There is no specific invasive species legislation in Gibraltar. However, the Nature Conservation Area (Upper Rock) Designation Order 1993 includes sections which deal with the introduction of fauna and flora that are not indigenous to the Upper Rock. Section 5.1(h) states that it is illegal to “introduce any animal or plant which is of a kind which is not ordinarily resident or is not a regular visitor to Gibraltar in a wild state or does not grow in the wild in Gibraltar, as the case may be”.

The JNCC database lists 81 non-native species which includes ten amphibians and reptiles, one invertebrate and 70 plant species. The Biodiversity Action Plan, Gibraltar (Perez, 2006) lists 64 non-native plant species and also includes sections on black rats (Rattus rattus), feral cats (Felis catus) and feral goats (Capra hirca). In addition the Barbary Macaque (Macaca sylvanus) is an introduced species but an important element of the world population which has declined substantially and is now probably less than 10,000 individuals.

Non-native Senecio angulatus

Problems with invasive non-native species

Some of the non-native plant species are highly invasive (eg (Acacia cyclops), (Ailanthus altissima), (Lantana camara), (Senecio angulatus)) and outcompete native flora and cover extensive areas. The feral goat population is regarded as having a negative impact on some of the native flora through overgrazing which has caused extensive erosion in some areas. The Gibraltar population of Barbary Macaques is thriving and has reached a level where it is regarded as becoming a pest.

Priority invasive non-native species and actions

In the Biodiversity Action Plan there are action plans for dealing with 22 alien invasive plant species which cover their distribution, biology, impacts and actions for managing/eradicating them. The species are: Rooikrans (Acacia cyclops), Bera’s Breech (A. mollis), Orange Wreath Wattle (A. saligna), Pinwheel and Tree Houseleeks (Aeonium haworthii) and (A. arboretum), Century plants (Agave americana) and (A. ghiesbreghtii), Tree of Haven (Ailanthus altissima), Tree and Soapy Aloe (Aloe arborescens) and (A. maculata), Hottentot Fig (Carpobrotus edulis x acinaciformis), African Cornflag (Chasmanthe floribunda), Purple Dewplant (Disphyma crassilfolium), Bush Lantana (Lantana camara) , Shrub Tobacco (Nicotiana glauca), Prickly Pear (Opuntia ficus-indica), Bermuda Buttercup (Oxalis pes-caprae), Cape Wattle (Paraserianthes lophantha), Kikuyu Grass (Pennisetum clandestinium), Cape Ivy (Senecio angulatus), Nasturtium (Tropaeolum majus) and Spineless Yucca (Yucca elephantipes).

The same Biodiversity Action Plan also proposes action plans for managing black rats and feral cats and eradicating feral goats.

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