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China's Natural Wetlands: Past Problems, Current Status, and Future Challenges


Abstract and Figures

Natural wetlands, occupying 3.8% of China's land and providing 54.9% of ecosystem services, are unevenly distributed among eight wetland regions. Natural wetlands in China suffered great loss and degradation (e.g., 23.0% freshwater swamps, 51.2% costal wetlands) because of the wetland reclamation during China's long history of civilization, and the population pressure and the misguided policies over the last 50 years. Recently, with an improved understanding that healthy wetland ecosystems play a vital role in her sustainable economic development, China started major efforts in wetland conservation, as signified by the policy to return reclaimed croplands to wetlands, the funding of billions of dollars to restore degraded wetlands, and the national plan to place 90% of natural wetlands under protection by 2030. This paper describes the current status of the natural wetlands in China, reviews past problems, and discusses current efforts and future challenges in protecting China's natural wetlands.
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Shuqing An, Harbin Li, Baohua Guan, Changfang Zhou, Zhongsheng Wang, Zifa Deng,
Yingbiao Zhi, Yuhong Liu, Chi Xu, Shubo Fang, Jinhui Jiang and Hongli Li
China’s Natural Wetlands: Past Problems,
Current Status, and Future Challenges
Natural wetlands, occupying 3.8% of China’s land and
providing 54.9% of ecosystem services, are unevenly
distributed among eight wetland regions. Natural wet-
lands in China suffered great loss and degradation (e.g.,
23.0% freshwater swamps, 51.2% costal wetlands) be-
cause of the wetland reclamation during China’s long
history of civilization, and the population pressure and the
misguided policies over the last 50 years. Recently, with
an improved understanding that healthy wetland ecosys-
tems play a vital role in her sustainable economic
development, China started major efforts in wetland
conservation, as signified by the policy to return re-
claimed croplands to wetlands, the funding of billions of
dollars to restore degraded wetlands, and the national
plan to place 90 % of natural wetlands under protection by
2030. This paper describes the current status of the
natural wetlands in China, reviews past problems, an d
discusses current efforts and future challenges in pro-
tecting China’s natural wetlands.
Healthy natural wetland ecosystems play a vital role in
sustainable development of China, which has been recognized
by the Chinese government (1, 2). Natural wetlands occupy 3.8%
of China’s terrestrial area (1), with the total wetlands areas
estimated at 8.0% (compared with 6.0% in the world). Natural
wetlands in China provide 54.9% of the annual ecosystem
services for the country (3, 4). In addition, 54% of endangered
species of ducks and geese in Asia have been recorded in China’s
wetlands (2, 5). Despite their importance as natural resources
and as natural regulators to environmental problems (3, 4);
however, natural wetlands in China suffered great losses and
degradation, not only because of wetland reclamation during the
country’s long history of civilization but also because of the
severe population pressure and the misguided policies over the
last 50 years (1, 5). In this paper, we will describe the current
status of the natural wetlands in China, review past problems
(especially over the last 50 years), summarize current efforts, and
discuss future challenges in protecting China’s natural wetlands.
Our goal is to provide a synthesis and the basic information
about the natural wetlands in China so that people from
institutions of scientific research and organizations of conserva-
tion abroad can learn and join in our efforts of wetland
protection and help us develop effective conservation strategies
for the science-based decision making by the government. It
should be pointed out that the Chinese government uses a
broader definition of wetlands than the Ramsar Convention (6)
in that deep lakes and large rivers are regarded as wetlands.
Natural Geography
China is a large country (9.6 million km
), with diverse
geomorphology (7, 8). Her vast territory is marked by many
unique geomorphological features: the Qinghai-Tibet Plateau in
her southwest (2.5 million km
; the highest and largest plateau,
known as the ‘roof of the world’’), the Tarim basin in her west
(0.4 million km
; the largest basin in the world), the Gobi desert
in her north (1.3 million km
; one of the largest hot deserts in
the world), and the Huang Tu plateau in the midwest (0.3
million km
; the largest loess plateau in the world) (Fig. 1) (7,
8). The aquatic system of China is composed of many rivers and
lakes, and a long coastline (18 000 km) in the east and
southeast, including the four largest rivers (and their associated
lakes), i.e., the Yangtze River (Change Jiang) in central China
(6300 km; the third longest in the world), the Yellow River
(Huang He) in the northern China plains (5464 km; ‘the cradle
of the Chinese civilization’’), the Songhua River in t he
northeastern plain (2308 km), and the Pearl River (Zhu Jiang)
in the south (2214 km) (Fig. 1) (7, 8). In general, the western
part of China is dominated by highlands, mountains, and
deserts, whereas the eastern part of China contains almost all
low-lying areas and supports dense populations and industrial
and agricultural bases of the country.
Main Types and Distribution Patterns
China has all of the 26 natural and 9 human-made wetland
types delineated in the Ramsar Convention (1, 9). The natural
wetlands in China are unevenly distributed among eight wetland
regions (9, 10): i) the northeast region dominated by freshwater
swamps; ii) the northwest region by saline lakes and swamps in
dry climate; iii) the southwest plateau region by subalpine lakes;
iv) the south and southeast region by rivers; v) the coastal
region by tidal swamps, salt marshes, and mud-lands; vi) the
middle-lower Yangtze River region by lake groups and river
systems; vii) the middle-lower Yellow River region by lake
groups and river systems; and viii) the Tibet plateau region by
alpine lakes and swamp groups (Fig. 1). Freshwater swamp is
the largest wetland type in area, most of which is located in
northeastern China (68 000 km
; dominated by species of
Carex, Phragmites, Juncus, Scirpus, Acorus, Cyperus) and the
Tibetan Plateau (55 000 km
; dominated by species of Kobresia,
Carex, Pedicularis, Phragmites, Blymus, Cyperus). Note that the
Tibetan Plateau possesses specific wetland types where the
average elevation is more than 3000 m. The top five largest
freshwater lakes of China (10 800 km
; dominated by species of
Potamogeton, Prgamites, Acorus, Juncus, Ranalisma, Brasenia,
Miscanthus, Vallisneria, Cyperus) are all distributed in the
middle and lower tributaries of the Yangtze River (e.g., Poyang
Lake, Dongting Lake), and many saline lakes exist in the
Tibetan Plateau and northwestern China. The tidal wetlands
(21 000 km
; dominated by species of Phragmites, Scirpus,
Spartina, Imperata, Typha, Suaeda, and Zoysia; with additional
850 km
of mangrove) are found along the coast, especially near
the estuaries of big rivers (11).
Ecosystem Services
China’s natural wetlands, occupying only 3.8% of the land,
provide a significant amount of ecosystem services, including
Ambio Vol. 36, No. 4, June 2007 335Ó Royal Swedish Academy of Sciences 2007
freshwater supply, flood regulation, wastewater storage and
natural purification, wildlife habitat, and aquatic life preserve
(3, 4). Based on the suggested values of all the major ecosystem
types (3, 4), the total value of natural wetlands could account
for 54.9% of the estimated 903 thousand million dollars (USD)
of annual ecosystem services in China (3). For example, the
freshwater resources in China are estimated at 2800 km
which 82.1% is contained in wetlands (i.e., swamps, rivers,
lakes) and 17.9% in 85 000 reservoirs (12). Based on previous
studies (10, 13–16) and our own calculations, wetlands provide
pollution control by removing 4.6 trillion gram (Tg) of total
nitrogen (TN) and 0.6 Tg of total phosphorus (TP) from water
resources in China, and carbon (C) storage of 0.35 quintillion
gram (Eg) (mostly in 13 000 km
of the peat lands). In addition,
China’s natural wetlands are important to migratory bird
conservation, providing habitats for 60% of the species of cranes
(e.g., Grus, Anthropoides, Rallus, Crex, Porzana, Otis) and 26%
of the species of geese and ducks (e.g., Anser, Branta, Cygnus,
Tadorna, Anas, Netta, Aythya, Aix, Mergus) of the world (2,
17). In particular, more than 90% of individuals of white crane
(Grus leucogeranus), red-crown crane (Grus japonensis), and
swans (Cygnus cygnus and Cygnus olor) winter in the coastal
wetlands and lakes in China (2, 18).
