Population structure, density and food sources of Terebralia palustris (Potamididae: Gastropoda) in a low intertidal Avicennia marina mangrove stand (Inhaca Island, Mozambique)
Population structure, density and food sources of Terebralia palustris (Potamididae: Gastropoda) in a low intertidal Avicennia marina mangrove stand (Inhaca Island, Mozambique)
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低潮间带白骨壤红树林林地中的 Terebralia palustris（Potamididae：腹足纲）的种群结构、密度和食物来源（莫桑比克伊纳卡岛）
DOI：
10.1016/j.ecss.2009.04.022
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
José Nestor de Paula
中科院分区：
文献类型：
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作者：
Gil Penha;Gil Penha;S. Bouillon;S. Bouillon;P. Mangion;A. Macia;José Nestor de Paula
将沼泽地草的种群结构和分布与莫桑比克南部白骨壤单一物种的微生境内的环境参数进行了比较。对沼泽红藻和潜在食物来源（叶子、气柄附生植物和表面沉积物）进行稳定碳和氮同位素分析，以确定沼泽红藻的摄食偏好。将不同体型和来自不同微生境的个体的稳定同位素特征与当地食物来源进行了比较。相距2.5-10m的表层沉积物样本显示δ13C存在一定的变化（-21.2‰至-23.0‰），这可能是由于海草、微藻和红树林叶子的不同贡献所致，而δ15N值在8.7‰至15.8‰之间变化，表明小尺度微观世界内存在非常高的变异性。在不同微生境中收集的沼泽蠕虫大小类别之间以及相同大小类别的个体之间，稳定同位素特征存在显着差异。结果还表明，较小的个体以沉积物为食，主要选择底栖微藻，而较大的个体以沉积物、附生植物和红树林叶子为食。研究发现环境参数和腹足动物种群结构和分布与不同大小类别和不同微生境中的个体的摄食偏好之间存在相关性。虽然有机含量和叶子的丰度是与腹足动物总密度（>85%）相关性最好的参数，但气孔和叶子的丰度以及颗粒大小与腹足动物大小分布的相关性更好（>65%）。年轻个体（高度<3厘米）主要出现在微生境中，其特征是落叶层和气泡密度低、有机质减少和颗粒尺寸较大，这些是有利于底栖微藻生长的潮间带下部开放区域的特征。随着壳高度的增加，沼泽红藻个体开始占据靠近红树林的微生境，其特点是气孔和枯枝落叶密度大，以及沉积物颗粒较小，导致沉积物中有机物的利用率更高。
Population structure and distribution of Terebralia palustris were compared with the environmental parameters within microhabitats in a monospecific stand of Avicennia marina in southern Mozambique. Stable carbon and nitrogen isotope analyses of T. palustris and potential food sources (leaves, pneumatophore epiphytes, and surface sediments) were examined to establish the feeding preferences of T. palustris. Stable isotope signatures of individuals of different size classes and from different microhabitats were compared with local food sources. Samples of surface sediments 2.5–10m apart showed some variation (−21.2‰ to −23.0‰) in δ13C, probably due to different contributions from seagrasses, microalgae and mangrove leaves, while δ15N values varied between 8.7‰ and 15.8‰, indicating that there is a very high variability within a small-scale microcosm. Stable isotope signatures differed significantly between the T. palustris size classes and between individuals of the same size class, collected in different microhabitats. Results also suggested that smaller individuals feed on sediment, selecting mainly benthic microalgae, while larger individuals feed on sediment, epiphytes and mangrove leaves. Correlations were found between environmental parameters and gastropod population structure and distribution vs. the feeding preferences of individuals of different size classes and in different microhabitats. While organic content and the abundance of leaves were parameters that correlated best with the total density of gastropods (>85%), the abundance of pneumatophores and leaves, as well as grain size, correlated better with the gastropod size distribution (>65%). Young individuals (height<3cm) occur predominantly in microhabitats characterized by a low density of leaf litter and pneumatophores, reduced organic matter and larger grain size, these being characteristic of lower intertidal open areas that favour benthic microalgal growth. With increasing shell height, T. palustris individuals start occupying microhabitats nearer the mangrove trees characterized by large densities of pneumatophores and litter, as well as sediments of smaller grain size, leading to higher organic matter availability in the sediment.