The weather of Heihe River in Qinling Mountains

The team investigated several typical wetlands in Xiaman Township and its surrounding areas in ruoergai county:

1 Heiqing Bridge

Heiqing Bridge is a well-preserved swamp in Xiaman Township, where aquatic vegetation grows well. More than a dozen birds have been observed, such as black-necked crane, white-eyed diving duck, wild duck, red-footed snipe, red-billed gull and tern. Most of these birds can only be found in wetlands. In the ditch, we also found plateau loach, which is the first time we have seen fish in Zoige. The main reason is that there is enough water and soil in the swamp, and the vegetation growth is obviously better than the surrounding grassland, which provides excellent habitat and foraging ground for birds. People and animals can't cross the swamp, which makes the environment here less disturbed by the outside world and becomes the last refuge of dozens of birds in Fiona Fang. There are no rodents (such as marmots, zokor) or traces of their activities anywhere in the grassland, which shows that marmots, zokor, pikas and other animals living in caves cannot survive in the swamp environment. In the swamp environment, the soil is soaked by water, and rodents have no possibility of digging holes. In the core area of the swamp, wild mammals rarely set foot in it. No amphibians and reptiles were found in the investigation, and no pests threatening vegetation were found.

2 Wetlands on both sides of the Yellow River

The soil near the river is rich in water and loose, and there are no rodents, but there are marmots on the sloping grass hundreds of meters away. The wild animals there are not very afraid of human beings, which shows that there is little interference from human beings.

3 xingcuo

"Xingcuo" means "Bird Lake" in Tibetan. Local Tibetans said that there used to be several square kilometers of lakes here, and during the spawning season, the meadow exposed to the lake was crowded with bird eggs. But what appeared before our eyes was the dry and cracked bottom of the lake, and there was local desertification, and there was no trace of waterfowl at all. Groundhog, zokor and pika can be seen everywhere.

(2) Grassland

Grassland is the most important typical environment in Xiaman Township, and the average height of vegetation is only about ten centimeters. Most grasslands are actually formed by wetland degradation. According to the preliminary statistics of the team, there are as many as 3,000 rat holes per hectare, and mounds formed on the ground abound. According to local Tibetans, before the 1980s, it was still a wetland, and no rodents were ever found. It can be said that the appearance of a large number of rodents is an important symbol of wetland degradation. At the same time, such a high density of rodents has caused great damage to the grassland. They dig many holes and eat grass roots, which accelerates grassland desertification. Rabbits, foxes, wolves and leopard cats were observed in this group, but the number of carnivores was obviously not enough to adjust the ecological balance of the whole grassland. Grassland provides an excellent hunting ground for carnivores, which is conducive to the recovery of their populations.

Our team also found an adult desert cat in the Angdangqiao grassland in the north of Xiaman Township, with a body length of about 80 cm, a brown coat, a tail length of 30 cm and obvious black stripes. There is no record of Zoige, a rare animal, in the county annals.

(3) Sandy land

Through the observation of several typical sandy lands in Xiaman Township and its surrounding areas, we only found a reptile sand lizard and several birds nesting in the sandy land, but no fresh caves for rodents were found. In semi-degraded grassland, the number of rat holes is also significantly less than that in healthy grassland.

Second, the ecological situation analysis

1 According to the county records, after the democratic reform, the government carried out a number of large-scale ditching and drainage in Zoige area, "demanding pasture from the swamp", and transformed the swamp into 1400 square kilometers, which led to the deterioration of waterfowl habitat environment and a sharp decline in the number and species of birds. Nowadays, in most areas, only some common birds can be seen.

