Parris Matthew J, Semlitsch Raymond D
Division of Biological Sciences, 105 Tucker Hall, University of Missouri, Columbia, MO 65211-7400, USA e-mail:
Oecologia. 1998 Aug;116(1-2):219-226. doi: 10.1007/PL00013822.
Asymmetric competition in larval amphibians can influence population dynamics and community structure. This density-dependent regulatory mechanism may be of particular importance for rare or endangered species such as the northern crawfish frog, Rana areolata circulosa. Interspecific competition of R. areolata with two congenerics, R. blairi and R. sphenocephala, was examined in artificial ponds. Analysis of covariance (differential mortality covariate) indicated that interspecific competition increased larval period length and decreased metamorphic body mass of R. areolata. The number of metamorphs produced was lower for R. blairi ponds when reared with R. areolata at high density. Body mass at metamorphosis was larger for R. sphenocephala when reared with R. areolata, suggesting that R. areolata facilitates larval growth in R. sphenocephala. These results indicate that the larval performance of R. areolata was reduced in the presence of interspecific competitors. Although many conservation efforts emphasize the preservation of critical habitat or particular rare species, interactive effects of biotic components in the focal community may also be important demographic regulators.
幼体两栖动物的不对称竞争会影响种群动态和群落结构。这种密度依赖性调节机制对于诸如北方小龙虾蛙（Rana areolata circulosa）等珍稀或濒危物种可能尤为重要。在人工池塘中研究了圆斑蛙与两种同属物种——布莱尔蛙（R. blairi）和楔头蛙（R. sphenocephala）的种间竞争。协方差分析（差异死亡率协变量）表明，种间竞争延长了圆斑蛙的幼体期，并降低了其变态时的体重。当与圆斑蛙高密度饲养时，布莱尔蛙池塘中产生的变态个体数量较少。当与圆斑蛙一起饲养时，楔头蛙变态时的体重更大，这表明圆斑蛙促进了楔头蛙幼体的生长。这些结果表明，在存在种间竞争者的情况下，圆斑蛙的幼体表现会降低。尽管许多保护措施强调保护关键栖息地或特定的珍稀物种，但重点群落中生物成分的相互作用效应也可能是重要的种群调节因素。
