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Dinosaurs and alders on display in the reserve
A bare Danxia landscape in the Chishui Queli National Nature Reserve
Reporters and researchers observe primroses growing in a Danxia rock cavity in the reserve
Danxia Stone Mountain fish fossils displayed in the reserve
■ Introduction
On March 12, a team of Scientists from China, the United States and Canada announced in Beijing that they had discovered the smallest dinosaur ever found in Cretaceous amber in Burma (broad dinosaurs including birds). The smallest dinosaur claimed to have been found so far, although there is still some controversy, "brushed the screen" Chinese and foreign media.
The toothed bird, hidden in amber, and all the dinosaurs, went extinct on Earth. All kinds of fossils are the backs it leaves for people.
In the upper reaches of China's Yangtze River, on the banks of the Chishui River, in the V-shaped valleys, there are also fossil dinosaur footprints, as well as some kind of dinosaur food, the ancient relict plant known as the "dinosaur grass", the alder tree, which still exists and leaves.
Chishui is the area with the highest concentration of alder in the world.
Not only that, by a V-shaped valley, a special shelter is formed, helping many creatures to escape the disaster, to continue, but also to preserve the real topographic landscape, is the "bottom book" of the large ecosystem and the evolution of the earth, and has become one of the focuses of researchers.
Why does the forest connected by V-shaped valleys attract people? What stories have happened and are happening in this forest?
Starting from today, this newspaper will successively launch a series of reports on the "Journey through the 'Huanbao District'", and follow the researchers of the Chishui Que que national nature reserve management bureau into this dense forest to explore the secrets hidden in it.
Guiyang Daily Rong media reporter Huang Qianhua Zhang Zhihong
■Series Report (1)
Travel through the secret realm of the alder
In Chishui City, nearly one-third of the low-altitude valleys are home to alder. However, the most concentrated area is the inaccessible valley between Hushi Town and Yuanhou Town. The world's most concentrated distribution area is in this area, and official data says there are more than 40,000 plants. Many years ago, the Chinese government established the Chishui Quercus National Nature Reserve (hereinafter referred to as the "Huanbao District") to protect this rare and endangered plant.
The first stop through the "Huanbao District" was jinshagou where the distribution of the alder was concentrated. It is a canyon with a length of more than 10 kilometers, from the surface of the stream to the top of the cliffs on both sides, most of which are more than 500 meters vertically high. In this altitude range, the differences brought about by the microclimate environment make the vegetation at different heights distinctive.
In the valley, the warm environment and the cover of tall trees provide shelter for the warm, moist and scattered light-loving alders, rare and endangered ferns such as South China Ziqi and Golden Retriever, and other lower plants or small insects and mammals. So that in the sudden change of climate hundreds of millions of years ago, dinosaurs in this area, leaving only a few footprints fossils after the extinction, their food alder is still alive.
A
From spores to alders, into seedlings such as "breaking through"
The presence of rivers, streams and ditches, and the lush forest vegetation cover, the air humidity in the valley is extremely high. For almost half of the 24 hours, the grass in the lower layer of the forest is wet, with water droplets on the leaves.
In Jinshagou, there are several common tall trees, including gyroscope fruit trees, yellow milk trees, bitter trees, and lampstand trees. Their canopy, located at the top of the gully forest, is leafy in summer, blocking most of the sunlight, and also reducing the evaporation of water vapor in the lower layer of the forest, so that the low plants such as Quercus chinensis and South China Ziqi below can not only protect themselves from the hot sun, but also avoid excessive water loss.
The alder tree, which has only a few bundle tube fibers in the stem, has no way to transport more nutrients to the upper part through the underground root system. In order to survive, it has evolved a unique way of absorbing nutrients.
In March on the Chishui River, the temperature is also around 10 degrees celsius at night, and sometimes reaches 20 degrees during the day. Under this temperature condition, the sap of most trees in the wild begins to flow, gradually entering the rapid growth period of the year.
On the stem of the alder, layers of densely packed air roots are on top, and crisp white spots also grow. These white spots, which are new roots that are growing and prolonging, have a strong water absorption capacity.
Liang Sheng of the Protected Areas Authority and colleagues have been studying the alder tree for 20 years. He said that the lack of bundle fibers mainly relies on gas rooting to absorb moisture in the air to maintain growth. The innermost starch of the stalk, which is wrapped in layers of air roots, is crisp and tender and rich in moisture.
The moisture in the air is more important for the seedlings.
