Mangrove species are uniquely adapted to tropical and subtropical coasts, and although relatively low in number of species, mangrove forests provide at least US $1.6 billion each year in ecosystem services and support coastal livelihoods worldwide. Globally, mangrove areas are declining rapidly as they are cleared for coastal development and aquaculture and logged for timber and fuel production. Little is known about the effects of mangrove area loss on individual mangrove species and local or regional populations. To address this gap, species-specific information on global distribution, population status, life history traits, and major threats were compiled for each of the 70 known species of mangroves. Each species' probability of extinction was assessed under the Categories and Criteria of the IUCN Red List of Threatened Species. Eleven of the 70 mangrove species (16%) are at elevated threat of extinction. Particular areas of geographical concern include the Atlantic and Pacific coasts of Central America, where as many as 40% of mangroves species present are threatened with extinction. Across the globe, mangrove species found primarily in the high intertidal and upstream estuarine zones, which often have specific freshwater requirements and patchy distributions, are the most threatened because they are often the first cleared for development of aquaculture and agriculture. The loss of mangrove species will have devastating economic and environmental consequences for coastal communities, especially in those areas with low mangrove diversity and high mangrove area or species loss. Several species at high risk of extinction may disappear well before the next decade if existing protective measures are not enforced.

In the Pacific islands the total mangrove area is about 343,735 ha, with largest areas in Papua New Guinea, Solomon Islands, Fiji and New Caledonia. A total of 34 species of mangroves occur, as well as 3 hybrids.These are of the Indo-Malayan assemblage (with one exception), and decline in diversity from west to east across the Pacific, reaching a limit at American Samoa. Mangrove resources are traditionally exploited in the Pacific islands, for construction and fuel wood, herbal medicines, and the gathering of crabs and fish.There are two main environmental settings for mangroves in the Pacific, deltaic and estuarine mangroves of high islands, and embayment, lagoon and reef flat mangroves of low islands. It is indicated from past analogues that their close relationship with sea-level height renders these mangrove swamps particularly vulnerable to disruption by sea-level rise. Stratigraphic records of Pacific island mangrove ecosystems during sea-level changes of the Holocene Period demonstrate that low islands mangroves can keep up

Geodiversity assessment is recent and is passing through a stage of methodological development and consolidation. With rapid environmental change, improving the developmental states of geodiversity assessment is of paramount importance. A scientometric analysis is presented to identify knowledge gaps, current trends and avenues for future research in quantitative geodiversity assessment literature. The study is categorised into three areas of analysis: (a) methodological intentions of geodiversity assessment, (b) current trends in geodiversity assessment methods and (c) current geographic trends. A ranking tool was developed to determine whether the current methodological intentions of geodiversity assessments trend towards combined geodiversity and biodiversity assessments or towards the independent assessment of geodiversity. Results showed that about 50% of publications independently assessed geodiversity with no consideration for biodiversity, 32% discussed or reviewed geodiversity by mentioning potential links to biodiversity and 12% more strongly linked geodiversity assessment to biodiversity assessment. Tools used by scholars to determine geodiversity values varied from statistical through to the more frequently adopted geographic information systems (GIS) and spatial analytical software approaches. Study sites selected for geodiversity assessments were predominantly terrestrial at the state-wide scale. Marine assessments, or seabed geodiversity, were mostly absent from the literature, with only two publications found. Brazil in South America had many geodiversity assessments and European scholars have played crucial roles in the development of quantitative geodiversity assessment in recent years. Subsequent research will benefit from developing a unified geodiversity assessment approach, reaching a consensus on an accepted definition and standardising the geodiversity concept, broadening research site environment types and developing strategies to promote further international and intranational collaboration.

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