Table of Content

08 March 2006, Volume 25 Issue 03

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Articles

Fluctuation of Acer truncatum sap flow in rapid growth season and relevant variables

WANG Ruihui^1，2;MA Luyi¹;XI Ruchun¹;XU Junliang¹

2006, 25(03):  231-237 . 

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By using auto-data collection system with thermal dissipation sap flow probe,and meteorological,soil and Licor6400 photosynthesis sensors,this paper measured the fluctuations of Acer truncatum sap flow and leaf transpiration in summer and autumn in the West Mountains of Beijing.The fluctuation of sap wood flow was affected by weather.Environmental stress or improvement altered the characters of sap flow wave motion.The daily course of sap flow showed a singlepeaked curve in clear days,i.e.,increased sharply after sunrise,reached the peak around noon,went down then,and reached the valley in next early morning.The starting time of sap flow and the appearing time of valley were 1-4 hours earlier in July than in other months.In June,the sap flow velocity (SFV) of upper trunk was apparently higher than that of middle and lower trunks,whereas in other months,the SFV of lower trunk was higher than that of upper and middle trunks.The difference was 2-3 times in July.Multiple regression analysis showed that SFV was deeply affected by environmental factors,e.g.,air temperature,solar radiation,air humidity,soil temperature and wind speed in the whole growth season,but the main affecting factors were differed with observation period and position,and only atmospheric temperature was always important.The fluctuation of sap flow could better explain the ecological strategy of A.truncatum to drought tolerance.

Neural network model for leaf chlorophyll content of roadside trees based on hyperspectral approaches

LIU Dianwei^1,2;SONG Kaishan²;ZHANG Bai²

2006, 25(03):  238-242 . 

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This paper compared the changes of leaf chlorophyll content between roadside trees affected by urban communication environment and corresponding trees growing in a less polluted environment—Jingyue National Forest Park,with the hyperspectral data of leaf samples obtained by using ASD Field NVIR Spectroradiometer.The results showed that urban communication environment had a strong effect on the chlorophyll content of roadside tree leaves,and deciduous tree leaves had more intensive response than conifers tree leaves.The hyperspectral reflectance of roadside tree leaves had a close relation with the chlorophyll content,and the relationship varied with wavelength.At 740～760 nm,the correlation coefficient was >0.72.PSSR (pigment specific simple ratio) index had a close relation with chlorophyll content,and a power regression model was established,with the determination coefficient around 0.82.BP (back propagation) neural network showed a more promising potential for predicting the tree leaf chlorophyll content with hyperspectral reflectance data,and the determination coefficient was >0.97.It was suggested that hyperspectral reflectance data could be used to detect the change of roadside tree leaf chlorophyll content caused by urban communication environment.

Rehabilitation of desertified lands in western Horqin steppe

JIANG Deming¹;ZONG Wenjun^1,2;LI Xiaolan^1,2;LIU Zhimin¹;YAN Qiaoling^1,2;HE Shanfeng^1,2

2006, 25(03):  243-248 . 

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This paper assessed the droughtresisting capacity of Artemisia halodendron,Caragana microphylla,Amorpha fruticosa and Lespedeza bicolor in western Horqin steppe,and approached the rehabilitation of desertified lands there.The results showed that A.halodedron and C.microphylla were more drought-resistant than A.fruticosa and L.bicolor.The application of waterconserving agent,solid water and film cover could increase the survival rate of planted trees by 10%-30%.1.0 m × 1.0 m straw checkboard was appropriate in the local sand-stabilization practice,with the consideration of sandstabilizing effects and cost.The combination of both mechanical and biological measurements could stabilize the sand dune in 2-3 years if sand binder was appropriate.Building enclosure,supplementary sowing,ploughharrowing,and applying fertilizer and soil-improving agent could ameliorate the degraded grassland,and raise the production by 2-4 times.Nitrogen fertilizer could raise the protein content of herbage.After the improvement of degraded grassland,an evident change in soil enzyme activities was detected,showing a good soil condition being built.

