The International Union for Conservation of Nature, (IUCN) describes invasive species as “animals, plants or other organisms introduced by man into places out of their natural range of distribution, where they become established and disperse, generating a negative impact on the local ecosystem and species.” Invasive species can negatively impact native ecosystems and the species they contain. These impacts may disrupt the ecosystem processes, degrade habitats, reduce biodiversity and introduce diseases to flora and fauna.
Island ecosystems and Invasive alien species
Island ecosystems appear to be more vulnerable to invasions. Island ecosystems tend to have fewer species present and are less complex with distance from the continent; simpler systems are less resilient to new arrivals. Introduced mammal predators (rats, feral cats, mongooses, stoats and pigs) and herbivores (rabbits, deer, goats and sheep), alien invasive plants and introduced diseases have had devastating effects on native and endemic island species and their habitats.
One example is the small Indian mongoose (Herpestes auropunctatus also referred to as Herpestes javanicus), introduced to many islands worldwide for control of rats and snakes, mainly in tropical areas, and also to islands in the Adriatic Sea. Mongooses are diurnal generalist carnivores that thrive in human-altered habitats. Predation by mongoose has had severe impacts on native biodiversity leading to the decline and extirpation of native mammals, birds, reptiles, and amphibians. In the Caribbean, mongooses prey on the ‘Critically Endangered (CR)’ Hawksbill turtle (Eretmochelys imbricata) eggs in fragmented beach habitats. Trapping around vulnerable beaches led to much greater breeding success for the turtles. Analysis of collection records indicates that the loss or decline of 14 Neotropical skink species in the Caribbean islands can be attributed to predation by the small Indian mongoose. The ground-dwelling and diurnal habits of skinks have made them particularly susceptible to mongoose predation. Mongooses on Mauritius have been blamed for the extirpation of introduced game birds and the decline of endemic species such as the ‘Endangered (EN)’ pink pigeon (Nesoenas mayeri). At least seven species of native vertebrates, including mammals, birds, reptiles, and amphibians, have almost disappeared on Amami-Oshima Island, Ryukyu Archipelago, Japan since the introduction of the mongoose in 1979.
Availability and access to authoritative information, on the occurrence, extent of impacts of IAS including prevention, eradication and containment options, has often been cited as one of the barriers for effective implementation of management of biological invasions
Island Biodiversity and Invasive Species Database
The Island Biodiversity and Invasive Species database (IBIS) was developed by the IUCN SSC Invasive Species Specialist Group in response to feedback from island conservation managers that there was a need for better access to data and information on invasive alien species on islands and how to manage this insidious threat. The resource is targeted at decision makers and practitioners to support them in prioritizing of management action, target setting and monitoring progress. The IBIS prototype was developed in 2011.
IBIS aims to record and provide information on the occurrence, biological status and impacts of invasive alien species on native species on islands (with a focus on those that are classified as ‘threatened’ in the IUCN Red List of Threatened Species- Critically Endangered (CR), Endangered (EN) and Vulnerable (VU)), and threatened species on National Red Lists) and the prevention and management of this threat.
The geographical scope of IBIS includes both oceanic (those that rose from the sea as a result of coral deposits, volcanic activity or tectonic forces) islands and continental (land areas that used to be connected to the mainland). The taxonomic coverage is broad including all taxa.
Only those native species that are under threat by invasive alien species on islands and protected areas and other designated areas of high biodiversity values on islands (such as Important Bird Areas, Key Biodiversity Areas) are the focus of this database
The development of first IBIS prototype was supported by the Critical Ecosystems Partnership Fund- Polynesia Micronesia Hotspot; the University of Auckland, Taiwan Forestry Commission- Conservation Division- Forestry Bureau, and a grant from the U.S. Department of State Federal Assistance Award.
Data and information compiled includes the occurrence, biological status of introduced and invasive species, and native species classified as ‘threatened’ in the IUCN Red List of Threatened Species and National Red Lists. Identification of the invasive species causing the impact including the mechanism of impact and outcomes are recorded in detail. All this information is recorded at both the island level and site (PA) level. Textual information describing the invasive species threat, invasive species management and outcomes are recorded.
Links are provided to invasive species profiles on the ISSG Global Invasive Species Database (GISD); threatened species datasheets on the IUCN Red List of Threatened Species and to any Eradication events on the Database of Island Invasive Eradications (DIISE).
Ceylon Cinnamon (Cinnamomum verum) is the primary invader of the tropical secondary forest on the islands of Seychelles. On Mahe it dominates 70-90% of the forest canopy.
Exploitation of native trees for timber production and the spread of Ceylon Cinnamon from plantations have led to this dominance.
The invasion of Ceylon Cinnamon has altered and degraded the habitats of many endemic and threatened gastropods, reptiles and plant species leading to stress on their declining populations.
BIOPAMA and IBIS
The enhancement of IBIS including improvement of the data structure, and other web-services was undertaken by Joint Research Centre (JRC) within the framework of the Biodiversity and Protected Area Management Programme (BIOPAMA). ISSG with support from the JRC and IUCN Oceania Regional Office is currently (2014-2015) working on including current and authoritative information for 15 Pacific Island countries including the Cook Islands, Fiji, Federated States of Micronesia (FSM), Kiribati, Marshall Islands, Nauru, Niue, Palau, Papau New Guinea, Samoa, Solomon Islands, Timor-Leste, Tonga, Tuvalu and Vanuatu.