Habitat Characteristics of Forest Fragments Determine Specialisation of Plant-Frugivore Networks in a Mosaic Forest Landscape

Chama, Lackson; Berens, Dana G.; Downs, Colleen T.; Farwig, Nina

doi:10.1371/journal.pone.0054956

Cited by 28 publications

(21 citation statements)

References 46 publications

(63 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Our results reveal large‐scale variability in interaction complementarity, estimated from specialization, as shown by other studies over regional extents (e.g., Chama et al, ). Local specialization values differed significantly from those expected by the random association of interacting frugivores and plants, suggesting that interaction complementarity resulted from ecological determinants (Dormann et al, ).…”

Section: Discussionsupporting

confidence: 88%

Frugivore biodiversity and complementarity in interaction networks enhance landscape‐scale seed dispersal function

2018

View full text Add to dashboard Cite

Animal biodiversity matters for the provision of ecosystem functions derived from trophic activity. However, the mechanisms underlying this pattern remain elusive since animal abundance and diversity, which are the components commonly used for representing biodiversity, provide poor information about ecological complementarity in species assemblages. An approach based on species interaction networks may overcome this constraint. Here, we relate frugivore biodiversity and frugivore–plant network structure with landscape‐scale seed dispersal function. We sampled, for two years, and at fourteen plots with variable assemblages of frugivores and plants in the Cantabrian Range (N Spain), data on the abundance and diversity of frugivorous birds, the consumption of fleshy fruits of woody plants and the landscape‐scale patterns of avian seed deposition. As a measure of interaction complementarity in seed dispersal networks, we estimated the degree to which frugivore and plant species specialize in their interacting partners. Specialization varied strongly across the seed dispersal networks of the different plots, being higher in networks harbouring smaller bird species that dispersed mostly small‐fruited plants, and also in networks with late‐ripening, dominant fruiting species dispersed mostly by wintering birds. Bird abundance markedly affected seed deposition. Plots harbouring more birds received a higher density of dispersed seeds and showed higher probabilities of seed arrival and seed deposition in open microhabitats. Bird diversity also had a positive effect on the density of dispersed seed and, to a lesser extent, seed arrival probability. Independently of frugivore abundance and diversity, the density of dispersed seeds increased in plots where seed dispersal networks showed a higher degree of specialization. This study considers the structure of interaction networks to re‐address the relationship between biodiversity and ecosystem functionality, evidencing that specialization in frugivore–plant networks drives the large‐scale process of seed dispersal. These results encourage the consideration of interaction complementarity as an underlying mechanism linking animal biodiversity and trophic‐related functions.

show abstract

Section: Discussionsupporting

confidence: 88%

Frugivore biodiversity and complementarity in interaction networks enhance landscape‐scale seed dispersal function

2018

View full text Add to dashboard Cite

show abstract

“…Consistently, an experimental study with nectar feeders in tropical forests showed a low specialization of hummingbird species under manipulated unlimited nectar resources, whereas the same hummingbird species partitioned their foraging niches under natural conditions with limited resources (Maglianesi et al ). However, increasing specialization when resource availability is low is not consistent with other studies of mutualistic seed‐dispersal (Albrecht et al , Chama et al ) and pollination networks (Fontaine et al ) which found increasing specialization with greater resource abundance. These results were interpreted using optimal foraging theory which assumes that at low resource abundance species tend to widen their foraging niche, due to a higher cost in foraging for specific resources (MacArthur and Pianka ).…”

Section: Discussioncontrasting

confidence: 54%

Effects of hummingbird morphology on specialization in pollination networks vary with resource availability