Dynamic changes of mire landscape in Northeast China

YAN Denghua¹;WANG Hao¹;HE Yan²;ZHANG Xuexia³;LU Fan¹

2006, 25(03):  249-254 . 

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With GIS and RS techniques,this paper analyzed the dynamic changes of mire landscape in Northeast China during 1986～2000.Northeast China is rich in mire,and the average mire ratio (the ratio of mire area to the total statistical area) is 3.66%.But,the distribution of the mire is not symmetrical,e.g.,Wusuli region has the largest mire ratio,while Suifenhe region has the least one.The mire in Northeast China has a shrinking trend,and its distribution center is to the northeast of the geometrical center,with the distance of 150.62 km,which reflects that the holistic state of the mire distribution is richer in northern part and less in southern part.The yearly change of the distribution center showed that the disturbance intensity was lighter in 1986-1996 than in 1996-2000,and the transfer of distribution center was differed with each sub-region in Northeast China.As for the transformation of the landscapes,the dynamic change of the mire is strongly affected by the agricultural activities including pasturing.The multi-year average patch area is 1.99 km²,and has an increasing trend.The fractal index of mire landscape showed an increasing trend,and the patch shape of the mire became more and more complicated.

eavy metals accumulation in mining area’s Miscanthus sinensis populations and its relationship with soil characters

LI Qinfen¹;DU Weibing³;LI Zhi’an³;WANG Zhengfeng³;PENG Shaolin^2,3

2006, 25(03):  255-258 . 

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This paper studied the heavy metals accumulation in Miscanthus sinensis populations which experienced different intensity and duration of pollution in a multiple heavy metal mining area.The results showed that the accumulation of Pb,Cd,Cu and Zn in M.sinensis was in the order of root > leaf > stalk.The average accumulation of Pb and Cd in M.sinensis was significantly correlated with the contents of the two metals in soil (P<0.05),but that of Cu and Zn did not show such a trend because the contents of the two metals in soil were higher than their maximum accumulation in M.sinensis,indicating that the contents of soil Cu and Zn were the main stress factor to M.sinensis.The absorptivity of Pb,Zn and Cu by M.sinensis increased with soil pH,but in the soils with same pH,the absorptivity was affected by the contents of these three metals in soil.As a whole,M.sinensis was a multiple heavy metals-tolerant species,and its tolerance to the four metals was in the order of Cd < Cu < Pb-Zn.

Changes of steppe ecosystem service values in Xilingol Biosphere Reserve of Inner Mongolia,China

TONG Chuan^1,2;LI Rong²;YONG Shipeng²

2006, 25(03):  259-264 . 

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Grassland ecosystem is the largest terrestrial ecosystem in China,and plays an important role in maintaining the ecological safety of Northern China.In this paper,the maps of steppe degradation in the Xilingol Biosphere Reserve of Inner Mongolia in 1985 and 1999 were drafted,based on remote sensing data and field survey.The changes of steppe ecosystem values were estimated by selecting the ecosystem functions such as soil erosion control,soil nutrient maintaining,nutrient cycling,C storage,and O₂ production.The total valuation of the steppe ecosystem services in 1987 and 1999 was 28.24×10⁸ Yuan RMB and 26.75×10⁸ Yuan RMB,respectively,with a decrease of 5.28%,while the valuation of the steppe ecosystem services per unit area in 1987 and 1999 was 2.99×10³ Yuan RMB·hm^-2 and 2.83×10³ Yuan RMB·hm^-2,respectively,with a decrease of 5.35%.The results indicated that owing to over-grazing,the steppe became more and more degraded,and the functions and ecosystem services of the steppe were also decreased.To restore the degraded steppe,keeping the densities of human and livestock under the carrying capacity of the steppe region should be the most essential solution.

Removal of nitrogen and phosphorus by integrated subsurface flowupward vertical flow constructed wetland process

TIE Jingxi;ZHENG Zheng;ZHONG Yun;Luo Xingzhang;WANG Yong;KONG Gang;YU Xin

2006, 25(03):  265-269 . 

