• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >Foraging ecology, bioenergetics and predatory impact of breeding double-crested cormorants (Phalacrocorax auritus) in the Beaver Archipelago, Northern Lake Michigan.
【24h】

Foraging ecology, bioenergetics and predatory impact of breeding double-crested cormorants (Phalacrocorax auritus) in the Beaver Archipelago, Northern Lake Michigan.

机译：在北密歇根州海狸群岛觅食双冠mor（Ph）的生态，生物能和捕食性影响。

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

As Double-crested Cormorant (Phalacrocorax auritus) populations have increased throughout the Great Lakes, many sport and commercial fish populations have declined. A high density of birds combined with their fish eating habits has led to their implication in these declines. From 1999 through 2002, a Smallmouth Bass (Micropterus dolomieui) population study was rekindled after a twenty plus year hiatus in the Beaver Archipelago. This work documents an intensive study on the population dynamics and foraging ecology of breeding cormorants of the same area between 2000 and 2004. The population size of breeding birds, well as their reproductive output, was estimated and the diet of birds was determined using regurgitates and the stomachs of harvested birds. Pellets were not used in analysis because they did not provide reliable quantitative data regarding bird diet. Breeding population size, as well as reproductive output, appears to vary substantially from year to year, and may be linked to the availability of alewife (Alosa pseudoharengus ). Breeding bird diet consists primarily of species of little commercial or sport value; the importance of individual prey species in bird diet varies temporally and spatially.; To determine important foraging areas, VHF radio telemetry was used to track the foraging activities of ten cormorants. Using triangulation, birds were monitored from both land and water daily, weather permitting, throughout the breeding season. In addition, rafting locations of cormorants were documented by boat survey throughout the breeding season. Radiotelemetery indicated that cormorants typically foraged 2.5 km for away from the colony, at the northeastern end of Beaver Island. This area overlaps with the area determined by rafting locations, however the latter were centered further south. Neither area overlaps with known bass habitat.; Colonial waterbirds are an important component of Great Lakes ecosystems. One important aspect is the role of these birds as top predators in aquatic food webs. In order to investigate this role, bioenergetics models, using allometric equations, were applied to breeding cormorants and their offspring in the study area. The models estimated the total prey biomass consumed as 1444.11 tonnes of prey in 2000, and 1586.17 tonnes of prey in 2001. Each year the majority of the prey biomass was aewife, with these fish comprising a greater percentage of prey biomass in 2001.; In addition, two types of simulation models, Rebuild and Forecast, to investigate a possible connection between the declining bass populations and the avian predators. Rebuild models indicate that is was unlikely that cormorants alone caused the observed bass decline; birds may have contributed to the decline in synergism with low recruitment, angling mortality or other factors. Forecast models suggest that direct cormorant predation on bass is not currently the leading factor limiting the bass population size in the region, even if bass are experiencing relatively low recruitment. Combined with the data collected on bird diet, foraging locations and bioenergetics, these models enhance our understanding of the relationships between cormorants and fish populations in the study area and may benefit fisheries managers in other systems.
机译：随着整个大湖地区双冠Cor（Ph）种群的增加，许多体育和商业鱼类的种群减少了。高密度的鸟类及其鱼类的饮食习惯导致了它们的减少。从1999年到2002年，在海狸群岛（Beaver Archipelago）中断了20多年之后，重新点燃了Smallmouth Bass（Micropterus dolomieui）种群研究。这项工作对2000年至2004年同一地区的繁殖breed的种群动态和觅食生态进行了深入研究。估算了繁殖鸟的种群规模及其繁殖产量，并使用反刍动物和鸟类确定了它们的饮食。收获的鸟类的肚子。由于未提供关于鸟类饮食的可靠定量数据，因此未在分析中使用药丸。繁殖种群的数量以及生殖产量似乎每年都存在很大差异，并且可能与alewife（Alosa pseudoharengus）的可用性有关。繁殖鸟类的饮食主要由商业价值或体育价值低的物种组成；鸟类饮食中单个猎物物种的重要性随时间和空间而变化。为了确定重要的觅食区域，使用了VHF无线电遥测技术来跟踪十只cor的觅食活动。在整个繁殖季节，在天气允许的情况下，每天使用三角测量法从陆地和水域监测鸟类。此外，在整个繁殖季节，通过船只调查记录了ants的漂流位置。无线电遥测表明，在比弗岛东北端，end通常在距该殖民地2.5公里的地方觅食。该区域与漂流位置确定的区域重叠，但是漂流位置位于更南端。两个区域都没有与已知的低音栖息地重叠。殖民地水鸟是大湖生态系统的重要组成部分。一个重要方面是这些鸟类在水生食物网中作为主要掠食者的角色。为了研究这种作用，将生物能量学模型（使用异速方程）应用于研究区域的cor及其后代的繁殖。这些模型估计，2000年消耗的猎物生物量总量为1444.11吨，2001年为1586.17吨。每年，猎物生物量的大部分为a鱼，而这些鱼在2001年占猎物生物量的比例更高；此外，还有两种类型的仿真模型：“重建”和“预测”，以研究鲈鱼种群减少与鸟类捕食者之间的可能联系。重建模型表明，单独的caused不太可能引起观察到的低音下降。鸟类可能因低募集，垂钓死亡率或其他因素而导致协同作用下降。预测模型表明，即使鲈鱼正处于相对较低的募集期，对鲈鱼的直接cor捕食目前也不是限制该地区鲈鱼种群数量的主要因素。结合收集的鸟类饮食，觅食地点和生物能学数据，这些模型可以加深我们对研究区域cor与鱼类种群之间关系的理解，并可能使其他系统的渔业管理人员受益。

著录项

  • 作者

    Seefelt, Nancy E.;

  • 作者单位

    Michigan State University.;

  • 授予单位 Michigan State University.;
  • 学科 Biology Zoology.; Biology Ecology.
  • 学位 Ph.D.
  • 年度 2005
  • 页码 219 p.
  • 总页数 219
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 动物学;生态学（生物生态学）;
  • 关键词

相似文献

  • 外文文献
  • 中文文献
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