Seagrass ecosystem contributions to people's quality of life in the Pacific Island Countries and Territories

Seagrass ecosystems provide critical contributions (goods and perceived benefits or detriments) for the livelihoods and wellbeing of Pacific Islander peoples. Through in-depth examination of the contributions provided by seagrass ecosystems across the Pacific Island Countries and Territories (PICTs), we find a greater quantity in the Near Oceania (New Guinea, the Bismarck Archipelago and the Solomon Islands) and western Micronesian (Palau and Northern Marianas) regions; indicating a stronger coupling between human society and seagrass ecosystems. We also find many non-material contributions historically have been overlooked and under-appreciated by decision-makers. Closer cultural connections likely motivate guardianship of seagrass ecosystems by Pacific communities to mitigate local anthropogenic pressures. Regional comparisons also shed light on general and specific aspects of the importance of seagrass ecosystems to Pacific Islanders, which are critical for forming evidence-based policy and management to ensure the long-term resilience of seagrass ecosystems and the contributions they provide

Seagrass ecosystems of the Pacific Island countries and territories: a global bright spot

Seagrass ecosystems exist throughout Pacific Island Countries and Territories (PICTs). Despite this area covering nearly 8% of the global ocean, information on seagrass distribution, biogeography, and status remains largely absent from the scientific literature. We confirm 16 seagrass species occur across 17 of the 22 PICTs with the highest number in Melanesia, followed by Micronesia and Polynesia respectively. The greatest diversity of seagrass occurs in Papua New Guinea (13 species), and attenuates eastward across the Pacific to two species in French Polynesia. We conservatively estimate seagrass extent to be 1446.2 km2, with the greatest extent (84%) in Melanesia. We find seagrass condition in 65% of PICTs increasing or displaying no discernible trend since records began. Marine conservation across the region overwhelmingly focuses on coral reefs, with seagrass ecosystems marginalised in conservation legislation and policy. Traditional knowledge is playing a greater role in managing local seagrass resources and these approaches are having greater success than contemporary conservation approaches. In a world where the future of seagrass ecosystems is looking progressively dire, the Pacific Islands appears as a global bright spot, where pressures remain relatively low and seagrass more resilient

Long term changes of Suva Reef flat communities from conventional in situ survey and remote sensing methods

This work is concerned with the combined use of conventionally-gathered data and remote sensing methods to study the communities of Suva Reef, Fiji. A principal objective was to observe coral reef processes that could not be studied effectively by either approach individually. The in situ surveys have provided detailed information on reef community dynamics at a small scale while the airborne images have been able to reveal the longer term general patterns.The results of in situ surveys show massive changes to the reef substratum caused by Echinometra mathaei excavations. The disturbance cause by E. mathaei was associated with increases of turf algae. Four decades of habitat changes were documented from airborne images. The magnitude and spatial extent of these changes were related to likely causes. In particular, the long term patterns of spatial changes of seagrass beds revealed that there were oscillations in the regrowth and losses. Seagrass beds extended towards the lagoon in some years and regressed in others.Other disturbances have also made significant contributions in shaping community structure of Suva reef flat between 1945 to 1991. Major causes of disturbances were tsunami and cyclone damage, flood damage, Acanthaster planci predation and effects of human activities. Tsunamis have probably caused more damage to the structure of the reef than any other disturbance occurring between 1945 and 1990.This investigation has demonstrated the effective of the combined observational approach in improving our ability to interpret the long term significance of reef changes. The understanding arising from the study will be able to underpin the development of scientically based plans for conservation and management of reefs.</p

A Novel Method of Assessing Bioerosion by the Sea Urchin Echinometra sp. A on a Fijian Reef

Sea urchins are major substratum eroders of coral reefs and the calcium carbonate condition of coral reefs may therefore reflect the abundance of sea urchins. The omnivorous urchins, Echinometra spp. are known as ?rock -borers? and are agents of large-scale bioerosion, particularly in the Caribbean, Eastern Pacific and Western Indian Ocean. By burrowing into coral rocks they protect themselves from predators, wave and current action, and to some extent from desiccation at low tide. Bioerosion estimates are known for a few specific reefs only. Although the Echinometra sp. A have not been named yet, they were mistaken for Echinometra mathaei for long in Fiji. This novel study attempted to estimate bioerosion rates of the low but consistent numbers of sea urchins, Echinometra sp. A (green-white-tipped) on the Nukubuco reef, Fiji by calculation of the net carbonate accumulation. Cage experiments reported bioerosion rates (kg CaCO3/m2/urchin/d) of 35-37 x 10-3 at the reef crest and 30-43 x 10-3 at the reef flat. This method of assessing bioerosion showed both strengths and weaknesses. However, the Nukubuco reef balance between reef growth and reef destruction is shifting, with bioerosion becoming the dominant process

A novel method for assessing bioerosion by the sea urchin Echinometra sp. on a Fijian reef

Sea urchins are major substratum eroders of coral reefs and the calcium carbonate condition of coral reefs may therefore reflect the abundance of sea urchins. The omnivorous urchins, Echinometra spp. are known as “rock -borers” and are agents of large-scale bioerosion, particularly in the Caribbean, Eastern Pacific and Western Indian Ocean. By burrowing into coral rocks they protect themselves from predators, wave and current action, and to some extent from desiccation at low tide. Bioerosion estimates are known for a few specific reefs only. Although the Echinometra sp. A have not been named yet, they were mistaken for Echinometra mathaei for long in Fiji. This novel study attempted to estimate bioerosion rates of the low but consistent numbers of sea urchins, Echinometra sp. A (green-white-tipped) on the Nukubuco reef, Fiji by calculation of the net carbonate accumulation. Cage experiments reported bioerosion rates (kg CaCO3/m2/urchin/d) of 35-37 x 10-3 at the reef crest and 30-43 x 10-3 at the reef flat. This method of assessing bioerosion showed both strengths and weaknesses. However, the Nukubuco reef balance between reef growth and reef destruction is shifting, with bioerosion becoming the dominant process

Seasonal changes in the Sargassum populations on a fringing coral reef, Magnetic Island, Great Barrier Reef region, Australia

Sargassum populations are one of the most conspicuous features of both the reef flats and the reef slopes of fringing coral reefs in the Great Barrier Reef region, in terms of their widespread occurrence and often high standing crop. Although an important element of the benthic community on inshore reefs, Sargassum spp. are generally absent from mid- and outer shelf reefs in the region. In this study, the temporal and spatial distribution patterns of the Sargassum populations on a fringing reef flat in Geoffrey Bay (Magnetic Island) were investigated quantitatively. Data on biomass, cover, density, mean thallus length and reproductive condition were collected at three sites on the reef flat over a 13 month period from March 1986 to March 1987. The Sargassum populations in Geoffrey Bay showed marked seasonal changes in growth and development. They exist as dense stands of large thalli in the warmer months, but persist largely as basal parts only (including the holdfasts with short primary axes) in the cooler months. The observed seasonality is discussed with reference to possible causal factors