Dissertation Research: Gulls as Cross-ecosystem Links in New England Coastal Communities.

一些最引人注目的群落变化的例子似乎是由特定物种丰度的变化驱动的，这种变化对生态系统的其他成员产生了级联效应。海鸟通过捕食和改变非生物因子发挥重大影响，从而决定了海洋和陆地生境组合的物种丰富度。在新英格兰，自20世纪初以来，海鸥数量急剧增加，并可能通过它们的活动改变沿海陆地和潮间带群落。然而，它们的影响几乎是未知的。本研究的目的是了解筑巢海鸥影响植物（陆生草本和潮间带藻类）组合的机制。海鸥通过捕食以食藻动物（滨鹬）为食的次级消费者（螃蟹），可能对潮间带藻类多样性产生自上而下的影响。鸟类通过鸟粪将源自海洋的营养物质和能量从潮间带转移到陆地生境，因此，它们可能自下而上影响陆地植物多样性。我建议结合实验操作和比较抽样的方法来调查这些影响。水生生态系统的政策（如海鸟恢复）可以影响水生和陆地系统。了解海鸥对海洋和陆地栖息地的影响将有助于明智的管理做法。

Some of the most striking examples of community change appear to be driven bychanges in the abundance of particular species with cascading effects on other members of anecosystem. Seabirds exert substantial effects through predation and by modifying abioticfactors, thereby determining species richness of assemblages in both marine and terrestrialhabitats. In New England, gulls have increased dramatically since the early 1900s, and arelikely transforming coastal terrestrial and intertidal communities through their activities.However, their impacts are virtually unknown. The goal of this research is to understand themechanisms by which nesting gulls impact plant (terrestrial herbaceous and intertidal algae)assemblages. Gulls may have top-down effects on algal diversity in the intertidal throughpredation on secondary consumers (crabs) that forage on algal grazers (littorines). Birdstransfer marine-derived nutrients and energy from intertidal to terrestrial habitats via guano,and as a consequence they may impact terrestrial plant diversity from the bottom-up. Ipropose a combination of experimental manipulations and comparative sampling methods toinvestigate these effects. Policies in aquatic ecosystems (e.g. seabird restoration) can affectboth aquatic and terrestrial systems. Understanding gull impacts in marine and terrestrialhabitats will contribute to informed management practices.