Elevational Gradients Shape Bee Network Structure and Community Composition Across Tropical Lowland to Montane Forests in Costa Rica

Mutualistic networks, such as those between plants and pollinators, play a crucial role in ecosystem stability and resilience. Previous theoretical work has posited that mutualistic networks with higher diversity, connectance, nestedness, interaction diversity and more generalist species are more resilient and stable. However, in some ecosystems, specialized interactions and specialists may promote network stability. Drivers of network properties in the neotropics, especially low and mid-elevations, remain relatively unknown, and thus this area should receive special attention. Replicated empirical networks comparing properties along environmental gradients in these regions can help contribute to resolving this debate. A total of 28 networks, replicated within five elevational bands spanning between 200 to 1500 m elevation, were constructed in smallholder farms in three life zones: tropical dry forests, premontane forests, and montane forests in the mountains of Costa Rica. Results revealed a marginally significant decreasing relationship between elevation and network specialization. Connectance and modularity both statistically differed by elevation band with modularity decreasing and connectance increasing with increasing elevation. Collectively, elevation explained 28.28% of the variation in bee community composition. These results suggest that neotropical lowland networks tend to be more specialized, more modular, and less connected compared to higher elevations. These findings contribute to the ongoing debate by demonstrating that network properties are sensitive to elevation in the neotropics, with lowland networks exhibiting more specialized and modular structures. Therefore, lowland elevations should remain a priority in conservation as they may harbor more species interactions.

Name thesis:degree_name

Master of Science (MS)

Discipline thesis:degree_discipline

Biological Sciences

Year

2024

Author dc:creator

• Hsu, Jenny

• bee;elevational gradient;lowland;mutualistic;network;tropical
• Entomology
• Terrestrial and Aquatic Ecology

Repository record dc:identifier

https://encompass.eku.edu/etd/836

OAI identifier oai:identifier

oai:encompass.eku.edu:etd-1834