At road section of Chuanfan Rock (Sail Rock), Pingtung, Kenting of Taiwan Provincial Highway 26, mud flowed to the road surface last summer due to heavy rain, and the Directorate General of Highway made a wall of cement ditch.
However, the environmental protection group believed that the high wall would block the terrestrial (land) crab from crossing the road to the sea to release eggs.
Land crab crossroads is a huge ecological issue in Kenting, and we already discussed it in detail in this article, I suggest reading it to understand more about this problem.
Directorate General of Highway suggested increasing the climbing grids which were friendly to terrestrial crab, and today they invited experts of terrestrial crab, Hong-chang Liu (劉烘昌) (third from the left) and other people to survey.
Because heavy rain caused the flow of mud to the road surface on the road section of Chuanfan Rock, Pingtung, Kenting of Taiwan Provincial Highway 26 last summer, the Directorate General of Highway performed emergency repairs to make a wall of cement ditch after the disaster.
Environmental protection groups believed that vertical, smooth, and high fences would block the land crab from crossing the road to the seaside to release eggs, which would lessen the opportunity of breeding for terrestrial crab.
Road section near Chuanfan Rock (Sail Rock) beach in Kenting
Third Maintenance Office Directorate General of Highways admitted that it initially assessed the road section of which terrestrial crabs not much prefer to cross and then built the climbing grid which was friendly to terrestrial crabs according to the suggestions of experts of terrestrial crab.
Before the end of the project at the end of the month, the Third Maintenance Office Directorate General of Highways invited scholars of land crab, including Hong-chang Liu (劉烘昌) and others, to visit the site today.
Hong-chang Liu (劉烘昌) reminded us that it was also necessary to consider the needs of land crabs to return.
Hong-chang Liu (劉烘昌) inspects newly installed grids for crabs
At road section of Chuanfan Rock, Kenting of Taiwan Provincial Highway 26, emergency repair projects were carried out due to the serious flow of slope mud last year.
At the beginning of the year, the environmental protection group found that the repaired ditch wall of road was very deep, and the surface of cement was smooth.
In Shadao beach area, instead of grids, the whole underway tunnel was installed.
This section was also a hotspot for terrestrial crabs to pass by to release eggs on the seashore, and the environmental protection group reflected to the highway-related unit that this kind of construction method would inhibit the breeding machinery of terrestrial crab.
The Fenggang branch of the Directorate General of Highway also discussed with the management office of Kenting National Park and the scholars, and the scholars suggested that to ensure that the terrestrial crabs would not be trapped in the ditch, a hard mesh could be added to connect the passages of terrestrial crabs at the top of the two walls.
In addition, the roughness of the walls could be increased, and the escape passage of the diagonal hemp rope could be established.
The cement wall could be equipped with hollow wood plank and other friendly measures.
Similar ropes already were installed earlier in Shadao beach section crab tunnel.
The Fenggang branch of the Third Maintenance Office Directorate General of Highways said that due to continuous heavy rain last summer, the mud flowed onto the road, causing an accumulation of dirt and sand on the road surface, which seriously affected the safety of the road.
To avoid repeated disasters, post-disaster emergency treatment and repair of the ditch wall were conducted to block the falling of a large amount of sediment topsoil from the mountainside caused by heavy rainfall.
Because there was still a considerable distance away from the disaster site (38.6k) to the road section for crab protection (39.5k to 41.5k), the construction method was not taken into consideration.
After reflected by the environmental protection group, to facilitate the passage of terrestrial crabs, either the ditch wall and the inside and outside cement wall surfaces of the ditch, which were vertical and smooth, could be roughened, or the surfaces of the ditch wall could be laid with rough linen, cloth bags, etc.
Scholar of terrestrial crab, Hong-chang Liu (劉烘昌) said in a meeting today, the section of Taiwan Provincial Highway 26 from Chunfan Rock of Kenting to Banana Bay was a hotspot for terrestrial crabs to cross the road and release their offspring.
The section of ditch wall with a total length of 170 meters belongs to the secondary hotspot, and the surface of cement ditch wall was long, high, and smooth, making the terrestrial crab entering the ditch probably could not escape and then die of dehydration.
The branches and wooden strips needed to be placed at the bottom part of ditch for formation of temporary habitat.
Besides, the design also needed to consider the need of crabs to return from seashore. Also, when adding hard grid as a passageway of terrestrial crabs, whether the density of grid was suitable for small terrestrial crabs to go through needed to be further verified.
Management office of Kenting National Park considered the roadside grid to be abrupt in term of landscape, and they would continue to observe the condition of improved habitat of terrestrial crab, before providing information to highway-related unit for improvement.