Aggregations of plants surrounded by sparsely vegetated areas in drylands can arise when larger plants facilitate the recruitment of smaller “protégé” plants—a phenomenon referred to as the “nurse plant” effect. Numerous drivers can generate a nurse plant effect; efforts to simultaneously quantify multiple drivers are rare. Given higher densities of protégés beneath the foundational shrubs Larrea tridentata and Neltuma glandulosa, multiple potential mechanisms underlying the nurse plant effect were quantified in the Chihuahuan Desert, New Mexico, USA. As expected, there was a greater concentration of soil nutrients and lower photosynthetically active radiation and soil temperatures beneath shrubs. Throughout the study, however, soil moisture was consistently higher in interspaces despite the greater water holding capacity of soils beneath shrubs. Nutrient concentrations were greater beneath N. glandulosa than L. tridentata, while protégé numbers did not significantly differ among the species. The canopy size of both species was positively related to understory shading, and the size of N. glandulosa was positively related to soil nitrogen and microbial biomass. The results of this study suggest that much of the abiotic nurse plant effect of this low-latitude system is explained by radiation interception and concomitant reductions in temperatures experienced by protégé plants as opposed to the direct effects of shrubs on soil water availability. As global change pressures intensify in drylands, a loss of perennial plant cover could have negative effects on soil biogeochemical pools and plant diversity. Quantification of the mechanisms driving the nurse plant effect across environmental and climatic gradients could improve our understanding of plant community dynamics in drylands.

Rangelands are Earth’s dominant land type, supporting the livelihoods of more than 2 billion people. Concerns about rangeland degradation typically focus on overgrazing. But climate change may be a gr...

The significant influence of shading highlights the role of environmental factors in shaping plant communities of this dryland system, while the evidence of seed depletion combined with the influence...

Biological soil crusts are complex communities composed of lichens, mosses, bacteria, and cyanobacteria that create a living skin on the soil surface across drylands worldwide. Although small in size...

Biological nitrogen fixation may impose stronger constraints on the carbon sink in natural terrestrial biomes and represent a larger source of agricultural nitrogen than is generally considered in ana...

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We need YOU as we rally in support of critical federal government services at risk of being lost forever. The U.S. Geological Survey Ecosystems Mission Area is responsible for many of the programs tha...

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In the face of recent abrupt shifts in federal funding for education research, including large-scale terminations of National Science Foundation (NSF) research grant awards, we have developed a rap...

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“The loss of this science doesn’t just mean fewer data points,” writes Kristina Young. “It means fewer tools to protect water supplies, fewer insights to guide wildfire mitigation and fewer answers wh...