Tracking the hardening coast

随着城市化的增加，世界海岸正在改变其身体状态：从液体和移动沙子以及侵蚀岩石和悬崖上，随着垫子，海墙和其他工程项目的增加，它们变得越来越难。结果可能导致沿海环境中沿海物种和养分的多样性较小。

一支新西兰和澳大利亚研究人员的团队对此进行了量化，该模型可以预测在未来几十年中，海岸线的距离可能会变得人工或硬化。

“Basically, all our infrastructure is hard,” says Dr Ana Bugnot, a marine ecologist at the University of Sydney and co-author on a paper describing the research,出版in自然的可持续性.

虽然有些天然海岸线可能是鲜明的，但也有许多柔软的沉积物繁重的环境，例如红树林，泥泞和沼泽。当城市化时，这两个环境通常都被身体硬结构所取代。

这对沿海生态系统产生了连锁反应，新的栖息地受益于“一个截然不同的生态界”。这些地方通常可以偏爱入侵物种，或者可以通过允许一个物种占主导地位来促进更加同质的生态系统。

Artificial habitats are often much simpler than natural environments, even if their physical nature hasn’t changed much.

“如果您想到岩石海岸或岩石露头，这些岩石通常具有许多不同的结构，” Bugnot说。

“Everything gets very simplified in human built structure. And that means that you have less habitat for the animals to colonise.”

这种沿海硬化已被记录在世界范围内，但是很难说出预计会增加多少。

“We’ve actually done quite well at documenting where things are hardening right now, where we have structures like sea walls and pontoons and wharves,” says co-author Dr Katherine Dafforn, an environmental scientist at Macquarie University.

“但是要将它们管理到未来，我们确实需要一种工具，可以帮助我们预测接下来会发生什么，并有助于管理多个利益相关者和用途的海洋空间。”

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Read more:Monitoring coastline erosion risk

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The researchers examined satellite data from 30 different cities around the world, mapping artificial and natural structures. They found that over half (approx. 53%) of the coastline in these 30 centres has been replaced with artificial structures.

They then combined this data with demographic, economic and shipping information to develop a predictive model for coastal hardening.

“This tool will help us to understand where and how much coastal hardening is going to occur in the future,” says Dafforn. “It’s super important to understand that, given predictions of sea level rise and population growth, that we know will drive more construction.”

Dafforn补充说，该工具可用于帮助管理海岸线。

“In situations where we shouldn’t build, we could probably use the tool to predict areas that might be more sensitive to changes from construction. But if we have to build, and there’s no other option, then this tool can help to understand where that might occur.

“And then we can build a structure for multifunctional purposes – so we don’t just need to construct for protection or infrastructure. We can build to encourage things like biodiversity, or to facilitate particular species that improve water quality.”

研究人员的一个特殊重点是防止入侵物种占据。

Using this model on New Zealand as a case study, the researchers found that over the next 25 years, New Zealand could expect an additional 243 to 368 kilometres of coastline where artificial structures will replace natural environment, depending on its economic growth.

“We hope that the study helps relevant agencies understand the scale of present-day coastal hardening and the socio-ecological significance of this,” says Dr Oliver Floerl, a senior marine scientist at the Cawthron Institute in New Zealand, and lead author on the paper.

“We also want to create an awareness that considerable further expansion is likely and that proactive mitigation strategies are needed.”