McClain Craig R, Webb Thomas J, Heim Noel A, Knope Matthew L, Monarrez Pedro M, Payne Jonathan L
Department of Biology University of Louisiana at Lafayette Lafayette Louisiana USA.
Ecology & Evolutionary Biology, School of Biosciences University of Sheffield Sheffield UK.
Ecol Evol. 2024 Jun 5;14(6):e11506. doi: 10.1002/ece3.11506. eCollection 2024 Jun.
Body size is a fundamental biological trait shaping ecological interactions, evolutionary processes, and our understanding of the structure and dynamics of marine communities on a global scale. Accurately defining a species' body size, despite the ease of measurement, poses significant challenges due to varied methodologies, tool usage, and subjectivity among researchers, resulting in multiple, often discrepant size estimates. These discrepancies, stemming from diverse measurement approaches and inherent variability, could substantially impact the reliability and precision of ecological and evolutionary studies reliant on body size data across extensive species datasets. This study examines the variation in reported maximum body sizes across 69,570 individual measurements of maximum size, ranging from <0.2 μm to >45 m, for 27,271 species of marine metazoans. The research aims to investigate how reported maximum size variations within species relate to organism size, taxonomy, habitat, and the presence of skeletal structures. The investigation particularly focuses on understanding why discrepancies in maximum size estimates arise and their potential implications for broader ecological and evolutionary studies relying on body size data. Variation in reported maximum sizes is zero for 38% of species, and low for most species, although it exceeds two orders of magnitude for some species. The likelihood of zero variation in maximum size decreased with more measurements and increased in larger species, though this varied across phyla and habitats. Pelagic organisms consistently had low maximum size range values, while small species with unspecified habitats had the highest variation. Variations in maximum size within a species were notably smaller than interspecific variation at higher taxonomic levels. Significant variation in maximum size estimates exists within marine species, and partially explained by organism size, taxonomic group, and habitat. Variation in maximum size could be reduced by standardized measurement protocols and improved meta-data. Despite the variation, egregious errors in published maximum size measurements are rare, and their impact on comparative macroecological and macroevolutionary research is likely minimal.
身体大小是塑造生态相互作用、进化过程以及我们对全球范围内海洋群落结构和动态理解的一个基本生物学特征。尽管测量容易，但由于研究人员之间方法多样、工具使用不同以及主观性，准确界定一个物种的身体大小面临重大挑战，导致出现多个往往相互矛盾的大小估计值。这些差异源于不同的测量方法和内在变异性，可能会严重影响依赖广泛物种数据集中身体大小数据的生态和进化研究的可靠性和精确性。本研究考察了27271种海洋后生动物69570次最大尺寸个体测量报告中的最大身体大小变化，测量范围从<0.2微米到>45米。该研究旨在调查物种内报告的最大尺寸变化如何与生物体大小、分类学、栖息地以及骨骼结构的存在相关。调查特别关注理解最大尺寸估计差异产生的原因及其对依赖身体大小数据的更广泛生态和进化研究的潜在影响。38%的物种报告的最大尺寸变化为零，大多数物种的变化较低，尽管有些物种超过了两个数量级。最大尺寸零变化的可能性随着测量次数增加而降低，在较大物种中增加，不过这在不同门类和栖息地有所不同。浮游生物的最大尺寸范围值一直较低，而栖息地未明确的小物种变化最大。一个物种内最大尺寸的变化明显小于更高分类水平上的种间变化。海洋物种内最大尺寸估计存在显著变化，部分可由生物体大小、分类群和栖息地解释。通过标准化测量方案和改进元数据可以减少最大尺寸的变化。尽管存在变化，但已发表的最大尺寸测量中的严重错误很少见，其对比较宏观生态和宏观进化研究的影响可能很小。
