Premium
Seed‐dispersal networks on the C anaries and the G alápagos archipelagos: interaction modules as biogeographical entities
Author(s) -
Nogales M.,
Heleno R.,
Rumeu B.,
GonzálezCastro A.,
Traveset A.,
Vargas P.,
Olesen J. M.
Publication year - 2016
Publication title -
global ecology and biogeography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.164
H-Index - 152
eISSN - 1466-8238
pISSN - 1466-822X
DOI - 10.1111/geb.12315
Subject(s) - nestedness , modularity (biology) , biological dispersal , biology , ecology , extinction (optical mineralogy) , ballooning , evolutionary biology , archipelago , habitat , physics , population , demography , sociology , paleontology , plasma , quantum mechanics , tokamak
Aim Mutualistic network parameters, such as modularity and nestedness, show non‐random linkage patterns. Both increase network stability in different ways. Modularity hampers extinction cascades, whereas nestedness resists network disassembly. We explore these parameters in seed‐dispersal networks in two archipelagos and the significance of life history, habitat, geography and phylogeny as drivers of linkage patterns and the applicability of modules as biogeographical entities. Location C anaries ( A tlantic O cean) and G alápagos ( P acific O cean). Methods We compiled data on plant–seed disperser interactions from own observations and the literature, estimated network parameters describing interaction patterns (connectance, nestedness and modularity) and constructed a backbone phylogeny for the analyses. Results The C anarian network was highly nested but weakly modular, whereas the G alápagos network showed the opposite characteristics. Most key network species are native and have a favourable conservation status. Modularity in the C anaries is correlated with habitats (indirectly affected by altitude and orientation), whereas in the G alápagos it mainly reflects the functional roles of species. Main conclusions The divergent link patterns for the archipelagos imply that the highly nested C anarian network is stable against disassembly, whereas the modular G alápagos network may show strong resistance against extinction cascades. This difference may be driven by the specific evolutionary dynamics on the archipelagos.