Due to the vigorous development of animal husbandry, animal husbandry is seriously overloaded, which leads to grassland degradation and habitat shrinkage, which seriously affects the free habitat and reproduction of wild animals. Influenced by religion, local Tibetans have long maintained the habit of not killing animals. However, after the democratic reform, with the trend of breaking superstition, many hunting teams appeared one after another, killing local wild animals on a large scale, resulting in some kinds of wild animals being endangered or even extinct in the local area (such as Tibetan wild donkeys). Since 1980, groups of foreigners came here to hunt and cherish wild animals for economic benefits, which led to the further depletion of local wild animal resources. The local biodiversity has been seriously damaged. Although senior consumers such as foxes and raptors can be seen occasionally, their numbers are far from enough to adjust the regional ecological balance.

After the swamp degenerates into grassland, the soil becomes hard, which is beneficial for rodents to breed, dig holes and feed on grass roots. They endanger grassland vegetation, make pasture resources more tense and accelerate grassland desertification. Coupled with the lack of natural enemies, rodents multiply and form disasters. In the face of grassland rodents, human beings were forced to use chemical agents to kill rodents, and the cumulative area of rodent control and pest control reached 2330 square kilometers. However, it backfired: chemicals polluted the grassland environment on a large scale, and other herbivores were also devastated. Polluted grass was eaten by cattle and sheep by mistake, participated in the material cycle, and carnivores were poisoned twice (raptors and carnivores died in large numbers, and snakes almost disappeared in the local area). However, the rodent damage has not been effectively controlled, but has intensified because of the reduction of natural enemies. In addition, after the ecological balance is destroyed, it is easy to cause grassland pests.

Serious human disturbance such as overgrazing leads to the degradation of grassland ecological function and the weakening of biodiversity, which creates favorable conditions for the invasion of alien species. Species invasion will have a great impact on the local environment, directly threaten local species in terms of species and quantity, and lead to endangered or even extinct local species.

Our team found that the skins of national key wild protected animals such as leopards, otters and wild donkeys were sold in market shops, and many wild animal products were sold in shops in tourist areas. For details, please refer to the Investigation Report on Zoige Species Trade being edited.

Three. Suggested measures

1 How to deal with the relationship between animal husbandry development and wildlife habitat protection is worth pondering.

Strive to restore the water storage function of wetlands and rebuild the beautiful homes of wild animals; Increase investment in sand prevention and control, and prevent the expansion of desertification while controlling the existing sandy land.

Without causing species invasion, we can consider introducing original species to adjust the ecological balance.

4 put an end to the extensive use of chemical agents to kill rats and insects. We should recognize marmots, zokor, etc. It is also an available resource. For example, zokor bone has been proved to replace tiger bone in treating rheumatism. In addition, rodents will play a positive role in grassland ecological environment when the number is appropriate, such as loosening soil and increasing soil permeability when digging holes.

5. Strengthen law enforcement and crack down on illegal hunting.

Four. Investigation on Geological and Geomorphological Conditions of Gewen Village and Its Surrounding Areas in Xiaman Township, ruoergai county

1 geographical location

Ruoergai county is located in the northern part of Anima Green Fold Belt of Songpan-Ganzi Fold System, the southern part of West Qinling Fold Belt and the Motianling Fold Belt of East Qinling Fold System, which is called Songpan-Ganzi Triangle Block. The interior of this area is divided into two geographical units, the south and the north, with Mount Rilang as the boundary. The watershed between the Yellow River and the Yangtze River can divide the whole county into two distinct geographical units and economic and natural regions. The central and western regions are typical hilly plateaus, accounting for 69% of the county area, and the terrain is inclined from south to north. The average altitude is 3500. The focus of this survey is Shaman Township, ruoergai county, which is located in the western part of the southern geographical region.

General situation of area 2

Triassic strata are exposed in a large area in this area, and Quaternary sediments are distributed in strips on both sides of modern riverbed. Monoclinal structure, no obvious fold. Buried faults are mainly southeast and northwest, and locally develop into north-south and east-west faults.

three storeys

Triassic strata, polluted or polluted marshes are widely distributed in the Yellow River, Baihe River and Heihe River basins. Quaternary strata are banded and flaky. The surface is composed of Quaternary alluvial deposits and lake deposits, which are common, providing good environmental conditions for swamp development and peat deposition.

