Population structure of the ribbed mussel Geukensia demissa in salt marshes in the southern Gulf of St. Lawrence, Canada
Population structure of the ribbed mussel Geukensia demissa in salt marshes in the southern Gulf of St. Lawrence, Canada
复制标题
加拿大圣劳伦斯湾南部盐沼中肋贻贝 Geukensia demissa 的种群结构
DOI：
--
复制
发表时间：
2011
影响因子：
--
通讯作者：
Caroline M. Longtin
中科院分区：
文献类型：
--
作者：
C. Watt;D. Garbary;Caroline M. Longtin
罗纹贻贝（Geukensia demissa）高度依赖绳草互花米草（Spartina alterniflora）来改善环境压力并稳定基质。互花米草 (Spartina alterniflora) 是沼泽地的基础物种，而米草 (G. demissa) 通常与绳草床相关。圣劳伦斯湾南部的沼泽正在经历侵蚀和退化，这可能是由于海平面上升导致盐分暴露增加并对互花米草产生负面影响。在加拿大新斯科舍省圣劳伦斯湾南部六个河口的九个地点对罗氏贻贝（Geukensia demissa）的种群结构进行了研究，该地区正在发生沼泽退化。在以互花米草密度和海拔为特征的三个盐沼区域中，用贻贝长度作为 G. demissa 年龄的代表：(1) 一个较低的区域，其中互花米草已死亡，但基底垫是连贯的；(2) 一个活的区域，但位于活沼泽边缘的低密度互花米草；(3) 距离盐沼一到三米的密集互花米草区域。 边缘。九个地点中的七个地点的三个区域的贻贝长度显着不同。平均长度随着海拔的增加而减小，并且七个地点没有小贻贝（即 1-3 厘米）。最小的贻贝出现在茂密的互花相思藻区，在沼泽地的较高处。西部两个地点的贻贝长度在不同区域之间没有差异，并且存在小贻贝（即 1-3 厘米），但很少见。九个地点中有七个没有小贻贝，而其余地点的大小频率分布表明，近期缺乏补充，对 G. demissa 的生存构成长期威胁。盐沼退化和互花米莎的死亡对 G. demissa 的补充产生了负面影响，种群数量明显下降。
The ribbed mussel, Geukensia demissa, is highly dependent on the cordgrass Spartina alterniflora for amelioration from environmental stress and substrate stabilization. Spartina alterniflora is a foundation species in marshes, and G. demissa is typically associated with cordgrass beds. Marshes in the southern Gulf of St. Lawrence are experiencing erosion and degradation, presumably as a result of increases in sea level, which increases salinity exposure and negatively impacts S. alterniflora. The population structure of the ribbed mussel, Geukensia demissa, was studied at nine sites in six estuaries in the southern Gulf of St. Lawrence in Nova Scotia, Canada, where marsh degradation is occurring. Mussel length was used as a proxy for age of G. demissa in three salt marsh zones characterized by density and elevation of Spartina alterniflora: (1) a lower zone in which the S. alterniflora was dead, but where the basal mat was coherent, (2) a zone of living, but low density S. alterniflora at the margin of the living marsh, and (3) a zone of dense S. alterniflora one to three meters back from the edge. Mussel length was significantly different across the three zones in seven of the nine sites. Mean length decreased as elevation increased, and small mussels (i.e., 1–3 cm) were absent at seven sites. The smallest mussels occurred in the dense S. alterniflora zone, higher in the marsh. Mussel length in the two western sites did not differ between zones, and small mussels (i.e., 1–3 cm) were present, but rare. The absence of small mussels in seven of the nine sites, and the size frequency distribution at remaining sites, suggests a lack of recent recruitment and a long-term threat to the survival of G. demissa. Salt marsh degradation and the death of S. alterniflora have negatively impacted G. demissa recruitment, and population decline is evident.