Hierarchical Spatial Structure of Stream Fish Colonization and Extinction
Hierarchical Spatial Structure of Stream Fish Colonization and Extinction
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溪流鱼类殖民与灭绝的层次空间结构
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发表时间：
2012
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通讯作者：
J. Roberts
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作者：
N. Hitt;J. Roberts
随着时间的推移，灭绝和殖民化的空间变化预计会影响群落组成。在溪流鱼类群落中，当地物种丰富度（α多样性）和物种周转率（β多样性）被认为是由上游溪流的高灭绝率和下游地区的高定殖率调节的。我们评估了Burton和Odum 1945（Ecology 26：182 - 194）在美国弗吉尼亚州最初调查的溪流中鱼类群落的时空结构，并探讨了物种性状对灭绝和定殖动态的影响。我们记录了在现场和溪流规模的鱼类群落结构的戏剧性变化。在观察到的34种鱼类中，有20种（59%）在这两个时期都存在，但有11种（32%）在研究区域定居，3种（9%）随着时间的推移而灭绝。流内，α多样性增加了两个三个流，但β多样性显着下降，在所有流由于鱼类群落同质化造成的常见物种的殖民化和灭绝的稀有物种。然而，在溪流中，鱼类群落随着时间的推移而变化。回归树表明，生殖生活史特征，如产卵丘建设，协会与土丘建设物种，高繁殖力的物种持久性或殖民化的重要预测。相反，本地鱼类不与土堆建设表现出最高的灭绝率从流。我们的研究结果表明，流鱼类殖民和灭绝动态表现出层次的空间结构，并建议丘建设鱼类作为关键物种的源头流殖民。
Spatial variation in extinction and colonization is expected to infl uence community composition over time. In stream fi sh communities, local species richness (alpha diversity) and species turnover (beta diversity) are thought to be regulated by high extinction rates in headwater streams and high colonization rates in downstream areas. We evaluated the spatiotemporal structure of fi sh communities in streams originally surveyed by Burton and Odum 1945 (Ecology 26: 182 – 194) in Virginia, USA and explored the eff ects of species traits on extinction and colonization dynamics. We documented dramatic changes in fi sh community structure at both the site and stream scales. Of the 34 fi sh species observed, 20 (59%) were present in both time periods, but 11 (32%) colonized the study area and three (9%) were extirpated over time. Within streams, alpha diversity increased in two of three streams but beta diversity decreased dramatically in all streams due to fi sh community homogenization caused by colonization of common species and extirpation of rare species. Among streams, however, fi sh communities diff erentiated over time. Regression trees indicated that reproductive life-history traits such as spawning mound construction, associations with mound-building species, and high fecundity were important predictors of species persistence or colonization. Conversely, native fi shes not associated with mound-building exhibited the highest rates of extirpation from streams. Our results demonstrate that stream fi sh colonization and extinction dynamics exhibit hierarchical spatial structure and suggest that mound-building fi shes serve as keystone species for colonization of headwater streams.