Tinoco

Graham

Aguilar

et al. 2016

Oikos

View full text Add to dashboard Cite

Specialization of species in interaction networks infl uences network stability and ecosystem functioning. Spatial and temporal variation in resource availability may provide insight into how ecological factors, such as resource abundance, and evolutionary factors, such as phylogenetically conserved morphological traits, infl uence specialization within mutualistic networks. We used independent measures of hummingbird abundance and resources (nectar), information on hummingbird traits and plant -hummingbird interactions to examine how resource availability and species ' morphology infl uence the specialization of hummingbirds in three habitat types (forest, shrubs, cattle ranch) sampled over 10 sessions across two years in the southern Andes of Ecuador. Specialization of hummingbird species in the networks was measured by three indices: d ' (related to niche partitioning), generality (related to niche width) and PSI (related to pollination services). Specialization indices d ' , generality and PSI of hummingbird species were infl uenced by resource availability. All indices indicated that specialization of hummingbirds increased when the availability of resources decreased. Variation in d ' was also explained by an interaction between resource availability and bill length; hummingbirds with a long bill switched from being more specialized than other species when resource availability was low to being similarly specialized when availability was high. Overall, our results highlight the importance of ecological and evolutionary factors determining the specialization of species in interaction networks. We demonstrate in particular that ecological gradients in resource availability cause substantial changes in consumers ' foraging behavior contingent on their morphology. Changes in pollinator specialization along resource gradients can have impacts on ecosystem functions, such as pollination by animals.

show abstract

“…Invaded forests in our study region still seem to sustain habitat conditions, which are suitable for forest specialists (e.g. high fruiting plant richness and dense canopy covers; Chama et al 2013). An explanation is that invasive plants mainly dominated at forest edges, whereas the forest interior often still showed near‐natural conditions.…”

Section: Discussionmentioning

confidence: 86%

Guild‐specific shifts in visitation rates of frugivores with habitat loss and plant invasion

Graß

Berens

Farwig

2013

Oikos

Self Cite

View full text Add to dashboard Cite

Habitat loss and plant invasions are two major drivers of global change in subtropical and tropical ecosystems. Both lead to a loss of biodiversity and alter species interactions, which may imperil vital ecosystem processes such as seed dispersal by frugivores. Reponses of frugivores to disturbance are often linked to their specialization on certain habitats or resources. Yet, it is poorly understood how habitat loss and plant invasion structure interactions between plants and different habitat or feeding guilds. Here we investigated whether visitation rates of frugivores change guild‐specifically with increasing habitat loss and invasion level in a heterogeneous subtropical landscape. In 756 h of observations, we recorded 1446 plant–frugivore interactions among 18 plant species and 42 avian frugivore species. Visitation rates of forest specialists decreased with increasing habitat loss, but not with changes in invasion level. In contrast forest generalists and forest visitors were unaffected by either driver. Similarly, obligate frugivores that overall showed a generalized fruit choice were unaffected by habitat loss and changes in invasion level. Contrary, visitation rates of specialized partial and opportunistic frugivores decreased with higher invasion level. Importantly, the negative effect of plant invasion on partial frugivores was more pronounced as habitat loss in the same study site increased, indicating a synergistic effect of the two drivers. The implications of our study are twofold: first, frugivores respond guild‐specifically to habitat loss and plant invasion. Thereby forest dependency is mainly related to habitat loss, and degree of frugivory mainly related to plant invasion. Forest generalists and obligate frugivores in turn may play a key‐role for forest regeneration in disturbed forest landscapes. Second, particularly frugivores with a specialized fruit choice may be threatened by synergistic effects between habitat loss and plant invasion.

show abstract

Habitat Characteristics of Forest Fragments Determine Specialisation of Plant-Frugivore Networks in a Mosaic Forest Landscape

Cited by 28 publications

References 46 publications

Frugivore biodiversity and complementarity in interaction networks enhance landscape‐scale seed dispersal function

Frugivore biodiversity and complementarity in interaction networks enhance landscape‐scale seed dispersal function

Effects of hummingbird morphology on specialization in pollination networks vary with resource availability

Guild‐specific shifts in visitation rates of frugivores with habitat loss and plant invasion

Contact Info

Product

Resources

About