Century-old land-use legacies outweigh hurricane disturbance in shaping soil microbial functioning in a tropical forest

Abstract Aims: Soil microbial communities are responsible for critical ecosystem functions like decomposition and nutrient cycling, yet their responses to long-term (press) versus episodic (pulse) disturbances remain poorly understood in tropical forests. Long-term land use can impose lasting changes to soil physical and chemical properties, constraining microbial functioning for decades. In contrast, short-term disturbances may temporarily disrupt soil structure but allow rapid recovery. This study aims to investigate the relative impacts of past land use change and recent hurricane disturbance on soil microbial functioning. Methods: We quantified soil abiotic properties, enzyme activity, and nutrient availability across adjacent cultivated and never cultivated forests in Puerto Rico. Within each forest, we compared the areas of uprooted trees and adjacent intact soils eight years after hurricanes Irma and Maria. Results: We found that land-use legacies structured soil conditions and microbial functioning nearly a century after abandonment. Never cultivated forests maintained higher soil moisture, lower bulk density and acidity, 2.3 fold greater potential complex carbon-degrading oxidative enzyme activity, and 22% higher ammonium availability. In contrast, cultivated forests had higher potential labile carbon-, nitrogen-, and phosphorus-degrading enzyme activity and 48% greater nitrate availability indicating divergent decomposition and soil nutrient cycling. By contrast, hydrolytic enzyme activity and nutrient availability did not differ between tree-fall and intact soil areas eight years after hurricane disturbance, despite differences in microtopography and soil temperature. Conclusion: Historic land-use legacies exert stronger and longer-lasting controls on soil microbial functioning than acute hurricane disturbance, with implications for ecosystem recovery under intensifying disturbance regimes.