Seasonal variation of a plant-pollinator network in the Brazilian Cerrado: Implications for community structure and robustness

• Published in: PloS one 2019-12, Vol.14 (12), p.e0224997-e0224997
• Main Authors: Rabeling, Simone Cappellari, Lim, Jia Le, Tidon, Rosana, Neff, John L, Simpson, Beryl B, Pawar, Samraat
• Format: Article
• Language: English
• Subjects: Analysis; Angiosperms; Animals; Bees; Bees - physiology; Biodiversity; Biodiversity hot spots; Biology; Biology and Life Sciences; Biomes; Brazil; Climate change; Climatic conditions; College campuses; Community structure; Drought; Droughts; Dry season; Dynamic stability; Earth Sciences; Ecology and Environmental Sciences; Ecosystem biology; Ecosystems; Environmental changes; Environmental conditions; Environmental quality; Extreme drought; Extreme weather; Flowering; Flowers & plants; Flowers - physiology; Foraging behavior; Foraging habitats; Keystone species; Life sciences; Magnoliopsida; Phenology; Plant communities; Plant diversity; Plant reproduction; Plants; Plants (botany); Pollination - physiology; Pollinators; Precipitation; Precipitation and drought; Rain; Rainfall; Rainy season; Robustness; Seasonal variations; Seasons; Specialization; Species composition
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0224997

Seasonal variation in the availability of floral hosts or pollinators is a key factor influencing diversity in plant-pollinator communities. In seasonally dry Neotropical habitats, where month-long periods of extreme drought are followed by a long rainy season, flowering is often synchronized with the beginning of precipitation, when environmental conditions are most beneficial for plant reproduction. In the Brazilian Cerrado, a seasonally dry ecosystem considered one of the world's biodiversity hotspots for angiosperms, plants with shallow root systems flower predominantly during the rainy season. Foraging activity in social bees however, the major pollinators in this biome, is not restricted to any particular season because a constant supply of resources is necessary to sustain their perennial colonies. Despite the Cerrado's importance as a center of plant diversity, the influence of its extreme cycles of drought and precipitation on the dynamics and stability of plant-pollinator communities is not well understood. We sampled plant-pollinator interactions of a Cerrado community weekly for one year and used network analyses to characterize intra-annual seasonal variation in community structure. We also compared seasonal differences in community robustness to species loss by simulating extinctions of plants and pollinators. We find that the community shrinks significantly in size during the dry season, becoming more vulnerable to disturbance due to the smaller pool of floral hosts available to pollinators during this period. Major changes in plant species composition but not in pollinators has led to high levels of turnover in plant-pollinator associations across seasons, indicated by in interaction dissimilarity (