Two Orchids and a Karst Plateau

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KyushuCalanthe

Just call me Tom
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Kyushu, Japan; warm temperate/subtropical climate
Yesterday I got to visit a unique place - a limestone karst plateau. Karst topography is a product of acidic water acting on carbonate bedrock, most notably limestone. Such terrain has characteristic formations such as sinkholes, caves, abundant underground water, and lots of odd rock formations at the surface. I could wax on, but if you really want more details, check out this excellent Wikipedia article about Karst Topography.

The Hiraodai Karst Plateau is the second largest in Japan. It is between 1,000 and 2,500 feet in elevation consisting of a row of flat topped mountains abruptly rising from the lowlands of northern Kyushu, just south of Kitakyushu City. About half is protected, the other is in private ownership. There is one immense limestone quarry that has essentially chopped off the top third of one mountain. Here is a typical scene of this karst plateau:

HiraodaiKarstland1SM.jpg


So what's the big deal? These areas due to their unique geography are home to unusual plants and animals. Surface water is uncommon in upland karst plateaus, but in some areas it bubbles up and can form small wetlands. In one wetland I found the endangered egret orchid, Pecteilis radiata, in flower - my prize of the day. There were more further out in the tiny wetland, but I didn't photograph them for fear of doing too much damage - these places are really fragile and easily overrun by human feet:

SagisouHiraodai.jpg


A bonus find in the same little wetland was a Platenthera, P. sagittifera. This too is a very rare plant in these parts, found only in a few boggy uplands:

MizutonboSP.jpg
MizutonboFLS.jpg


Other rarities exist in this place including more orchids such as Pogonia japonica, Pogonia minor, Epipactis thunbergii, and Bletilla striata. What is ironic is that the Pecteilis, Pogonia japonica, and Bletilla are all common in cultivation, but endangered in the wild. The reason is simple - their habitats are very rare nowadays. Protection of the remaining habitat is critical, and a number of wetlands have been preserved. However, due to degradation of such habitat through human use - both consumptive and non-consumptive - these plants are disappearing from many places.
 
Beautiful shots. Thanks! The first one is surreal. Looks like it could be from the Lord of the Rings movie. I bet it was a beautiful countryside and a wonderful day trip. I never knew Japan had karst geology. That was a surprise to me. I would have assumed that it was too narrow across the islands for limestone underground water channels, but now that I think of it, even Okinawa had caves. Pretty cool landscape features.
 
Thanks for the tour, Tom. Now I'm thinking I should add limestone/oyster shell to the radiata.

Hey Dot, I wouldn't add lime to them since they need acidic conditions. They are most often found in areas without limestone.

Hera, Japan has been part of mainland Asia many times in the past due to falling sea level. I have no idea how this area formed, but it is pretty old, dating back to the Paleozoic era (~400 mya).

Thanks for the comments folks, it is a cool place to see.
 
Rose and Dot, that was my bad. The orchids grow in tiny wet spots - seepage slope bogs - near the limestone fields, but not directly in them. P. radiata once was found in many more places in Japan, but much of its former habitat is now rice patties. These upland bogs are where they are found today because that is the only habitat left.
 

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