Development and validation of functional indicators for avian seed dispersal

• Applicant: Professorin Dr. Katrin Böhning-Gaese
• Subject Area: Animal Physiology and Biochemistry ; Ecology and Biodiversity of Plants and Ecosystems
• Term: from 2013 to 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 227674681

• Final Report Year: 2019

Final Report Abstract

In this study, we investigated how structural and functional diversity of bird communities and the interactions between frugivorous birds and fruiting plants change along land use and elevational gradients. First, we examined the spatial and temporal pattern of bird communities along the elevational gradient and related the variation to climatic factors and resource availability. Second, we compared how structural diversity (such as species richness and abundance) and functional diversity of bird communities change across elevational and land use gradients. Third, we investigated how elevation and land use affect interactions networks of frugivorous birds and fruiting plants. Fourth, we examined how structural and functional diversity of fruiting plants and avian seed dispersers are associated with the ecosystem function of fruit removal. Finally, we investigated the ability of birds to consume fruits with different sets of traits in natural compared to fragmented forests. Our results illustrate that bird communities, as well as the interactions between frugivorous birds and their plant resources show strong variation among continuous and fragmented forests along the elevational gradient. Spatial and temporal variability are often associated with climatic factors, but also relate to biotic factors and community structure. For instance, we could show that changes in the ratio between fruiting plants and frugivorous birds across the elevational gradient strongly affect the structure of plant-frugivore interaction networks. Our results also demonstrate that the effects of fragmentation on structural diversity can be uncoupled from responses in functional diversity. Our findings therefore suggest that quantifications of structural and functional diversity are needed to understand how human impacts affect species diversity and ecosystem functions across elevational gradients.

Publications

• (2018) Different responses of taxonomic and functional bird diversity to forest fragmentation across an elevational gradient. Oecologia
  Santillán, V., M. Quitián, B. A. Tinoco, E. Zárate, M. Schleuning, K. Böhning-Gaese & E. L. Neuschulz
  
• (2018) Elevation-dependent effects of forest fragmentation on plantbird interaction networks in the tropical Andes. Ecography, 41, 1497-1506
  Quitián, M., V. Santillán, C. I. Espinosa, J. Homeier, K. Böhning-Gaese, M. Schleuning & E. L. Neuschulz
  
• (2018) Morphological trait matching shapes plant-frugivore networks across the Andes. Ecography, 41, 1910-1919
  Bender, I. M. A., W. D. Kissling, P. G. Blendinger, K. Böhning-Gaese, I. Hensen, I. Kühn, M. C. Munoz, E. L. Neuschulz, L. Nowak, M. Quitián, F. Saavedra, S. Santillán, T. Töpfer, T. Wiegand, D. M. Dehling & M. Schleuning
  
• (2018) Temperature and precipitation, but not resource availability drive spatio-temporal variation in bird assemblages along a tropical elevational gradient. PLOS ONE
  Santillán, V., M. Quitián, B. A. Tinoco, E. Zárate, M. Schleuning, K. Böhning-Gaese & E. L. Neuschulz
  
• (2019) Direct and indirect effects of plant and frugivore diversity on structural and functional components of fruit removal, Oecologia,189, 435-44
  Quitián, M., V. Santillán, C. I. Espinosa, J. Homeier, K. Böhning-Gaese, M. Schleuning & E. L. Neuschulz
  
• (2019) Functional responses of avian frugivores to variation of fruit resources in natural and fragmented forests. Functional Ecology 33, 399-410
  Quitián, M., V. Santillán, I. M. A. Bender, C. I. Espinosa, J. Homeier, K. Böhning-Gaese, M. Schleuning & E. L. Neuschulz