Effect of biological soil crusts on soil chemical properties: a study from Tunisian arid ecosystem

<p>Biological soil crusts (BSCs) composed of cyanobacteria, green algae, bryophytes, and lichens are a major biotic<br>component of arid and semi-arid rangeland environments worldwide. They are recognized and studied in many<br>parts of the world. However, they have been the subject of very few studies in Africa. The current study deals with<br>the assessment of the influence of BSCs on soil chemistry in an arid ecosystem in Southern Tunisia. Our main<br>objective is to test whether biological soil crusts are able to improve soil chemical properties. Our investigation<br>showed that biological soils crusts had an expressive effect on soil chemistry. In fact, biologically crusted soils had<br>higher levels of pH, electrical conductivity, organic matter, organic carbon, nitrogen, phosphorus, Ca, K, Na, Cl<br>and lower C: N ratio compared to biologically un-crusted soils. The differences between crusted and un-crusted<br>soils were statistically significant at 95% confidence. The PCA results demonstrate further that BSCs significantly<br>enhance soil surface properties. These data support other studies revealing an improvement of the soil chemical<br>properties by means of biological soil crusts.