Table 4 Study quality assessment based on external validity of methods
Method validity | High | Low |
|---|---|---|
Methods to measure species richness and density of bird-dispersed seeds | Field observation of seed dispersal by birds on perches Seed rain collection representing dispersal by birds (i.e., daytime only to exclude bats, exclude non-bird dispersers through method) | Seed rain collection representing dispersal by animals and non-specific to birds (i.e., open at night, non-exclusion of other potential dispersers) |
Methods to measure seedling species richness and density | Long-term monitoring of plots under perches with known seed rain data and with predator and herbivore exclusion set-up | Sampling under perch sites without known seed rain data |