Current Threats
China’s natural wetlands are under great threats from
reclamation, water diversion and dam construction, pollution,
resource overuse, biological invasion, and desertification and
climate change. The government has recognized 323 natural
wetland areas in China as being of national importance (1, 2).
These natural wetland areas of national importance account for
39.6% of the total area of natural wetlands, including 149 lakes
(with a total area of 42 800 km
), 92 swamps (73 500 km
), 60
costal wetlands (21 000 km
), and 22 rivers (5300 km
). Among
them, however, about 60 lakes, 18 swamps, and 15 coastal
wetlands are still in great danger t o reclamation, water
pollution, and overharvest of fisheries, whereas about 89 lakes
and 26 swamps are being threatened by excessive water
diversion and 64 lakes by sedimentation (1, 18, 19). These and
other emergent threats (e.g., biological invasion, global climate
change) must be eliminated or minimized to preserve the natural
wetlands in China.
Loss of Wetlands and Their Ecological Services
Unfortunately, China’s natural wetlands suffered tremendous
loss over the past 50 years. In terms of the total area, the country
lost 23.0% of freshwater swamps, 16.1% of lakes, 15.3% of rivers,
and 51.2% of costal wetlands (Table 1). Such large-scale wetland
destruction may have caused an estimated annual loss of
ecosystem services by 1.57 thousand million dollars (USD)
(Table 1). For example, the lost areas of swamps, lakes, and
Figure 1. Distribution patterns of
natural wetlands in the mainland of
China. The natural wetlands in
China are grouped into eight re-
gions: the northeast region domi-
nated by freshwater swamps, the
northwest region by saline lakes
and swamps in dry climate, the
southwest plateau region by sub-
alpine lakes, the south and south-
east region by rivers, the coastal
region by tidal swamps, salt
marshes, and mud-lands, the Tibet
plateau region by alpine lakes and
swamp groups, and the regions
along the middle-lower sections of
the Yangtze and Yellow rivers by
lake groups and river systems.
336 Ambio Vol. 36, No. 4, June 2007Ó Royal Swedish Academy of Sciences 2007
rivers may have amounted to a reduction of water storage
capacity by 237 km
(i.e., 8.5% of their total storage capacity) (12,
19, 20), whereas during the same time, the construction of 85 000
or so reservoirs increased water storage only by 36 km
addition, the five largest lakes in the middle and lower tributaries
of the Yangtze River alone lost 44 km
of their volumes and
resulted in increased flooding frequency from once every 50 years
to once every 10 years (18). Given that, on average, swamps
(including lacustrine and riverine wetlands) can remove TN by
29.8 g m
and TP by 3.8 g m
and costal wetlands
(including tidal swamp, salt marsh, and mud-land) remove TN
and TP by 25.0 and 5.0 g m
, respectively (10, 13, 14), the
loss of these wetlands may have led to an annual reduction of
water purification capacity by 2.8 Tg TN and 0.4 Tg TP in China.
These lost water purification capacities amounted to 151.4% of
TN and 64.0% of TP discharged in 2000 from the industrial and
domestic activities in China (21). The loss of wetlands also
resulted in extinction of many species that required wetlands as
their vital habitats (Table 2). Among the known animal species
that became extinct over the past 100 years or so, most of them
were wetlands species (Table 2), including Xinjiang big-head fish
(Aspiorhynchus laticeps), estuary crocodile (Crocodilus porosus),
phoenix-head sheldrake (Tadorna cristata), and wild David deer
(Elaphurus davidianus). Most of the extinctions were because of
the loss of habitats caused by wetlands destruction (22). Another
extraordinary loss of wetlands species was the wild rice (Oryza
meyeriana), which was discovered in the swamps of the Hainan
Island of Southern China in 1970s and was used to create a
hybrid rice; this new crop increased the rice production by 3.0
quadrillion gram (Pg) in China (23), but wild rice populations
disappeared from its natural environments (10, 23).
In addition to direct destruction of wetlands, there were
other problems associated with wetland health and conserva-
tion, such as water pollution, C storage loss, and biological
invasion. These problems were just as severe as the wetland loss
in China.
Water Pollution
Water pollution, from bo th point and nonpoint sources,
presents serious problems that not only damage wetlands and
other natural resources but also threaten public health and
livelihood. One doggerel by local people vividly depicts the
dynamics of water pollution in Eastern China over the last 50
years: ‘Cleaning rice and vegetable in the 1950s; washing cloth
in the 1960s; becoming dirty in the 1970s; disappearing of fish
and shrimp in the 1980s; causing bodily injury in the 1990s.’’ In
the early 1970s, water quality began to show effects of increased
discharge of wastewater from industrial and domestic activities
and runoffs from nonpoint sources, such as fertilizers used in
agriculture. Over the period of 1980–2000, the wastewater
discharge increased by 180% from industry and 380% from
residential sources (24), and much of the wastewater was poorly
treated or untreated and full of pollutants (21). During 1950–
2000, the annual consumption of fertilizers in China increased
by 530 times, whereas the area of aquatic culture increased by
6.3 times and its production by 125 times (Fig. 2) (25). Much of
the fertilizers (50%–70%) ended up in the natural wetlands either
by direct discharge or by accumulation of runoffs (21, 25).
Exce ssive nutrient loading and poorly treated wastewater
discharge greatly affected water quality of rivers and lakes.
Among the 1200 monitored rivers, 70.8% was polluted and
Table 2. The numbers of species that live or are extinct in natural wetlands of China.
No. species Species lost or endangered
Wetland China Percentage Wetland China Percentage
Moss 270 2200 12.3 15 40 37.5
Fern 70 2400 2.9 25 110 22.7
Gymnosperm 20 250 8.0 5 65 7.7
Angiosperm 1200 30 000 4.0 75 1000 7.5
Subtotal 1560 34 850 4.5 120 1215 9.9
Mammal 30 580 5.2 60 135 44.4
Bird 270 1250 21.6 85 180 47.2
Reptilian 120 380 31.6 15 20 75.0
Amphibian 280 280 100.0 10 10 100.0
Fish 1040 3860 26.9 170 200 85.0
Subtotal 1740 6350 27.4 340 545 62.4
Total 3300 41 200 8.0 460 1760 26.1
The species data for wetlands were based on the first national wetland inventory from 1996 to 2003 (2, 5), with minor corrections made based on recent publications (9–11, 15, 17, 18). The
species data for China come from ‘‘National Report of Biodiversity of China’’ (1998) (22).
Table 1. The losses of the natural wetlands and the associated ecosystem services in China over the last 50 years.
Wetland Type
Area in 1950
Area in 2000
Area loss
Area loss
Ecosystem services
USD km
Value loss
Freshwater swamps 178 137 41 23.0 1958.0 80.3
Lakes 143 120 23 16.1 849.8 19.6
Rivers 95 82 13 15.3 849.8 11.1
Coastal wetlands 43 21 22 51.2 2091.8 46.0
Total 459 360 99 21.6 157.0
The data for wetland area in 2000 came from the first national wetland inventory (1) and those in 1950 were reconstructed by the authors based on the refs. 1, 5, 9, 11, 14, 15, 17, 18, 19, 26, 28,
29, 31–35, and 46. The average estimates of ecosystem services in US dollars were cited from references 3 and 4, and the value loss was calculated as the product of the lost area and the
average ecosystem service value. The freshwater swamps include typical swamps, wet meadows, and saline marshes of northwestern regions; the lakes include open water area at mean water
level and the lacustrine swamps; the rivers include river courses and riverine swamps; and the coastal wetlands only include tidal swamps, salt marshes, and mud-lands. The shallow sea
wetland was excluded from the coastal wetlands in this table because the data are questionable. The inventory data contain only those that are more than1km
in area for wetlands and 10 m in
width for rivers.
