Can invasive species replace native species as a resource for birds under climate change? A case study on bird-fruit interactions

Gallinat, A. S., Primack, R. B. & Lloyd-Evans, T. L. (2019). Can invasive species replace native species as a resource for birds under climate change? A case study on bird-fruit interactions.Biological Conservation, 241. PDF.

Summary

Fleshy fruits provide birds with a high-energy food source during their fall migration. In turn, birds spread consumed seeds across the landscape. As birds delay migration due to climate change, plants that provide more fruit into October and November may gain a dispersal advantage. To better understand these bird-fruit interactions, Gallinat et al. (2020) investigated 25 fleshy-fruited plants (10 invasive and 15 native) at Manomet, a migratory bird stopover site along the coast of Massachusetts. By monitoring fruit phenology and abundance, they found that invasive fruit increased in early-October to mid-November, while native fruit declined. However, fecal samples revealed that songbirds preferentially consumed native fruit throughout the fall, regardless of timing, abundance, or ripeness. Although invasives offered more fruit to late travelers, native fruit provided an important—and preferred—forage for birds throughout the fall migration season.

Take home points

• Climate change has caused many bird species to delay migration later in the fall, which shifts bird-fruit interactions at stopover sites.

• Even though invasive fruit was more abundant late into the fall, birds preferred eating native fruit throughout the fall migration.

Management implications

• Planting fleshy-fruited natives at stopover sites promotes the spread of native plants and provides birds with important nutrition during fall migration.

• Consider phenology when choosing which native species to plant, such as fruiting time and peak ripeness.

Keywords

Impact Study; Observation; Invasive Plant