Chin J Plan Ecolo ›› 2015, Vol. 39 ›› Issue (7): 704-716.DOI: 10.17521/cjpe.2015.0067

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Spatial distribution of species and influencing factors across salt marsh in southern Chongming Dongtan

DING Wen-Hui1, JIANG Jun-Yan1, LI Xiu-Zhen1,*(), HUANG Xing1, LI Xi-Zhi1, ZHOU Yun-Xuan1, TANG Chen-Dong2   

  1. 1State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China
    2Chongming Dongtan National Nature Reserve, Shanghai 202150, China
  • Online:2015-07-01 Published:2015-07-22
  • Contact: Xiu-Zhen LI
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    # Co-first authors

Abstract: Aims The relationship between vegetation structure and environment factors is an important subject in plant ecology. The elevation and soil salinity of the tidal flat are the important factors affecting the vegetation community. Both the elevation and salinity at our sites showed clear gradients. The aims of this study were to: (1) investigate the major species and their distributions in southern Chongming Dongtan; and (2) quantify the two factors that influence the vegetation distribution: elevation and soil salinity. Methods Based on the spatial grid sampling and the spatial interpolation in 2013, we analyzed the distribution of key species as well as their empirical relationships with the environmental factors. Important findings We found that both elevation and soil salinity were significantly different among the vegetation cohorts (p < 0.01). Along the elevation gradient, sedges distributed mainly in the low tidal zone of 2.93-4.07 m, while Gramineae species were found in the middle and high tidal flat (3.13-4.31 m). Soil salinity of the 30 cm surface in Scirpus mariqueter and Spartina alterniflora zone was around (3.2 ± 0.6) g·kg-1, which was significantly higher than that of other groups (2.0 ± 0.3) g·kg-1 (p < 0.01). Scirpus mariqueter, a key and pioneer species at our sites, was mainly found at elevation of 2.53-3.97 m, with 80% of the area overlapping with the habitats of Spartina alterniflora. More than 90% of the Scirpus mariqueter located in the northeast of the study area. The soil salinity of the study site was 1.6-4.5 g·kg-1, with Scirpus mariqueter and Spartina alterniflora showed positive adaptations. Spartina alterniflora replaces Scirpus mariqueter with increasing elevation due to its high competitive ability. The total area of Scirpus mariqueter was 294 hm2, with a dominant area of only 120 hm2. Scirpus mariqueter occupied 15.7% of the sedge dominated area and 6.9% of the total study area, which is the least among six species (Phragmites australis, Imperata cylindrica, Spartina alterniflora, Carex scabrifolia, Scirpus triqueter and Scirpus mariqueter). It is of great challenge to restore and protect this important endemic species.

Key words: East Chongming Island, salt marsh, spatial distribution, tidal flat, elevation, soil salinity, Scirpus mariqueter