Fig 1.
Map of the study sites and types of forest-grassland ecotones from different physiographic regions.
(a) Forest-grassland ecotones sampled in nine localities belonging to three different physiographic regions of Rio Grande do Sul state, Brazil: Campanha region (red numbers: 1-Santana do Livramento; 2-Santo Antônio das Missões; 3-São Francisco de Assis), Campos de Cima da Serra region (yellow numbers: 4-Cambará do Sul; 5-Jaquirana; 6-São Francisco de Paula) and Serra do Sudeste region (blue numbers: 7-Encruzilhada do Sul; 8-Herval; 9-Santana da Boa Vista). (b) Sampling design with bait points. (c) Different physiognomies of forest-grassland ecotones sampled.
Fig 2.
Relationship between local variables and ant taxonomic and phylogenetic metrics in forest-grassland ecotones in South Brazil.
The best generalized linear mixed models (ΔAICc = 0.0) using sites as a random factor: (a) to (d) plots represent relationships in forests (black dots) and (e) to (h) plots represent relationships in grasslands (grey dots).
Table 1.
Best-supported models (GLMMs) in forests.
Table 2.
Best-supported models (GLMMs) in grasslands.
Fig 3.
Boxplot showing ant species richness and phylogenetic diversity among physiographic regions in South Brazil.
Forest-grassland ecotones from the SS region had more (a) ant species and (b) phylogenetic diversity than the CC region. Different regions of Rio Grande do Sul state: Campanha region—CA (red boxes), Campos de Cima da Serra region—CC (yellow boxes) and Serra do Sudeste region—SS (blue boxes). Tukey post-hoc tests (a) CA:CC (p = 0.50); CA:SS (p = 0.11); CC:SS (p = 0.02) and (b) CA:CC (p = 0.34); CA:SS (p = 0.13); CC:SS (p = 0.01).
Table 3.
Best-supported models (GLMMs) at regional scale.
Fig 4.
Ordination diagrams of ant species composition.
(a) Principal Coordinates Analysis (PCoA) of forest-grassland ecotones based on ant species composition (frequency matrix) with Bray-Curtis similarity index. Black dots represent forest sampling sites and grey dots grasslands sampling sites. (b) PCoA at the regional scale with nine sites belonging to three physiographic regions. Different regions of Rio Grande do Sul state: Campanha region—CA (red dots), Campos de Cima da Serra region—CC (yellow dots) and Serra do Sudeste region—SS (blue dots).
Table 4.
Variation partitioning analysis.