The sporangia that grow on the underside of the leaf burst, and the spores are ejected, some floating under the fallen leaves, and some falling into the air roots of the stem of the mother plant. But whether it falls on the mud, on the stem of the mother plant, or on the stone covered with lichen and moss, the mature alder spores, as long as they get the opportunity to "sleep" - spend more than 20 hours in the dark environment, can quickly sprout in the humid air and grow into seedlings.
However, in the natural environment, there are not many spores that can germinate, perhaps less than one in 100,000.
It is difficult to encounter suitable conditions for germination and rooting, which is a problem for the wild breeding of alder. Fortunately, it has enough spore volumes—most of the leaves of the alder, up to a meter long, or even larger. Behind a leaf of alder, hundreds of millions of spores can be produced a year.
Even so, the spores that can sprout may not eventually grow into a handsome alder tree. At the seedling stage, there are very few aerophytic roots of alder, mainly relying on weak underground roots and thin leaves to absorb nutrients. In addition, rain may wash away unstable alder seedlings, and too dense vegetation may also cause young alder seedlings to die due to lack of sunlight.
Therefore, the trees that can successfully sprout and eventually grow up are the winners of nature's competition.
B
It can grow more than 10 centimeters a year, but the tree is ten meters tall but sad
After overcoming one difficulty after another, the seedlings are 20 to 30 cm tall, and there are more gas roots on the stems before they can be counted as seedlings and begin to enter the rapid growth period.
About 10 years ago, Liang Sheng saw with his own eyes that a tree about 1 meter high was bent by a young bud at the top. "But now, above the bend, about 2 meters have grown." He said that according to this calculation, the alder that has entered the rapid growth stage can grow 10 to 20 centimeters in height a year when the environment is suitable.
This calculation was verified in the rare botanical garden built by the reserve.
In 2015, the "Huanbao District" bred a batch of quercus seedlings by artificially collecting spores and planting them near a stream ditch. Now, the shortest of these trees is also 40 cm high, most of them are 60 to 70 cm high, and some are close to 100 cm.
The starch-based stems cannot support the large leaves of the alder that sway at high altitudes; the limited bundle of tube fibers, and the air humidity that decreases with the height, cannot meet the higher demand of the alder.
Therefore, even in the Jinsha ditch with the largest distribution of alder in the protected area, it is very rare to have a height of more than 10 meters. "In fact, most of them are only 5 to 7 meters high." Liang Sheng said.
C
Endemic fish are bred in the Valley
The nutrient absorption method of quercus quercus is also destined to be accompanied by streams and ditches and high humidity environments for life. "Many people try to plant them in urban flower beds and courtyards, but most of them are unsuccessful." He said.
In almost every valley of the "Huanbao District", there is a small river, or a small stream. Jinshagou, one of the concentrated areas of the distribution of quercus, is particularly typical, under the bushes and in the rocky beach, the river looms, flowing day and night to the Chishui River several kilometers away.
The small rivers and streams in the forest create a microclimate suitable for the survival of the alder community, and at the same time provide opportunities for more organisms. Among them, including the Chishui River, and even the endemic fish of the Yangtze River.
The water in the small river of Jinshagou can be directly drunk. Every year in the late spring and early summer, after a heavy rain, there is often a scene of "fish jumping the dragon gate", and some fish weighing about one to three pounds will go up against the water and try to jump over the rapids and fall of the rocks.
In early March, the daytime temperature in Jinshagou was close to 20 degrees on sunny days. In small rivers, fish are significantly more active, especially on sunny days, where they chase in the crystal clear waters.
Villagers who are familiar with the local customs say that from now until the end of June, the fish in the small river will begin to spawn and hatch.
This is a fish swimming from the Chishui River, mainly Chinese barbed catfish, yellow jaws, three-lined and other fish. Some of them are rare and endemic fish species in the upper reaches of the Yangtze River, spawning and breeding in rocky rapids, and some are very sensitive to water quality.
The water flow speed, suitable depth, less interference, and clear water environment are their ideal spawning grounds and nursery areas.
This is also more or less the case in other valley rivers and streams in the reserve. The data shows that there are about 100 kinds of fish in the rivers and streams of the "Huanbao District".
This is in line with the monitoring and research results of the Fisheries Institute of the Chinese Academy of Sciences: the Chishui River and its many tributaries are becoming shelters and breeding grounds for more fish. Breaking through the obstruction between the Chishui River and its tributaries and protecting the ecology of the tributaries is of great significance to the ecological restoration of the Chishui River and even the Yangtze River and the protection of biodiversity.
("Chishui Valley Exploring Dinosaur Footprints" is provided by Guiyang Evening News, please indicate the source of reprint, without written authorization, may not be reproduced or mirrored.)