The past and present. History and background, baggage and direction ; A framework for the design of plant diversity studies -- An experimental approach to sampling. Single-scale sampling ; Multiscale sampling ; Comparing multiscale sampling designs : taking an experimental approach ; Case study : comparing rangeland vegetation sampling techniques -- Scaling to landscapes. Case study on multiphase and multiscale sampling ; Case study : designing a monitoring program for assessing patterns of plant diversity in forests nationwide ; Case study : patterns of plant invasions in forests and grasslands ; Case study : evaluating the effects of grazing and soil characteristics on plant diversity ; Case study : assessments of plant diversity in arid landscapes -- Modeling patterns of plant diversity. Nonspatial statistical modeling of plant diversity ; Spatial analysis and modeling -- Monitoring plant diversity. Concepts for assessing temporal changes in plant diversity ; Case study : monitoring shifts in plant diversity in response to climate change -- Research needs. Case study : testing a nested-intensity sampling design ; Quantifying trends in space and time.