Witman Jon D, Cusson Mathieu, Archambault Philippe, Pershing Andrew J, Mieszkowska Nova
Department of Ecology and Evolutionary Biology, Box G-W, Brown University, Providence, Rhode Island 02912, USA.
Ecology. 2008 Nov;89(11 Suppl):S66-80. doi: 10.1890/07-1201.1.
Energy variables, such as evapotranspiration, temperature, and productivity explain significant variation in the diversity of many groups of terrestrial plants and animals at local to global scales. Although the ocean represents the largest continuous habitat on earth with a vast spectrum of primary productivity and species richness, little is known about how productivity influences species diversity in marine systems. To search for general relationships between productivity and species richness in the ocean, we analyzed data from three different benthic marine ecosystems (epifaunal communities on subtidal rock walls, on navigation buoys in the Gulf of St. Lawrence, and Canadian Arctic macrobenthos) across local to continental spatial scales (<20 to >1000 km) using a standardized proxy for productivity, satellite-derived chlorophyll a. Theoretically, the form of the function between productivity and species richness is either monotonically increasing or decreasing, or curvilinear (hump- or U-shaped). We found three negative linear and three hump-shaped relationships between chlorophyll a and species richness out of 10 independent comparisons. Scale dependence was suggested by more prevalent diversity-productivity relationships at smaller (local, landscape) than larger (regional, continental) spatial scales. Differences in the form of the functions were more closely allied with community type than with scale, as negative linear functions were restricted to sessile epifauna while hump-shaped functions occurred in Arctic macrobenthos (mixed epifauna, infauna). In two of the data sets, (St. Lawrence epifauna and Arctic macrobenthos) significant effects of chlorophyll a co-varied with the effects of salinity, suggesting that environmental stress as well as productivity influences diversity in these marine systems. The co-varying effect of salinity may commonly arise in broad-scale studies of productivity and diversity in marine ecosystems when attempting to sample the largest range of productivity, often encompassing a coastal-oceanic gradient.
诸如蒸散、温度和生产力等能量变量在局部到全球尺度上解释了许多陆地植物和动物群体多样性的显著差异。尽管海洋是地球上最大的连续栖息地，具有广泛的初级生产力和物种丰富度，但关于生产力如何影响海洋系统中的物种多样性，我们所知甚少。为了探寻海洋中生产力与物种丰富度之间的一般关系，我们使用生产力的标准化指标——卫星衍生叶绿素a，分析了来自三个不同底栖海洋生态系统（潮下带岩壁上的表栖动物群落、圣劳伦斯湾导航浮标上的群落以及加拿大北极大型底栖动物）的数据，这些数据跨越了从局部到大陆的空间尺度（小于20公里至大于1000公里）。从理论上讲，生产力与物种丰富度之间函数的形式要么是单调递增或递减，要么是曲线形（驼峰形或U形）。在10次独立比较中，我们发现叶绿素a与物种丰富度之间存在三种负线性关系和三种驼峰形关系。较小（局部、景观）空间尺度上比大（区域、大陆）空间尺度上更普遍存在的多样性-生产力关系表明了尺度依赖性。函数形式的差异与群落类型的关联比与尺度的关联更为紧密，因为负线性函数仅限于固着性表栖动物，而驼峰形函数出现在北极大型底栖动物（混合表栖动物、底内动物）中。在其中两个数据集（圣劳伦斯表栖动物和北极大型底栖动物）中，叶绿素a的显著影响与盐度的影响共同变化，这表明环境压力以及生产力会影响这些海洋系统中的多样性。在试图对最大范围生产力进行采样（通常涵盖沿海-海洋梯度）的海洋生态系统生产力和多样性的大规模研究中，盐度的共同变化效应可能普遍存在。
