Living Blue Planet Report page 12
Habitats
While human exploitation is identified as the major cause of the
declines in marine species, habitat loss and degradation are also
major threats. The following section looks at trends in three key
marine ecosystems: coral reefs, seagrass and mangroves. It also
looks at the status of deep-sea habitats in the North Atlantic and
polar ecosystems in the Antarctic.
Coral reefs
Coral reefs provide some of the most biologically rich, productive
and economically valuable ecosystems on Earth. Over 25 per cent
of all marine species live in coral reefs, and yet they cover less than
0.1 per cent of the ocean, about half the area of France (Spalding
et al., 2001).
Globally, around 850 million people live within 100km of
a coral reef and directly benefit from the economic, social and
cultural services it provides (Burke et al., 2011). Reefs support many
economically important fish species, providing food for hundreds
of millions of people. They also protect the coast from storms
and erosion, and generate jobs and income from fishing, tourism
and recreation.
Three-quarters of the world’s coral reefs are currently
threatened (Burke et al., 2011). Pressures include increased fishing,
poor water quality from coastal agriculture, deforestation, coastal
development and shipping, as well as rising ocean temperatures and
acidity brought on by global warming. At current projected levels
of warming and acidification, coral reefs could be lost altogether by
2050 (Hoegh-Guldberg et al., 2015).
Recent studies indicate that tropical reefs have lost more
than half their reef-building corals over the last 30 years (Hoegh-
Guldberg et al., 2015). Figure 8 shows an overall large decline in
coral cover in the Indo-Pacific and the Caribbean since the 1970s.
This degradation threatens both the reefs and the communities and
economies they sustain.
Over 25 per cent
of all marine species
live in coral reefs, yet
they cover an area
about half the size
of France
25%