TY - JOUR
T1 - Fragmented tropical forests lose mutualistic plant–animal interactions
AU - Marjakangas, Emma Liina
AU - Abrego, Nerea
AU - Grøtan, Vidar
AU - de Lima, Renato A.F.
AU - Bello, Carolina
AU - Bovendorp, Ricardo S.
AU - Culot, Laurence
AU - Hasui, Érica
AU - Lima, Fernando
AU - Muylaert, Renata Lara
AU - Niebuhr, Bernardo Brandão
AU - Oliveira, Alexandre A.
AU - Pereira, Lucas Augusto
AU - Prado, Paulo I.
AU - Stevens, Richard D.
AU - Vancine, Maurício Humberto
AU - Ribeiro, Milton Cezar
AU - Galetti, Mauro
AU - Ovaskainen, Otso
N1 - Publisher Copyright:
© 2019 The Authors. Diversity and Distributions published by John Wiley & Sons Ltd
PY - 2020/2/1
Y1 - 2020/2/1
N2 - Aim: Forest fragmentation is among the principal causes of global biodiversity loss, yet how it affects mutualistic interactions between plants and animals at large spatial scale is poorly understood. In particular, tropical forest regeneration depends on animal-mediated seed dispersal, but the seed-dispersing animals face rapid decline due to forest fragmentation and defaunation. Here, we assess how fragmentation influences the pairwise interactions between 407 seed disperser and 1,424 tree species in a highly fragmented biodiversity hotspot. Location: Atlantic Forest, South America. Methods: We predicted interaction networks in 912 sites covering the entire biome by combining verified interaction data with co-occurrence probabilities obtained from a spatially explicit joint species distribution model. We identified keystone seed dispersers by computing a species-specific keystone index and by selecting those species belonging to the top 5% quantile. Results: We show that forest fragmentation affects seed dispersal interactions negatively, and the decreased area of functionally connected forest, rather than increased edge effects, is the main driver behind the loss of interactions. Both the seed disperser availability for the local tree communities and in particular the proportion of interactions provided by keystone seed dispersers decline with increasing degree of fragmentation. Importantly, just 21 keystone species provided >40% of all interactions. The numbers of interactions provided by keystone and non-keystone species, however, were equally negatively affected by fragmentation, suggesting that seed dispersal interactions may not be rewired under strong fragmentation effects. Conclusions: We highlight the importance of understanding the fragmentation-induced compositional shifts in seed disperser communities as they may lead to lagged and multiplicative effects on tree communities. Our results illustrate the utility of model-based prediction of interaction networks as well as model-based identification of keystone species as a tool for prioritizing conservation efforts. Similar modelling approaches could be applied to other threatened ecosystems and interaction types globally.
AB - Aim: Forest fragmentation is among the principal causes of global biodiversity loss, yet how it affects mutualistic interactions between plants and animals at large spatial scale is poorly understood. In particular, tropical forest regeneration depends on animal-mediated seed dispersal, but the seed-dispersing animals face rapid decline due to forest fragmentation and defaunation. Here, we assess how fragmentation influences the pairwise interactions between 407 seed disperser and 1,424 tree species in a highly fragmented biodiversity hotspot. Location: Atlantic Forest, South America. Methods: We predicted interaction networks in 912 sites covering the entire biome by combining verified interaction data with co-occurrence probabilities obtained from a spatially explicit joint species distribution model. We identified keystone seed dispersers by computing a species-specific keystone index and by selecting those species belonging to the top 5% quantile. Results: We show that forest fragmentation affects seed dispersal interactions negatively, and the decreased area of functionally connected forest, rather than increased edge effects, is the main driver behind the loss of interactions. Both the seed disperser availability for the local tree communities and in particular the proportion of interactions provided by keystone seed dispersers decline with increasing degree of fragmentation. Importantly, just 21 keystone species provided >40% of all interactions. The numbers of interactions provided by keystone and non-keystone species, however, were equally negatively affected by fragmentation, suggesting that seed dispersal interactions may not be rewired under strong fragmentation effects. Conclusions: We highlight the importance of understanding the fragmentation-induced compositional shifts in seed disperser communities as they may lead to lagged and multiplicative effects on tree communities. Our results illustrate the utility of model-based prediction of interaction networks as well as model-based identification of keystone species as a tool for prioritizing conservation efforts. Similar modelling approaches could be applied to other threatened ecosystems and interaction types globally.
KW - Atlantic Forest
KW - Hierarchical Modelling of Species Communities
KW - co-occurrence
KW - ecological network
KW - fragmentation
KW - frugivory
KW - joint species distribution model
KW - keystone species
KW - seed dispersal
KW - zoochory
UR - http://www.scopus.com/inward/record.url?scp=85075359083&partnerID=8YFLogxK
U2 - 10.1111/ddi.13010
DO - 10.1111/ddi.13010
M3 - Article
AN - SCOPUS:85075359083
SN - 1366-9516
VL - 26
SP - 154
EP - 168
JO - Diversity and Distributions
JF - Diversity and Distributions
IS - 2
ER -