Analysis on Ecological Benefits of Urban Wetlands and Protection Measures with A Case of Nansha Wetland

Zhihao LlN，Yansong PANG，Ruicong XU，Qishuai LlU，Limao HUANG，Yijia LlN，Xilun HAN，Chubin Jl，Jingyong LlUSchool of Environmental Science and Engineering，Guangdong University of Technology，Guangzhou 510006，China

Analysis on Ecological Benefits of Urban Wetlands and Protection Measures with A Case of Nansha Wetland

Zhihao LlN，Yansong PANG*，Ruicong XU，Qishuai LlU，Limao HUANG，Yijia LlN，Xilun HAN，Chubin Jl，Jingyong LlU
School of Environmental Science and Engineering，Guangdong University of Technology，Guangzhou 510006，China

Nansha wetland plays a crucial role in ecological balance of the Pearl River Delta or even Guangzhou.The research，based on researches available，analyzed ecological benefits of Nansha wetland and proposed protection measures in order to better protect urban wetlands and achieve sustainable development of ecological resources of Nansha wetland.

Urban wetland；Nansha district；Ecological benefits；Environment protection

A wetland is one of three important ecosystems on Earth. Specifically，plants and microbes contained in urban wetlands play the role of transforming toxic substances produced from industrial production and household garbage into non-toxic or even beneficial substances.Therefore，wetlands are often referred to as“Earth’s kidneys”and urban wetlands as a“biological supermarket”，providing a special environment for different plants and animals and enriching urban biodiversity. What’s more，wetlands are also considered as a“product treasury”［1］，supplying subsistence and production materials and significantly advancing social and economic development. Nansha wetland is located in the southeast of Guangzhou，a geometric center of the Pearl River Delta，characterized by long sunshine hour and abundant water and heats［2］.Because of special geographical location and climate characters，Nansha wetland plays a key role in improving eco-environment，conserving urban water and protecting biological diversity in the Pearl River Delta，as well as providing entertainment，traveling and resting sites.In addition to that，Nansha wetland is indispensible in scientific research in terms of test materials and base，due to complicated ecosystems，diversified animals and plants，and endangered species.

Ecological Benefits of Nansha Wetland

lntroduction of wetlands

Nanshan district has 53 322 hm2wetlands，representing 89.2%and the wetlands are volatile，dividing into five types and 12 subtypes，accounting for 54% of wetlands in Guangdong Province.According to statistics，marsh plants totals 318 in Nansha wetland，including 26 species pteridophyte of 18 families，4 species gymnosperm of 3families，and288 species angiosperm of 69 families.For example，Cycas revoluta and Glyptostrobus pensilis in the wetland are national grade one protected plants and Cibotium barometz and Nelumbo nucifera are national grade two protected plants.Furthermore，animals are diversified in the wetlands，totaling389 species，without consideration of insects and zooplankter，including 116 commercial fishes，149 birds，67 macrobenthos species，28 species of reptile，16 species of mammal and 13 species of amphibian.In addition to that，Nansha wetland has 16 national key protection animals，55 species under protection of international agreement and convention，as well as 107 species of terrestrial wildlife［3］.Nansha is situated in the Pearl River estuary，where water temperature and salinity are suitable for aquatic animals. Hence，with abundant biological resources，Nansha wetland is a spawning ground as well as a breeding ground.Fishes here involve local species and seasonal fish（Fig.1）.

Huge biological impounding reservoir

Most parts of the Pearl River Delta are tropics in the south of the Tropic of Cancer，with annual mean precipitation of 1 600 mm and even 2 000-2 600 mm in some areas.It is notable that Nansha wetland is of significance for hydrologic features in the Pearl River Delta.

Nansha wetland would store floods in rainy season in soils or surface water，which controls flooding to certain extent.Some would be held for several days and discharged after weeks or months and some would evaporate and permeate［4］.

Additionally，plants in Nanshan wetland would reduce flood rates and balance water amount of rivers.

To control and purify water

Generally speaking，Nansha wetland would remove organic nutrients，inorganic nutrients，toxic pollutants and suspended solids.Therefore，wetlands can be considered as a treatment pond.Furthermore，Nansha wetland has some special properties. For example，after water enters the wetland，the rate slows down dramatically，so that nutrients and suspended substances would sediment on the wetlands.And aerobic process and anaerobic fermentation of wetlands，such as nitrification and chemical deposition，would remove chemicals from water［5］，as well.The high biological production of wetlands directly results in high uptake ratio of nutrients and with plant dead or harvested，the decomposition process proceeds slowly，forming peat to sediment or be transported from the wetlands.It is notable that wetland sediments contain a variety of decomposer and decomposition process，and wetland chemicals would be reduced due to soil-water interface.

Of Nansha wetland，plants grow densely in a large scale，and water depth tends to be volatile，reducing water flow speed and removing toxic substances or nutrients on sediments，which is beneficial for maintaining water quality in communities or downstream areas and preventing floods. Still，it should be recognized that flooding would restore soil nutrients，benefiting agriculture of the wetlands.

To prevent natural destruction and protect river banks from erosion

Plants of Nansha wetland will prevent or reduce erosions on river banks or estuaries，thanks for fixation of root systems and plant piling，and the plants will weaken water hits，intercepting sediments［6］.The test indicated that mangrove forest will prevent tidewater from flowing and reduce water flow speed to just 1/10 of tidewater among forests.

