Effects of extreme climate events on the circadian pattern of fruit dropping and seed dispersal by terrestrial frugivorous mammals

Brayan Heiner Morera Chacon

Seed dispersal is a key process for the persistence and propagation of plant populations and communities, as well as for the restoration of altered environments. Climate change can impact the dispersal capacity of plants through different mechanisms. For example, plants can respond to changes in precipitation and temperature by modifying fruiting phenology or the quality and quantity of their fruits. These responses could alter the foraging pattern and diet of frugivores, having critical consequences for seed dispersal. One of the expected effects of climate change is the increase in
the frequency and intensity of big storms, which may affect the seed dispersal of some plant species, especially those plants dispersed by the wind. Interestingly, it could also affect the dispersal of fleshy fruit plants by causing extreme mass drop events of non-persistent fruits that are consumed by frugivores once they fall to the ground. The frequency and intensity of such events and the timing of their occurrence may be crucial for the reproductive success of plants that are dispersed by terrestrial (non-arboreal) mammals. Surprisingly, despite numerous research efforts on fruit phenology and its
consequences for fruit consumers, very little is known about the circadian patterns of fruit ripening and falling, let alone on their ecological consequences for seed dispersal. Much less is known how extreme weather events might influence this key ecological process.

Installing camera traps to monitor the ripening and fall of nance fruits in the dry tropical forest of Costa Rica. ©Brayan Morera.

Installing camera traps to monitor the ripening and fall of nance fruits in the dry tropical forest of Costa Rica. ©Brayan Morera.

This project will fill important gaps in our knowledge of the temporallystructured interactions of the fruit dropping circadian pattern and the diel activity of frugivores as well as how they can be affected by climate change. The objective is to investigate the potential effects of climate change on fruit dropping patterns and plant-frugivore interactions in an ecosystem highly vulnerable to climate change, the tropical dry forest of Costa Rica. Specifically, the circadian pattern of fruit dropping in the nance tree (Byrsonima crassifolia) will be quantified, and how such a pattern is altered by changing climatic factors (e.g., wind speed, rainfall) and its consequences for the mutualistic interactions between the nance and vertebrate frugivores will be assessed. This project responds to the need to generate information for conservation planning and to address the adaptation of species and ecosystems to climate change.

Collared peccary (Dicotyles tajacu). ©Brayan Morera.

Collared peccary (Dicotyles tajacu). ©Brayan Morera.

Header: nace fruits. ©Brayan Morera.

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