Control methods for Berberis aquifolium in coastal dunes in Belgium
The Belgium coastal dunes are a diverse habitat that include many rare and threatened plant species. However, the dunes are highly fragmented habitats and are also threatened by invasive alien plants which have increased in these habitats from 5 to 20 % since the 1970s. Non-native shrubs and trees are major invaders in Belgium coastal dune systems (Table 1).
Table 1. Non-native tree, liana and shrub species established within the Belgian coastal dunes.
* Species on the EPPO List of Invasive Alien Plants and ** Species on the EPPO A2 List.
Species | Growth form | Surface area (m²) | % dune areas |
Rosa rugosa (Rosaceae) | Shrub | 56757 | 63 |
Berberis aquifolium (Berberidaceae) | Shrub | 34035 | 50 |
Prunus serotina* (Roseaceae) | Tree | 5461 | 52 |
Syringa vulgaris (Oleaceae) | Shrub | 4544 | 30 |
Ribes odoratum (Grossulariaceae) | Shrub | 2986 | 11 |
Symphoricarpos spp. (Caprifoliaceae) | Shrub | 2874 | 26 |
Robinia pseudoacacia (Fabaceae) | Tree | 1458 | 4 |
Cotoneaster spp. (Rosaceae) | Shrub | 1392 | 41 |
Lycium barbarum (Solanaceae) | Shrub | 420 | 15 |
Ailanthus altissima* (Simaroubaceae) | Tree | 209 | 9 |
Tamarix spp. (Tamaricaceae) | Shrub | 169 | 9 |
Elaeagnus spp. (Elaegnaceae) | Shrub | 108 | 11 |
Lonicera spp. (Caprifoliaceae) | Liana | 106 | 13 |
Prunus spp. (Rosaceae) | Tree | 88 | 13 |
Parthenocissus spp. (Vitaceae) | Liana | 83 | 4 |
Ligustrum ovalifolium (Oleaceae) | Shrub | 72 | 9 |
Ribes sanguineum (Grossulariaceae) | Shrub | 58 | 26 |
Amelanchier spp. (Rosaceae) | Shrub | 44 | 9 |
Yucca spp. (Asparagaceae) | Tree-like succulent | 25 | 15 |
Cornus spp. (Cornaceae) | Shrub | 15 | 24 |
Baccharis halimifolia** (Asteraceae) | Shrub | 13 | 11 |
Buddleja davidii* (Scrophulariaceae) | Shrub | 7 | 7 |
Euonymus japonicus (Celastraceae) | Shrub | 5 | 2 |
Pseudosasa japonica (Poaceae) | Shrub | 4 | 2 |
Rosa spp. (Rosaceae) | Shrub | 4 | 4 |
Quercus spp. (Fagaceae) | Tree | 3 | 4 |
Sorbus spp. (Rosaceae) | Tree | 2 | 4 |
Viburnum spp. (Adoxaceae) | Shrub | 1 | 2 |
Berberis aquifolium (Berberidaceae) is native to North America and within the EPPO region the species has been recorded in Belgium, Bulgaria, France, Germany, the Netherlands, Russia, Switzerland, the United Kingdom and Uzbekistan. In Belgium, the species was recorded in the wild in 1906 and naturalised between 1920 and 1950. B. aquifolium can invade a variety of habitats, from natural habitats (grassland, forests and coastal dunes), to anthropogenic habitats. In these habitats, the species can outcompete native vegetation and cause negative impacts on biodiversity. Control options have been evaluated where four treatments were tested (1) manual uprooting using a shovel, (2) foliar herbicide application (5% glyphosate), (3) stem cutting + herbicide (glyphosate) application on the stump (4) same as option 3 with the application of saturated salt (NaCI) instead of herbicide. Effectiveness was measured as the lack of regrowth one year after treatment. In total 118 plants were treated, and the following results were obtained. Spraying the foliage of B. aquifolium with herbicide was the most effective method with 26 out of 31 plants killed. Stem treatment with glyphosate had an intermediate effect with 13 out of 20 individuals killed. Manual uprooting killed 12 out of 33 individuals. The species develops a highly branched root system that can be difficult to uproot manually. Salt application post cutting had little effect on individuals with 23 out of 25 plants showing regrowth.
Sources
Adriaens T, Verschelde P, Cartuyvels E, D’hondt B, Vercruysse E, van Gompel W, Dewulf E, Provoost S (2019) A preliminary field trial to compare control techniques for invasive Berberis aquifolium in Belgium coastal dunes. NeoBiota 53, 41-60.