Water balance in a banded vegetation pattern: A case study of tiger bush in western Niger

摘要: Abstract The tiger bush is a patterned woodland with alternating bare area and vegetated stripes. In Niger, it covers one third of the Sahelian zone. These natural forests are considerable economical interest since they main source livestock forage domestic energy. Its sustainable exploitation needs improved understanding its dynamics. redistribution water between thicket intervening areas decisive for supply vegetation. Tiger patterning replicates an elementary unit composed area, upslope border, core downslope margin thicket. (Each zone characterised by specific soil crusting associated vegetation). Both storage runoff have been monitored after each rain, over period 4 yr, including contrasting rainy seasons, on different zones composing bush. On three crusted zones, has piecewise linear relationship rain: closed plots, yield vs. annual rainfall ratio reaches 54% soil, 2% border 18% border. measured infiltration confirms these rates independent plots. thicket, corresponds sum contributions weighted their relative lengths. This model predicts that contributes up to 62% supply, while direct rain 27%, senescence 10% contribution negligible (1%). average in equal 4× incident rainfall, but not homogeneous within By most favourable location, depth be about 8× rainfall. important runoff, mainly generated impervious crosses without infiltrating, entirely benefit core. Nothing left only rainfed. often described as location young plants rainfed part year. end season, increasing porosity, due vegetation termite activity let last rains. simple balance based measurement satisfactorily validated observed infiltration.