Gideon Deme Gywa, Yoila David Malann, Christopher J. Whelan, Abdel H. Halloway, Joel S. Brown

Abstract

Aim
While biodiversity trends and patterns are shaped by both biotic interactions and abiotic factors, biodiversity may vary in space and time when responding to environmental conditions across clines. However, we lack the knowledge of how biotic and abiotic factors determine species co-occurrence to influence community assemblage that can impact biodiversity trends and patterns across scales.

Location
The Americas

Methods
We downloaded a sample of species occurrence data from the Global Biodiversity Information Facility (GBIF) and environmental variables that are hypothesized to influence the association between hawk moths and hummingbirds’ co-occurrence across gradients. We then used the generalized additive models to understand how variations in environmental conditions across gradients will influence the co-occurrence between species.

Results
We found that the peak of species abundance and richness of both families was highest at the equator along latitude, while species abundance and richness increased with longitude. Increased colder temperatures, drier conditions, and low resource availability simultaneously reduced the occurrence of both hummingbirds and hawk moths across clines. In contrast, warmer annual temperatures and reduced seasonality concurrently increased the occurrence of both hummingbirds and hawk moth species. Interestingly, we found that hummingbird abundance and species richness persisted with increasing elevation when compared to hawk moths.

Main Conclusion
Our results suggest that hummingbirds and hawk moths co-occur more along the tropics and in certain areas of the temperate regions of the Americas that have suitable environmental conditions. We also found a pattern that suggests the possibility of niche partitioning between hummingbirds and hawk moths with increasing elevations, indicating hummingbirds with higher abundance and richness at higher elevations compared to hawk moths. We hypothesize that hummingbirds have traits that offer them certain advantages to occupy higher elevations, necessitating the need for future studies to use a multi-scale approach (e.g., integrating occurrences records and traits) when assessing biodiversity trends and patterns, and how these trends and patterns are shaped by both biotic interactions and abiotic factors are essential for the successful implementation of regional conservation programs of species.