Fruit harvesting: A potential threat to the persistence, spatial distribution, and establishment of plants

TL;DR

This study models how human fruit harvesting impacts plant survival, distribution, and persistence, revealing that frugivores can mitigate negative effects and highlighting the importance of considering human activities in plant conservation.

Contribution

It introduces new models of plant-frugivore-human interactions to quantify the impact of fruit harvesting on plant populations and their spatial distribution.

Findings

Intense fruit harvesting can lead to plant extinction without frugivores.

Frugivores help maintain plant dispersal and distribution.

Human harvesting shifts plant distribution from random to aggregated.

Abstract

Plant-frugivore interactions play a central role for plant persistence and spatial distribution by promoting the long-range dispersal of seeds by frugivores. However, plant-frugivore interactions are increasingly being threatened by anthropogenic activities. An important anthropogenic threat that could expose plant-frugivore systems to extinction risk is fruit harvesting. Here, we develop an individual-based and a pair-approximation model of plant-frugivore-human interactions to elucidate the effects of human harvesting of fruits on plant establishment, persistence, and spatial distribution. Our results show that frugivores strongly affect global density of plants and gradually shift their spatial distribution from aggregated to random, depending on the attack rate and dispersal efficiency of frugivores. We find that, in the absence of frugivores, plants experiencing intense fruit harvesting cannot persist even if their fecundity is high. In the presence of frugivores, fruit harvesting profoundly affects the global dispersal of seeds and thus changes the spatial distributions of plants from random to aggregated, potentially causing plant extinction. Our results demonstrate that sufficiently efficient frugivores mitigate the negative impact of fruit harvesting on plant populations and enable plant establishment precluded by harvesting. Taken together, these results draw attention to previously underappreciated impacts of fruit harvesting in plant-frugivore-human interactions.