Fruiting plants rely on animals to eat their fruit and spread their seeds across the landscape. Unfortunately, nearly all of the fruit-eating birds that Caly evolved with have gone extinct! However, new frugivores (fruit-eating animals) have recently been introduced to the islands, including songbirds, game birds, pigs, and rodents. Just because an animal eats a fruit, doesn’t necessarily mean that it’s dispersing seeds. The digestive tract of each animal species is physically and chemically different, and these varying conditions can either help seeds germinate or destroy them.
To explore how well rare plants like Caly are spreading seeds with their new community of frugivores, DLNR staff are working with researchers from the Hawaiʻi VINE Project, a group of scientists studying seed dispersal in Hawaiʻi’s novel forest ecosystems. From this team, Samuel Case, PhD student at the University of Wyoming, is investigating the role of introduced game birds in seed dispersal. To study the effects of the game bird gut passage on seeds, he is feeding fruits of native and non-native plants to captive game birds and then sowing passed seeds to test for germination.
Cooperation between scientists and land managers can lead to an improved understanding of our natural resources, which ultimately guides effective conservation practices. So far, Case and his colleagues have discovered many previously unknown seed dispersal interactions, including game birds (Kalij Pheasants and Erckel’s Francolins) taking fruit of federally endangered Delissea waianaeensis, a close relative of Caly that is also found in the Waiʻanae Mountains.
Watch some of his video captures of game birds eating fruit of D. waianaeensis below!