Process-Based Species Pools Reveal the Hidden Signature of Biotic Interactions Amid the Influence of Temperature Filtering.
A persistent challenge in ecology is to tease apart the influence of multiple processes acting simultaneously and interacting in complex ways to shape the structure of species assemblages. We implement a heuristic approach that relies on explicitly defining species pools and permits assessment of the relative influence of the main processes thought to shape assemblage structure: environmental filtering, dispersal limitations, and biotic interactions. We illustrate our approach using data on the assemblage composition and geographic distribution of hummingbirds, a comprehensive phylogeny and morphological traits. The implementation of several process-based species pool definitions in null models suggests that temperature-but not precipitation or dispersal limitation-acts as the main regional filter of assemblage structure. Incorporating this environmental filter directly into the definition of assemblage-specific species pools revealed an otherwise hidden pattern of phylogenetic evenness, indicating that biotic interactions might further influence hummingbird assemblage structure. Such hidden patterns of assemblage structure call for a reexamination of a multitude of phylogenetic- and trait-based studies that did not explicitly consider potentially important processes in their definition of the species pool. Our heuristic approach provides a transparent way to explore patterns and refine interpretations of the underlying causes of assemblage structure.
Jean-Philippe
JP
Lessard
Ben G
BG
Weinstein
Michael K
MK
Borregaard
Katharine A
KA
Marske
Danny R
DR
Martin
Jimmy A
JA
McGuire
Juan L
JL
Parra
Carsten
C
Rahbek
Catherine H
CH
Graham
D063147:Animal Distribution; D000818:Animals; D001717:Birds / Q000502:physiology*; D017753:Ecosystem; D004777:Environment; D005843:Geography; D010802:Phylogeny; D011891:Rain; D013020:South America; D013696:Temperature
community assembly; dispersal limitation; niche differentiation; regional species pool; scale