To provide a traveling and entertainment site with aesthetic value

Nansha wetland is abundant with rare species and special landscapes，and the wetland types are multiple. With extensive areas，it brings valuable resting and traveling benefits because of diversified habitats and considerable altitude differences.It is notable that Nansha wetland provides a traveling and entertainment site，making contribution to local and even national economy.Hence，Nansha wetland is of high protection value and important in terms of social significance，which would improve the importance of wetland tourism，advancing Nansha economy.

Still，aesthetic value of Nansha is hard to be described，which is a part of landscape aesthetics.Specifically，a landscape is an integrated content of an area，but wetlands are key content of landscapes，creating diversity and becoming a focus［7］.Tourists require a little reflection at enjoying natural beauty in the context of extensive Nansha wetland，mountains，rivers as well as rare fowls and strange animals（Fig.2）.

To maintain local temperate and humid climate

Wetlands have effects on microclimate.For example，transpiration of the wetland maintains local temperature and precipitation，and rainfalls would return to the atmosphere through forest transpiration.If Nansha wetland is destroyed，local precipitation would decline，which would influence human activities，such as farming.In addition，morning fogs from Nansha wetland would reduce nearby soil water，and increase surrounding temperature and humidity，playing an active role for local residents.

Protection Measures of Wetlands

In this year，Regulations of Nansha District，Guangzhou，was approved by the 10thmeeting of 12thGuangdong NPC Standing Committee，proposing to legalize development and construction of Nansha district in terms of administrative management，planning and construction，cooperation with HK and Macao，eco-environment protection and financial development，and defining to strengthen cooperation in industry development，social administration，comprehensive service，and talents cultivation.

Guangzhou administrative departments and local governments should highlight wetland regulations and formulate complete rules in order to guarantee legalization of wetland protection and sustainable development in Guangzhou.

Based on surveying and monitoring，wetland information system and information base should be constructed，which promotes establishment of long-term management system carrying out of researches［8］.With economy evolvement，wetlands develop prosperously，and the management is challenged，including wetland information management，wetland forest surveying，natural forest protection and prevention of forest disease or pest damages.It is difficult to adapt to modern development just relying on human management and only by information technology to establish information management system could wetland information，such as forests and development，be presented in a more direct way to achieve data visualization，geoanalysis and practical application.

Meanwhile，the administrative departments should construct a database，including biodiversity，communities，physical environment，and chemical environment.It is clear that the construction of database helps information exchanges among wetlands. Still，wetland special committee should conduct different meetings on wetlands and reinforce cooperation at home and abroad，involving plant species，biodiversity protection，and plant diversity in order to share resources，technology and talents.

On the other hand，regular notification and warning are necessary on invaded plants to improve guidance on introduction of local plants and risk evaluation on plant introduction.For administrative departments，research funds can be provided to guarantee the evaluation system on wetland function be constructed， effective monitoring on wetland and protection measures.

Besides，different administrative departments should take part in promoting wetland ecosystem information to improve ecological consciousness of the public and to make contribution to wetland development.At the sametime，the department could build wetland education bases and hold activities of wetland with social organizations，to cultivate more talents for protecting wetlands.

Conclusions

Urban wetlands perform well in adjusting climate，impounding，and balancing runoff water，which is considered as urban biological impounding reservoir capable of degrading and enrich industrial and household pollutants.In future，it is necessary to establish a scientific plan on developing wetland systems and incorporate into urban plan system in order to build a sustainable urban wetland monitoring，evaluation and management system to control pollution or degradation.At the sametime，highlights should be given to the combination of administrative management，law restriction，and market incentives to resolve difficulty in protecting urban wetland and carrying out research of biodiversity protection of wetlands.As for the public，it is of significance to improve the consciousness of wetland protection and strengthen people’s participation and monitoring to establish urban wetland information systems for better management.

Acknowledgement

I would like to express my gratitude to Guangzhou Nansha Wetland Park’s help and supports and social elites in participating the research.

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Responsible editor:Xiaoue WANG

Responsible proofreader:Xiaoyan WU

城市湿地生态效益分析及保护策略——以南沙湿地为例

林志浩，庞衍松*，许锐聪，刘琪帅，黄李茂，林益嘉，韩西伦，纪楚滨，刘敬勇 （广东工业大学环境科学与工程学院，广东广州 510006）

南沙湿地区域对广州乃至珠江三角洲地区的生态平衡起着不可估量的作用。论文在前期考察的基础上，综合分析了南沙湿地生态效益，提出了南沙湿地的保护策略，以期达到保护城市湿地生态环境，实现南沙湿地生态资源可持续发展的目的。

城市湿地；南沙；生态效益；环境保护

广东省大学生创新训练计划项目（201411845073）。

林志浩（1993-），男，广东普宁人，本科在读，环境工程专业，E-mail：740113114@qq.com。*通讯作者，讲师，E-mail：179140290@qq.com。

2015-01-04

2015-02-05

Supported by Guangdong Undergraduate Training Programs for Innovation（201411845073）.

.E-mail:179140290@qq.com

January 4，2014Accepted:February 5，2015