Effects of established perennial grasses on introduction of native forbs in California

  • Published source details Brown C.S. & Bugg R.L. (2001) Effects of established perennial grasses on introduction of native forbs in California. Restoration Ecology, 9, 38-48.


This study is summarised as evidence for the following.

Action Category

Disturb soil before seeding/planting

Action Link
Grassland Conservation
  1. Disturb soil before seeding/planting

    A replicated, randomized, paired, controlled study in 1993 on road verges in California, USA (Brown & Bugg 2001) found that disturbing soil before sowing forb seeds increased the emergence and cover of sown forbs compared to sowing seeds alone, but disturbing the soil before planting forb seedlings had no effect on seedling growth. Plots where soil was disturbed before sowing had greater emergence (11%) and cover (97%) of sown forbs than plots where soil was not disturbed before sowing (7% and 14% respectively). However, the proportion of planted forb seedlings showing aboveground growth did not differ significantly between disturbed and undisturbed plots (data not reported). In January 1993, five blocks, each with three 7.62 x 7.62 m plots, were established on grass verges. In each block, one plot was tilled to a depth of 10–15 cm and sown with seeds of seven native forb species, while one plot was not tilled but was sown with seeds. In January–April 2003, thirty seedlings of each of two forb species, narrow-leaf milkweed Asclepias fascicularis and blue-eyed-grass Sisyrinchium bellum, were planted 30 cm apart in each plot.  In April 1993, cover and emergence of forbs was estimated in two 0.5 x 0.25 m quadrats/plot. Aboveground growth of seedlings was assessed in each plot in March–May 1993.

    (Summarised by: Philip Martin)

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