Niche packing, but not niche expansion, explains the co-occurrence of hummingbirds-visited plants

Tropical mountains often harbour high species richness. Yet the mechanisms behind such high richness remain poorly understood. One prominent hypothesis for high species richness is niche partitioning, which reduces competition and promotes coexistence. Here, we evaluate niche structure and specialisation of plant species based on the floral traits related to pollination interactions across an elevational gradient in the northern Andes. Niche structure can vary among sites, either expanding or contracting, or becoming more or less packed. We sampled eleven communities of hummingbird-visited plants along an elevation gradient in the Ecuadorian Andes and measured a series of functional traits associated with hummingbird pollination. We used the traits of all co-occurring species to calculate community weighted means, functional richness, and mean nearest neighbour distances and evaluated how they varied across elevation. Additionally, we measured specialisation based on plant-hummingbird i..., , , # Niche packing, but not niche expansion, explains the co-occurrence of hummingbirds-visited plants [https://doi.org/10.5061/dryad.tdz08kq89](https://doi.org/10.5061/dryad.tdz08kq89) ## Description of the data and file structure ### Files and variables #### File: niche\_packing\_occ.csv **Description:**Â floral abundance per site ##### Variables #### File: niche\_packing\_sites.csv **Description:**Â geospatial information of each locality ##### Variables * site * longitude * latitude * elevation (m or ft) #### File: niche\_packing\_traits.csv **Description:**Â trait means for each plant species ##### Variables * FlowerSymmetry: binary variable (0 - non actinomorphic; 1 - actinomorphic) * FlowerType: binary variable (0 - non pendular flowers; 1 - pendular flowers) * AntherDehiscence: binary variable (0 - non poricidal, 1 -with poricidal anthers) * Tubelength: continuous (length of floral tube measured in cm) * StamenLength:Â continuous (length of stamen measured in cm) * StyleL...