Multi-scale biomass estimation of desert shrubs:a case study of Haloxylon ammodendron in the Gurbantunggut Desert,China

Abstract

Shrubs are an important component of desert ecosystems.Their biomass allocation and biomass estimation are important indices to study the structure,function,mass,and energy flow of desert ecosystems. However,research on desert shrub biomasses is still limited.The current destructive biomass estimation is unsuitable for use in arid lands where the ecosystem is weak,so it is important to estimate the shrub biomass using models at multiple scales.In this study,the constructive shrub species Haloxylon ammodendron in the Junggar Desert was used as an example.A number of plant morphological parameters were chosen,and the aboveground(AGB)and belowground biomass(BGB)models were established at the individual plant,plot and regional scales using allometric(power function)equations.The biomass estimation was then performed using the same model.Based on the canopy volume(CH),the formula AGB=0.3628×CH0.9605 accurately reflected the AGB individual accumulation characteristics.The individual BGB was estimated using BGB=0.8737× AGB0.9394.The total canopy cover(TC)of H.ammodendron was an effective parameter to calculate the total AGB and BGB(TAGB=0.6757×TC1.1343,TBGB=0.6384×TC1.0959)in sampling plots with an area of 0.1 hm2.On a large,regional scale,the relative canopy cover(RC)had a positive effect on estimating the AGB and BGB densities(DAGB=0.0921×RC1.1343,DBGB=0.0796×RC1.0959),from which the total regional biomass storage of H.ammodendroncould be obtained.It showed that the issue of scaling was successfully resolved using the RC of the H.ammodendronbiomass density.There was no scale limit when RC was used.In future, the RC of H.ammodendron can also be obtained quickly through aerial photography,remote sensing,etc, thus the total AGB and BGB in relevant regions would be estimated accurately using the aforementioned biomass density models.