Running to the mountains: changes in plant-pollinator networks structure over space

Area of Science:

• Ecology
• Conservation Biology
• Biodiversity Research

Background:

• Plant-pollinator networks are vital for ecosystem functioning and biodiversity, particularly in mountainous regions.
• These networks are influenced by biotic and abiotic factors across elevation gradients and seasons, affecting species interactions and community structure.

Purpose of the Study:

• To investigate plant-pollinator network structures across different elevations (1000-1800m) and habitats in a Mediterranean mountain area.
• To determine the consistency of network structures across spatial contexts and assess the impact of abiotic drivers on network properties.

Main Methods:

• Documented 3343 plant-pollinator interactions involving 343 pollinator and 44 plant species across 14 study sites.
• Analyzed network metrics including nestedness, specialization, modularity, interaction diversity, and robustness.
• Correlated network metrics with environmental factors such as elevation, habitat type, rainfall, and soil temperature.

Main Results:

• Observed low nestedness, increasing with rainfall and higher in forests. Specialization increased with rainfall.
• Network modularity was higher in outcrops, influenced by soil temperature and rainfall. Interaction diversity was greater in outcrops, positively related to rainfall.
• Network robustness was inversely correlated with specialization. Flower and pollinator diversity, along with climate, predicted network properties.

Conclusions:

• Plant-pollinator network structures vary significantly across habitat types and elevations in Mediterranean mountains.
• Abiotic factors, especially rainfall and temperature, play a key role in shaping network structure, specialization, and robustness.
• Findings highlight potential vulnerabilities of pollination networks to environmental changes and climate change impacts in mountain biodiversity hotspots.