Determinantes ambientais da diversidade genética da fauna marinha brasileira: uma meta-análise

Abstract

Genetic diversity is a fundamental dimension of biodiversity, playing a key role in species evolution and in the resilience of populations to global climate change. This study aimed to conduct a systematic review of the scientific literature on population genetics of Brazilian shallow waters marine fauna and to synthesize its results using linear mixed models (LMMs) and meta-regressions, to evaluate the influence of environmental variables on genetic diversity. Studies were included if they measured, or allowed the measuring of, haplotype diversity (h) and nucleotide diversity (3,14) in at least three populations with five or more individuals of Brazilian marine species distributed along the coast and oceanic islands, based on mitochondrial molecular markers. The literature search was conducted in the Web of Science, Scopus, PubMed, and Periódicos CAPES databases on December 2, 2025, yielding 1,210 records, of which 63 were included, comprising 64 species and 375 populations. Data synthesis was performed using LMMs, including a spatial autocovariate as a fixed effect to consider the spatial dependence between populations. Results robustness to evolutionary dependence between species as assessed through phylogenetic models (pGLMMs). Model robustness to h and r precision was assessed through sensitivity analyses restricted to populations with 25 or more individuals. Risk of bias in the meta-regressions was evaluated using funnel plots, Egger’s test, Rosenthal’s Failsafe-N, and leave-one-out analyses. The LMMs revealed a weak but consistent positive effect of mean annual sea surface temperature (SST) on h (Estimate = 0.04; p = 0.001), whereas no robust effect was observed for 3,14. This pattern suggests that temperature primarily influences recent demographic events, with no evidence of detectable differences in mutation rates among environments. Meta-regressions conducted using Fisher’s Z-transformed correlation coefficients (Zr) for 40 species with four or more populations corroborated this result (Zr = 0.464; CI = 0.28–0.65; p < 0.0001). The effect was consistent across the most represented phyla and independent of the methodological approaches employed. Robustness analyses found no evidence of publication bias and supported consistency in the results. Limitations of this study include the exclusive use of mitochondrial markers, representing only a fraction of the genome, as well as taxonomic and geographic bias. Overall, the results reinforce that the phylogeographic patterns in Brazilian marine fauna genetic diversity emerge from the interaction between environmental variables, life history and evolutional processes. Therefore, more integrative conservation strategies, aided by high resolution genomic approaches, could highly benefit the understanding and preservation of Brazilian marine biodiversity.