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This paper studied the removal effects of NH₄⁺-N,NO₃^--N,TN and TP by the integrated subsurface flow-upward vertical flow constructed wetland process.When the treatment loading was 30 L·d^-1 and the calculated hydraulic retention time (HRT) was 4.8 days,the process had good removals of NH₄⁺-N,NO₃^--N,TN and TP,and the average removals were 95%,52%,79%,81%,respectively.According to the operating time,the removal efficiency of the three nitrides could be divided into two phases,with the corresponding removals of NH₄⁺-N,NO₃^--N,TN being 93% and 99%,35% and 98%,and 71% and 98%,respectively,while the removal efficiency of TP was kept stable during the experiment.

Dynamics of rotifer and crustacean zooplankton in a newly constructed reservoir

LIN Qiuqi;ZHAO Shuai ying;HAN Boping

2006, 25(03):  270-276 . 

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In 2000-2003,an investigation was made on the dynamics of rotifer and crustacean zooplankton in the Feilaixia Reservoir which was constructed in 1999.Sixty-eight species of rotifera,18 species of cladocera,and 13 species of copepoda were observed.The abundance of rotifera,cladocera and copepoda was 0.2-88.6,01-13 and 0.4-13.8 ind·L^-1，respectively,with the peak occurred in March 2002,the fourth year after filling.When the filling started,rotifera was dominated firstly by Keratella cochlearis,and then by Synchaeta pectinata whose population size increased rapidly in March,2002.Since then,as the population of S.pectinata decreased,K.cochlearis became the dominant species.Diaphanosoma brachyurum and Bosmina longirostris were the alternate dominant cladoceran species at first,while B.longirostris became the predominant one after August 2001.As for copepoda,nauplii and copepodites,their young ones were often much more abundant than the adults.During investigation,the water retention time was less than 14 days,and the high flushing rate made the zooplankton abundance in the reservoir very low.The temporal variation of rotifera,cladocera and copepoda was primarily affected by water retention time.There was little evidence for the regulation of zooplankton’s temporal fluctuation by the changes in food quantity or quality.Only S.pectinata and B.longirostris had a strong positive correlation with chlorophyll a.In 2002,the year with the longest water retention time (14 days) and relatively rich food,the populations of S.pectinata and B.longirostris increased rapidly,and the ‘upsurge’ of zooplankton abundance was observed.

Phenological responses of Leymus chinesis to climate factors

LI Rongping¹;ZHOU Guangsheng¹;WANG Yuhui¹;HAN Xi²

2006, 25(03):  277-280 . 

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This paper studied the phenological characters of Leymus chinensis,a dominant species in Inner Mongolia steppe,and its responses to climate factors.The results showed that the leafing of L.chinensis was significantly correlated with the average temperature from March to April,and would be advanced by 4.35 days when the temperature raised 1 ℃.Leaf coloring had a significant correlation with sunlight hours.With increasing sunlight hours,the leafing date of L.chinensis would be deferred,while the coloring date would be advanced.The growth season length of L.chinensis was closely correlated with the average wind speed from April to October.The stronger the average wind speed,the longer the growth season.

Effects of intercropping white clover in tea plantation on soil environment in subtropical hilly region

SONG Tongqing¹;XIAO Runlin¹;PENG Wanxia^1,2;WANG Jiurong¹;LI Shenghua³;LIU Xiaofei²

2006, 25(03):  281-285 . 

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This paper investigated the effects of four years intercropping white clover in a one-year old tea plantation on soil environment,and tea yield and quality in subtropical hilly region.The results showed that intercropping white clover decreased soil bulk density,increased soil porosity and the contents of soil organic matter,total nitrogen,available nitrogen and available potassium,and partly consumed soil organic phosphorous.It increased the moisture content in key soil layer (0～20 cm) during key time (April-June),and also,postponed and shortened the period of high temperature in summer and the continual drought in autumn.Intercropping showed duplex effects of raising and keeping temperature at cold time while lowering temperature during hot season,making the temperature of same soil layer more stable.Intercropping also postponed the coming of high and low temperature,shortened the duration of extreme high temperature,lightened the effects of high temperature on tea tree growth,and thus,boosted the growth of tea tree,and improved the tea yield and quality.Compared to single-cropping,intercropping decreased the ratio of polyphenol to amino acid in spring and autumn tea by 17.10% and 30.90%,respectively, and increased the tea yield by 32.65%.