Ambio Vol. 36, No. 4, June 2007 337Ó Royal Swedish Academy of Sciences 2007
63.1% were severely polluted (5). Fishes and shrimps disap-
peared from 33% of the total length of these rivers. The Huaihe,
Haihe, and Liaohe in temperate China were among the most
polluted rivers (14). It was reported in 2000 that 75% of lakes
were eutrophic and that 20% of these lakes lost their basic
ecosystem functions, especially those nearby the cities with
rapid economic development (5). The Chaohu, Taihu, and
Tianchi lakes were severely polluted, and their ecosystem
structure was almost collapsed (18). The gloomy picture of
the polluted wetlands can be translated into an alarming crisis
of public health, because of the limited freshwater resources in
China. China has 2800 km
freshwater resources (i.e., about
2206 m
per person) (5, 12). However, because of water
pollution, only 40%–50% of the freshwater resources can be
used directly for human consumption (12, 20), which makes
China one of the lowest per capita freshwater use in the world
(below the United Nations level of water stress at 1700 m
less per person annually) (2, 12, 20). How to effectively use the
freshwater resources (e.g., by increasing wetland areas and,
thus, storage, or by cleaning up the polluted waters) will remain
a daunting challenge for China in the years to come.
Loss of Carbon Storage
Wetlands, especially peat lands, are major carbon (C) sinks
among different ecosystem types (3, 4). There are 13 000 km
peat lands in China, most of which are distributed in the
Tibetan Plateau (79%) and the northeastern China (21%) (9).
Most of peat lands are dominated by grass and sedge species,
and have a mean C content of 28.2% in weight (15). The rate of
peat accumulation is 0.48 mm y
in the Tibetan Plateau and
0.40 mm y
in northeast China (26). Peat mining for uses as
fertilizers and cement additives was the primary cause of peat
land destruction in China. With 5.0 Tg of peat mined annually
and 4500 km
of peat land destroyed during the last 50 years
(15), peat mining resulted in a C release of 1.48 Tg y
addition, large areas of the swamps, including 75.6% of swamps
in the northeastern China, were converted to croplands (Fig. 3).
The (nonpeat) swamps are mainly dominated by Phragmites,
Acroras, and Carex, and have high organic carbon content in
the soil because of their low decomposition rate. For these
swamps, the C content is 1.5% on average (with a range of
0.3%–5.0%), and the mean bulk weight is 1.22 g cm
(with a
range of 0.28–1.44 g cm
in the top 25 cm of soil) (15, 16, 26).
The conversion of the swamps to croplands alone led to the C
storage loss of 4.58 Tg y
. The total loss of C storage (6.06 Tg
) from peat mining, and swamp destruction accounted for
0.8% of C emission of China in 2000 (21).
Biological Invasion
The official statistics indicate that 127 alien invasive species
have been detected in China, including 10 animals and 11 plants
found in wetlands (27). The Environmental Protection Admin-
istration of China declared 16 notorious invasive species,
including 5 wetlands species. These 16 species may cause 7.0
annually, much of which is attributed to the 5 species that
invaded wetlands (24). For example, alligator weed (Alter-
nanthera philoxeroides) was first recorded in the suburbs of
Shanghai in 1892, and water hyacinth (Eichhornia crasssipes)
was introduced into China in 1901 as a garden flower (24, 27).
Native to South America, both species were used as forage from
1950 to 1980, and currently occur in most lakes and rivers in
eastern China (Fig. 4). Smooth cord grass (Spartina alterni-
flora), native to the Atlantic coast of North America, was
introduced in 1979 to protect coastal dikes and to reduce coastal
erosions from tides, and it is currently distributed in 1120 km
of coastal areas. It was estimated that these three invasive
species may have caused a total annual economic loss of 2.0
thousand million dollars (USD) (2, 22, 27) in terms of jammed
coastal waterways and economic species loss from habitat
conversion and ecosystem collapses (10, 27).
Numerous factors contributed to the loss and degradation of
natural wetlands in China. The most important among them
were land demands by a large population, a lack of
understanding of wetland values, a misguided reclamation
policy, a lack of environmental laws and regulations, and water
diversion needed because of rapid economic growth. Here, we
discuss three main causes for wetland loss over the years:
reclamation, misguided policy, and water diversion.
Reclamation was the primary cause for wetland loss (1, 2).
Reclamation of wetlands has a long history in China. For
example, lakes along the midsections of the Yangtze River were
firstly reclaimed about 2000 years ago (28), Jianghan-Dongting
lakes in the middle Hanjing Dynasty (AD 25–380), and the
Poyang Lake in the late Han Dynasty (BC 202 to AD 220).
Figure 3. Wetland destruction in the Sanjiang Plain and Dongting
Lake. The Sanjiang Plain swamps used to be the largest freshwater
swamps in China, whereas Dongting Lake used to be the largest lake
in China; but both of them became the second largest because of
large-scale reclamation. The data for the Sanjiang Plain swamps
came from refs. 15, 26, 34, with the area data in 1825 and 1900
reconstructed by the authors based on the information reported in
refs. 17, 18, and 33. The data for Dongting Lake came from refs. 12,
19, 23, and 28–30.
Figure 2. The changes in agricultural activities during the last 50
years in China. The data for irrigated cropland area and fertilizer use
came mainly from refs. 25 and 35, with the modifications of the data
before 1970 by the information in refs. 12 and 40. The data for
aquatic culture and production were obtained mainly from refs. 40
and 41, with minor corrections based on refs. 12, 35, 42 and 43.
338 Ambio Vol. 36, No. 4, June 2007Ó Royal Swedish Academy of Sciences 2007
Through history, additional waves of reclamation occurred
during late Song (AD 1250–1276), Ming (AD 1470–1560), late
Qing dynasties (AD 1780–1910), and the last century (mostly
from 1950–2000) in the Dongting Lake, and during early Tang
(AD 620–650), late Song (AD 1130–1270), late Qing dynasties
(AD 1780–1910), and late last century (AD 1950–2000) in the
Poyang Lake. The Dongting Lake, once the largest lake in
China, shrank from the surface area of 18 730 km
1500 years
ago to the current size of 2625 km
(Fig. 3) (28–30). The lakes
lost a total area of 13 000 km
to reclamation during the last 50
years alone, with most of the loss occurring along the Yangtze
River (e.g., 41.0% loss in Poyang Lake, 34.2% loss in the lake
group of Jianghan-Dongting) (17, 19). Other wetland types also
suffered a great loss. Coastal wetlands in the Northern Jiangsu
Province, the largest in China, were reclaimed since the late Han
dynasty (BC 202 to AD 220). In addition, much of the 30 000
coastal lands generated during the last 4000 years by the
sediment buildup near the mouths of major rivers in Jiangsu
Province was reclaimed; only 900 km
of these newly created
wetlands remained undeveloped (31, 32). The largest swamps in
China, the Sanjiang Plain, lost 83.7% of its total area during
1825–2000, with most of the reclamation taking place during the
last 50 years (Fig. 3) (15, 33). It was estimated that a total of 133
500 km
of croplands, fishponds, salt ponds, and residential
lands was obtained from the conversion of coastal wetlands in
China (32). Overall, reclamation alone may account for 82% of
the total wetland loss in China.
