A framework for the restoration of seed dispersal and pollination

Species reintroduction is a management strategy to restore ecosystem functioning through the reestablishment of ecological interactions and related ecological processes, like pollination and seed dispersal. Selecting the best species to achieve this goal remains challenging. We present a trait-based framework to estimate the effects of species reintroductions on seed dispersal and pollination. Our framework assesses the potential contribution of a consumer species (e.g. seed disperser) by considering both the originality of its interactions and the availability of resources it consumes. Originality refers to the degree of uniqueness versus redundancy of a species' interactions compared with the interactions of the current consumer community. Resource availability, defined by the distribution of trait values in the resource community that enable interactions (like fruit size), determines the potential magnitude of a species' effect. The framework also allows assigning different weights to unique interactions, thereby facilitating decisions on whether to prioritize species that potentially add unique interactions if selected for reintroduction. Using our framework, we compared the potential effects of two reintroduced frugivores (agoutis and howler monkeys) on seed dispersal in an Atlantic Forest site. While both species have similar potential effects when not accounting for interaction originality, howlers interact with more common fruit's trait values, whereas agoutis have more unique interactions and with a broader variety of trait values. We also provide ways of generalizing our approach to include other factors, e.g. species abundances, to assess the consequences of other scenarios affecting community composition, such as species extinctions and invasions.