Faunal composition of grasshopper in different habitats of Northeast China

SUN Xiaoling^1,2;REN Bingzhong³;ZHAO Zhuo²;GAO Changqi⁴;ZHOU Guangping⁵

2006, 25(03):  286-289 . 

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Based on our investigation and relevant references,a total of 107 species of grasshopper,belonging to 7 families and 39 genera,was recorded in 8 sampling sites of Northeast China.The analysis of grasshopper community structure,faunal composition,and geographical distribution suggested that Palaearctic species were dominant in Northeast China,occupying 87.85% of the total.In the 8 types of habitats,Changbai Mountain had the most abundant faunal composition of grasshopper,whereas Xianghai Natural Reserve had the least one.Compared to other habitats,Xianghai Natural Reserve had a lower similarity index.

haracteristics of water consumption and utilization of Populus alba×berolinensis under water stress

LIU Dan^1，2;CHEN Xiangwei^1，3

2006, 25(03):  290-294 . 

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Employing LI-6400 photosynthesis system (LI-COR,1995,USA),this paper studied the gas exchange,water consumption,and water use efficiency of Populus alba×berolinensis seedlings under different water supply.The results showed that among test environmental factors,soil moisture content was the dominant one affecting seedlings transpiration.The water consumption of the seedlings decreased with increasing drought stress,but the effects of meteorological factors were not obvious when soil moisture content was lower than 50% of field capacity.P.alba×berolinensis seedlings could grow well when soil moisture content was higher than 70% of field capacity.

Interspecific correlations among dominant populations of ligneous species in Mianshan Mountain of Shanxi

ZHANG Guiping^1,2;ZHANG Feng1,3;RU Wenming^1,2

2006, 25(03):  295-298 . 

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The study on the interspecific correlations among 210 species-pairs of 21 dominant populations of ligneous species showed that 109,87 and 99 species-pairs were positively correlated,while 101,122 and 111 speciespairs had negative correlations,and the ratios of positive and negative correlations were 1.08,0.71 and 0.89,based on χ² test for 2×2 contingency table,Pearson correlation coefficient test,and Spearman rank correlation coefficient test,respectively.According to the adaptability to the environment and the relationships between plants and environment,21 species were divided into two ecological species groups,i.e.,light-favoring and shade-tolerant plants.Compared with Pearson correlation coefficient test,Spearman rank correlation coefficient test was more sensitive.A positive association and correlation occurred between the species having similar biological traits,e.g.,the ecological adaptability to similar habitats and the overlapping niches in some degree,while the negative association and correlation occurred between the species having different biological features,e.g.,different adaptability to habits or segregated niches in some degree.

Effects of liquid film mulching on cotton root growth and development

YANG Qinghua;HUANG Yong;MA Erpei

2006, 25(03):  299-302 . 

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Based on the theory of sustainable development of cotton field,effects of liquid film mulching on the growth and development of cotton roots were observed by with the methods of ninhydrin and molybdenum blue,and bidirectional soil section slicing,respectively.The study showed that mulching could quicken the growth and development of cotton roots during early growth period,which reflected in the enhanced root vigor and the root dry weight per plant.However,mulching was disadvantageous for cotton roots to penetrate into deep soil layers,and deep roots decreased quickly.Compared with plastic film mulching,liquid film mulching obviously increased the absorption and synthetic ability of cotton roots during whole growth period.The distribution of root systems in soil was comparatively reasonable,and deep roots decreased slowly,which contributed to the proportional development of cotton plants,and prevented cotton plants from pre-mature senescence.It was suggested that the application of liquid film could be a feasible technique in cotton cultivation practice.

