Structural vegetation protection provided by Caatinga when it is leafless to first rainfall events

In the Brazilian Caatinga, plants retain leaves for only 3 to 4 months during the rainy season (February to June); for the dry season, only stems, branches, and roots persist. This field study investigated how these structural elements protect the soil and environment during the dry season, simulating both initial rainfall events in rainy seasons and after extended dry periods. Sixteen simulated rainfall events were conducted to compare the effects of the structural elements of Caatinga and bare soil. Stems, branches, and litter together reduced flow velocity by 54.89% by increasing hydraulic resistance by 75.68%, increasing water infiltration by 47.77%, and reducing the runoff coefficient by 52.77%, while significantly lowering soil detachment rates. Hydraulic resistance to overland flow was governed by the Froude number and was described by an exponential model (R 2 = 0.9783). Thus, even under dry-season stress, the structural elements of the Caatinga help sustain the semi-arid ecosystem by providing hydraulic protection.