Monitoring and Management of Biological Soil Crusts
Monitoring is the collection and analysis of repeated observations so that changes over time can be assessed. Typically, monitoring is used to evaluate changes in landscape condition in relation to defined management goals. The objectives of a monitoring
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32.1 Introduction Monitoring is the collection and analysis of repeated observations so that changes over time can be assessed. Typically, monitoring is used to evaluate changes in landscape condition in relation to defined management goals. The objectives of a monitoring program will determine the position in the landscape in which measurements will be made and the period over which data will be collected and assessed. Monitoring is often designed so that measurements can be made by more than one observer, and the level of change which is acceptable is usually determined before monitoring commences. The principal aim of monitoring is to provide an objective basis for either changing or maintaining a current management practice. Thus, monitoring is intimately associated with management, with a feedback of information to the land manager and therefore the management process. In this chapter we discuss how soil crusts can be monitored, and the role of grazing, fire, and recreational use in the management of landscapes in which biological soil crusts are a major component. Monitoring using remotely sensed techniques are discussed in Chapter 31.
32.2 Crusts and Rangelands Monitoring During the past century, rangeland managers grappled with methods to assess the health and trend of landscapes (see Tueller 1988). Techniques concentrated on the recording of vascular plant attributes such as cover, frequency, presence/absence, abundance, and biomass of various species, particularly perennial plants (Friedel and Bastin 1988; Friedel et al. 1988; Holechek et al. 1989; Milton et al. 1998). While many scientists acknowledge the close links between biological soil crusts and rangeland condition assessment (see Klopatek 1992), soil crusts Ecological Studies, Vol. 150 J. Belnap and O.L. Lange (eds.) Biological Soil Crusts: Structure, Function, and Management © Springer-Verlag Berlin Heidelberg 2001
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and their component organisms have rarely been recorded during field-based assessment (West 1990). Early efforts to classify the surface of soils and to include biological soil crusts in these assessments were developed in the semiarid woodlands of eastern Australia (Tongway and Smith 1989). This system was later refined and extended to other landscape types (Tongway and Hindley 1995). In eastern Australia, the Department of Land and Water Conservation has been collecting data (including crust cover) on the condition and trend of rangelands since the mid-1980s (Green 1992), and workers in the western US (Pellant 1996; USDI 1997) have recently included crust cover as a component of monitoring programs.
32.2.1 Long-Term Monitoring Efforts Biological soil crusts are frequently monitored as part of a larger study rather than being monitored for their own sake, and the length of time between successive monitoring events will depend on the aims of the study and the purpose for which the data are intended. Two examples of long-term monitoring of crust cover illustrate how the data differ in their intensity of m
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