Reintroduction（2011）1:25 – 30

INVITED ARTICLE

Efforts to improve biodiversity in paddy field ecosystem of SouthKorea* Jae Ok Kim1, Seung Heon Lee1 and Kyu Sang Jang1
Abstract Paddy ﬁelds have worked as a nursery of bio-

control (water puriﬁcation, climate mitigation, and organic

diversity and cultural diversity. Moreover, paddy ﬁelds

waste processing) (Lee ₂₀₀₁). But the environment of

have provided multiple functions like flood control,

paddy ﬁelds has been changed to increase rice supply as

ground-water recharge, preventing soil loss, and water

consequences of the economic development and urban-

puriﬁcation. The 10th Ramsar convention was a goodizing (MIFAFF ₂₀₁₀). According to the report by the

chance to appeal recognitions of useful beneﬁts of paddy

Korea Rural Community Corporation, rice cultivatedﬁelds. At that meeting, this resolution declaried that theareas decreased from ₁₂₄,₄₀₀ ha in ₁₉₉₀ to ₉₅,₀₀₀ ha inpaddy ﬁelds offer unique habitats for living things. How-

₂₀₀₇ (Fig. ₂). Until the large areas of paddy ﬁelds have

ever, environment of paddy fields in Korea has been

been converted to house, building and road. As a result ofchanged by the economic development, urbanization andthese changes, biodiversity grown in the rice ﬁeld has

increase of rice supply. Thus it is necessary to have stron-

greatly decreased. The ₁₀th Conference Meeting of theger efforts to improve and protect the paddy ﬁeld ecosys-

Contracting Parties to the Convention on Wetlands wastem. In this paper, we would like to introduce the current

held in Korea, ₂₀₀₈.

status of Korean agriculture and environmental change in

One of the adopted resolutions proposed at this meeting

paddy ﬁelds by economic development. We suggest some

was to regard paddy ﬁelds as a wetland. The resolution

suitable methods for improving biodiversity in Korean

gives recall and recognition of importance of paddy ﬁeld

agricultural environment.
Key words Paddy ﬁeld ecosystem, Biodiversity, Fishway, Small pool, Habitats

Introduction
Rice has been cultivated as a major source of food in
₁₁₄ countries and all the continents (KRC ₂₀₀₁). Although

paddy ﬁelds were originally wetlands and artiﬁcially constructed devices for rice production, they have worked asa nursery of biodiversity and cultural diversity (Kim et al.
₂₀₀₁). This is from the fact that paddies support importantFig. ₁. Pyramid of paddy ﬁeld ecosystem.

wetland biodiversity such as ﬁsh, amphibians, and insects(Fig. ₁).
Moreover, multiple functions of paddy ﬁelds have beenrecognized including water cycle control (ﬂood prevention, ground water recharge, prevention of soil erosion,
sediment collapse and landslides) and environment load
₁

Rural Research Institute of Korea Rural Community Corporation:#₃₉₁, Haean-ro, Sangrok-gu, Ansan-si, Gyeonggi-do ₄₂₆-₉₀₈,
South Korea* E-mail:Fig. ₂. Yearly variation of rice cultivate area in Korea.
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Reintroduction（2011）1:25 – 30

total river length (National and Local) and ₅.₀ times ofas a part of wetland to enrich biodiversity.
In Japan several ecological restoration programs includ-

small river length in Korea (Hong ₂₀₁₀) (Table ₁ and ₂).

ing paddy-drainage ﬁshway, winter-ﬂooding, and buffer

Therefore, irrigation and drainage canals and rice paddy

zone construction have been conducted in various parts ofﬁelds are important zones for sustainable ecosystem man-the country. Japanese government has also declared toagement in agricultural area.

restore paddy field ecosystem in the agriculture land
improvement law.
So, through this approach, Stronger efforts to improve

Importance of paddy ﬁeld

and protect the paddy ﬁelds ecosystem are required. In

Why paddy ﬁelds are important? Paddy ﬁeld has vari-this paper, the current agricultural situation of Korea,

ous kinds of beneﬁcial functions. The ﬁrst is a ﬂood con-especially the current changes of paddy ﬁeld environ-trol capacity of rice field. The most common natural

ments through economical development will be intro-

disaster in Korea is ﬂooding during summer due to the

duced. Finally we propose the recommendations totopographic and meteorological characteristics (Leeimprove biodiversity in our agricultural environment.