Misguided Policy
The accelerated loss of lakes, coastal wetlands, and swamps
because of reclamation in the last 50 years (Fig. 3) was primarily
the outcome of the reclam ation pol icy by the Chinese
government in that period (5, 10, 33, 34). As a country of
agriculture, China has more people but less arable lands (122
million hectares) than the United States (638.8 million hectares)
(35, 36). It was always (and still is) a struggle to produce enough
grain for the population. As mentioned above, land reclamation
had been regarded as a key solution, either from mountains
(e.g., rice terraces) or from lakes and swamps. Thus, the strive
for food security was the force that drove the reclamation policy
of the Chinese government, and the large-scale reclamation
during the last 50 years was sponsored by the government
because building networks of levees and ditches required the
kind of financial support and manpower that only governments
could provide. However, recent natural disasters (e.g., the
Yellow River dried up in 1997, the Yangtze River floods of
1998, Beijing’s sandstorms of 2000s) brought the attention of
the government and the public to the severe environmental
problems caused by the policy of economic growth at all cost.
The realization of environmental consequences of misguided
policies also led to a change of attitude toward the environment
in general and wetlands in particular (1, 2, 5). As a result, it is
safe to say that large-scale reclamation will not be allowed, even
though the coastal wetlands and natural swamps are still under
threat, because many local governments continue to consider
them as potential land resources.
Water Diversion
Decreased water recharge was another key cause for natural
wetland loss in China (1, 10, 30). Water diversion to agricultural
and industrial uses greatly reduced water flow into wetlands
over the last 50 years. The area of the irrigated croplands
increased by 340% from 1950 to 2000 (Fig. 2), and much of the
water was lost because of low water use efficiency of irrigation
(15%–35%) (12, 25, 35). The excessive use of water by
agriculture and other industries resulted in the extremely low
river flow in the lower sections of many rivers (e.g., Yellow,
Talimu, Heihe); for example, a stretch of the lower Yellow
River (704 km) had no water flow for 226 days in 1997 (12, 37).
Meanwhile, more than 120 000 dams were constructed, with
46 000 dams and 7000 water gates along the Yangtze River
alone (including the Three Gorges Dam, the biggest dam in the
world) (12, 23). These dams and water gates not only isolated
70% of the natural lakes from rivers but also interrupted the
migration routes of aquatic species and drastically changed the
fauna of lakes (38, 39). In western China, lake areas are
encroached by the desertification process caused by droughts
and the loss of vegetation cover (1, 9, 17, 18). The lakes of
Figure 4. The distribution of three
important invasive plant species in
China’s natural wetlands. The lo-
cations for the smooth cord grass
are based on ref. 10, whereas the
locations of both alligator weed
and water hyacinth came from ref.
27, with minor corrections based
on refs. 2 and 24.
Ambio Vol. 36, No. 4, June 2007 339Ó Royal Swedish Academy of Sciences 2007
Manasi, Luobupo, Juyanhai, and many others dried up and
became desert in northwest China, and the water levels in the
lakes on the Tibetan Plateau decreased by 1.0–1.5 m, primarily
because of global warming (17, 18). Qinghai Lake, the biggest
lake on the plateau (4305 km
), decreased by 17.2 cm y
water level and by 8.4 km
in area during 1908–1956 and by
10.8 cm y
and 9.7 km
during 1957–1988, whereas the
desert area around the lake increased to 1670 km
from 450 km
during the past 50 years (17, 18).
The severe environmental problems associated with wetlands
loss were recognized by the Chinese government in early 1970s
(5, 10), even though it did not appreciate the importance of the
full range of ecosystem services provided by wetlands until
recently (2, 10). The government passed the first environmental
law in 1972 (10) and started taking a series of actions to remedy
the problems (5, 18), including establis hment of natural
reserves, wetland restoration, water pollution control, fish
population conservation, newly originated wetland protection,
and invasive species management. These actions have shown
promising results in reversing the trends of wetland loss and
degradation (2). In China, natural wetlands are protected under
a three-class system: the wetland reserves (i.e., full protection
from development and most human activities), the wetland
parks (i.e., full protection from development but use for
ecotourism), and the scenic parks (i.e., protection from
development but open to the public for recreation). We
highlight some of these important actions taken or to be taken
by the government in protecting, r estoring, and creating
wetlands in China.
Wetland Reserves
A wetland reserve is composed of a core area, in which human
activities are prohibited, and a buffer zone, in which some
human activities may be allowed upon approval. The Chinese
government started to establish natural reserves of wetlands in
the early 1970s. By 1980, 14 wetlands reserves, with a total of
5970 km
, were under protection (2, 24). By 2003, 477 reserves
were established to protect wetlands and rare and endangered
aquatic animals and plants (Fig. 5), including 69 managed by
the national government, 166 by the provincial governments,
and 242 by the local governments; the total conservation area
has reached 425 000 km
, including 145 000 km
of wetlands,
280 000 km
of marine and terrestrial ecosystems adjacent to
the wetlands (2). In addition, the government plans to establish
225 new wetland reserves by 2010 and another 135 by 2030
when about 90% of natural wetlands in China will be under the
protected status (2).
Wetland Restoration
China began restoring degraded wetlands in the early 1990s. To
date, it has funded more than 200 pilot programs with 20.7
thousand million dollars (USD) to protect and restore existing
natural wetlands, to create wetlands that have been lost, and to
address other wetland-related issues (2, 5). During 2000–2005, a
total of 36 projects were funded by the ‘‘863’ environmental
action plan, including 25 to restore water quality of natural
lakes and rivers, and 11 to restore pollution purificati on
capacity of urban wetlands (24). Funding has also been planned
for at least 100 thousand million dollars (USD) to start another
53 large programs by 2030 that will restore and recreate
additional 14 000 km
of natural wetlands (1, 2, 5). The new
policy to return some of the reclaimed croplands to the original
wetlands or lakes is in effect (2, 23). According to the National
Program of Wetland Protection Engineering issued in 2003, the
Chinese government will allocate 112.5 million dollars (USD)
during 2006–2010 to restore the degraded wetlands and to
establish wetland parks and wetland reserves (2). For example,
the government of Jiangsu province has started working on
many projects, including restoration of Taihu Lake, Hongze
Lake, and swamps along the Yangtze River; establishment of
wetland parks at Qinghu Lake, Yangcheng Lake and Qinghuai
River; and establishment of wetland reserves of the Big Canal,
Hongze Lake, and Taihu Lake.
Water Pollution Control
A wastewater control action plan (24) was implemented to
improve water quality and to protect the wetlands in the late
1990s, specifically to treat the heavily polluted rivers of Huaihe,
Haihe, and Liaohe; the lakes of Chaohu, Taihu, and Dianchi;
and the coast of the Bohai Sea. The action plan focused on
point and nonpoint source pollution control, wastewater
purification, and water resource and discharge management,
and was composed of 2420 projects, with the total funding of
23.5 thousand million dollars (USD) in the last five years. The
plan called for, but has not fulfilled, a reduction of chemical
oxygen demand by 5.0 Tg, including 50% from domestic
wastewater, 40% from industrial wastewater, and 10% from
rural areas by the year 2005. In addition, numerous laws and
regulations about water quality have been enacted by the
national, provincial, and local governments.
Fish Population Conservation
The regulation to prohibit fish harvesting in reproductive
periods was implemented in Poyang Lake and Taihu Lake in
1986, in Dongting Lake in 1995, and in the Yangtze River
estuary and marine fishing grounds in 2002 (40–43). The action
plan to restock wetlands with fingerlings from hatcheries was
started in 1999, and 245 thousand million individuals, including
both commercial and endangered fish species, had been released
into lakes, rivers and marine wetlands by 2005 (40–43). In
addition, the Worl d Wildlife Fund (WWF)-China funded
projects that were to reconstruct free migration channels among
four selected lakes (Zhangdu Lake, Hong Lake, and Tian’e
Lake in Hubei Province, and Baidang Lake in Anhui Province)
and the Yangtze River (23).
