Vegetation and vertebrate abundance as drivers of bioturbation patterns along a climate gradient

positively associated with increasing vegetation cover in Santa Gracia and La Campana (Fig 3B). Overall, there was no clear trend in the relationship between the hole density of inverte- brates and increasing vegetation cover whereas vertebrates’ hole density increased with increasing vegetation cover (S2A Fig in S3 Appendix). After the exclusion of non-significant independent variables, the fixed predictors season, vegetation cover, hole density and hillside elevation within the fitted GLMM for excavated soil volume explained 85% of the model variation (AIC = 296.67, p < 0.001, S4 and S6 Tables in S3 Appendix). The patterns of excavated soil volume varied for invertebrates and vertebrates with increasing vegetation cover along the climate gradient (Fig 4A). The raw data revealed another trend, as the excavated soil volume increased with increasing vegetation cover for both, inver- tebrates and vertebrates (S2B Fig in S3 Appendix). In addition, the excavated soil volume increased disproportionally with increasing hole density, with a larger increase for vertebrates than for invertebrates (Fig 4B). Fig 3. Fitted relationship between the hole density and fixed effects for invertebrates (yellow) and vertebrates (blue) at each site (Pan de Azu´car, Santa Gracia, La Campana, Nahuelbuta). (A) Season (autumn: March-April/ spring: September-November), (B) vegetation cover [%]. Data from both field campaigns were used. https://doi.org/10.1371/journal.pone.0264408.g003 PLOS ONE Vegetation and vertebrate abundance as drivers of bioturbation patterns along a climate gradient

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