₂₀₀₁).

During the rainy season, rice ﬁelds store rain water
temporarily and the total holding capacity of rainwater in

The summary of rice cropland and canal in Korea

the ﬁelds is ₁₈ times of the Soyang Dam, the largest dam

Paddy ﬁeld and cropland area cover ₁₂.₀% and ₆₀.₄%

in Korea. The most important source of water used dailyof the land area in Korea, respectively. Also, total length

by man is ground water. Total amount of the holdingof irrigation and drainage canal at the agricultural area

capacity of underground water at the rice ﬁeld in Korea isreaches ₁₈₃,₀₀₀ km, which is approximately ₂.₈ times ofabout ₅.₄₅ billion tons. It is equivalent to ₂.₉ times of theTable ₁. The status of the river in Korea (Unit: km).
Total
lengthRepairplan

Completed

Completed
rate (%)

National River
Local River
Small River

₃,₂₆₀
₁₇,₅₉₅₃₅,₈₁₅

₃,₁₁₃
₁₄,₆₅₅₃₅,₈₁₅

₂,₉₈₆
₁₂,₈₄₉₁₂,₉₅₅

₉₅.₉
₈₂.₆
₃₆.₁

Total

₅₆,₆₇₀₅₃,₅₈₃

₂₈,₇₉₀–<From National Emergency Management Agency, Ref.>
Table ₂. Length of irrigation and drainage canals in paddy
ﬁelds in Korea (Unit: km, ₂₀₀₉).
Total length
Irrigation canalDrainage canal

Natural Canal

Structure Canal

₁₁₆,₀₀₀

₆₂,₀₀₀ (₅₃.₄%) ₅₄,₀₀₀ (₄₆.₆%)

₆₇,₀₀₀₅₁,₀₀₀ (₇₆.₁%) ₁₆,₀₀₀ (₂₃.₉%)<From Korea Rural Community Corporation, Ref.>available storage capacity of the largest dam in Korea.
Rice ﬁeld also has a function to prevent soil loss. It takes
approximately ₂₀₀ years to create just only ₁ cm of topsoil. About ₁₇ million tons of eroded soil are trapped bypaddies every year in Korea. Biological mechanisms of
the soil and paddies decompose contaminants ﬂow into
the paddy ﬁeld. Through photosynthesis, paddies ﬁx carbon dioxide from the air and emit oxygen. The rice plantis one of the most efﬁcient crops in absorbing carbon
dioxide. In summer time, evaporated water from paddy
ﬁelds cools the atmosphere about ₂–₃ degree. Paddy ﬁelds
are home for variety of wildlife such as ﬁshes, birds,
invertebrates, amphibians and reptiles (Fig. ₃). As statedabove, paddy ﬁelds have many functions that beneﬁts ourFig. ₃. Paddy ﬁeld as habitats for various living things.
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Kim et al.: Efforts to improve biodiversity in paddy field ecosystem of South Korea

lives as well as many creatures. So we have to protect andpreserve continuously the paddy ﬁeld ecosystem.

Environmental changes of paddy ﬁelds
Many things have changed around paddy ﬁelds environment since the outbreak of the war. One of the most
several changes is expanded policy of food production.
Land consolidation to increase rice production was carried out on a nationwide scale (Fig. ₄). This movement
facilitated mechanized farming, increased food production and a rise in the agricultural income (Fig. ₅). Also,
irrigation system changed from natural to structured canalFig. ₄. Landscape change before (upper) and after (lower) landconsolidation (in Gyeonggi province of Korea).

Fig. ₅. Landscape change before (left) and after (right) the mechanized farming.

Fig. ₆. Change of irrigation system past (upper) and present (lower).


