Universidade Federal Rural do Rio de Janeiro, Departamento de Biologia Animal, Laboratório de Ecologia de Peixes, 23897-030, Seropédica, RJ, Brazil.
Universidade Federal Rural do Rio de Janeiro, Departamento de Biologia Animal, Laboratório de Ecologia de Peixes, 23897-030, Seropédica, RJ, Brazil.
Mar Environ Res. 2019 Jun;148:26-38. doi: 10.1016/j.marenvres.2019.05.006. Epub 2019 May 4.
The spatial structure of the fish diversity and site-scale and landscape-scale environmental effects were investigated across hierarchical levels in tropical coastal ecosystems. Total diversity (γ) was hierarchically partitioned into α and β components using both the additive and multiplicative methods. A model selection based on the AICc was applied to generalized linear mixed models relating diversity measures to environmental variables and including random effects for hierarchical levels and season. Short-term seasonal effects were negligible. Spatial effects were more relevant at the site level and negligible at the subregion level, due to the high spatial heterogeneity and the natural pooling of ecosystems, respectively. Site-scale environmental effects were more relevant at the subregion level, with eutrophic conditions (continental influence) favoring the species richness (α and γ) and higher absence of species (β) in oligotrophic conditions (marine influence). At the system level, the positive effect of the distance from the ocean on γ and higher β in oligotrophic conditions reinforced the positive continental influence on fish diversity. Environmental homogenization processes were most likely associated with the negative effect of the pasture cover on α at the system level, and γ and β at the site level. The negative effect of the forest cover on the later diversity measure evidenced its relevance to maintain richer but more similar assemblages, whereas the positive continental influence was most likely due to the loss of stenohaline marine species. This study evidenced that disentangling spatial, land use, and marine vs. continental effects on diversity components is critical to understand the primary determinants of the fish diversity in tropical coastal ecosystems.
本研究在热带沿海生态系统中，从层次水平上调查了鱼类多样性的空间结构以及局域和景观尺度环境效应。采用加性和乘法方法，将总多样性（γ）分层为α和β两个分量。基于 AICc 的模型选择被应用于广义线性混合模型，将多样性测度与环境变量相关联，并包括层次和季节的随机效应。短期季节性效应可以忽略不计。由于空间异质性高和生态系统的自然汇集，空间效应在局域尺度上更为相关，而在次区域尺度上则可以忽略不计。局域尺度的环境效应更为相关，富营养条件（大陆影响）有利于物种丰富度（α和γ），而在贫营养条件（海洋影响）下，物种缺失（β）更高。在系统水平上，远离海洋的距离对γ的正效应以及贫营养条件下β的增加，强化了大陆对鱼类多样性的正影响。环境同质化过程可能与草原覆盖对系统水平上的α以及局域水平上的γ和β的负效应有关。森林覆盖对后期多样性测度的负效应表明其对维持更丰富但更相似的集合具有相关性，而大陆的正影响可能是由于狭盐性海洋物种的丧失所致。本研究表明，分解多样性成分的空间、土地利用、海洋与大陆效应对于理解热带沿海生态系统中鱼类多样性的主要决定因素至关重要。
