Long-term monitoring of phenology of tropical trees in KMTR.


Long-term phenological observations in the temperate regions have established that climate change can lead to rapid and considerable shifts in phenology. Consequently, several phenological monitoring stations across the world were established in the tropical regions in the 1990s and data from these are now emerging. Tropical phenology is complex, with the frequency of flowering and fruiting not strictly tied to the annual calendar and phenological response to climate may not be linear. Here we describe the phenological patterns of trees in a wet evergreen forest in the Kalakad Mundanthurai Tiger Reserve of the Western Ghats, India, based on a long-term dataset where 729 individual trees belonging to 90 species were monitored every month from January 1991 to April 2021. We link the fruiting patterns to rainfall and temperature available at the site to establish its response to climate. Fruiting appears to be positively related to minimum temperature. Rainfall did not have any effect, but the number of rainy days had a significant positive effect on fruiting. Fruiting has also decreased over the 30-year period, and so is minimum temperature. Fruiting was also negatively affected by strong El Nino events. It therefore appears that the fruit production in the forest is likely to decline over time and, along with El Nino events that affect fruit production, a negative consequence on the frugivore community can be expected in the area. However, more nuanced analysis is needed for firmer conclusions.