Protection of Newly Originated Wetlands
Protection of newly created wetlands is one of the national
wetland action plans in China (2, 5). The runoff of 1570 km
into the sea (59.0% from the Yangtze River) carries 15.3
Figure 5. Wetland protection efforts as depicted by the increase in
the number and area of natural reserves in China. The data came
from refs. 2, 5, and 17.
340 Ambio Vol. 36, No. 4, June 2007Ó Royal Swedish Academy of Sciences 2007
thousand million tonne of sediments into the estuaries each
year, including 6.4 thousand million tonne from the Yellow
River, 5.2 thousand million tonne from the Yangtze River, 1.6
thousand million tonne from the Haihe River, and 0.9 thousand
million tonne from the Pearl River (12, 44, 45). From the
sediments, 10 000 to 15 000 km
of new wetlands may originate
in the estuaries of major rivers and nearby coasts in the next 50
years (31, 32, 37, 46). It is also estimated that over 100 000 km
of submerged alluvial deposits off the coast of the Yellow Sea
may become terrestrial lands within 50–100 years if the current
sedimentation rate remains unchanged (45). In addition, at the
completion in 2008, the Three Gorges Dam will create a giant
artificial lake of 1150 km
of surface area, with additional 460
of permanent wetlands and 4900 km
of transient wetlands
near the lake shores because of high soil moisture (12, 23). The
South-to-North Water Diversion project is also expected to
contribute to the fresh wetland generation in Northern China
(2, 21). The National Program of Wetland Protection Engi-
neering calls for protection of the newly created wetlands by
establishing natural reserves and wetland parks (2).
Despite all that has been done, many challenges remain in terms
of wetland policy, management, and science. First, success in
wetland conservation requires science-based policies and effec-
tive laws and regulations. China still needs a specific law for
established. Current laws and regulations can be effective in
stopping wetland loss and water pollution at large scales, i.e.,
protecting wetlands from reclamation and point-source pollu-
tion. However, cleaning up of water pollution will take a long
time, and the water-resource shortage will remain a problem for
years to come. Therefore, it will be a major challenge to the
Chinese government to maintain a consistent policy on and a
long-term commitment to wetland conservation and water-
quality control. In addition, a system for monitoring and
assessing at the national scale will need to be developed to
ensure the effectiveness of the implementation of the policies,
laws, and regulations, and the accountability of the funded
programs. Second, effective implementation of the national
wetland action plan requires a concerted efforts at all levels. The
policies, laws, and regulations may fail to produce the expected
outcomes unless new ideas and incentives are developed to
provide local people with alternative ways of livelihood that will
not cause disturbances to wetlands. It will be a challenge to find a
balance between protection of wetlands and revitalization of the
local economy in wetland regions. Significant obstacles to
wetland preservation, such as local bureaucracy, lack of trained
managers, misuse of wetland funding, and lack of appreciation of
the ecosystem management principle, will also need to be
removed. Educational campaigns to increase public awareness
about wetland-related issues just started, but it will take a long
time to change peoples’ attitudes. Third, science is needed to
provide the information for decision making and for training
wetland professionals to manage natural reserves and wetland
parks, and to educate local people. China lacks the scientific
expertise and technical know-how in wetland restoration and in
water pollution control and clean-up. Efforts to enhance
scientific exchanges and communications will be needed to
narrow the gaps and to generate scientific advancements to solve
many of the problems. Another major challenge is the lack of
graduate programs for wetland sciences in universities, which is
the main reason for the lack of trained researchers and managers.
There are only a few such wetland graduate programs in China.
Sustainable development in China requires new attitudes,
sound policies, and great efforts in protecting natural wetlands
and preserving their valuable ecosystem services. The natural
wetlands in China are still under great threats by the large
population and rapid economic growth. In fact, the economic
miracle of China in the last 20 years came at the huge expense of
the environment, especially the natural wetlands (1, 21). To
reverse the trends, China faces enormous challenges. However,
significant actions are being taken, including the plan designed
to place 90% of the natural wetlands under protection by 2030,
the policy to return reclaimed croplands to wetlands (swamps,
lakes), and the funding allocated to restore natural wetlands (2,
5, 17). These actions will ensure that natural wetlands are
protected and damages to wetlands in the past are repaired so
that the country receives the full benefits of the ecosystem
services provided by wetlands in the years to come. The future
of China’s wetlands looks promising, because China under-
stands that protecti ng wetl and ecosystems is a national
imperative to guarantee a sustainable development of the
economy of the country.
References and Notes
1. Li, K. and Zhang, M. 2005. The resource and conservation suggestion of wetlands in
China. Wetland Sci, 3, 81–86 (In Chinese).
2. State Forestry Administration of China. 2005 . Wildlife and Wetland Reserves
Information. (
3. Chen, Z. and Zhang, X. 2000. The value of the ecosystem services of China. Chin. Sci.
Bull. 45, 17–22.
4. Costanza, R., d’Arge, R., de Groot, R., Farber, S., Grasso, M., Hannon, B., Limbueg,
K., Naeem, S., et al. 1997. The value of the world’s ecosystem services and natural
capital. Nature 387, 253–259.
5. State Forestry Administration of China. 2000. China’s National Wetland Conservation:
Action Plan. China Forestry Publishing House, Beijing, 118 pp. (in Chinese).
6. Ramsar Convention on Wetlands. 2006. Classification System for Wetland Type. (http://
7. Compiling Committee of Geography of China. 1985. Natural Geography of China.
Science Press, Beijing, pp. 250–395 (In Chinese).
8. Zhao, J. 1995. Natural Geography of China. 3rd, Higher Education Press, Beijing, p. 58
(In Chinese).
9. Lang, H., Lin, P. and Lu, J. 1998. Conservation and Research of Wetlands in China. East
China Normal University Press, Shanghai, 420 pp. (In Chinese).
10. An, S. 2003. Ecological Engineering of Wetlands. Chemical Industry Press, Beijing, 528
pp. (In Chinese).
11. Zhao, D. 1999. Coastal Vegetation of China. Ocean Press, Beijing, 297 pp. (In Chinese).
12. Ministry of Water Resource of China. 2000. Report on Freshwater Resource of China.
13. Jin, X. 2001. Control and Management of Eutrophic Lakes. Chemical Industry Press,
Beijing, 224 pp. (In Chinese).
14. Xiao, D., Hu, Y. and Li, X. 2001. Landscape Ecology of Wetlands along the Coast of
Bohai Sea. Science Press, Beijing, 417 pp. (In Chinese).
15. Zhao, K. 1999. Swamps of China. Science Press, Beijing, 718 pp. (In Chinese).
16. China’s Soil Dataset. 2005. Swamp Soil Properties. ( (In
17. Chen, Y. 1995. Studies of Wetlands in China. Jili Science and Technology Press,
Changchun, 385 pp. (In Chinese).
18. State Forestry Administration of China. 1996. Protection and Wise Uses of Wetlands.
China Forestry Publishing House, Beijing, 460 pp. (In Chinese).
19. China’s Lake Dataset. 2005. Regional Data. (
(In Chinese).
20. An, S., Wang, Z., Zhou, C., Guan, B., Deng, Z., Zhi, Y., Liu, Y. and Xu, C., et al. 2006.
The headwater loss of the western plateau exacerbates China’s long thirst. Ambio 35,
21. Liu, J. and Diamond, J. 2005. China’s environment in a globalizing world. Nature 435,
22. State Environmental Protection Administration of China. 1998. National Report of
Biodiversity of China. China Environmental Science Press, Beijing, 430 pp. (In Chinese).
