Interactive Effects of Harvester Ant Nests and Abandoned Sheep Corrals on Soil Nutrient Dynamics and Vegetation in Semiarid Pastures

Semiarid regions like the Negev Desert face significant challenges due to low precipitation, nutrient-poor soils, and grazing-induced land degradation. Traditional grazing practices, particularly sheep corrals, have created nutrient-rich hotspots that have influenced soil nutrient dynamics and vegetation patterns for decades. Simultaneously, harvester ants (Messor spp.) act as ecosystem engineers, modifying soil properties and promoting biodiversity. However, the interplay between ant nests and abandoned sheep corrals in influencing soil and vegetation remains understudied. This study assessed the synergistic effects of harvester ant nests and abandoned sheep corrals on soil nutrient dynamics and vegetation characteristics in semiarid pastures. Using a factorial experimental design, we compared four treatment combinations: open spaces and corrals, with and without ant nests. Key variables measured included soil properties (e.g., pH, electrical conductivity [EC], nitrate, potassium, and sodium absorption ratio [SAR]), vegetation height, biomass, and species composition. Results revealed that harvester ant nests within corrals significantly mitigated salinity (reducing EC and SAR) and redistributed potassium, restoring soil properties closer to open-pasture conditions. Vegetation shifts were evident, with taller cereals (Avena sterilis) dominating open areas with ant nests, while nutrient-enriched corrals favored nitrophilous species such as Chenopodium murale. Despite these changes, plant biomass differences across treatments were not statistically significant. These findings highlight the potential of integrating harvester ants into ecological restoration strategies for degraded semiarid landscapes. By redistributing nutrients and seeds, reducing salinity, and supporting plant richness, harvester ants act as natural agents of restoration. This study underscores the importance of leveraging biotic interactions and traditional grazing practices for sustainable land management and ecosystem recovery in semiarid regions.