Biocrusts increase the resistance to warming-induced increases in topsoil P pools

Area of Science:

• Environmental Science
• Soil Science
• Ecology

Background:

• Climate change, including global warming and altered rainfall, significantly impacts dryland biogeochemical cycles.
• Increasing atmospheric nitrogen (N) deposition can destabilize ecosystems, making phosphorus (P) a potentially limiting nutrient.
• The effects of climate change on soil P pools in drylands and the role of biocrusts are poorly understood.

Purpose of the Study:

• To investigate the impact of warming and reduced rainfall on soil P pools in Spanish drylands.
• To determine if biocrusts modulate these climate change impacts on soil P.

Main Methods:

• Two long-term experiments (8-10 years) were conducted in Aranjuez and Sorbas, Spain.
• Simulated warming (~2.5°C) and rainfall reduction (~30%) were applied to topsoil (0-1 cm).
• Soil P pools (non-occluded, organic, calcium-bound, occluded, and total P) were analyzed in the presence and absence of biocrusts.

Main Results:

• Warming significantly increased most soil P pools in Aranjuez, but only non-occluded P in Sorbas.
• Rainfall reduction did not affect soil P pools at either site.
• Biocrusts generally increased soil P pools and provided resistance to warming and, in some cases, rainfall reduction.

Conclusions:

• Soil P pools in drylands respond variably to warming and rainfall reduction.
• Biocrusts play a crucial role in modulating climate change effects on soil P dynamics.
• Warming-induced declines in biocrusts may reduce their capacity to buffer climate change impacts on dryland soil P.