Status and trends of biodiversity, including benefits from biodiversity and ecosystem services
The biodiversity of Solomon Islands is of global importance. The country has been recognized as a “Centre of Plant Diversity”, counting 4,500 species of plants, 3,200 of which are known to be native (indigenous). Despite this high level of biological diversity, endemism for plant species is generally low. However, 57% of palms, 50% of orchids, 75% of climbing Pandanus species are considered endemic. Solomon Islands also presents a high diversity in terms of animal species, with BirdLife International having categorized the Solomon Islands “Endemic Bird Area” (EBA) with the “highest number of restricted range species in any Endemic Bird Areas” of the World (94). Currently known bird species total 223 species, of which a staggering 82% are endemic and two extinct. The number of mammals is higher than in any other Pacific island region and natural heritage is unique in terms of marine species. Due to the high diversity of saltwater fish and coral species found in coastal and marine areas, Solomon Islands has been placed under the Bismarck Solomon Seas Ecoregion which covers Northern New Guinea, Papua New Guinea and Solomon Islands (up to the Makira province) and the Coral Triangle. Marine fauna is characterized by low levels of endemism and the presence of numerous and widespread mangrove species.
Over the past years, Solomon Islands has witnessed an overall decline in biodiversity. Sixteen plant species are already listed under the IUCN Red List as threatened. Out of the 53 species of mammals known throughout the country, 20 are considered threatened. There is general erosion in agricultural biodiversity due to increased importation of species and products. While farmers traditionally conserved local varieties in their food gardens, they are now attracted by new and imported varieties, causing local varieties to be abandoned. As a matter of fact, there are currently more imported food crops than indigenous foods in the country. Many of the local or indigenous food varieties have been lost, especially local varieties of sweet potatoes, taro, yams, cassava and bananas.
Biodiversity constitutes a key source of revenues, alimentation and health for rural populations (representing 85% of the total population) with a “subsistence” mode of life. As such, biodiversity also constitutes a powerful source of cultural identity. Further, most of the economic activities of the country, notably the exportation of exotic wood, heavily rely on ecosystems and ecosystem services, with their destruction having direct repercussions on the Gross Domestic Product and rate of employment. Finally, ecosystems perform a large role in preventing the occurrence of extreme natural events, such as flash-flooding, which can cause considerable human and economic losses.
Main pressures on and drivers of change to biodiversity (direct and indirect)
The main threats that continue to endanger the country’s biodiversity are logging, inappropriate land use practices, mining and prospecting, over-exploitation of natural resources, population growth, natural disasters, invasive species, pollution and climate change. In the terrestrial environment, industrial logging and development of large-scale monocultural agricultural plantations of oil palm, coconut and cocoa, and the clearance of land for subsistence gardens, are the major activities directly threatening biodiversity. New threats, such as climate change and invasive species, are increasing in magnitude, however are still not so obvious to the general public. Terrestrial alien and native invasive species have not been well documented to date, however a list produced by the Pacific Islands Ecosystem at Risk project in Hawaii contains a total of 368 invasive and potential invasive species for Solomon Islands. In the marine environment, the major treats are over-exploitation of marine resources, pollution from land-based sources and climate change. Threats such as high population growth, directly related to the high demands for and consumption of biodiversity resources, can also be regarded as a driver, as can the external demand for biodiversity goods and products and changes in people’s lifestyles.