Influence of biological soil crusts on soil environments and vascular plants
Biological Soil Crusts: Structure, Function, and Management
The presence of biological soil crusts can significantly change the physical and chemical soil environment. Such alterations can affect the germination, survival, and nutritional status of vascular plants. Some landscape surveys have found a negative relationship between biological soil crusts and vascular plant cover (West 1990; Johansen 1993; Eldridge 1993). Based on this, some authors have concluded that crust organisms limit vascular plant cover (Savory 1988). However, it is also possible that soil crusts merely occupy all soil surfaces not first covered by vascular plants. In support of this, numerous authors have reported that vascular plant cover either shows no correlation with crust cover (Anderson et al. 1982; Beymer and Klopatek 1992; Jeffries and Klopatek 1987; Kleiner and Harper 1972,1977) or that there is a positive correlation between vascular plant and crust cover (Carleton 1990; Dadlich et al. 1969; Graetz and Tongway 1986; Ladyman and Muldavin 1994; Lesica and Shelley 1992; Miicher et al. 1988).
Many studies have addressed aspects of the relationship between crusts and vascular plants. These studies have been done at sites with different soil textures, physical and chemical crusting, soil surface roughness and stability, climate regimes, species composition of the biological crusts, and vascular plant species (each with different strategies for germination and survival). It is essential that all these differences be accounted for when generalizing about the relationship between soil crusts and vascular plants. In this chapter, we will discuss how crusts modify soils in ways that can affect vascular plants. We will then address the effects of biological soil crusts on seed dispersal and germination, and how crusts affect vascular plant survival and nutritional status in different climate regimes. Finally, we will discuss the overall effects of crusts on plant community structure.
Belnap, J., Prasse, R., and Harper, K. T., 2003, Influence of biological soil crusts on soil environments and vascular plants, in Belnap, J., and Lange, O. L., eds., Biological Soil Crusts: Structure, Function, and Management: Berlin, Springer-Verlag, p. 281-300.