Biodiversity in
agricultural regions
2 Biodiversity
in farmland ecosystems
4 Measures
to increase biodiversity in farmlands
5 Biodiversity
of animal husbandry systems in agricultural regions
6 Biodiversity
of marginal lands in agricultural regions
7
Conservation of biodiversity in agricultural regions
Agricultural regions are generally the
areas where plant cultivation is the main enterprise. The chief type of
ecosystem found in agricultural regions are: farmlands (95,100,000 ha and 10%
of the national territory). In addition to farmlands, there are: plantations
(6,126,000 ha, ¡«0.6% of the national territory); villages
and towns (3%, including roads and irrigation ditches); agricultural nature
reserves and the marginal land of agro-regions(including 35,368,000 ha of
reclaimable idle lands and 88,987,000 ha of grassy mountains, slopes and flats
(making up about 13% of the national territory). Because China¡¯s agro-regions
are widely distributed, spanning many degrees of latitude and longitude, there
are not only diversified agricultural ecosystems, marginal lands also have many
ecosystems and habitat types.
China is one of the most ancient
agricultural countries in the world. The species cultivated, managed and
utilized are extremely rich. More than 600 species and subspecies of crop
plants are used in farmland cultivation, and more than 590 species and
subspecies of livestock and poultry in animal husbandry.
The native organisms of agricultural
regions contain rich wild relatives of crop plants and domestic animals which
are valuable genetic resources for agricultural breeding. For example, there
are wild species of horses, donkeys, camels and yaks in grasslands and deserts.
Many kinds of wild relatives of crops, vegetables, fruits and dry fruits, tea
and mulberry trees, as well as various rare and endangered animals and plants
can be found in marginal lands and the wild components of agricultural regions.
2
Biodiversity in farmland
ecosystems
Eighty-seven percent of Chinese farmland
is concentrated in 22 humid provinces, located to the southeast of the 400mm
isohyet. Though the 5 provinces/autonomous regions (Inner Mongolia, Gansu,
Qinghai, Xinjang and Tibet) lying northwest of the line occupy one half of the
national territory, here there is only 13% of the national farmland. Farmland
can be divided into two categories: paddy fields and dry farming land.
(1) Paddy
fields
Chinese paddy fields are mainly for rice
production with a small proportion for aquatic vegetables and other crops,
including lotus roots, water caltrop (Trapa bispinosa), water nut (Eleocharis
dulcis), Gorgon euryale (Euryale ferox), Fewflower wildrice (Zizania
caduciflora), and Taro (Colocasia antiquorum). The total acreage of
such paddy fields is about 25,000,000 ha, accounting for 26.3% of the country¡¯s
farmlands, while the output of rice makes up 38.9% of the total food output of
the country (in 1994). Paddy fields are now distributed mainly in the Yangtze
River watershed and to the south of it but, during recent decades, rice
cultivation has developed in the watershed of the Yellow River and to the north
of it. The acreage of rice paddies in Heilongjiang Province is now ranked 12th
among all the provinces and autonomous regions. China has many rice crop
resources. There are about 50 cultivars of rice in production at present, and
53,547 rice germplasm samples from various parts of the country are preserved
in the National Crop Gene Bank (NCGB). The breeding of hybrid rice in China has
contributed greatly to the diversification of rice cultivars as well as to
increasing production. The rice germplasm resources also play an important role
in rice breeding in the world. The Chinese paddy field system is generally
divided into the double-cropping rice region located to the south of the
Yangtze River and the single-cropping rice region of the Yellow River watershed
and to the north of it, according to the manner of cultivation. The following 6
regions are further divisions: the double-cropping rice region of South China;
the double-cropping rice region of Central China; the single-double-cropping
rice region of Southwest China; the single cropping rice region of North China;
the early maturing single cropping rice region of Northeast China and the
single cropping rice region of Northwest China.