Carbon storage loss during land readjustment and optimization of ecological compensation

ZHONG Xuebin^1,2;YU Guangming¹;HE Guosong²;LUdi¹

2006, 25(03):  303-308 . 

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Land readjustment could change the structure of land use,and destroy the balance of ecosystem carbon cycle.In the period and after a definite time of land readjustment,the carbon storage in agricultural ecosystem would be decreased,making the ecosystem turn from carbon sink to carbon source.Based on the estimation of the ecosystem carbon storage in Cuiyuan village of Jingmen City,and with a linear programming model,this paper approached the optimal structure of land use for the land readjustment in the study area,which could compensate the ecosystem carbon storage loss.The results showed that an increment of cultivated area to 11.96% of the total area should be the maximization to meet the needs of building road system,irrigation system,and housing estate.To make the balance of ecosystem carbon cycle,artificial forest area should be increased by 3.90 hm².

Dynamic research on regional grain safety

CHEN Xiuduan¹;REN Zhiyuan²

2006, 25(03):  309-313 . 

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Grain safety research is important for the development of an area.Since the seventies of last century,related researches have been made by the specialists in different domains of science both at home and abroad,from different points of view and with case studies in some regions.In this paper,the grain safety was analyzed from the aspects of quantity,quality and sustainable development,and a case study was made in the Baota District of Yan’an,a hilly and gully area of the Loess Plateau.The results showed that the grain production of this District could not fully meet the welltodo requirement 400 kg per capita,especially under the conditions of increasing cultivated area run-off and grain-dependent animals breeding,which made the grain safety more important.As for grain quality,this district was relatively safe because of less harmful substance in grain.But,due to the fact that it is in the suburb of Yan’an,this district is under greater pressure of limited cultivated land,and thus,it is essential to improve its land-use structure,promote science and technology level,or purchase grain from other places to meet local demands.

Transgenic organisms and biosafety

WANG Jialian^1，2

2006, 25(03):  314-317 . 

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Since 1970s,transgenic technology,a representative of modern biotechnology,has played an important role in solving food shortage and environmental pollution,and being developed into a powerful modern biotechnological industry.With the appearance of various kinds of transgenic organisms and the continual coming into market of their products,biosafety has become the focus of public concerns.This paper analyzed the possible negative effects of transgenic organisms on biodiversity,environment and human health,summarized the present situations about the management of transgenic organisms’ safety at home and abroad,and put forward the strategies to reinforce the management of transgenic organisms’ safety.

Research advance in photodegradation of organic pollutants in surface soil

ZHANG Lihong^1,2,3;LI Peijun¹;LI Xuemei⁴;GONG Zongqiang¹;ZHANG Hairong¹;XU Huaxia¹

2006, 25(03):  318-322 . 

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Soil is an important medium in which various organic pollutants can exist,while photodegradation is an effective abiotic transformation means for organic pollutants in surface soil.To better understand the environmental behaviors of soil-bound pollutants,it is meaningful to investigate the photodegradation of organic pollutants in surface soil.Many researches on this aspect have been made since 1990s.This paper discussed the effects of soil factors,e.g.,composition,texture,moisture,pH,and depth on photodegradation,and described the methods and dynamic models applied in photodegradation researches,e.g.,direct photodegradation of organic compounds in surface soil,photodegradation of organic compounds in soil solution,and solvent washing and subsequent photodegradation.The photodegradation of pesticides and other organic pollutants in soil was also reviewed,and the prospects of future research were analyzed.

Conservation countermeasures on rare and endangered plant resources in Three Gorges Reservoir Area

ZHAI Hongbo;ZHAO Yiting;WEI Xiaoxia

2006, 25(03):  323-326 . 

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This paper analyzed the present situation of rare and endangered plant resources in Three Gorges Reservoir Area,and aimed at the ecological and social problems faced with,put forward corresponding conservation countermeasures,which included moving the rare and endangered plants to another places,strengthening the protection of germ plasm resources,establishing special and general nature reserves,constituting monitoring system on the rare and special plant resources,enhancing scientific research,propaganda and education,reserving the existed environment of rare and endangered plants,and restoring vegetation.

