The transition from land to sea is one of the most biodiverse habitats on our planet. But most of the world’s coasts have already been badly damaged by humans and other environmental influences, a study reveals. According to this, only a good 15 percent of the coasts on our planet are ecologically intact, they are mainly in the north of Russia, Greenland and Canada. In most other countries, more than half of the coasts are severely degraded.
Where the land merges into the sea, the changing tides and the diverse, changing environmental influences create a diverse and species-rich habitat. “Coastal regions contain a high level of biodiversity and provide millions of people with valuable ecosystem services such as food or protection from storms,” explains Brooke Williams from the University of Queensland. Accordingly, it is important to protect these valuable biotopes.
Intact refuges almost only in the far north
However, in order to conserve these habitats, it is first important to know their condition – and this is where there has been a problem so far. Therefore, Brooke and her colleagues have now carried out a comprehensive inventory of the world’s coasts, for the first time including both the above and below water parts of the coastal zone together. “Until now, the two have only ever been considered separately in terms of protection and surveys,” says co-author Benjamin Halpern from the University of California at Santa Barbara. “By now assessing both zones together, we can better identify where these connected land and sea areas are still relatively untouched and where not.”
The evaluation showed that in 2013 only around 15.5 percent of the world’s coastal zones were ecologically undamaged. “Intact coastal biotopes have therefore become very rare even in the most up-to-date usable data. However, the pressure on these areas is increasing, so today there are certainly even fewer,” says Halpern. According to the survey, Canada, Russia, Greenland and parts of Chile, Australia and the USA have the largest sections of still largely untouched coastal landscapes. However, even the coasts in the far north are endangered: “Climate change is melting the sea ice and is thus exposing more and more coasts to environmental changes, but also to settlement and raw material extraction,” says Halpern.
degradation even in protected areas
The coasts in most other countries are significantly more damaged. In more than 80 percent of them, significantly less than half of the coastlines are still ecologically intact, as the researchers determined. On average around the world, 47.9 percent of all coasts are already badly affected – mainly due to human intervention. These severely damaged and degraded areas also include particularly species-rich habitats such as coastal zones with seagrass beds or coral reefs in the sea and savannahs on the land side. Even in protected areas, around 43 percent of coasts are already under severe pressure, the team reports.
“Our results show that urgent action is needed to preserve these coastal regions and regenerate those that are already degraded,” says Williams. She and her colleagues hope their inventory can help improve conservation efforts. “Understanding why certain coastal systems are under pressure can help us to develop more targeted management strategies,” adds Williams’ colleague Amelia Wenger.
Source: University of California-Santa Barbara; Specialist article: Conservation Biology, doi: 10.1111/cobi.13874