Spatial networks of fleshy‐fruited trees drive the flow of avian seed dispersal through a landscape

• Published in: Functional ecology 2014-08, Vol.28 (4), p.990-998
• Main Authors: Rodríguez‐Pérez, Javier, García, Daniel, Martínez, Daniel, Piersma, Theunis
• Format: Article
• Language: English
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Applied ecology; Autoecology; Aves; Biological and medical sciences; Birds; Crataegus monogyna; crops; Dispersal; dispersal hubs; Evolutionary ecology; frugivores; Fruit crops; Fruiting; Fruits; functional connectivity; Fundamental and applied biological sciences. Psychology; General aspects; genes; Human ecology; Ilex aquifolium; Landscape ecology; Landscapes; plant–frugivore interactions; secondary forests; Seed dispersal; seed rain; Seeds; structural connectivity; Trees; Turdus spp; Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution
• ISSN: 0269-8463; 1365-2435
• DOI: 10.1111/1365-2435.12276

Seed dispersal by animals leads to plant genes, individuals and species flowing across the landscape, but this process has been seldom seen as the explicit result of structural or landscape connectivity. For two years, we studied avian seed dispersal of fleshy‐fruited trees in a secondary forest of the northern Iberian Peninsula, considering the areas under the canopies of fruiting trees as hubs of seed deposition. Using graph‐theory models, we set a spatially explicit network in a continuous landscape, with individual fruiting trees as nodes and expected frugivore movements as links between nodes. We calculated the contribution of each tree to network connectivity, finding strong inter‐annual variability derived from tree properties (position, fruit crop and species). Trees contributing the most to connectivity accumulated larger seed clumps under their canopies, demonstrating agreement between a network structural connectivity and the functional connectivity of seed dispersal flow. This pattern, however, is accentuated when the large‐scale distribution of fruiting crops closely matches that of individual trees, suggesting between‐year variation in resource tracking by avian frugivores. Our findings reveal connectivity to be an emerging property of plant‐disperser systems, operating at the scale of individual fruiting plants, but contingent on the yearly, large‐scale templates of fruiting crops.