Node-by-node disassembly of a mutualistic network driven by species introductions.

MARIANO A. RODRIGUEZ CABAL; M. NOELIA BARRIOS GARCIA; GUILLERMO C. AMICO; MARCELO A. AIZEN; NATHAN J. SANDERS

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA

NATL ACAD SCIENCES

Lugar: Washington DC, USA; Año: 2013 p. 16503 - 16507

0027-8424

Interaction webs summarize the diverse interactions among species in communities. The addition or loss of particular species and the alteration of key interactions can lead to the disassembly of the entire interaction web, although the nontrophic effects of species loss on interaction webs are poorly understood. We took advantage of ongoing invasions by a suite of exotic species to examine their impact in terms of the disassembly of an interaction web in Patagonia, Argentina. We found that the reduction of one spe- cies (a host of a keystone mistletoe species) resulted in diverse indirect effects that led to the disassembly of an interaction web through the loss of the mistletoe, two key seed-dispersers (a marsupial and a bird), and a pollinator (hummingbird). Our results demonstrate that the gains and losses of species are both consequences and drivers of global change that can lead to un- derappreciated cascading coextinctions through the disruption of mutualisms.