PHENOLOGICAL RESPONSES OF Stylosanthes guianensis (AUBL.) SW. var. guianensis TO CLIMATE CHANGE IN BRAZILIAN BIOMES

Abstract

Stylosanthes guianensis var. guianensis is a forage legume with a wide distribution in Brazilian biomes, indicating potential for adaptation to different temperatures and humidity levels. Changes in the flowering phenophase indicate its resilience to disturbances from climate change and La Niña and El Niño events. Analyses using circular statistics of 110 herbarium records between 1952 and 2022 suggest flowering with a uniform pattern in the Caatinga and weak evidence of flowering seasonality in the Cerrado and Atlantic Forest concentrated in March. There were significant differences at a 5% probability level in the late phenological response to El Niño in April, differing from the Neutral and La Niña phases. The comparison of the days of the phenological cycle in two periods indicated different long-term influences on flowering in the biomes. In the period after 1977, more sensitive to climate changes, the distribution of flowering was later than in the previous period, in the three biomes. We concluded that the flowering of S. guianensis var. guianensis responds to long-term variations associated with climate change and ENSO events differently across the biomes. We recommend expanding the collection of specimens of this plant and efforts to monitor its phenophase as an indicator of climate change to assist in pasture management.