When we think of deserts and drylands, we often picture barren expanses of sand with sparse, hardy plants eking out an existence against the odds. Yet, hidden beneath the obvious flora lies a remarkably complex and vital community we rarely hear about: biological soil crusts, or “biocrusts.” These are thin, delicate layers composed of organisms like cyanobacteria, mosses, lichens, and fungi that bind soil particles together, preventing erosion and helping the land retain moisture.
What’s truly astonishing is how these fragile, almost invisible networks quietly hold entire ecosystems together. By fixing atmospheric nitrogen, biocrusts enrich the soil, making it more hospitable for plant life. They also improve water infiltration, ensuring that scarce rainfall doesn’t simply run off but instead nourishes seeds and roots. Their presence often marks the difference between a desolate landscape and one that can support a surprising diversity of life—from desert wildflowers and shrubs to the insects, reptiles, and birds that depend on them.
Though they flourish in extreme conditions, biocrusts are alarmingly sensitive to disturbances. Off-road vehicles, human foot traffic, and livestock grazing can break these delicate crusts, setting the stage for severe soil erosion and drastically altering entire ecosystems. As we seek ways to maintain biodiversity and prevent land degradation, recognizing and protecting biocrusts—these unsung ecological engineers—becomes increasingly important. Understanding their role could reshape our approach to conservation in some of the world’s most vulnerable landscapes.
References
Belnap, J., Weber, B., & Büdel, B. (2016). Biological soil crusts as an organizing principle in drylands. In Weber, B., Büdel, B., & Belnap, J. (Eds.), Biological Soil Crusts: An Organizing Principle in Drylands (pp. 3–13).
Springer.Garcia-Pichel, F., Belnap, J., Neuer, S., & Schanz, F. (2003). Estimates of global cyanobacterial biomass and its distribution. Algological Studies, 109(1), 213–227.
