Natural monument protection: Bioprotection for the Great Wall of China

Mosses, lichens and bacteria have protected parts of the world's longest structure from weathering. An international research group has now examined natural monument protection in more detail.

DThe Great Wall of China is considered the largest structure in the world and has therefore been included in the UNESCO World Heritage List. However, this protective wall, which is several thousand kilometers long, is only in excellent or renovated condition in a few places, such as the excursion resort of Badaling north of Beijing. According to some reports, more than half of the structure is now severely damaged or completely disintegrated, with erosion from wind and weather playing an important role. An international research group has now discovered that a biocrust consisting of cyanobacteria, mosses and lichens growing naturally on the wall helps to protect the wall against further erosion and decay.

Although people often talk about “the” Great Wall of China, this impressive protective wall against the intrusion of hostile peoples from the north is not a coherent structure. Rather, it consists of many, often independent, segments that were built by different dynasties in China over the course of several centuries.