I and Triassic

Strata from north to south, from old to new.

Lower part: mainly carbonate deposits;

Middle and upper parts: clastic deposits.

Upper Triassic is the most widely distributed in China, and the lower strata are mainly composed of medium-thick layered fine sandstone, feldspathic fine sandstone, sandstone, calcareous sandstone and siltstone, with thin layers of limestone and slate.

B, quaternary

Peat layer is mainly distributed in polluted or being polluted swamps, and it is irregularly distributed in sheets.

Lithologic characteristics: peat layer, silty clay layer, clay layer, fine sand layer, coarse sand layer, etc. The edge of peat layer is very irregular harbor-like; Large deposit with large thickness; The smaller the scale, the smaller the thickness.

Alluvial layer, slope accumulation layer and riverbed impact layer are irregularly distributed in a fan shape; The slope accumulation layer is irregularly distributed along the piedmont. Mainly breccia, containing a small amount of sand; The riverbed impact layer is distributed along the Yellow River, Baihe River, Heihe River and their tributaries, and it is strip-shaped or net-shaped. It is mainly composed of sediments with various particle sizes, filled with silt and clay, and gravel deposits can be seen.

Because the lithology of rock strata in this area is mostly sandstone, siltstone and fine sandstone, the underground rock strata here have become a huge sand source. Once the upper vegetation is seriously damaged, the exposed soil layer is rapidly eroded by the local windy weather for more than 200 days every year, and the exposed soil layer will accelerate weathering, producing a large amount of fine sand and endangering the grassland.

4 topography

It is characterized by wide valley hills, swamps accessible by swamps, few faults, and most of the hills are monoclinic rocks. The mountains are round and wide, and the relative height is less than 100 meters.

There are also rivers and artificial ditches in this area. When the river dries up, the abandoned sand in the old riverbed will become a sand source again.

Five soil types

The soil types in humid areas are mainly swamp soil, peat soil, subalpine meadow soil, alpine meadow soil, aeolian sandy soil and artificial grassland soil. Among them, swamp soil and swamp meadow soil account for 409,654.38+0 million hectares, accounting for 66.2% of the total area of humid areas.

The following are soil samples obtained by our team at the artificial excavation ditch in Houshan, Gewen Village, Xiaman Township:

A layer AB layer b layer c layer

Thickness (cm) 0 ~ 21.521.5 ~ 46.246.2 ~ 83.283.2 ~1/4.2.

Color brown gray light gray black gray black.

The composition is characterized by root system and small-scale layered structure, and no stones.

6 Local sand control

The rocks in Manxiang area are mostly purple or red argillaceous fine sandstone with bedding and easy weathering. During the inspection, it was found that there was an artificial rock wall on the ridge behind the village Committee of Gewen Village in Xiaman Township. According to reports, the rock wall here was built in 1979 to protect an alpine willow planted in 1975 from sandstorms. At that time, under the call and leadership of the township government, it took two or three years to build a red argillaceous fine sandstone rock wall (without foundation) with a height of 1.5 meters around Hongliulin. Facts have proved that the windproof effect of the wall is good, and most mangroves survive and grow well. In recent years, due to the nearby herdsmen building houses and taking stones on the spot, it is considered to be destroyed, leaving only a relic about half a meter high at most, and the weathering phenomenon is more serious, which has become one of the sand sources of desertification on the top of the mountain. There is also a similar windbreak wall at Sharman Ranch.

From the analysis of various situations, there are natural reasons for desertification in the township areas under the jurisdiction of Zoige. First of all, the geographical and geological conditions in this area determine the existence of huge underground sand sources; In addition, there are many rivers and ditches in this area, and the abandoned sand in the old riverbed is another sand source. Coupled with some human factors, grassland desertification in this area is serious. When we investigated, we saw two mobile sand dunes, and the scope was not small. Therefore, it is imperative to take timely and reasonable protective measures. At the same time, the influence of natural conditions should be fully considered in the sand control process to avoid further damage caused by thoughtlessness.

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