Variation in nutrient resorption by desert shrubs

Plant nutrient resorption prior to leaf senescence is an important nutrient conservation mechanism for aridland plant species. However, little is known regarding the phylogenetic and environmental factors influencing this trait. Our objective was to compare nitrogen (N) and phosphorous (P) resorption in a suite of species in the Asteraceae and Chenopodiaceae and assess the impact of soil salinity on nitrogen resorption. Although asters and chenopods did not differ in N resorption proficiency, chenopods were more proficient than asters at resorbing P. Plant responses to salinity gradients were species-specific and likely related to different salt-tolerances of the species. During the three year study, precipitation varied 6.4- and 9.9-fold from the long term averages at our two desert sites; despite these differences, annual variation in nutrient resorption was not linked to annual precipitation. More detailed studies are required to understand the influence of salinity and precipitation on resorption. Understanding controls on this trait may give insight into how species will respond to anthropogenic soil salinization and desertification.