The kinds of crops in the paddy field
system are not monotonous due to the household farming system, rotational
cropping and interplanting. In addition to aquatic vegetables, there are a
number of dry farming land crops such as sugar cane, peanuts, potatoes,
legumes, rapes, wheat and barley, hemps, green manure and vegetables, which are
rotated with rice in the paddy fields. Because the paddy fields are a kind of
semi-artificial wetland ecosystem, they are important habitats for amphibians
and reptiles. Many kinds of waterfowl also choose paddy fields as feeding
grounds as well as temporary refuges. For example, various cranes, gulls and
herons, wild swans ducks and ibises (including the rare Red ibis), all like to
dwell in paddy fields. The Water rail (Pallus
aquaticus indicus) even chooses rice fields for breeding. More than 200
species of important weed plants of rice fields are also known. It is difficult
to make a precise estimate of the number of invertebrates in such habitats, but
the total number should be large. For example, in the single-cropping rice
field region of Jurong County, Jiangsu Province, there are altogether 157
arthropods, including 37 species of pests, 42 species of parasitic insects, 57
species of predators, as well as 21 species of neutral insects (neither harmful
to rice, nor preying on other animals). There are 373 species of rice field
spiders in the country. They belong to 23 families and 109 genera. The natural
enemies of rice field pests are 1303 species (belonging to 137 families and 613
genera); of these, 419 are parasitic, 820 are predatory, and 64 are pathogenic.
All these illustrate the richness of China¡¯s paddy field biodiversity.
(2) Dry
farming land
The acreage of Chinese dry farming lands
is about 75,800,000 ha, constituting 73.7% of the total acreage of farmlands in
the country. Dry farming lands are distributed mainly in the Yellow River
watershed and areas to north of it as well as Sichuan Province. Dry farming
lands in other southern provinces comprise only 20% of the country¡¯s total.
Based on a diversified geo-climatic, Chinese dry farming lands can be generally
divided into 9 large regions: the northeast, Inner Mongolia and along the Great
Wall, Huang-Huai-Hai, the Loess Plateau, the middle and lower reaches of the
Yangtze River, the Southwest, South China, Gansu and Xinjiang, and the Qingzang
regions.
The kinds of dry farming crops are more
plentiful than in paddy fields. The main crops in the current dry farming
system contain more than 30 species. The following crops have relatively larger
areas: wheat (30,235,000 ha), corn (20,694,000 ha), soybean (9,454,000 ha),
potatoes (9,220,000 ha), vegetables, melons and fruit (9,262,000 ha), forage
(7,356,000 ha) and cotton (4,985,000 ha). In addition, there are various
cereals, peanuts, oil bearing crops, hemps, sugar bearing crops, tobacco and
medicinal herbs. Dry farming crops together comprise more than 600 species,
including more than 30 species of cereals, 209 species of vegetables, 425
species of forage, and dozens of others. Among these, there are more than 200
species of crops which originated in China.
Owing to the long history of farming, and
the complex geo-climatic environment, the types of dry farming crop cultivars
in China are very abundant. For example, of the wheat and soybean farmed today,
each has more than 50 cultivars, and for corn, millet, sweet potato and peanut,
there are more than 30, and 18 for cotton. There are 170,000 germplasm samples
of dry farming crops preserved in the National Crops Gene Bank (NCGB).
Dry farming lands are also important
habitats for other living things. Various medium and small animals choose dry
farming lands as their feeding grounds, temporary habitats, refuges and even
breeding places. Many animals of different climatic regions belong to the
forest-grassland-farmland type. Their habitats include not only forests, but
also grasslands and farmlands. Some rare and valuable species, such as the
Giant panda, sometimes occur in agricultural regions. The Black-necked crane,
an endangered species, chooses valley farmlands in Tibet as their main feeding
and roosting grounds during winter. Many kinds of wild species have become
crop-associated species. For example, it is known that the weed plants recorded
from farmlands comprise 73 families and more than 560 species. Pathogenic pest
insects, birds and beasts, harmful to crop plants comprise more than 1,300
species, and natural enemies number about 2,000, such as: more than 900 species
of ichneumon flies (Ichneumonidae), more than 300 species of ladybug
(Coccinellidae), over 100 species of important natural enemies (Aphidoidea),
over 400 species of tachina flies (Tachinidae), and over 200 species of
farmland spiders. Among the latter, the important natural enemy spiders of
cotton fields comprise 21 families, 89 genera, and 205 species.
