Seed dispersal by changing frugivore assemblages: a mechanistic test of global change effects

Rodríguez-Pérez, J., García, D., Martínez, D. and Morales, J. M. (2017) Seed dispersal by changing frugivore assemblages: a mechanistic test of global change effects. Oikos, 126(5), pp. 671-681. (doi: 10.1111/oik.03176)

Abstract

In the face of global change it is important to understand how changes in species abundance and richness can affect ecosystem functions. Here we modelled seed dispersal by animals in a fragmented secondary forest of the Cantabrian Range (northwestern Iberian Peninsula), simulating the activity of six frugivorous bird species when dispersing three species of fleshy-fruited trees. We calculated the density and richness of seeds deposited across a forested landscape, as well as the density of seeds arriving to open areas. We 1) study the complementarity of functional traits of each species with frugivore assemblages varying in species compositions (i.e. abundance and richness of bird assemblages), 2) identify those bird species whose functional roles are not redundant, and 3) explore the response of seed dispersal to random losses and to two non-random bird loss scenarios (i.e. overhunting and fewer individuals from migrant species). We found that simulations with the avian composition observed in the field (i.e. with uneven abundances of six bird species) led to values of seed dispersal higher to those emerging from four bird species equally abundant. The selective removal of dominant bird species led to significant decays in seed dispersal, suggesting non-redundant roles of abundant bird species. Seed dispersal decays were stronger under non-random than random scenarios of bird loss. In terms of seed density, the functional decays also differed between the scenarios of overhunting and reduced arrival of migrant birds, notably beyond 50% changes in bird species composition. Our results illustrate the need to integrate species composition (controlling for bird abundance and richness) and their sensitivity to disturbances when predicting the impact of global change on ecosystem functions.

• Item Type: Articles
• Additional Information: This research was supported by the Spanish National Program of Research and Development (MiCINN-CGL2008-1275, MinECo-CGL2011-2843 and MinECo-CGL2015-68963-C2-2-R grants to DG), and the FPI Program - European Social Fund (grant BES2009-25093 to DM).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Morales, Professor Juan
• Authors: Rodríguez-Pérez, J., García, D., Martínez, D., and Morales, J. M.
• College/School: College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
• Journal Name: Oikos
• Publisher: Wiley
• ISSN: 0030-1299
• ISSN (Online): 1600-0706
• Published Online: 22 September 2016

Related URLs

• Other