Dominant species maintain ecosystem function with non-random species loss
Dominant species maintain ecosystem function with non-random species loss
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DOI：
10.1046/j.1461-0248.2003.00454.x
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发表时间：
2003-06-01
期刊：
影响因子：
8.8
通讯作者：
Knapp, AK
中科院分区：
文献类型：
--
作者：
Smith, MD;Knapp, AK
干旱和破碎化等广泛的压力因素造成的物种损失很可能是非随机的，取决于群落中的物种丰度。我们实验性地减少了稀有和不常见的植物物种的数量，同时只独立地减少了完整的天然草原中占优势的草种的丰度。这使我们能够模拟一个非随机模式的物种损失，物种丰度的基础上，从社区形成的自然生态相互作用和不均匀的物种丰度分布的特点。在两个生长季节，总地上净初级生产力（ANPP）下降的优势物种的丰富度减少，但不受影响的三倍下降，不太常见的物种丰富度。相反，剩余的稀有和不常见物种的生产力随着丰富度的下降而下降，部分原因是这些物种之间的互补相互作用的丧失。然而，优势草产量的增加抵消了物种损失的负面影响。我们的结论是，优势种，作为控制器的生态系统功能，可以提供短期的阻力，减少生态系统功能时，物种的损失是非随机的。然而，稀有和不常见物种-群落中最多样化的组成部分-之间互补性相互作用的同时丧失，可能导致更多物种的丧失，并预示着生态系统功能的长期侵蚀。
Loss of species caused by widespread stressors, such as drought and fragmentation, is likely to be non-random depending on species abundance in the community. We experimentally reduced the number of rare and uncommon plant species while independently reducing only the abundance of dominant grass species in intact, native grassland. This allowed us to simulate a non-random pattern of species loss, based on species abundances, from communities shaped by natural ecological interactions and characterized by uneven species abundance distributions. Over two growing seasons, total above-ground net primary productivity (ANPP) declined with reductions in abundance of the dominant species but was unaffected by a threefold decline in richness of less common species. In contrast, productivity of the remaining rare and uncommon species decreased with declining richness, in part due to loss of complementary interactions among these species. However, increased production of the dominant grasses offset the negative effects of species loss. We conclude that the dominant species, as controllers of ecosystem function, can provide short-term resistance to reductions in ecosystem function when species loss is nonrandom. However, the concurrent loss of complementary interactions among rare and uncommon species, the most diverse component of communities, may contribute to additional species loss and portends erosion of ecosystem function in the long term.