How does the functional diversity of frugivorous birds shape the spatial pattern of seed dispersal? A case study in a relict plant species.
Genetic markers used in combination with network analysis can characterize the fine spatial pattern of seed dispersal and assess the differential contribution of dispersers. As a case study, we focus on the seed dispersal service provided by a small guild of frugivorous birds to the common yew, Taxus baccata L., in southern Spain. We build the spatial networks of seed dispersal events between trees and seed-plots within the studied population-local network-and the spatial network that includes all dispersal events-regional network. Such networks are structured in well-defined modules, i.e. groups of tightly connected mother trees and seed-plots. Neither geographical distance, nor microhabitat type explained this modular structure, but when long-distance dispersal events are incorporated in the network it shows a relative increase in overall modularity. Independent field observations suggested the co-occurrence of two complementary groups, short- and long-distance dispersers, mostly contributing to the local and regional seed rain, respectively. The main long-distance disperser at our site, Turdus viscivorus, preferentially visits the most productive trees, thus shaping the seed rain at the landscape scale and affecting the local modular organization. We end by discussing how DNA barcoding could serve to better quantify the role of functional diversity.
Integrative Ecology Group, Estación Biológica de Doñana, (EBD-CSIC), C/Américo Vespucio s/n, Sevilla 41092, Spain jessica.lavabre@gmail.com.
Jessica E
0000-0002-6750-3310
JE
Lavabre
Integrative Ecology Group, Estación Biológica de Doñana, (EBD-CSIC), C/Américo Vespucio s/n, Sevilla 41092, Spain Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, Zurich 8057, Switzerland.
Luis J
LJ
Gilarranz
Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, Zurich 8057, Switzerland.
Miguel A
MA
Fortuna
Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, Zurich 8057, Switzerland.
Jordi
J
Bascompte
D000818:Animals; D044822:Biodiversity; D005247:Feeding Behavior; D020387:Food Chain; D005819:Genetic Markers; D008954:Models, Biological; D058614:Seed Dispersal; D017422:Sequence Analysis, DNA; D020308:Songbirds / Q000502:physiology*; D013030:Spain; D020946:Taxus / Q000235:genetics / Q000502:physiology*
D005819:Genetic Markers
Taxus baccata; ecosystem services; gene flow; heterogeneous landscape; modularity; spatial network