Fig 1.
Macro-climatic ranges of the 1307 panicoid species from the climate data set including 237 C3 and 1070 C4 species ignoring phylogenetic relationships.
The line widths of the bars are proportionate to the number of species in each bin. All quantitative analyses treated the Aridity Index (AI) and the Mean Temperature of the Coldest and Warmest Quarters (MTCQ and MTWQ) as continuous characters, but the variables are here binned for illustrative purposes. Following the United Nations Environment Programme we use the AI categories: <0.03 hyper arid, 0.03–0.2 arid, 0.2–0.5 semi-arid, 0.5–0.65 dry sub-humid, >0.65 humid. Following the Köppen climate classification, the limit between tropical and subtropical climates falls at approx. 18ºC.
Table 1.
Nodes retained in the working phylogeny used for the PGLS regressions.
At suprageneric level, we retained nodes that appear in several published phylogenetic analyses. At generic level we retained nodes that were both well supported and well sampled in recent phylogenetic studies. Node number refers to subtribes in Figs 2–4 and S2 Fig Phylogenetic tree. Number of species refers to the number of species in each clade for which climate data was available (a total of 1307 species, marked in bold).
Fig 2.
The climatic extremes of MTWQ in the 1307 panicoid grasses included in the climate data set.
The topology shows the nodes retained in the working phylogeny used in the phylogenetic contrast analyses of the climate data set. The circle cladogram has been rooted in Gynerium for illustrative purpose, in the phylogenetic contrast analyses the cladogram was rooted as in S2 Fig Phylogenetic tree. Branch lengths were obtained from the Bayesian analyses, in the present tree; terminal taxa were assigned the mean branch length within each terminal clade (for details of the nodes see the 400 taxa cladogram, S2 Fig Phylogenetic tree). Clades with gray background colour are C4 clades. C4 species that do not form a clade are marked with gray lines (in Arthropogoninae and Neurachninae). Branch numbers refer to names of subtribes in Table 1. All quantitative analyses treated the MTWQ as a continuous character, but for illustrative purposes the values have been binned in the figure. Cen. = Centotheceae, Cyp. = Cyperochloeae, Thy. = Thysanolaeneae.
Fig 3.
The climatic extremes of MTCQ in the 1307 panicoid grasses included in the climate data set.
The topology shows the nodes retained in the working phylogeny used in the phylogenetic contrast analyses of the climate data set. The circle cladogram has been rooted in Gynerium for illustrative purpose, in the phylogenetic contrast analyses the cladogram was rooted as in S2 Fig Phylogenetic tree. Branch lengths were obtained from the Bayesian analyses, in the present tree; terminal taxa were assigned the mean branch length within each terminal clade (for details of the nodes see the 400 taxa cladogram, S2 Fig Phylogenetic tree). Clades with gray background colour are C4 clades. C4 species that do not form a clade are marked with gray lines (in Arthropogoninae and Neurachninae). Branch numbers refer to names of subtribes in Table 1. All quantitative analyses treated the MTCQ as a continuous character, but for illustrative purposes the values have been binned in the figure. Cen. = Centotheceae, Cyp. = Cyperochloeae, Thy. = Thysanolaeneae.
Fig 4.
The climatic extremes of the Aridity Index in the 1307 panicoid grasses included in the climate data set.
The topology shows the nodes retained in the working phylogeny used in the phylogenetic contrast analyses of the climate data set. The circle cladogram has been rooted in Gynerium for illustrative purpose, in the phylogenetic contrast analyses the cladogram was rooted as in S2 Fig Phylogenetic tree. Branch lengths were obtained from the Bayesian analyzes, in the present tree; terminal taxa were assigned the mean branch length within each terminal clade (for details of the nodes see the 400 taxa cladogram, S2 Fig Phylogenetic tree). Clades with gray background colour are C4 clades. C4 species that do not form a clade are marked with gray lines (in Arthropogoninae and Neurachninae). Branch numbers refer to names of subtribes in Table 1. All quantitative analyses treated the Aridity Index as a continuous character, but for illustrative purposes the values have been binned into the categories established by the United Nations Environment Programme: <0.03 hyper arid, 0.03–0.2 arid, 0.2–0.5 semi arid, 0.5–0.65 dry sub-humid, >0.65 humid. Cen. = Centotheceae, Cyp. = Cyperochloeae, Thy. = Thysanolaeneae.
Table 2.
Results from the phylogenetic contrasts comparing range limits between C3 and C4 species in the climate data set containing 1307 panicoid grasses.
The PGLS regressions were performed at subfamily level (Panicoideae), and in the tribes Paspaleae and Paniceae. The model with lowest AIC value was selected as the best fitting model. P-values in bold indicate significant differences in means among C3 and C4 species. Branch lengths: 1: all branch lengths equal; 2: length of internal branches from Bayesian trees, length of terminal branches mean of all terminals in Bayesian trees; 3: length of internal branches as in 2, length of terminal branches mean of terminals in each individual clade of the Bayesian trees.