Research advances in arbuscular mycorrhizal fungi-legumes-rhizobia symbiosis

ZHAO Dandan;LI Tao;ZHAO Zhiwei

2006, 25(03):  327-333 . 

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The symbiosis formed by arbuscular mycorrhizal fungi,rhizobia and legumes is a special association in plant-microbe symbiosis.In this paper,the research advances in the nutritional relationships between microorganisms and plants,effects of co-inoculation with rhizobia and arbuscular mycorrhizal fungi on legumes,factors affecting the effectiveness of the co-inoculation,and molecular interactions in arbuscular mycorrhizal fungi-legumes-rhizobia symbiosis were reviewed,and the problems needed to be further studied as well as the prospects of basic research and application of this symbiosis were discussed.

Ecological footprint model and its research advances

LIU Miao^1,2;HU Yuanman¹;LI Yuehui¹;CHANG Yu¹;ZHANG Wei^1,2

2006, 25(03):  334-339 . 

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This paper introduced the calculation methods of ecological footprint,and reviewed the research advances in ecological footprint at home and abroad,with the focus on energy footprint calculation.At present,the study of ecological footprint at abroad was centralized on the long time series calculation and analysis and the improvement of calculation method,and based on these,an improved ecological footprint method,“actual land demand” method,was submitted.In China,the work was more defined to the case studies of ecological footprint.In this review,the advantages and disadvantages of ecological footprint methods were also discussed,and the future research directions of ecological footprint were put forward.

Effects of soil sterilization on preventing continuous pepper cropping obstacles

HOU Yongxia¹;ZHOU Baoli¹;WU Xiaoling¹;FU Yawen¹;WANG Yueying²

2006, 25(03):  340-342 . 

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By using soil sterilization,this paper studied the effects of biotic factors on the growth and development of three years continuously cropped pepper and its active oxygen scavenging enzyme activities,and approached the effects of soil sterilization on preventing continuous pepper cropping obstacles.The results showed that the pepper plant height,stem diameter,leaf area,chlorophyll content,fresh weight of aboveground part and roots,and root vigor were higher in sterilized than in non-sterilized treatment,while the activities of superoxide dismutase (SOD) and peroxidase (POD) were declined,which indicated that soil sterilization improved plant haleness,but reduced the activities of active oxygen scavenging enzymes.Compared with monoculture soil treatment,the haleness of pepper plant was significantly poorer,and the activities of SOD and POD were higher.It was possible that soil sterilization could effectively overcome the barrier caused by harmful microbes,but not hurdle the barrier caused by allelochemicals.

etland ecosystem in Xiushan Island of Zhejiang Province

ZHAO Shujiang^1,2;LIANG Bing²;ZHANG Shuyi²

2006, 25(03):  343-346 . 

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Xiushan Island is located in the Zhoushan Fishery waters of East China Sea,which has a vast stretch of wetlands.The nearshore or around- shore parts of the wetlands,with peculiar island characteristics,are tightly associated with the living resources,especially fishery resources of Zhoushan Fishery waters.The peculiar ecological properties of the wetlands are characterized by particular island position.There is a high biodiversity of plants and animals in the wetlands,including over 300 species of plants and 108 species of birds (belonging to 26 families),such as oriental white stork (Ixobrychus minutus),known as the first class national protected animal,and swine hoe (Hydropotes inermis),known as the second class national protected animal.Xiushan wetlands comprise several tightly connected parts with different ecological functions,i.e.,subtidal zone wetland (shallow bay),intertidal zone wetland (mud,reed marshes),upper tidal zone (salty marsh,marsh),and degenerated wetland (salt field,culture pond,paddy field).As less attention was paid in the past,serious fragmentation took place in the wetland ecosystems.Recently,a natural protected area of the wetlands was constructed in Xiushan Island,and the wetland ecosystems have gained preliminary protection.