Plantations
are used to grow perennial cash crops, including tea, fruits, various tropical
cash crops and mulberries. The main cash crop plantations have a total area of
6,426,000 ha (mulberries not included). The main types of plantations are:
apples (2,228,000 ha, chiefly distributed to the north of the Qinling Mt-Huaihe
line), tea trees (1,163,000 ha, to the south of the above line), oranges
(1,126,000 ha, to the south of the Yangtze River), tropical crops (870,000 ha,
in South China), pears (597,000 ha, to the north of Yangtze River) and grapes
(142,000 ha, North and Northwest China). In addition, there are still other
fruit crops, such as peaches, apricots, plums, hawthorns, cherries, Chinese
date, date plum persimmon (Diospyros
lotus), persimmon, strawberries, chestnuts, walnuts, yangtao, actinidia,
pineapples and litchi. They are either planted in tracts, or interplanted with
ordinary dry farming crops, but no data on their area¡¯s exists. The richness of
China¡¯s fruit species ranks first in the world. Statistics show that there are
50 families of fruit trees in the world and China has 45 of them, with 81
genera and 248 species. China is the originating country of tea trees and
mulberry-silkworms, with more than 600 varieties of the former, and 15 species and
about 1,000 varieties of the latter. According to historical records of 1904,
there are 1,277 varieties of silkworms (Bombyx
mori) (having overlapping classifications) and which have been collected
and identified. In The Varieties of
Sillkworm (1984), however, the recorded varieties are only 510. China has
used cocoons of the wild silkworms since the Xi Han Dynasty (24 BC~206 AD). The
main species of tussah belong to the genus Antheraea,
with 35 species, and their forage plants of the oak genus Quercus, have more than
110 species in China. The other investigated and utilized wild silkworms have
many genera. In 1958, a very precious wild silkworm, the so called ¡°Heaven
Silkworm¡± (Antheraca yamamai) was
found in Ning¡¯an County, Heilongjiang Province, and this gives a beautiful
jade-green silk. A nature reserve has been set up to protect it.
Most the
plantations developed recently from wastelands possess a relatively rich
biodiversity due to their locations on hilly lands or mountain slopes, close to
forests with a high biodiversity. In addition, because of fewer cultivation
activities in the plantations, many wild organisms use them as habitats.
4
Measures to increase biodiversity
in farmlands
Based on
long-term practical experiences, Chinese farmers and agricultural scientists,
in accordance with the natural and social conditions of China, have created
many effective measures to increase biodiversity. These measures not only keep
the systems stable, but also heighten production. Crop rotation, agroforestry
and ecological agriculture are the three most important measures.
(1) Crop rotation
Examples of
crop rotation include: on year on ripe rotation in Northeast China (three years
rotation system of soybean¡úsorghum¡úmillet); change-of-crops
within a year with wheat, corn (or soybean and sweet potato) as the chief
cereals in irrigated lands, a rotation system of winter wheat with
drought-enduring crops in dry farming lands and rotation and change-of-crops
systems of one year one ripe, or two years three ripe, on the slopes of hills
in the North China Region; wheat (or barley)-late rice¡úrape-(early) middle season
rice¡úgreen
manure-early rice and rice-rice-sweet potato (or wheat)¡úrice-rice-lying fallow¡úrice-green manure (rape and
broad bean) in paddy fields and broad bean (pea and wheat)-corn (sweet potato)¡úwheat-corn (peanut) on bry
farming land of the hills in Southern China and other areas. The numerous and
complicated rotation systems in different parts of China greatly increase the
diversity of crops within the same site, and not only sufficiently utilize soil
fertility, but also improve production.
(2) Agroforestry
Examples of
agroforestry include: the intercropping of paulownia and food crops, the
intercropping of Chinese date and food crops, ¡°tiao¡± (Ash, Shrubby amorpha and
Entire willow) and food crops, Persimmon and food crops, fruits (apple,
Hawthorn and Chinese walnut) and food crops, in northern China; the
intercropping of vegetables and cereals, mulberry and cereals in the Yangtze
and Huaihe region; Pond cyress and fish and duck mixed-farming in areas
criss-crossed by rivers, rivulets, lakes and ponds of Hubei; various types of
¡°ji tang¡± (mulberry ji and fish tang, sugar cane ji and fish tang, fruit ji and
fish tang) in Guangdong Province; the forests (Ash, Mulberry, Chinese fir,
Tungoil tree, Cypress, Chinese tallowtree and Walnut) and food crops
intercropping on hills and mountains of southern China; rubbertree (pure
rubbertree) and tea plant intercropping in Hainan, Leizhou, Southern Yunnan,
Southern Guangxi and Suthern Fujian.
(3) Eco-agriculture
The
eco-county, eco-village, eco-hamlet, eco-family system which integrate farming,
forestry, animal husbandry and sideline production in the countryside, all
contribute to increasing biodiversity, especially the ¡°three-dimensional
cultivating-breeding¡± types, such as rice-duckweed-fish, rice-duck-fish and
forest-duck-fish.