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Reintroduction（2011）1:25 – 30

several works were started to improve paddy ﬁeld ecosystems. Importance of rice ﬁelds as agricultural wetlands
was reﬂected in global certiﬁcation from resolution in
Ramsar.
 The ﬁrst challenge is winter-ﬂooding for winter water

birds in paddy ﬁeld (Fig. ₈). Paddy ﬁelds are habitats
of endangered species, especially water birds. Winterﬂooded ﬁelds are used by water birds including ducks
Fig. ₇. The trends of rice self-sufﬁciency rate in Korea (Datasource: Korea Rural Economy Institute).

and geese migrating through East Asia-Australia ﬂyway. The Cheorwon-gun near North Korea is also
famous for the wintering sites of migratory birds such

(Fig. ₆). In the past, most of rice paddies depended on

as cranes. Winter-ﬂooding is not only beneﬁcial forsolely on rainfall for water. But after irrigation system

migratory birds but also for other living things such as

established, rice paddies can obtain sufﬁcient water for

invertebrates and, ﬁshes in winter. Therefore we plan toagriculture. Consequently, we get the rice self-sufﬁciency

expand the winter-ﬂooding in paddy ﬁelds in Korea andsince ₁₉₈₅ roughly (Fig. ₇). But, after the development ofstart basic research to estimate necessary amount of

the paddies biodiversity in paddy ﬁelds has decreased

water to conduct such activities. We hope that people

seriously. At the ecological pyramid based on the paddies,from several areas join winter-ﬂooding program for thethe most top organisms was oriental white stork and it

sustainable paddy ﬁeld ecosystem management.

became extinct in ₁₉₇₄ in Korea. The species richness as The second action is to build an eco-bridge like a ﬁsh-well as their abundance of other living things was also

way that is a structure on or around artiﬁcial barriers toaffected by changes of paddy infrastructure. We need tofacilitate natural migration of ﬁsh between paddy ﬁelds

pay much attention for biodiversity improvement in paddy

and drainage canals (Fig. ₉). Various types of ﬁshways

ﬁelds.

have been designed and installed already in Japan, but
we are still in the preliminary stage for ﬁshway development in Korea. The ﬁrst ﬁshway was installed in

Efforts to improve biodiversity in South Korea

Daeho reclaimed land in Korea, ₂₀₁₀ (Fig. ₁₀). Results

After the ₁₀th Ramsar convention in Changwon, Korea,

obtained from this ﬁshway monitoring revealed that

Fig. ₈. Winter-ﬂooded paddy ﬁelds in Cheorwon-gun, Korea.

Fig. ₉. Landscape of divided canal with paddy ﬁeld.
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Kim et al.: Efforts to improve biodiversity in paddy field ecosystem of South Korea

Fig. ₁₀. Examples of ﬁshway to connect between paddy ﬁeld and irrigation canal.

Fig. ₁₁. Small pools next to paddy ﬁelds.

various ﬁshes such as rice-ﬁsh and mud-ﬁsh use it.

Table ₃. Invertebrates found in small pool.

Many ﬁsh used the ﬁshway at dawn of day. We foundDivision

Species

Rate (%)

that this ﬁshway effectively worked to save ﬁsh at agri-

Non-Insecta
Ephemeroptera
OdonataHemiptera
Coleoptera
Diptera

₁₇
₁
₁₀
₁₀
₁₆
₈

₂₇.₄₂
₁.₆₁
₁₆.₁₃
₁₆.₁₃
₂₅.₈₁
₁₂.₉

culture area of water shortage.
 The third work is to reinstall small scale pool next topaddy ﬁelds (Fig. ₁₁). In the old days, there are manysmall pools named Dum-bumg at a side of paddy ﬁelds(Fig. ₁₂) but most of these small pools have disap-

Total

₃₄ Families, ₆₂ Species

peared through improvement of irrigation system.

the midsummer drainage period. Therefore, small pool

Small pools have ecological merits besides irrigation

plays an important role as shelters for many animals

function. During winter and midsummer drainage,

during midsummer drainage period. If farmers are

small pools play important roles like an oasis to organ-interested in environment-friendly farming, they can

isms. Hongsung-gun is famous for environment-

install small pools at a low cost. It takes only two hun-friendly farming with a long history about ₅₀ years indred and ﬁfty thousand won to establish small pool of

Korea. These regional farmers voluntarily install small

₉ square meters. Throughout this investigation wepools to improve ecological environment of paddy

understand that establishing small pool is a goodﬁelds. There are many living things like ﬁsh, inverte-

method for improving paddy ﬁeld ecosystem in Korea.

brate, amphibians, and reptiles, in small pool (Table ₃).

