Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada.
PeerJ. 2023 Feb 16;11:e14823. doi: 10.7717/peerj.14823. eCollection 2023.
In highly diverse systems such as coral reefs, many species appear to fulfil similar ecological roles, suggesting that they might be ecologically equivalent. However, even if species provide similar functions, the magnitude of those roles could modulate their impact within ecosystems. Here, we compare the functional contributions of two common, co-occurring Caribbean sea cucumber species, and , in terms of ammonium provisioning and sediment processing on Bahamian patch reefs. We quantified these functions through empirical measures of ammonium excretion, and in situ observations of sediment processing coupled with fecal pellet collections. On a per-individual level, excreted approximately 23% more ammonium and processed approximately 53% more sediment per hour than . However, when we combined these species-specific functional rates to species abundances to produce reef-wide estimates, we found that contributed more than to sediment processing at 57% of reefs (1.9 times more per unit area across all surveyed reefs), and more to ammonium excretion at 83% of reefs (5.6 times more ammonium per unit area across all surveyed reefs), owing to its higher abundance. We conclude that sea cucumber species can differ in the rates at which they deliver per capita ecosystem functions but their ecological impacts at the population level depend on their abundance at a given location.
在高度多样化的系统中，如珊瑚礁，许多物种似乎发挥着相似的生态作用，这表明它们可能在生态上是等效的。然而，即使物种提供相似的功能，这些功能的重要性也可能调节它们在生态系统中的影响。在这里，我们比较了两种常见的、共同出现的加勒比海参物种 和 ，在巴哈马斑块礁上，它们在氨供应和沉积物处理方面的功能贡献。我们通过氨排泄的实证测量，以及与粪便颗粒收集相结合的沉积物处理原位观测，来量化这些功能。在个体水平上， 每小时排泄的氨约多 23%，处理的沉积物约多 53%。然而，当我们将这些特定物种的功能速率与物种丰度结合起来，以产生整个珊瑚礁的估计值时，我们发现， 在 57%的珊瑚礁上（整个调查珊瑚礁的单位面积上多 1.9 倍）的沉积物处理方面的贡献超过 ，在 83%的珊瑚礁上（整个调查珊瑚礁的单位面积上多 5.6 倍）的氨排泄方面的贡献超过 ，这是由于它的丰度更高。我们的结论是，海参物种在提供人均生态系统功能的速率上可能存在差异，但它们在种群水平上的生态影响取决于它们在特定地点的丰度。