5
Biodiversity of animal
husbandry systems in agricultural regions
In China,
except for the three northeastern provinces, the four northwestern provinces
(autonomous regions), Inner Mongolia, Sichuan and Tibet which are called
grassland-animal-husbandry areas, all other agricultural regions are
concurrently running animal husbandry farming and their joint outputs comprise
more than 70% of the total output of animal husbandry in the country as a
whole. Animal husbandry in agricultural regions is of two distinct types: the
specialized and concentrated animal farms in the suburbs of most big cities and
separate household animal breeding practices as a sideline business in the vast
agricultural regions of China.
China is
one of the few countries in the world with a long-standing history of animal
husbandry. According to preliminary statistics, China has more than 590
domestic animal varieties and types, local endemic varieties are rich, and
often have excellent genetic and economic characteristics. For example, the
Small-tailed cold sheep in Heze, Shandong Province, has the reproductive rate
of more than 270% in a single lambing. A mature Taihu female pig gives birth to
an average of more than 15 piglets at one farrow. The Jinding duck in Fujian
Province and the Shaoxing duck in Zhejiang Province lay 260~300 eggs a year.
The dwarf horse in Baise, Guangxi Autonomous Region, is only about 1 metre
high. In addition, there are a great number of local domestic animals famous
for their excellent products, including the hide and fur of the ¡°Tan¡± sheep in
Ningxia Autonomous Region, the wool from the Albas fine-haired goat in Inner
Mongolia, and the bristles from the Rongchang pig in Sichuan Province.
Nevertheless, along with the development of modernized animal husbandry
techniques, local varieties are being replaced by fast-growing ones, thus
leading to a loss of local varieties, their advantages being recognized only
gradually afterwards. For example, in the late 1980s, after some
multi-young-pig varieties were introduced from France, the original Chinese
multi-young pigs were paid attention to. In the middle 1990s, China¡¯ fine hair
goat has also received attention, yet, at this moment, many categories of the
original Chinese multi-young-pigs have become extinct. Even today, the value of
the hide and furs of the ¡°Tam¡± sheep of Ningxia and the bristles of the Sichuan
Rongchang pigs are still neglected and the species have become endangered. The
Wu Zhi Shan pig is suitable for use in organ transplants, but there remain only
3 individuals.
6
Biodiversity of marginal
lands in agricultural regions
Marginal lands in agricultural regions
include reclaimable but uncultivated lands, grass hills, slopes and flats, the
residual wetlands after land reclamation, small stretches of forests managed by
farmers and the hedges of farms. The reclaimable waste lands are mostly found
in Heilongjiang, Inner Mongolia and Xinjiang, while the grassy hills, slopes
and flats are mainly located in Yunnan, Jilin, Hubei, Sichuan, Guangxi, Shaanxi
and Guizhou Provinces. Other types of marginal lands are spread throughout the
country. The agriculturally reclaimed and cultivated proportions are generally
not bigger than 50% of the total area, even in densely populated provinces. The
actual acreage of marginal lands is, therefore, rather large.
Marginal lands are less disturbed by
human activities than the farmland systems and their biodiversity is relatively
richer. Many kinds of rare, valuable and endangered plants and animals exist on
the marginal lands. The following places are some biodiversity-rich spots.
(1) The
Sanjiang Plain Wetlands Reclamation Region in Heilongjiang
This wetland is a very
important breeding ground for wild swans, wild ducks, cranes and snipe. It
possesses some first class nationally protected animals, such as Mergus squamatus, Grus japonensis, Ciconia
ciconia, Haliaeetus albicilla and
Cervus nippon, and second class protected animals, such sas Snipe, Platalea leucorodia, Cygnus spp., Ursus arctos, Selenarctos thibetanus, Cervus elaphus, Felis lynx, Alces alces and
Lepus timidus.
(2) Te Songpan Wetland in Northern Sichuan
Province
This wetland consists of high-cold
meadow-mire vegetation and is an important breeding ground for the rare
Black-necked crane. Other rare and endangered animals such as muskrats (Ondatra
zibethica) and otters also live here.
(3) The
Yili River Valley
Many relic plants of the Tertiary Period
are preserved in the Yili River Valley, of which the 130 species of wild fruit
trees are most eminent, e.g., wild apple, wild apricot, wild plum, Prunus
podus, Rubus idaeus, pear, wild peach, cherry, Amygdalus,
hawthorn and wild walnut. All are valuable genetic fruit tree resources.
