此地点的物种说明： L. robustum, along with other invasive plants such as the strawberry guava (Psidium cattleianum), are contributing to the degradation of native forest on Mauritius. The floristic composition of the diverse forest is shifting toward a few exotic species. L. robustum was introduced into the island of Mauritius in the early 20th century or late 19th century. It was probably introduced as part of a botanical seed exchange between the Peradeniya Botanical Gardens in Sri Lanka and the Pamplemousse Botanical Gardens in Mauritius (Evans, 1999). It may have been introduced earlier (in the 1890s) as an ornamental plant (Lavergne et al. 1999). From 1902 the forest services planted L. robustum as nursery plants to protect conifer plantations from deer, provide firewood and control invasions of other invasive weeds (such as Psidium cattleianum, Rubus alceifolius and Cordia curassavica) (Lavergne et al. 1999). In less than fifty years it has invaded about 57,000 ha of forest, forming dense, impenetrable thickets and no part of the Mauritius uplands, including both secondary and primary forest, is free of L. robustum (Lavergne et al. 1999). The endemic black bulbul of Mauritius (Hypsipetes olivaceus) have been observed eating the fruits of L. robustum; this may assist the plants spread into native forests.
此地点的管理信息： Integrated management: Conservation Mangaement Areas have been established in Mauritius to protect native fauna from displacement by more competitive alien weed species (such as L. robustum and the strawberry guava, Psidium cattleianum). Since 1951 sixteen Nature Reserves have been set up to preserve native ecosystems. The reserves cover 2.5 % of the island and range from 1.5 ha to 3,611 ha in size (the Perrier Nature Reserve and Macchabee-Bel Ombre Nature Reserve, respectively). In 1994 under the Wildlife and National Parks Act, 1993 the Macchabee-Bel Ombre and Combo nature reserves were combined to form the 6,754 ha Black River Gorges National Park (Mungroo and Tezzo, 1996). Nine intensively managed vegetation plots, known as Conservation Management Areas (CMAs), have been established. CMAs cover a total of 44 ha and range from 1.5 ha to 19 ha in size, the largest of which is located within the National Park. The CMAs are fenced (a low stone wall to keep out deer and pigs) and weeds are manually uprooted four times a year. Control of alien invasive plant species in the CMAs has proved promising. Endangered plants have been found growing in these areas and regeneration of endemic plants is occuring, providing a better habitat for endemic endangered birds such as the pink pigeon and the echo parakeet (Mungroo and Tezoo, 1996). Manually uprooting weeds is labour intensive and cannot be applied to large areas.In 1996, a a biodiversity assessment of a 6 ha plot (within the 25 ha fenced Brise Fer CMA) was implemented by the Mauritian Wildlife Foundation (MWF) and the Government of Mauritius. Trials on the chemical control of exotic weeds were initiated (Mungroo and Tezzo, 1996). Results from chemical control trials in the Brise Fer CMA (undertaken during six weeks in 1993) were unpromising: L. robustum and P. cattleianum (strawberry guava) were cut with rangers knife at about waist height and herbicide was applied to the stump by small brush at a concentration of 10% (one part Garlon to 9 parts water). More recent trials with Garlon (at the manufacturers concentration) on stumps about 20 cm from the ground has proven to be more effective in controlling the exotic weeds. As Garlon is expensive trials with other herbicides are currently underway (Mungroo and Tezzo, 1996).
地点批注： Mauritius is located about 800 km southeast of Madagascar and about 2000 km from the African continent. It has a land area of 1,865 km² and its highest peak is 828 m. It has a tropical to sub-tropical climate influenced by frequent cyclones during the summer (November to April) and recieves 1,000 to 5,000 mm of rainfall annually (Mungroo and Tezoo, 1996). Sugar cane is the principal cash crop grown, (occupying around 88% of cultivable land); other exported plants include cut flowers, fruits, pineapples, vegetables, and in smaller quantities tobacco, vanilla and coffee. A diverse range of crops are grown for local consumption. Forest plantations include mainly imported exotic species like Pinus spp., Eucalyptus spp. and Casuarina spp. (FAO, 1995). Only 2.5% of the original vegetation remains on the island (Lavergne et al. 1999). Of the 1000+ introduced species on the island 730 have become naturalised. Of these, 50 are considered invasive (Lavergne et al. 1999).
影响： 与其它入侵物种相互作用: Introduced bird species, such as the red-whiskered bulbul (Pycnonotus jocosus), benefit from the plant by feeding on its fruit; in return they assist in the plants dispersal. The extrodinarily high fruit production may also help sustain populations of pigs and monkeys, which aid in the plants dispersal and contribute to the degradation of native flora (Mungroo and Tezoo, 1996), in turn creating habitats more favourable to the plants establishment. 改变演化模式: It is estimated that L. robustum represents 10% and 72% of the total adult and seedling populations in the native Mauritian forest remnants, respectively (Lavergne et al 1999). The presence of L. robustum is correlated with the inability of native vegetation to re-establish. 栖地改变: Threatened native birds, such as the pink pigeon (see Columba mayeri in IUCN Red List of Threatened Species), the echo parakeet (see Psittacula eques in IUCN Red List of Threatened Species), the Mauritius kestrel (see Falco punctatus in IUCN Red List of Threatened Species), the Mauritius cuckoo-shrike (see Coracina typica in IUCN Red List of Threatened Species), the Mauritius black bulbul (Hypsipetes olivaceus see in IUCN Red List of Threatened Species), Mauritius olive white-eye (see Zosterops chloronothus in IUCN Red List of Threatened Species), Mauritius fody (Foudia rubra see in IUCN Red List of Threatened Species) and the Mascarene paradise flycatcher (Terpsiphone bourbonnensis, race desolata) are negatively affected by the expansion of exotic plants such as L. robustum. Although all birds use exotic vegetation to some extent, only the kestrel and flycatcher occur in totally exotic habitats. This is partly because insects and other invertebrates are more abundant and diverse in native vegetation than in exotic vegetation (Safford and Jones, 1998). 生态系统变化: L. robustum is a major threat to native ecosystems. In the Mauritian wet forests it is one of the worst plant pests, along with Psidium cattleianum (strawberry guava) and Rubus alceifolius (Lavergne et al 1999). 竞争: L. robustum, together with Psidium cattleianum, is invading indigenous forest in the Mascarene islands, reducing the available habitat for the 11 endemic palm species. According to the IUCN Red List (2000) all 11 palm species are threatened and nine are critically engangered (consist of less than 100 individuals) (Maunder et al 2002).