Mutualistic relationships, such as those between plants and pollinators, may be vulnerable to the local extinctions predicted under global environmental change. However, network theory predicts that plant–pollinator networks can withstand species loss if pollinators switch to alternative floral resources (rewiring). Whether rewiring occurs following species loss in natural communities is poorly known because replicated species exclusions are difficult to implement at appropriate spatial scales. We experimentally removed a hummingbird‐pollinated plant, We employed a replicated Before‐After‐Control‐Impact experimental design and quantified plant–hummingbird interactions using two parallel sampling methods: pollen collected from individual hummingbirds (‘pollen networks’, created from >300 pollen samples) and observations of hummingbirds visiting focal plants (‘camera networks’, created from >19,000 observation hours). To assess the extent of rewiring, we quantified ecological specialization at the individual, species and network levels and examined interaction turnover (i.e. gain/loss of pairwise interactions). Our results suggest that, at least over short time‐scales, animals may not necessarily shift to alternative resources after losing an abundant food resource—even in species thought to be highly opportunistic foragers, such as hummingbirds. Given that rewiring contributes to theoretical predictions of network stability, future studies should investigate why pollinators might not expand their diets after a local resource extinction.
Elevational gradients in alpine ecosystems are well suited to study how plant and pollinator communities respond to climate change. In the Austrian Alps, we tested how the taxonomic and functional diversity of plants and their pollinators change with increasing elevation and how this affects plant–pollinator network structure. We measured the phenotypes of flowering plants and their pollinators and observed their interactions in 24 communities along an elevational gradient. To assess variation in floral and pollinator traits, we then quantified trait spaces (
- NSF-PAR ID:
- 10495730
- Publisher / Repository:
- Springer Science + Business Media
- Date Published:
- Journal Name:
- Alpine Botany
- ISSN:
- 1664-2201
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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