(4) Xixia
County, Henan Province
This county has well preserved tree
species of a typical temperate forest with 17 class II and class III nationally
protected species. In addition, there are valuable meaicinal berbs such as Tall
gastrodia (Gastrodia elata) and various Actinidia.
(5) Jiangshan County, Zhejiang
Province
Jiangshan County has typical and
well-preserved plant communities of the mid-subtropical zone, including 14
species of class II and class III nationally protected plants, e.g., Ginkgo, Pseudolarix
amabilis, Fokienia, hodginsii, Liriodendron chinense, Emmenopterys
henryi, Pteroceltis tatarionowii, Magnolia amoena, M. cylindrica,
M. officinalis, M. officinalis subsp. biloba,
Eucommia ulmoides, Stewartia sinensis and Halesia macgregorii. In
addition, there are 10 species of provincially protected plants, including
tea-oil trees. The mountains of the area were once home to the South China
tiger and 20 other species of endangered animals, including the leopard,
Hair-capped aeer, Golden cat and Salamander.
(6) Western Otog Banner in Ordos
A great number of Tertiary relic desert
plants occur here, including nationally protected species such as Ammopiptanthus
mongolicus, Helianthemum soongorium, Potaninia mogolica,
Tetraena maongolica and Tugarinowia mongolia.
In addition, there are a great number of
wild crop relatives scattered in many places. The important ones are as
follows:
a. Wild rice is found in the Counties of
Dongxiang, Guixi, Yushan and Yongxin of Jiangxi Province, Boluo County and
Yingde County in Guangdong Province, Yanxian County in Hainan Province,
Xishaungbanna and Mengjiang County in Yunnan Province, and Chalin County in
Hunan Province. Three types of wild rice have been found in Yunnan Province,
including common, medicinal and the wart-grained wild rice.
b. Wild soybeans have been found in Wuhe
County, Anhui Province, Chayu County in Tibet, Xiongxian County in Hebei
Province, Yikezhao Prefecture in Inner Mongolia, Keshan County in Heilongjiang
Province, Kenli County in Shandong Province and Bijie County in Guizhou
Province.
c. A number of vegetables originate from
China. Wild cucumber has been discovered in Yunnan Province, wild carrots in
Tibet, Edgeworth amphicarpaea in Yinan County, Shandong Province, and Yaxian
County, Hainan Province, wild Chinese onion in Shennongjia, Hubei Province, and
wild wallich garlic (Allium wallichii) in Lichuan County, Hubei
Province.
d. Tea is native to China. In Yunnan
Province, both cultivated species and wild species of tea plants are numerous.
Eight genera and 70 species of Camellis found in Tengchong County and
wild big tea trees have been found in Menghai County and 19 other counties.
e. Wild species of mulberry are also
abundant and include the primitive Japanese mulbery in the Shennongjia
Mountains, and the long spike mulberry found in Weifeng County, Hubei Province.
f. Psathyrostachys has been found
on the Huashan Mountain of Shanxi Province, and wild buckwheat (Fagopyrum
gricilepes) in Weining County, Guizhou Province.
7 Conservation of biodiversity
in agricultural regions
Early work
on biodiversity conservation in agricultural areas concentrated only on the
protection of cultivar resources. The in
situ conservation of ecosystems and wild species in agricultural regions
has only been on the national agenda since the mid-1980s. The Ministry of
Agriculture has set up a Department of Environmental Protection and Energy,
which is responsible for biodiversity conservation. The Ministry has listed 35
marginal lands with high biodiversity values, in a plan to establish nature
reserves, several of which have been investigated and established, including
the ¡°Heavenly Silkworm¡± reserve in Ning¡¯an County, Heilongjiang Province, and
several grassland reserves in the Wutaishan area of Shanxi Province and in
Inner Mongolia. The Ministry of Agriculture has also carried out
eco-agriculture and agro-forestry and, at the same time, taken part in
formulating various laws and regulations concerning biodiversity conservation.
Currently, to protect biodiversity in agro-regions, an issue that should not be overlooked is the protection of land resource. Because of expanding cities and towns, covering land activities with various development and village and town enterprises, as well as other causes, the farmlands of China are fast-decreasing. During the recent 4 years, the average net decrease was 337,800 ha per year. China is a country with more people and less farmland. There are 94,670,000 ha of farmland in the whole country while the average per capita farmland is only 0.08 ha, i. e., less than 1/3 of the world average. If farmland decreases further (while the population still increases). The pressure which the population will exert upon the land will undoubtedly be exacerbated, resulting in further reductions of biodiversity.