Rising sea levels kill trees along the Atlantic coast, creating a “ghost forest” visible from space.


<スパンクラス="キャプション">A panoramic view of the ghost forest on the North Carolina coast.</ span> <span class ="帰属"> <スパンクラス="ソース">  Emily Ury </ span>,<a class= CC BY-ND src = “https://s.yimg.com/ny/api/res/1.2/cikCREWI4MnqCmM1.Ah8_w–/YXBwaWQ9aGlnaGxhbmRlcjt3PTcwNTtoPTMwMy4wNTIwODMzMzMzMzMzMz/https://s. -~ B / aD02MTk7dz0xNDQwO2FwcGlkPXl0YWNoeW9u / https://media.zenfs.com/en/the_conversation_us_articles_815/29e0eceff5bf895eb0e6532e9da0b500” data-src=”https://s.yimg.com/ /YXBwaWQ9aGlnaGxhbmRlcjt3PTcwNTtoPTMwMy4wNTIwODMzMzMzMzMz/https://s.yimg.com/uu/api/res/1.2/utdvjeDujCXf8G16SZfpjg–~B/aD02MTk7dz0xNDQwO2FwcGlkPXl0YWNoeW9u/https://media.zenfs.com/en/the_conversation_us_articles_815/29e0eceff5bf895eb0e6532e9da0b500 “/>
A panoramic view of the ghost forest on the North Carolina coast. Emily Urie, CC BY-ND

Trekking to my research site near North Carolina Alligator River National Wildlife SanctuaryThrough the section of the trail, which is completely submerged, through the water to the depth of the knee. Permanent flooding is commonplace on this lowland peninsula behind the Outer Banks of North Carolina. Trees that grow in the water are small and fainted. Many people have died.

Evidence of depletion of forests is everywhere along the North Carolina coast. Almost every roadside ditch that I pass by while driving in this area is lined with dead trees and dead trees.

As An ecologist studying the response of wetlands to rising sea levels, I know this flood is evidence that climate change is changing the landscape along the Atlantic coast. It is a symbol of environmental change that threatens wildlife, ecosystems, local farms and forestry.

Like all living things, trees die. But what’s happening here isn’t normal. Large patches of trees die at the same time, and saplings are not growing in their place. And it’s not just about local issues. Seawater raises salt levels in coastal forests along the entire Atlantic coastal plains, from Maine to Florida. A vast belt of adjacent forest is dying. They are now known in the scientific community as “ghost forests”.

The insidious role of salt

sea ​​level rise Caused by climate change Wetlands are moistened in many parts of the world. It also makes them more salty.

In 2016, I started working in a forested wetland in North Carolina, studying the effects of salt on plants and soil. Every few months, wear heavy rubber waders and mesh shirts to prevent insect bites and carry over 100 pounds of salt and other equipment along the flooded path to the research site. We are salting an area as large as a tennis court with the aim of mimicking the effects of rising sea levels.

After two years of effort, salt did not appear to affect the plant or soil processes we were monitoring. Instead of waiting for the experimental salt to slowly kill these trees, the question I need to answer is how many trees are already dead and how many wetlands are vulnerable. was. To find the answer, I had to go to a place where the trees were already dead.

Sea-level rise is flooding the North Carolina coast, and saltwater is seeping wetland soil. Salt moves through groundwater when freshwater is depleted, such as during droughts. Brine also passes through canals and ditches and infiltrates inland with the help of winds and high tides. Dead trees with pale trunks without leaves or limbs are a clear sign of high salt levels in the soil. In the 2019 report,Wooden tombstone.. “

When a tree dies, more salt-tolerant shrubs and grass move to its place.In a newly published study I co-authored Emily Barnhart And Justin Light With Duke University Saiyo The University of Virginia shows it in North Carolina This change was dramatic..

The state’s coastal areas are suffering from rapid and widespread forest loss due to the chain of impacts on wildlife, including endangered wildlife. Red Wolf And Red flower cap badge woodpecker..Wetland forest Isolate and store large amounts of carbonTherefore, depletion of forests also contributes to further climate change.

Evaluation of ghost forests from space

A bird’s-eye view was needed to understand where and how fast these forests were changing.This perspective comes from the following satellites NASA Earth Observing System, An important source of scientific and environmental data.

Satellite image of the North Carolina coast

Satellite image of the North Carolina coast

Since 1972 Landsat satellite, Jointly operated by NASA and the United States Geological Survey Continuous image of the earth’s surface It reveals both the changes caused by nature and humans. Landsat images were used to quantify changes in coastal vegetation since 1984, and high-resolution Google Earth images were used to identify ghost forests. Computer analysis helped identify similar patches of dead trees throughout the landscape.

Image of Google Earth with a road separating healthy and dead forests.

Image of Google Earth with a road separating healthy and dead forests.

The result was shocking. More than 10% of the forested wetlands in the Alligator River National Wildlife Sanctuary have been found to have been lost in the last 35 years. This is a land protected by the federal government and there is no other human activity that could kill the forest.

Rapid sea level rise These forests appear to outweigh their ability to adapt to wetter, more salty conditions. Abnormal weatherIs supported by climate change, causing further damage from severe storms, more frequent hurricanes and droughts.

The largest annual loss of forest cover in the study area was found to have occurred in 2012 after periods of extreme drought, forest fires and storm surges. Hurricane Irene This triple wormy seems to have been a turning point that caused a large number of tree deaths throughout the region.

Saltwater intrusion is rapidly killing forests along the North Carolina coast.

Saltwater intrusion is rapidly killing forests along the North Carolina coast.

Should scientists fight or support the transition?

As the world’s sea level continues to rise, Gulf of Mexico To Chesapeake Bay And in other parts of the world Incur a big loss From saltwater intrusion.Many in the conservation community are rethinking their land management approaches and exploring more. Adaptation strategy, Promoting the inevitable transition of forests to salt marshes and other coastal landscapes.

For example, in North Carolina Nature reserve We are implementing some adaptive management approaches such as: “Create a living coastlineIs made from plants, sand and rocks to provide a natural buffer from high tides.

[Deep knowledge, daily. Sign up for The Conversation’s newsletter.]

A more radical approach is to introduce salt-tolerant wetland vegetation into the threatened zone. This strategy is controversial because it goes against the desire to keep the ecosystem intact.

But if the forest is dying anyway, having a salt marsh is a much better result than allowing the wetland to be returned to open water. Open waters are not bad in nature, but they do not provide many of the ecological benefits of salt marshes. Active management makes it possible to extend the life of coastal wetlands, continue carbon storage, provide habitat, improve water quality and protect productive farmlands and forests in coastal areas.

This article will be republished from conversation, A non-profit news site aimed at sharing ideas from academic experts. It was written by: Emily Urie, Duke University..

read more:

Emily Urie was funded by NASA and the North Carolina Sea Grant. Additional support for this project came from the National Science Foundation.

Posted on