23. WWF China. 2005. Wetland Biodiversity and Services. (
24. State Environmental Protection Administration of China. 2005. Environmental Report.
25. National Bureau of Statistics of China. 2000. Agricultural Data. (
26. China’s Swamp Dataset. 2005. Regional Sata. ( (In
27. Li, Z. and Xie, Y. 2002. Invasive Alien Species in China. China Forestry Publishing
House, Beijing, 211 pp. (In Chinese).
28. Dou, H. and Jiang, J. 2000. Dongting Lake. China Science and Technology University
Press, Hefei, 344 pp. (In Chinese).
29. Zhao, S., Fang, J., Miao, S., Gu, B., Tao, S., Peng, C. and Tang, Z. 2005. The 7-decade
degradation of a large freshwater lake in central Yangtze river, China. Environ. Sci.
Technol. 39, 431–436.
30. Zhao, S. and Fang, J. 2004. Impact of impoldering and lake restoration on land-cover
changes in Dongting Lake area, Central Yangtze. Ambio 33, 311–315.
31. Ren, M. 1986. Survey Report of Costal Jiangsu
. Ocean Press, Beijing, 517 pp. (In
32. Chen, J. 2000. To explore lower tidal flats for expending living spaces of China. Engr.
Sci. 2, 27–30.
33. Deng, W., Zhang, P. and Zhang, B. 2004. Regional Development of Northeast China.
Science Press, Beijing, 432 pp. (In Chinese).
34. Liu, H., Zhang, S., Li, Z., Lu, L. and Yang., Q 2004. Impacts on wetlands of large-scale
land-use changes by agricultural development: the Small Sanjiang Plain, China. Ambio
33, 306–310.
35. China’s Scientific Dataset. 2005. Agricultural Data. (
ku1new.asp) (In Chinese).
36. Liu, Y. 2006. Shrinking Arable Lands Jeopardizing China’s Food security. (http://www.–1)
Ambio Vol. 36, No. 4, June 2007
341Ó Royal Swedish Academy of Sciences 2007
37. Shi, C. and Zhang, D. 2005. A sediment budget of the lower Yellow River, China, over
the period from 1855 to 1968. Geografiska Annaler Series A-Physical Geography 87A,
38. Xie, P. 2003. Three-Gorges Dam: risk to ancient fish. Science 302, 1149.
39. Park, Y., Chang, J., Lek, S., Cao, W. and Brosse, S. 2003. Conservation strategies for
endemic fish species threatened by the Three Gorges Dam. Conserv. Biol. 17, 1748–1758.
40. China’s Yearbook. 2000. Fishery Data. ( (In
41. Chinese Academy of Fishery Science. 2005. Fishery Data. ( (In
42. China’s Fishery Information Website. 2005. Fishery Data. ( (In
43. State Ocean Administration of China. 2005. FisheryData. (
44. Hori, K., Saito, Y., Zhao, Q. and Wang, P. 2002. Architecture and evolution of the tide-
dominated Changjiang (Yangtze) River delta, China. Sediment. Geol. 146, 249–264.
45. Liu, X., Wang, K. and Zhang, G. 2004. Perspectives and policies: ecological industry
substitutes in wetland restoration of the Middle Yangtze. Wetlands 24, 633–641.
46. Estuary and Coastal Information Website. 2005. Coastal Wetland Information. (http:// (In Chinese).
47. Acknowledgments: We gratefully acknowledge the financial support from the projects of
National Water Projects in Resource and Environment Programs (2003AA06011000–4,
2002AA601012–06), National Basic Research Projects (2002CB111504) and National
Science Foundation of China (30400054). H. Li wishes to acknowledge that this paper
has not been subjected to the policy review by USDA Forest Service and, therefore, does
not necessarily reflect the views of the agency and no official endorsement should be
48. First submitted 25 September 2005. Accepted for publication 30 October 2006.
Dr. Shuqing An, the corresponding author, is a professor of
wetland science at Nanjing University, and his research interests
include wetland ecology, invasive species management and
biogeochemical cycles. Addresses: The State Key Laboratory of
Pollution Control and Resource Reuse, Nanjing University,
Nanjing 210093, China; The Institute of Wetland Ecology and
School of Life Science, Nanjing University, Nanjing 210093,
Dr. Harbin Li is a research ecologist with USDA Forest Service,
and his research interests include wetland ecology and manage-
ment, quantitative landscape ecology, ecological modeling, and
ecosystem management with decision-support tools. Address:
USDA Forest Service Southern Research Station, Center for
Forested Wetlands Research, Charleston, SC 29414, USA.
Baohua Guan is a postdoctoral fellow. Address: The State Key
Laboratory of Pollution Control and Resource Reuse, Nanjing
University, Nanjing 210093, China; The Institute of Wetland
Ecology and School of Life Science, Nanjing University, Nanjing
210093, China.
Changfang Zhou is an associate professor with a PhD. Address:
The Institute of Wetland Ecology and School of Life Sciences,
Nanjing University, Nanjing 210093, China.
Zhongsheng Wang is an associate professor with a PhD.
Address: The Institute of Wetland Ecology and School of Life
Sciences, Nanjing University, Nanjing 210093, China.
Zifa Deng is a doctoral student. Address: The Institute of Wetland
Ecology and School of Life Science, Nanjing University, Nanjing
210093, China.
Yingbiao Zhi is an associate professor with a PhD. Address: The
Institute of Wetland Ecology and School of Life Sciences, Nanjing
University, Nanjing 210093, China.
E-mail: n
Yuhong Liu is a doctoral student. Address: The Institute of
Wetland Ecology and School of Life Science, Nanjing University,
Nanjing 210093, China.
Chi Xu is a doctoral student. Address: The Institute of Wetland
Ecology and School of Life Science, Nanjing University, Nanjing
210093, China.
Shubo Fang is a doctoral student. Address: The Institute of
Wetland Ecology and School of Life Science, Nanjing University,
Nanjing 210093, China.
Jinhui Jiang is a doctoral student. Address: The Institute of
Wetland Ecology and School of Life Science, Nanjing University,
Nanjing 210093, China.
Hongli Li is a doctoral student. Address: The Institute of Wetland
Ecology and School of Life Science, Nanjing University, Nanjing
210093, China.
342 Ambio Vol. 36, No. 4, June 2007Ó Royal Swedish Academy of Sciences 2007
... Wetlands provide many ecosystem services, such as providing material resources, reducing water pollution, controlling floods, and drought, and mitigating climate change; in addition, wetlands are of great significance to maintaining species diversity, especially for wintering waterbirds (An et al., 2007;Mitsch and Gosselink, 2015). As a typical wetland type (Wu and Zheng, 2020), floodplain wetlands create the ecotone between the terrestrial and aquatic with plenty of wetland vegetation and hydrological rhythm (Wang et al., 2013;Li et al., 2019c;Qiu et al., 2021). ...
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The distribution and composition of wetland habitats for wintering waterbirds are heavily influenced by water level fluctuations. Through polder construction and aquaculture activities, paddy fields and aquaculture ponds have decreased the lateral connectivity of water level fluctuations in the lake. However, the impacts of water level fluctuations on habitat suitability, which can be seen using high-resolution images analysis, often cannot separate disturbances caused by the paddy fields and aquaculture ponds, and it is difficult to capture the actual impact of water level fluctuations on wetland habitats. Based on remote sensing image data and hydrological data, we selected Caizi Lake as a study site and comparatively analyzed the changes in wintering waterbird habitats in a water level sequence under the two scenarios. Our work showed that paddy fields and aquaculture ponds should be considered as potential options for creating more suitable habitats for migratory waterbirds if combined with reasonable and effective management of the water level within the paddy fields and aquaculture ponds. The present study results could facilitate the management and sustainable utilization of Caizi Lake wetlands and provide support for creating small habitats by managing the water levels of paddy fields and aquaculture ponds.
