||Functionally specialised birds respond flexibly to seasonal changes in fruit availability
||Bender, I.M.A.; Kissling, W.D.; Böhning-Gaese, K.; Hensen, I.; Kühn, I.
; Wiegand, T.; Dehling, D.M.; Schleuning, M.
||Journal of Animal Ecology
||BZF; OESA; iDiv
||avian frugivory; bipartite network; fleshy-fruited plants; fruiting phenology; functional diversity; plant–animal mutualism; resource specialisation; seasonal variability; trait matching; trophic interactions
|UFZ wide themes
between resource and consumer species result in complex ecological
networks. The overall structure of these networks is often stable in
space and time, but little is known about the temporal stability of the
functional roles of consumer species in these networks.
- We used a
trait-based approach to investigate whether consumers (frugivorous
birds) show similar degrees of functional specialisation on resources
(plants) in ecological networks across seasons. We additionally tested
whether closely related bird species have similar degrees of functional
specialisation and whether birds that are functionally specialised on
specific resource types within a season are flexible in switching to
other resource types in other seasons.
- We analysed four seasonal
replicates of two species-rich plant–frugivore networks from the
tropical Andes. To quantify fruit preferences of frugivorous birds, we
projected their interactions with plants into a multidimensional plant
trait space. To measure functional specialisation of birds, we
calculated a species’ functional niche breadth (the extent of seasonal
plant trait space utilised by a particular bird) and functional
originality (the extent to which a bird species’ fruit preference
functionally differs from those of other species in a seasonal network).
We additionally calculated functional flexibility, i.e. the ability of
bird species to change their fruit preference across seasons in response
to variation in plant resources.
- Functional specialisation of
bird species varied more among species than across seasons, and
phylogenetically similar bird species showed similar degrees of
functional niche breadth (phylogenetic signal λ = 0·81) and functional
originality (λ = 0·89). Additionally, we found that birds with high
functional flexibility across seasons had narrow functional niche
breadth and high functional originality per season, suggesting that
birds that are seasonally specialised on particular resources are most
flexible in switching to other fruit resources across seasons.
high flexibility of functionally specialised bird species to switch
seasonally to other resources challenges the view that consumer species
rely on functionally similar resources throughout the year. This
flexibility of consumer species may be an important, but widely
neglected mechanism that could potentially stabilise consumer–resource
networks in response to human disturbance and environmental change.
|Persistent UFZ Identifier
|Bender, I.M.A., Kissling, W.D., Böhning-Gaese, K., Hensen, I., Kühn, I., Wiegand, T., Dehling, D.M., Schleuning, M. (2017):
Functionally specialised birds respond flexibly to seasonal changes in fruit availability
J. Anim. Ecol. 86 (4), 800 - 811