LTREB, Community Ecology on Rocky Shores: Long-Term Research in the Subtidal Zone (Massachusetts, 1978 - 2003)

LTREB，岩石海岸的群落生态学：潮下带的长期研究（马萨诸塞州，1978 年 - 2003 年）

• 批准号: 9811576
• 负责人: Kenneth Sebens
• 金额: $ 30万
• 依托单位: University of Maryland, College Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-12-01 至 2003-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9811576&HistoricalAwards=false
• 关键词: LTREB; Community; Ecology; Rocky; Shores

9811576SebensRocky subtidal communities at three sites in Northern Massachusetts have now been under continuous study for up to 20 years. Methods include photography of marked quadrats, transects of predator abundance, and measurement of selected aspects of the physical environment. Since 1978, there has been a dramatic increase in sea urchin (Strongylocentrotus droebachiensis) population density and a decrease in most fish populations. Dr. Sebens and collaboartors have also recorded the appearance and effects of several non-indigenous species; the predatory nudibranch Tritonia plebeia and the colonial ascidian Botrylloides sp. have been the most successful, and have had measurable effects on indigenous assemblages. Other non-indigenous ascidians (Botryllus schlosseri, Styela clava, Diplosoma sp.) appeared only rarely at these sites, and have not yet developed stable local populations. Tritonia had a severe impact on populations of the octocoral Alcyonium siderium, which still have not recovered. The removal of Alcyonium by Tritonia and the doubling of sea urchin population density (both during 1984-1986) caused a major decline in most other invertebrates on vertical rock surfaces, and an increase in the extent of surfaces dominated by crustose coralline algae. Horizontal surfaces dominated by kelp and foliose red algae during 1978--1988 were reduced to urchin barrens (coralline-dominated) when urchins expanded into new areas in 1989. Botrylloides sp. established colonies on rock walls and horizontal surfaces, even where urchin grazing is intense, and thus may have defenses that deter urchins. The synergistic effects of urchin population increase, and the appearance of several nonindigenous species within one decade, has caused a major shift in invertebrate and algal assemblages at these sites. Continued high urchin densities could favor urchin-resistant spatial dominants, which include coralline algae, sea anemones (Metridium senile), sponges (Isodictya spp.), and nonindigenous species such as Botrylloides sp. These studies of subtidal rock surfaces (1978-1997) in northern Massachusetts have produced and tested hypotheses concerning the long-term stability and short term regulation of community structure on rocky substrata. The previous research focused on the interactions among species on rock walls, on population biology of several of the most common species, and on the effects of water movement on individual, population, and community processes. The present project is an extension of the long-term research: an experimental and correlative approach will be used to address the interactions among predation, physical effects, larval dispersal, recruitment, and the resulting impact on community structure. The goals of the study are to: 1) identify important chronic and transient processes structuring the community (physical, biological), 2) determine which processes have strong direct and indirect effects (e.g. sea urchin predation) on community structure, 3) conduct quantitative studies of recruitment and its effects on the community, and 4) incorporate these findings into a model of species coexistence and community structure on isolated sub-units of a landscape, using multiple dispersal scales. Once complete, the long-term data set will be examined statistically (autocorrelation, cross-correlation, other time-series analyses) to determine which physical processes and which predator populations are most strongly correlated with changes in percent cover of the common space occupiers. This project continue long-term studies during 4-6 trips annually, using photographic, video, and direct (SCUBA) sampling (quadrat, transect) at five field sites along 8 km of the Massachusetts coast.

9811576 sebens马萨诸塞州北部三个地点的岩石潮下群落已经被连续研究了20年之久。方法包括标记样方的摄影，捕食者丰度的样条，以及物理环境的选定方面的测量。自1978年以来，海胆种群密度急剧增加，而大多数鱼类种群密度下降。塞本斯博士及其合作者还记录了几个非本地物种的外观和影响；掠食性裸鳃Tritonia plebeia和殖民地海鞘Botrylloides sp.是最成功的，并对本地群落产生了可测量的影响。其他非本地海鞘（Botryllus schlosseri, Styela clava, Diplosoma sp.）在这些地点很少出现，尚未形成稳定的本地种群。Tritonia对八珊瑚Alcyonium siderium的种群造成了严重的影响，这些种群至今仍未恢复。海胆种群密度翻倍（均发生在1984-1986年）和海褐藻对海藻的清除，导致垂直岩石表面上大多数其他无脊椎动物的数量大幅下降，而以甲壳珊瑚藻为主的表面范围增加。1978- 1988年期间以海带和叶红藻为主的水平面在1989年海胆扩张到新的区域时减少为海胆贫瘠区（以珊瑚为主）。Botrylloides sp.在岩壁和水平面上建立了殖民地，甚至在海胆密集放牧的地方，因此可能有防御措施来阻止海胆。海胆数量增加的协同效应，以及十年内几个非本地物种的出现，导致了这些地点无脊椎动物和藻类聚集的重大变化。持续的高海胆密度可能有利于抗海胆的空间优势物种，包括珊瑚藻、海葵（Metridium）、海绵（Isodictya spp.）和非本地物种，如Botrylloides sp.。这些对马萨诸塞州北部潮下岩石表面（1978-1997）的研究已经产生并验证了关于岩石基质上群落结构的长期稳定性和短期调节的假设。以往的研究主要集中在岩壁上物种之间的相互作用，几种最常见物种的种群生物学，以及水运动对个体、种群和群落过程的影响。本项目是长期研究的延伸：将采用实验和相关的方法来研究捕食、物理效应、幼虫扩散、招募及其对群落结构的影响之间的相互作用。本研究的目的是：1)确定构建群落的重要的慢性和瞬时过程（物理的、生物的）；2)确定哪些过程对群落结构有强烈的直接和间接影响（如海胆捕食）；3)对群落的补充及其影响进行定量研究；4)利用多个分散尺度，将这些发现纳入景观中孤立亚单元的物种共存和群落结构模型。一旦完成，将对长期数据集进行统计检查（自相关、交叉相关、其他时间序列分析），以确定哪些物理过程和哪些捕食者种群与公共空间占有者覆盖百分比的变化最密切相关。该项目每年进行4-6次的长期研究，使用摄影，视频和直接（水肺）采样（样方，样带）在马萨诸塞州沿海8公里的五个实地点进行。