggested that economic condition of pastoralists should be taken into account when assessing grazing impact on the ecosystem.