Marine Atlas: Maximizing Benefits for Kiribati

REEFS AT RISK: REEF RISK LEVEL

Kiribati’s reefs are at risk and the direct and indirect impacts of climate change are exacerbating a system already under threat, jeopardizing marine values worth billions of dollars.

As seen in the previous maps, coral bleach- ing is the silent reef killer, caused by rising sea levels and ocean acidification. Kiribati’s reefs are remote and often pristine; however, even they are not immune from the threat of coral bleaching. In 2015–2016, persistent elevated ocean temperatures as high as 31.4°C affected the northern Line Islands. This resulted in widespread coral bleaching, with more than 80 per cent coral mortality in some locations, particularly around Kiritimati (NOAA Coral Reef Watch). This event was

linked to a very strong El Niño event that affected much of the Pacific reefs.

development, including coastal engineering, landfilling, run-off from coastal construction, sewage discharge (see also chapter “The dose makes the poison”) and impacts from unsustainable tourism (see also chapter “Beyond the beach”); watershed-based pollution, focusing on erosion and nutrient fertilizer run-off from agriculture entering coastal waters via rivers; marine-based pollution and damage, including solid waste, nutrients, toxins from oil and gas installa- tions and shipping, and physical damage

However, climate change is not the only threat to coral reefs; local human activities are also posing a threat to Kiribati’s reefs. The cumulative risk of these threats is shown on the map of Kiribati’s reefs, classi- fied by estimated present threat from local human activities, according to the Reefs at Risk integrated local threat index. Threats considered in the index include: coastal

Crown-of-thorns starfish damage Kiribati’s reefs. Outbreaks often occur when their natural predators are overfished.

from anchors and ship groundings (see also chapter “Full speed ahead”); and overfishing and destructive fishing, including unsustain- able harvesting of fish or invertebrates, and damaging fishing practices such as the use of explosives or poisons (see also chapters “Fishing in the dark” and “Small fish, big importance”). This multitude of man-made threats leaves Kiribati’s reefs at risk. Analysis of the threat index indicates that 28.1 per cent of the reef area is classified as facing a low risk, 56.0 per cent a medium risk and 15.9 per cent a high risk, with no reefs facing a very high risk at the time of assessment (2011). The areas of increased risk to reefs correspond to the main population centres, particularly in the Gilbert group and around Kiritimati (Christmas Island). Kiribati has also been identified as one of the nine countries most

vulnerable to coral reef degradation, due to a combination of high dependence on the reefs, high threat exposure and low adap- tive capacity (Burke et al., 2011). The reefs are important to the economies of local communities, for subsistence and for coast- al protection. The islands of Kiribati are built entirely of coral reefs and would not exist if it were not for their protective fringe (Burke et al., 2011).

Acropora coral field in Kiribati was exposed to multiple impacts, including a crown-of-thorns outbreak and cyclone damage.

MAXIMIZING BENEFITS FOR KIRIBATI

CLIMATE CHANGE THREATS

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