Stability and generalization in seed dispersal networks: a case study of frugivorous fish in Neotropical wetlands.

Autor:	Correa SB; Odum School of Ecology, University of Georgia, Athens, GA 30602, USA Department of Genetics, University of Georgia, Athens, GA 30602, USA., Arujo JK; Centro de Biodiversidade, Instituto de Biociências, Universidade Federal de Mato Grosso, Av. Fernando Correia 2367, Cuiabá, MT, Brazil., Penha J; Centro de Biodiversidade, Instituto de Biociências, Universidade Federal de Mato Grosso, Av. Fernando Correia 2367, Cuiabá, MT, Brazil., Nunes da Cunha C; Centro de Biodiversidade, Instituto de Biociências, Universidade Federal de Mato Grosso, Av. Fernando Correia 2367, Cuiabá, MT, Brazil., Bobier KE; Department of Genetics, University of Georgia, Athens, GA 30602, USA., Anderson JT; Odum School of Ecology, University of Georgia, Athens, GA 30602, USA Department of Genetics, University of Georgia, Athens, GA 30602, USA jta24@uga.edu.
Jazyk:	angličtina
Zdroj:	Proceedings. Biological sciences [Proc Biol Sci] 2016 Aug 31; Vol. 283 (1837).
DOI:	10.1098/rspb.2016.1267
Abstrakt:	When species within guilds perform similar ecological roles, functional redundancy can buffer ecosystems against species loss. Using data on the frequency of interactions between fish and fruit, we assessed whether co-occurring frugivores provide redundant seed dispersal services in three species-rich Neotropical wetlands. Our study revealed that frugivorous fishes have generalized diets; however, large-bodied fishes had greater seed dispersal breadth than small species, in some cases, providing seed dispersal services not achieved by smaller fish species. As overfishing disproportionately affects big fishes, the extirpation of these species could cause larger secondary extinctions of plant species than the loss of small specialist frugivores. To evaluate the consequences of frugivore specialization for network stability, we extracted data from 39 published seed dispersal networks of frugivorous birds, mammals and fish (our networks) across ecosystems. Our analysis of interaction frequencies revealed low frugivore specialization and lower nestedness than analyses based on binary data (presence-absence of interactions). In that case, ecosystems may be resilient to loss of any given frugivore. However, robustness to frugivore extinction declines with specialization, such that networks composed primarily of specialist frugivores are highly susceptible to the loss of generalists. In contrast with analyses of binary data, recently developed algorithms capable of modelling interaction strengths provide opportunities to enhance our understanding of complex ecological networks by accounting for heterogeneity of frugivore-fruit interactions. (© 2016 The Author(s).)
Databáze:	MEDLINE
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