The threat of alien invasive grasses to lowland Cape floral diversity : an empirical appraisal of the effectiveness of practical control strategies : research in action
Year: 2005
Type: article
Abstract: European annual grasses in highly fragmented natural ecosystems along
the South African west coast are displacing
wildflowers, which form the basis of a
growing lucrative, nature-based tourist
industry. We examined the cost-effectiveness
of different labour-intensive strategies linked
to a national poverty relief programme for
controlling invasive annual grasses in
renosterveld. The treatments tested involved
combinations of grass mowing, hand-clearing,
light and intense burning and pre-emergent
herbicide application randomized over
forty-eight 100-mlsupg2l/supg plots in the Tienie Versfeld
Wildflower Reserve. Springtime vegetation
responses were monitored over two successive
years; labour, capital equipment and consumable
costs were audited. Total clearing costs associated with intense burning of uncut grass (R415/ha), grass mowing (R924/ha) and
light intensity burning of mowed grass (R1338/ha) were all less than those (up to R1 927/ha) reported for clearing dense stands
of woody aliens. However, costs of hand-clearing
of grass (R6 743/ha) and pre-emergent herbicide application (R13 380/ha) were much greater. Intense burning, the cheapest strategy
overall, was ineffective as this promoted recruitment
of both alien invasive annual and perennial grasses and inhibited recruitment of native geophytes. We conclude that mowing of
grass-infested renosterveld prior to grass seed maturation, and the removal of the cut grass biomass for use as fodder in restricted feed lots to offset clearing costs, provides the most
credible strategy for controlling the annual
grass populations to conserve native floral
diversity over the short term.
Source: South African Journal of Science
Authors: C.F. Musil, Suzanne J. Milton, George W. Davis
Language: English
Subfield: Nature and Landscape Conservation
Field: Environmental Science
Domain: Physical Sciences
SDGs: Life on land, Zero hunger
Open Access status: diamond
OpenAlex ID: W1190807