Sweatman Jennifer L, Layman Craig A, Fourqurean James W
Concordia College, Department of Biology, 901 8th St. S, Moorhead, MN 56562, United States.
North Carolina State University, 127 David Clark Labs, Campus Box 7617, Raleigh, NC 27695-7617, United States.
Mar Environ Res. 2017 May;126:95-108. doi: 10.1016/j.marenvres.2017.02.003. Epub 2017 Feb 11.
Habitat fragmentation impacts ecosystem functioning in many ways, including reducing the availability of suitable habitat for animals and altering resource dynamics. Fragmentation in seagrass ecosystems caused by propeller scarring is a major source of habitat loss, but little is known about how scars impact ecosystem functioning. Propeller scars were simulated in seagrass beds of Abaco, Bahamas, to explore potential impacts. To determine if plant-herbivore interactions were altered by fragmentation, amphipod grazers were excluded from half the experimental plots, and epiphyte biomass and community composition were compared between grazer control and exclusion plots. We found a shift from light limitation to phosphorus limitation at seagrass patch edges. Fragmentation did not impact top-down control on epiphyte biomass or community composition, despite reduced amphipod density in fragmented habitats. Seagrass and amphipod responses to propeller scarring suggest that severely scarred seagrass beds could be subject to changes in internal nutrient stores and amphipod distribution.
栖息地破碎化在许多方面影响生态系统功能，包括减少动物适宜栖息地的可用性以及改变资源动态。螺旋桨划痕导致的海草生态系统破碎化是栖息地丧失的主要来源，但对于这些划痕如何影响生态系统功能却知之甚少。在巴哈马群岛阿巴科岛的海草床中模拟螺旋桨划痕，以探索潜在影响。为了确定植物与食草动物的相互作用是否因破碎化而改变，在一半的实验地块中排除了双壳类食草动物，并比较了有食草动物控制的地块和排除地块之间的附生植物生物量和群落组成。我们发现在海草斑块边缘从光限制转变为磷限制。尽管破碎化栖息地中的双壳类密度降低，但破碎化并未影响对附生植物生物量或群落组成的自上而下控制。海草和双壳类对螺旋桨划痕的反应表明，严重划痕的海草床可能会出现内部养分储存和双壳类分布的变化。