 The last is to carry out environment-friendly large-scaleAlso, throughout the experiment we found that mud-land consolidation project. For example, various eco-ﬁsh moved from paddy ﬁelds to the small pool during

logical restoration systems were induced with land con-Fig. ₁₂. Many types small pool at Hongsung-gun, Korea.
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Reintroduction（2011）1:25 – 30

Fig. ₁₃. Environment-friendly readjustment project at Cheorwon-gun, Korea.

solidation at Cheorwon-gun, Korea in ₂₀₀₈. Under ation can apply immediately in paddies to enrich theirland consolidation project conducted in ₅₂ ha area, ﬁsh-biodiversity.

way was installed in three sites, large scale pool in two

 Paddy ﬁelds are important wetlands in monsoon Asia

sites and small scale pool in nine sites (Fig. ₁₃). Fish-

as a habitats of migratory water birds and living crea-

ways, small and large pools were regularly surveyed fortures. Studies to improve ecological functions of paddy

monitoring restoration trend after the end of land con-ﬁeld should be conducted continuously.

solidation. Unfortunately ﬁshway did not effectively

 Finally, it is hoped that many scientists can share theirwork because of their structure problems. The main

results, valuable experiences and problems collected inproblem is that highly seasonal variation of water level

paddy ﬁeld ecosystems in Korea.

of the river. During the low water level period, this ﬁshway cannot work and thus it is needed to repair. In contrast, small and large pool works well and variousorganisms used those pool throughout the year. Therefore, we concluded that small pools are more efﬁcientapproach than ﬁshway for various kinds of living thingsin land consolidation area. Also ecologists ought to take
into account surrounding environment such as waterlevel, agricultural management system, ﬁshes fauna,
etc. when installing the ﬁshway.

Conclusions
 Rice has been cultivated in ₁₁₄ countries around theworld. Paddy ﬁelds are very important places in various
aspects including society, economy, culture and ecology. Therefore, we must preserve our precious paddy
ﬁeld ecosystems.
 Four approaches including winter-ﬂooding, ﬁshway,

small pool, and environment-friendly land consolida-30

References
Hong SG (₂₀₀₁) Progress of irrigation and drainage in Korean
paddy ﬁeld. In Kwon SK, Choi HC, Chung SO, Kim JC,
Kim TC, Heu MH, Lee BW, Lee KH (eds) Rice Culture in
Asia. Korean National Committee on Irrigated Drainage(KCID), Ansan, pp. ₈₁ – ₁₁₁.
Kim JC, Lee YJ (₂₀₀₁) Overview. In Lee SH, Lee YJ, Park JH(eds) History of Irrigation in Korea. Korean National Committee on Irrigated Drainage (KCID), Ansan, pp. ₁₁ – ₁₅.
KRC (₂₀₁₀) Agricultural production infra improvement project.
In Hong MP (ed) Project Summary of Korea Rural Community Corporation. Korean Rural Community Cooperation(KRC), Seoul, pp. ₉₆ – ₁₀₈.
Lee SK (₂₀₀₁) The public beneﬁts provided by the paddy ﬁeld.
In Chung DK (ed) Paddy a Field for Life. National Agricultural Cooperative Federation, Seoul, pp. ₂₁ – ₄₇.
MIFAFF (₂₀₁₀) Application of restoration items for bio-diversity
enhancement in paddy ﬁeld. In Park HS (ed) A Study on theDevelopment of Ecological Infrastructure to Improve Biodiversity in Paddy Wetlands. Ministry for Food, Agriculture,
Forestry and Fisheries (MIFAFF), Seoul, pp. ₁₂₁ – ₁₈₅.

(Accepted: June ₃₀, ₂₀₁₁)