Table 1 Best GLMs for tree cover (T) and grass cover (G) in the three mean annual rainfall (MAR) ranges: low MAR (R1, MAR ≤ 630 mm y−1), intermediate MAR (R2, 630 mm y−1 < MAR < 1200 mm y−1) and high MAR (R3, MAR ≥ 1200 mm y−1).

From: Grass and tree cover responses to intra-seasonal rainfall variability vary along a rainfall gradient in African tropical grassy biomes

MAR range

Vegetation cover

Best model

R2

R1-Low MAR

Tree

logit(T) = −3.85 + 0.55·MAR

0.22

Grass

logit(G) = 0.22–0.42·SI + 0.38·λw

0.56

R2-Intermediate MAR

Tree

logit(T) = −1.48 + 0.49·λw + 0.14·λw2

0.38

Grass

logit(G) = 0.73–0.17·log10(AFI)−0.17·λw

0.37

R3-High MAR

Tree

logit(T) = −1.62–0.41·αw

0.32

  1. Predictors are: MAR, rainfall seasonality index (SI), logarithmic average fire interval (log10(AFI)), wet-season daily rainfall intensity (αw) and wet-season daily rainfall frequency λw. Predictor variables were standardized such that in the GLMs their coefficient magnitude is a measure of their importance in the model. Best models were those with the smaller Akaike information criterion (AIC), see Supplementary Tables S2–S6. No significant model was found for grass cover in R3. The explained deviance (R2) is reported for each case. See Material and Methods in the main text for a detailed description of the statistical models and selection procedures.
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