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Providing evidence to improve practice

Individual study: The effect of gypsum, organic mulch and seed additions on the restoration of succulent karoo vegetation at Rietfontein, Western Cape, South Africa

Published source details

Beukes P.C. & Cowling R.M. (2003) Evaluation of restoration techniques for the Succulent Karoo, South Africa. Restoration Ecology, 11, 308-316


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Add gypsum to soil (alongside planting/seeding) Shrubland and Heathland Conservation

A randomised, controlled study in 1994–1998 in a succulent karoo shrubland in Western Cape, South Africa (Beukes & Cowling 2003) found that applying gypsum, followed by sowing the seeds of shrubland species increased the number of seedlings of these species, and increased seedling survival of one of two species. Applying gypsum followed by sowing the seeds of the species Karoo bietou Tripteris sinuata, Spiny ruschia Ruschia spinosa and Gha grass Chaetobromus dregeanus increased the number of seedlings of these species compared plots where unmulched, unseeded plots (data not provided). Applying gypsum followed by seeding increased the survival of seedlings of Karoo bietou relative to areas that where gypsum had not been applied and that were not seeded (data not provided), but there was no difference in the survival of Gha grass. In 1994 eight 12.5 m2 plots were established. In four plots gypsum (CaSO4) was applied at a rate of 5 tonnes/ha, followed by sowing of the seeds of shrubland species. In the other four plots no mulch was applied, and no seeds were sown. Seedlings in each plots were counted annually between 1994 and 1998.

(Summarised by Phil Martin)

Add mulch to soil (alongside planting/seeding) Shrubland and Heathland Conservation

A randomised, controlled study in 1994–1998 in a succulent karoo shrubland in Western Cape, South Africa (Beukes & Cowling 2003) found that applying mulch, followed by sowing seeds of shrubland species increased the number of seedlings of these species, but did not increase seedling survival. Applying mulch followed by seeding with the seeds of the species Karoo bietou Tripteris sinuata, Spiny ruschia Ruschia spinosa and Gha grass Chaetobromus dregeanus increased the number of seedlings of these species compared with unmulched, unseeded plots (data not provided). However, applying mulch followed by seeding did not increase the survival of seedlings relative to unmulched, unseeded plots (data not provided). In 1994 eight 12.5 m2 plots were established. In four plots mulch was applied, followed by sowing with the seeds of shrubland species. In the other four plots no mulch was applied, and no seeds were sown. Seedlings in each plots were counted annually between 1994 and 1998.

(Summarised by Phil Martin)