Background information and definitions
Raking can be used to reduce the length of grass as well as pulling out individual plants. In addition, it may create disturbances to topsoil allowing shrubland species to establish.
Supporting evidence from individual studies
A randomized, replicated, controlled, paired study in 2005–2008 in creosote bush shrubland that was invaded by non-native grasses in California, USA (Steers & Allen 2010) found that raking reduced invasive grass cover but did not increase the number of annual plant species, and also reduced the cover of native grasses and forb species in two of four cases. In four of four cases areas that were raked had lower non-native grass cover (36–39%) than areas that were not raked (60–65%). In four of four cases the number of annual plant species in areas that had been raked (2–4 species/plot) did not differ significantly from the areas that had not been raked (3–4 species/plot). However, in two of four cases cover of native grass and forb species was lower in areas that had been raked (4–18%) than in areas that had not been raked (23–37%). In January 2006 and 2008 twelve 8 m x 8 m plots were raked to remove invasive grasses while twelve other plots were not raked. Plant cover was recorded in March-April 2006 and 2008 in 0.5 m2 quadrats located in each plot.Study and other actions tested