Soil natural disturbances (biopedturbations) and their impact in ecological processes has been broadly studied in drylands. Biopedturbations of burrowing animals contribute to the heterogeneity that support different plant communities at small and large scale. In dryland systems, where biological soil crust (BSC) are important components, natural disturbances impact the hydrology, plant establishment, nutrients and characteristics of the soil. No studies investigating the relationships of burrowing animals, BSC and plant communities have been conducted in the hyperarid regions of the Atacama Desert.
We investigated the interactions among the major components of the hyperarid Lomas ecosystem, and asked if the biopedturbations by fossorial birds that disrupt the BSC cover have an effect on abiotic factors and the vascular plant community germination. Although fossorial birds’ activity creates pits and mounds, we target only the mounds as biopedturbations. Active biopedturbations were the burrows where birds’ activity keeps the top soil of the mound loose; and inactive biopedturbations were the mounds colonized by an early successional BSC because of the burrows’ abandonment. We analyzed active and inactive avian biopedturbations compared to undisturbed BSC and artificial scalped soil in four separated experiments. We measured soil moisture content, soil chemical characteristics, seedbank germination and field seedling emergence. The evaluation of field emergency was conducted in the beginning of the wet season.
Results/Conclusions
The structural change created by fossorial birds leads to higher soil moisture in active biopedturbations compared to scalped soil and BSCs. Differences in the soil chemical environment were less pronounced. In the seedbank experiment, thirteen plant species were identified, and biopedturbations had higher plant diversity but lower abundance than on intact BSC. In the field observations only eight herbaceous species were found, but richness and abundance of seedlings was still greater on biopedturbations. This suggests that structural differences in BSC along with reduced soil moisture impact the ability of seed to germinate in the field, even though BSC contain a larger seedbank. Our study and experiments show that fossorial birds cause biopedturbations that affect ecosystems functions and may be operating as local ecosystem engineers in the Peruvian coastal desert.