Layman Craig A, Quattrochi John P, Peyer Caroline M, Allgeier Jacob E
Marine Sciences Program, Department of Biological Sciences, Florida International University, 3000 NE 151st St, North Miami, FL 33181, USA.
Ecol Lett. 2007 Oct;10(10):937-44. doi: 10.1111/j.1461-0248.2007.01087.x.
Much research has focused on identifying species that are susceptible to extinction following ecosystem fragmentation, yet even those species that persist in fragmented habitats may have fundamentally different ecological roles than conspecifics in unimpacted areas. Shifts in trophic role induced by fragmentation, especially of abundant top predators, could have transcendent impacts on food web architecture and stability, as well as ecosystem function. Here we use a novel measure of trophic niche width, based on stable isotope ratios, to assess effects of aquatic ecosystem fragmentation on trophic ecology of a resilient, dominant, top predator. We demonstrate collapse in trophic niche width of the predator in fragmented systems, a phenomenon related to significant reductions in diversity of potential prey taxa. Collapsed niche width reflects a homogenization of energy flow pathways to top predators, likely serving to destabilize remnant food webs and render apparently resilient top predators more susceptible to extinction through time.
许多研究都集中在识别那些在生态系统碎片化后易灭绝的物种，但即使是那些在碎片化栖息地中生存下来的物种，其生态角色可能与未受影响地区的同种物种有着根本的不同。碎片化导致的营养级角色转变，尤其是大量顶级捕食者的营养级角色转变，可能会对食物网结构和稳定性以及生态系统功能产生深远影响。在这里，我们基于稳定同位素比率，使用一种新的营养生态位宽度测量方法，来评估水生生态系统碎片化对一种有恢复力的、占主导地位的顶级捕食者的营养生态学的影响。我们证明，在碎片化系统中，捕食者的营养生态位宽度会缩小，这一现象与潜在猎物类群多样性的显著降低有关。缩小的生态位宽度反映了流向顶级捕食者的能量流动途径的同质化，这可能会导致残余食物网不稳定，并使看似有恢复力的顶级捕食者随着时间的推移更容易灭绝。