... In recent years, with the booming population and the intensifying industrialization, wetlands have been excessively exploited and utilized. Ecological problems including the shrinkage of waters, has weakened capabilities of water storage and caused degradation of ecological functions, and the declining biodiversity seriously threatens China's ecological security and sustainable development [7,8]. To increase the economic incentives for wetland conservation, the Chinese government has implemented a series of ecological compensation policies in recent years [9]. ...
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The paper follows a field survey of 773 rural households in 14 towns in five prefectures (cities and districts) around the Poyang Lake, and uses a multivariate ordered logistic model to explore the factors influencing satisfaction with wetland ecological compensation policies (WECPs) from the perspective of rural households’ subjective cognition of WECPs and income factors. The research shows the following. (1) the overall score for satisfaction of farmers with WECPs is 3.56, which indicates satisfaction between “fair” and “fairly satisfied,” and there is room for policy optimization. (2) The subjective cognition of policies and the income-related factors have significant impacts on the satisfaction of farmers with WECPs. Among them, cognition of policy objectives, evaluation of compensation rates, timely distribution of compensations, government supervision, changes in household incomes and importance of compensation on households all have significant positive influences on policy satisfaction. (3) The degree of education, the proportion of household labor forces and the proportion of household non-agricultural incomes have a significant positive impact on the policy satisfaction of farmers. Therefore, in future policy implementation, we should strengthen publicity and guidance of the policy, raise compensation rates appropriately, strengthen government supervision, pay attention to rural livelihood, and establish an ecological compensation mechanism featuring fairness and long-term effectiveness.
... Global climate change will probably pose another severe threat to freshwater biodiversity, particularly in headwater wetlands on the Qinghai-Tibetan Plateau, which will affect the Yangtze, Yellow and Lancan/Mekong rivers. In the Yangtze River, headwater network wetlands drain 25% of the total flow (An et al., 2006) and these are sensitive to climate change and land-use change (Alexander et al., 2007). Extensive urbanization has caused a massive loss of natural aquatic habitats. ...
... Coastal areas and small islands exhibit a high human population density, and humans living in coastal areas have benefited from land reclamation from the coastal wetlands [1]. However, the loss and degradation of coastal wetlands caused by land reclamation have been a global concern during the past decades [2]. ...
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Reclaimed coastal areas were mostly used for agricultural purposes in the past, while land-use conversion was initiated in recent decades in eastern China. Elucidation of the effects of land-use conversion on soil properties and stoichiometry is essential for addressing climate change and ecological conservation. In this study, five land-use types in a reclaimed area were chosen to compare the differences of soil properties and stoichiometry, which comprised paddy, upland, upland-forest, forest, and vegetable garden, with a soil age of about 100 years. The results indicated that these land-use types significantly differed in soil water concentration, pH, bulk density, soil salt concentration, soil organic carbon content, total nitrogen content, and total phosphorus, as well as C:N, C:P, and N:P ratios. Positive correlations were found among soil organic carbon, total nitrogen, and total phosphorus; and among pH, bulk density, and soil salt concentration. Total phosphorus and soil organic carbon contents were the main factors shaping the topsoil among the land-use types. Contents of soil organic carbon, total nitrogen, and total phosphorus in paddy and vegetable garden soils were higher than that in upland and upland-forest soils, while bulk density, pH, and soil salt concentration showed the opposite trends. Forest soil demonstrated intermediate values for most properties. And the highest C:N occurred in the upland and vegetable garden, the highest C:P in paddy and vegetable garden, while the lowest C:N and C:P occurred in upland-forest. The highest and lowest N:P occurred in paddy and upland, respectively. The stoichiometric characteristics presented a narrow range of the ratio, and the C:N:P averaged 48:3:1 similar to the stoichiometry of average Chinese cropland soils. Rotations including legume, the use of organic fertilizers, and appropriate fertilization strategies were suggested for improving cropland management.
Coastal wetlands have been globally fragmented by reclamation activities, leading to reduced connectivity, which play an important role in maintaining the integrity of ecosystem functioning. However, practical wetland management rarely considers the connectivity effects of reclamation. How to identify hot-spot targets for wetland protection and restoration aimed to improve wetland connectivity presents a big challenge in the decision-making process. Here, we integrated GIS-based graph theory model and circuit theory model to evaluate the influences of coastal reclamation on wetland connectivity and identify conservation priority and restoration priority at multiple (patch, corridor and key node) scales, respectively, in the Yellow River Delta (YRD), China. The results indicated that since 1980s, reclamation has significantly reduced the area and landscape connectivity of different wetlands in this delta, especially saline marshes. According to important contributions of individual patches to the overall landscape connectivity, 515.36 km² of natural wetland and 430 km² of reclaimed wetland were identified to be protected and restored primarily. Our models also showed that coastal reclamation increased the resistance of species movement among wetland habitats. Potential corridors crossing natural wetlands (674.4 km) and crossing the reclaimed wetlands (21.92 km) should be protected and restored. In addition, 83 key ecological nodes such as pinch points (9.96 km²) and barrier points (46.54 km²) should be given priority conservation and restoration, respectively. This work answers the question of where and how to protect and restore wetland hotspots to improve landscape connectivity. The idea of optimizing the replacement of patches, corridors and key ecological nodes in the YRD has guiding significance for wetland management and biodiversity conservation in other regions with poor data.
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Wetlands are large sinks of carbon dioxide (CO2) and sources of methane (CH4). Both fluxes can be altered by wetland management (e.g., restoration), leading to changes in the climate system. Here, we use multiple models to assess CH4 emissions and CO2 sequestration from the wetlands in China and the impacts on climate under three climate scenarios and four wetland management scenarios with various levels of wetland restoration in the 21st century. We find that wetland restoration leads to increased CH4 emissions with a national total of 0.32-11.31 Tg yr-1. These emissions induce an additional radiative forcing of 0.0005-0.0075 W m-2 yr-1 and global annual mean air temperature rise of 0.0003-0.0053 °C yr-1, across all future climate and management scenarios. However, wetland restoration also resulted in net CO2 sequestration, leading to a combined net greenhouse gas sink in all climate management scenarios, except in the highest restoration level combined with the hottest climate scenario. The highest climate cooling was achieved under medium restoration, with the climate scenario consistent with the Paris agreement target of below 2 °C, with a cumulative global warming potential of -3.2 Pg CO2-eq (2020-2100). Wetland restoration in the Qinghai-Tibet Plateau offers the greatest cooling effect.
Accurately investigating long-term information about open-surface water bodies can contribute to water resource protection and management. However, due to the limits of big-data calculations for remote sensing, there has been no specific study on the long-term changes in the water bodies in the Yellow River Basin. Thus, in this study, we developed a new combined extraction rule to build an entire annual-scale open-surface water body dataset for 1986-2020 with excellent effectiveness in eliminating the interference of shadows in the Yellow River Basin using all of the available Landsat images. For the first time, the spatial distribution, change trends, conversion processes, and the heterogeneity of the surface water bodies in the Yellow River Basin were analyzed comprehensively to the best of our knowledge. The extraction results had an overall accuracy of 99.70 % and a kappa coefficient of 0.90, which were validated using 34,073 verification points selected on high-resolution Google Earth images and random Landsat images. The total area of water bodies initially decreased (1986-2000) and then increased (2001-2020); however, only the size of the permanent water bodies increased in most areas, while the size of most of the seasonal water bodies decreased. In regions with human-made water bodies, the non-water areas were substantially converted to seasonal and permanent water bodies; however, in areas with natural water bodies, many permanent and seasonal water bodies were gradually converted to non-water areas. Thus, most of the increases in the water bodies occurred in the form of artificial lakes and reservoirs, while most of the decreases in the water body area occurred in natural wetlands and lakes. The areas of both the permanent and seasonal water bodies were positively correlated with precipitation, but only the area of the seasonal water bodies was negatively correlated with temperature.
