• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Aquatic Sciences >Cichlid species diversity in naturally and anthropogenically turbid habitats of Lake Victoria, East Africa
【24h】

Cichlid species diversity in naturally and anthropogenically turbid habitats of Lake Victoria, East Africa

机译：东非维多利亚湖自然和人为混浊生境中的丽鱼科动物物种多样性

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

During the past decades, major anthropogenic environmental changes occurred in Lake Victoria, including increased predation pressure due to Nile perch introduction, and decreases in water transparency and dissolved oxygen concentrations due to eutrophication. This resulted in a collapse of the haplochromine cichlids in the sub-littoral waters of the Mwanza Gulf in 1986-1990, followed by a recovery of some species in the 1990s and 2000s, when Nile perch densities declined. We studied two data sets: (1) haplochromines from sand and mud bottoms in the pre-collapse period; (2) haplochromines from sub-littoral areas during the pre-collapse, collapse and recovery periods. Water over mud is murkier and poorer in oxygen than water over sand, and differences in haplochromine communities in these natural habitats during the pre-collapse period may predict the effects of anthropogenic eutrophication during the collapse and recovery periods. In the pre-collapse period, haplochromine densities over sand and mud did not differ, but species richness over sand was 1.6 times higher than over mud bottoms. Orange- and white-blotched colour morphs were most common at the shallowest sand station. More specifically, insectivores and mollusc-shellers had higher numbers of species over sand than over mud, whereas for mollusc-crushers no difference was found. Laboratory experiments revealed that mollusc shelling was more affected by decreased light intensities than mollusc crushing. During the pre-collapse period, spawning occurred year-round in shallow areas with hard substrates and relatively clear water. In deeper areas with mud bottoms, spawning mainly occurred during months in which water clarity was high. No effects of hypoxia on spawning periods were found. It follows that clearer water seems to support differentiation in feeding techniques as well as year-round spawning, and both may facilitate species coexistence. Water clarity is also known to be important for mate choice. These observations may explain why, since the decline of Nile perch, haplochromine densities have recovered, the numbers of hybrids increased and species diversity in the current eutrophic sub-littoral waters has remained 70 % lower than before the environmental changes.
机译：在过去的几十年中，维多利亚湖发生了重大的人为环境变化，包括由于引入尼罗河鲈引起的捕食压力增加，以及由于富营养化导致水的透明度和溶解氧浓度降低。这导致1986-1990年Mwanza海湾近沿海水域中的单倍铬丽鱼丽鱼科动物崩溃，随后在1990年代和2000年代尼罗河鲈密度下降时某些物种恢复。我们研究了两个数据集：（1）塌陷前来自沙子和泥浆底部的单倍铬碱； （2）在崩塌前，崩塌和恢复期，来自滨海次区域的单倍铬碱。泥土上的水比沙子上的水更暗淡，氧气更贫乏，并且在崩塌前这些自然生境中单倍铬碱群落的差异可以预测在倒塌和恢复期间人为富营养化的影响。在崩塌前期，沙子和泥浆上的单倍铬碱密度没有变化，但沙子上的物种丰富度是泥浆底下的1.6倍。橙色和白色斑点的颜色变形在最浅的砂站最常见。更具体地说，食虫和软体动物脱壳者在沙上的物种数量多于在泥土之上的物种，而对于软体破碎机，没有发现差异。实验室实验表明，比软体动物破碎更容易受到光强度降低的影响。在崩塌前期，产卵整年发生在具有坚硬底物和相对清澈水的浅层地区。在底部有泥浆的较深地区，产卵主要发生在水透明度高的月份。未发现缺氧对产卵期的影响。因此，更清澈的水似乎支持饲养技术以及全年产卵的分化，并且两者都可以促进物种共存。已知水的透明度对于选择配偶也很重要。这些观察结果可以解释为什么自尼罗河鲈下降以来，单倍铬素密度得以恢复，杂种数量增加，而目前富营养化的沿海近岸水域的物种多样性仍然比环境变化之前低70％。

著录项

  • 来源
    《Aquatic Sciences》 |2013年第2期|169-183|共15页
  • 作者

    Frans Witte; Ole Seehausen; Jan H. Wanink; Mary A. Kishe-Machumu; Marjolein Rensing; Tijs Goldschmidt;

  • 作者单位

    Institute of Biology Leiden, University of Leiden,P.O. Box 9505, 2300 RA Leiden, The Netherlands,Netherlands Centre for Biodiversity, Naturalis,P.O. Box 9517, 2300 RA Leiden, The Netherlands;

    Department of Aquatic Ecology and Evolution, Institute of Ecology and Evolution, University of Bern,Baltzerstrasse 6, 3012 Bern, Switzerland,EAWAG Centre for Ecology, Evolution and Biogeochemistry,Seestrasse 79, 6047 Kastanienbaum, Switzerland;

    Institute of Biology Leiden, University of Leiden,P.O. Box 9505, 2300 RA Leiden, The Netherlands,Koeman en Bijkerk bv, Ecological Research and Consultancy,P.O. Box 111, 9750 AC Haren, The Netherlands;

    Institute of Biology Leiden, University of Leiden,P.O. Box 9505, 2300 RA Leiden, The Netherlands,Tanzania Fisheries Research Institute, Dar es Salaam Center,P.O. Box 78850, Dar es Salaam, Tanzania;

    Institute of Biology Leiden, University of Leiden,P.O. Box 9505, 2300 RA Leiden, The Netherlands;

    Institute of Biology Leiden, University of Leiden,P.O. Box 9505, 2300 RA Leiden, The Netherlands;

  • 收录信息 美国《科学引文索引》(SCI);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

    dissolved oxygen concentrations; eutrophication; haplochromine cichlids; light conditions; molluscivores; spawning periods;

    机译：溶解氧浓度;富营养化单倍铬碱丽鱼科鱼;光照条件;软体动物产卵期;

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号