Correlated loss of ecosystem services in coupled mutualistic networks

Abstract

Networks of species interactions promote biodiversity and provide important ecosystem services. These networks have traditionally been studied in isolation, but species are commonly involved in multiple, diverse types of interaction. Therefore, whether different types of species interaction networks coupled through shared species show idiosyncratic or correlated responses to habitat degradation is unresolved. Here we study the collective response of coupled mutualistic networks of plants and their pollinators and seed dispersers to the degradation of Europe's last relict of old-growth lowland forest (Białowieża, Poland). We show that logging of old-growth forests has correlated effects on the number of partners and interactions of plants in both mutualisms, and that these effects are mediated by shifts in plant densities on logged sites. These results suggest bottom-up-controlled effects of habitat degradation on plant-animal mutualistic networks, and predict that the conversion of primary old-growth forests to secondary habitats may cause a parallel loss of multiple animal-mediated ecosystem services.

Massively Introduced Managed Species and Their Consequences for Plant–Pollinator Interactions

“…In some cases, MIMS such as A. mellifera and oilseed rape occupy a central position in the networks, being characterized by high degree and a high contribution to nestedness. This position is comparable to that often found for invasive pollinator and plant species in mutualistic networks (Albrecht et al, 2014;Stouffer et al, 2014;Traveset and Richardson, 2014;Traveset et al, 2013), and have been highlighted as an important driver of eco-evolutionary feedbacks favouring trait complementarity between the two levels of a mutualistic network (for example, plants and pollinators) and increasing trait convergence within levels (Guimaraes et al, 2011). For A. mellifera, this similarity with invasive species is not surprising since it is considered as invasive in some parts of the world (Goulson, 2003).…”

“…Indeed, abundant species generally are more likely to be generalists in observed mutualistic networks, due to higher encounter probability (Fort et al, 2016). MIMS might thus, in some cases, increase connectance and nestedness of plant-pollinator networks as well as decrease network modularity, as has been suggested for invasive species (Albrecht et al, 2014;Stouffer et al, 2014;Traveset et al, 2013). Increased network connectance and nestedness might favour species persistence and community stability (Rohr et al, 2014;Th ebault and Fontaine, 2010), but it could also decrease species diversity if competition between pollinators for resources and between plants for pollinator access is important (Benadi et al, 2012;Valdovinos et al, 2013).…”

Phylogenetic and Functional Diversity of Fleshy-Fruited Plants Are Positively Associated with Seedling Diversity in a Tropical Montane Forest

“…This relationship suggests that an increase in resource diversity increases the number of feeding niches of frugivorous birds (Dehling et al, 2016), consistent with a bottom-up control of mutualistic plant-animal interactions (Albrecht et al, 2014). Frugivorous birds have the ability to track fruits and respond directly to the spatial-temporal availability of fruits (Hampe, 2008;García et al, 2011).…”

“…In contrast, a high degree of animal redundancy, and a low degree of trait matching, would dilute the signal of frugivore traits on seedling diversity, e.g., because many large frugivores are able to feed on different fruit sizes (Bender et al, 2017;Muñoz et al, 2017a). It has been shown that mutualistic plant-animal interactions are influenced by bottom-up effects of plants on animal diversity (e.g., Albrecht et al, 2014), whereas top-down effects on these interactions are usually weaker . If bottom-up effects are more pronounced than top-down effects, one might expect an association between the diversity of plant and seedling communities even in a scenario where species traits have little effect on mutualistic interactions.…”

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“…The web of interactions promote community resilience and help deliver important ecosystem services [1]. Interactions between organisms can take many forms and fall along the continuum from antagonistic to synergistic; for example, commensalism, competition, predation, no interaction, mutualism, and amensalism [2,3].…”