Coastal zones (CZ) are ecologically and environmentally significant, and it is thus critical to study the interactions among different types of natural CZ waters for better understanding biogeochemical processes. Water samples (n = 101) were analyzed for multiple stable isotopes (δ18O-H2O, δD-H2O, δ15N-PON, δ15N-NO3􀀀 , and δ18O-NO3􀀀 ) in seawater, river water, reservoir water and groundwater at Tianjin CZ to demonstrate the spatial variations in the CZ aqueous environment and to identify key influencing processes factors of the N geochemical cycle. This study confirmed that weathering dominated upstream water properties, whereas seawater intrusion determined the downstream and midstream water chemical components, where the seawater fraction was 44% and 11%, respectively. Evaporation and precipitation processes were active across the whole CZ area, but their impacts on water chemical components were less significant than seawater intrusion and weathering. Dam regulation in CZ rivers has significantly affected water chemical components and the nitrogen cycle. The isotopic evidence indicated that bacterioplankton and phytoplankton were the primary forms of PON. The dual nitrate isotopes revealed that animal manure and industrial sewage contributed the leading nitrate to river water. The spatial variation of their contribution was quantitated (from upstream to midstream and downstream: 62%, 91% and 83%, respectively). Considering the potential isotopic fractionation of nitrification reduction from upstream to downstream, 39%, 61% and 57%, respectively. This study proposes a quantitative framework for detecting CZ areas with similar hydrodynamic conditions and climate characteristics found at the Tianjin CZ, which has important implications for CZ water management and environmental protection policies.
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In this classroom, high-school biology students learned how pine beetle outbreaks in North America have become some of the worst in a decade. To make sense of this phenomenon, students created iterative models with in-depth explanations over the course of the unit. These models were formative in developing students’ conceptual understanding of ecology and applying their knowledge to a real-world context. The models showed students the detrimental effects of the outbreaks and helped them wonder about efforts to manage them and preserve the forests. This allowed the teacher to connect their learning to an ecological engineering task. This task pushed students to research various solutions and preventative measures scientists, engineers, or foresters might use to help forests recover from pine beetle attacks. Students used this information along with their models and explanations to write an engineering proposal to states who have never encountered the beetles before. From this unit, the teacher was easily able to connect and transition into an engineering activity in the biology classroom through creating in-depth models and explanations; and students were provided with clear, explicit connections between science and engineering. Keywords: Models, Engineering, Ecosystems, Pine Beetles, Ecological Engineering
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The services of ecological systems and the natural capital stocksthat produce them are critical to the functioning of the Earth’s life-support system. They contribute to human welfare, both directly and indirectly, and therefore represent part of the total economic value of the planet.We have estimated the current economic value of 17 ecosystem services for 16 biomes, based on published studies and a few original calculations. For the entire biosphere, the value (most of which is outside the market) is estimated to be in the range of US$16–54 trillion (1012) per year, with an average of US$33trillion per year. Because of the nature of the uncertainties, thismust be considered a minimum estimate. Global gross national product total is around US$18 trillion per year.
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The largest damming project to date, the Three Gorges Dam has been built along the Yangtze River (China), the most species-rich river in the Palearctic region. Among 162 species of fish inhabiting the main channel of the upper Yangtze, 44 are endemic and are therefore under serious threat of global extinction from the dam. Accordingly, it is urgently necessary to develop strategies to minimize the impacts of the drastic environmental changes associated with the dam. We sought to identify potential reserves for the endemic species among the 17 tributaries in the upper Yangtze, based on presence/absence data for the 44 endemic species. Potential reserves for the endemic species were identified by characterizing the distribution patterns of endemic species with an adaptive learning algorithm called a “self-organizing map” (SOM). Using this method, we also predicted occurrence probabilities of species in potential reserves based on the distribution patterns of communities. Considering both SOM model results and actual knowledge of the biology of the considered species, our results suggested that 24 species may survive in the tributaries, 14 have an uncertain future, and 6 have a high probability of becoming extinct after dam filling.
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The function and services are the important components of the life-support system in the planet, as well as the basic elements for sustainable development of environment and society. It is a must to evaluate it for incorporating it with the social-economic system. It is also an important approach to draw the public attention on the environmental and ecosystem conservation. In this study, the ecosystem function and services in China were estimated by employing the classification and economic parameters from Costanza et al. The type and area of terrestrial ecosystems were extracted from Vegetation Map of China (1:4 000 OOO), and then the distribution map of ecosystem services of China was drawn. According to our calculation, the total value of ecosystem services in China is 77 834.48×108 RMB yuan per annum. The value for terrestrial ecosystem is 56 098.46×108 yuan per annum, and that for marine ecosystem is 21 736.02×108 yuan per annum. The value of ecosystem services in China is 1.73 times bigger than GDP in 1994. The value for forest ecosystem services is 15 433.98×8 yuan per annum, which is 27.51% of the total annual ecosystem services in China. Although wetland is little in area, its ecosystem service value is huge, which is 26 736.9×8 yuan per annum. The value for grassland ecosystem is 8 697.68×8 yuan per annum. Coastal ecosystem service is 12 223.04×8 yuan per annum. Overall, the ecosystem service in China contributes 2.71% to that of our planet. The estimation method employed in this study was a conservative one, and should be improved in the future studies.
Introduction Major Factors Shaping China's Physical Geographical Environment Climatic Features of China Geomorphological Features of China Surface Water and Ground Water Soil Geography Biogeography of China Comprehensive Physical Regionalization and Land Classification in China Humid and Subhumid Temperate Northeast China Humid and Subhumid Warm- temperate North China Humid Subtropical Central China and South China Humid Tropical South China Temperate Grassland of Nei Mongol Temperate and Warm-temperate Desert of Northwest China The Qinghai-Xizang Plateau A Glossary of Geographic Place Names Climatic Statistics for 20 Selected Stations.
This study investigates the sediment fluxes through the Yellow River sediment routing system, which are among the largest in the world, by constructing a sediment budget of the system over the period from 1855 to 1968. The framework of the sediment budget includes four functional units with the upper and middle reaches of the river as the sediment source and its lower reaches, its delta, and the deep sea as the sediment sinks. Sediment yield from the source and amounts of deposition in the lower Yellow River and the modern Yellow River delta were estimated for completing the sediment budget. The sediment budget produced for the period from 1855 to 1968 was characterized by a sediment input of 1.837 × 1011 tonnes and a distribution of the sediment between the lower Yellow River, the delta, and the deep sea of 64%, 33%, and 3%, respectively. The details of the sediment budget show that the importance of sedimentation in the lower Yellow River changed greatly with variations in the condition of the dykes and other human activities. A comparison of the sediment budgets of the delta for different timescales shows that the proportion of sediment dispersed to the deep sea decreases as the timescale over which the sediment fluxes are investigated increases.
Wetlands are considered multi-functional ecosystems with important protection and use functions. However, before the 1980s, wetlands in the middle reaches of the Yangtze River, China were mainly reclaimed as paddy fields. In wetland restoration since 1998, there has been an urgent need to develop ecological industry substitutes that are economically efficient while having no negative effects on wetland ecology. Based on the research projects conducted in this region, five industry options were recommended, including 1) growing hydrophytes with high economic value, 2) raising livestock on the seasonal grasslands, 3) planting commercial seasonal vegetables, 4) developing aquaculture in the low-lying paddy fields, and 5) ecological tourism. Policies promoting these industries were aimed at solving problems concerning 1) input shortages and local farmers’ unfamiliarity with required agricultural technologies and 2) integrated use of the regional ecological environment with wildlife protection.