Action: Use herbicides to remove invasive plant species
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- One replicated, randomized, controlled study in the USA found no effect of invasive plant control using herbicide on the total native plant species richness.
Invasions by non-native species are considered a major threat to biodiversity. One way of controlling invasive plants is by using herbicides. This action may also affect the abundance of plants other than the targeted species, and as result influence the forest structure and composition.
Supporting evidence from individual studies
A replicated, randomized, controlled study in 2000-2005 in temperate broadleaf forest in Ohio, USA (Hochstedler et al. 2007) found no effect of control of invasive garlic mustard Alliaria petiolata on native plant species richness and diversity. Species richness was similar between treatments in both old-growth (sprayed: 8.7; unsprayed: 8.0 species/plot) and second-growth forests (sprayed: 10.6; unsprayed: 10.5). The same was true for species diversity (Shannon’s index old-growth: sprayed 1.7, unsprayed 1.4; second-growth: sprayed 2.0, unsprayed 2.0). Data were collected in 2005 in 25 sprayed (garlic mustard individuals sprayed with glyphosate herbicide Roundup© PRO at the start of winter in 2000-2004) and 25 unsprayed plots (1×1 m). Plots were randomly placed in each of 16 ha second-growth and 20 ha old-growth forest sections.