Aim: Environmental niche tracking is linked to the species ability to disperse. While well investigated on large spatial scales, dispersal constraints also influence small-scale processes and may explain the difference between the potential and the realized niche of species at small-scales. Here we test whether niche size and niche fill differ systematically according to dispersal syndrome within isolated oceanic islands. We expect species with higher dispersal abilities (anemochorous or endozoochorous) will have a higher niche fill, despite of their environmental niche size.

Location: Azores archipelago

Taxon: Native seed plants

Methods: We combined a georeferenced database of the species distribution within the archipelago (Azorean Biodiversity Portal/GBIF) with an expert-based dispersal syndrome categorization and a high-resolution climatic grid (CIELO model). Using four climatic variables (Annual Mean Temperature, Mean Diurnal Range, Annual Precipitation, Precipitation Seasonality), we calculated a 4-dimensional hypervolume to estimate the niche size of each species. Niche fill was quantified as the suitable climatic space of the island that was occupied by the focal species.

Results: Endozoochorous species display higher niche fill compared to epizoochorous and hydrochorous species, and larger niches than anemochorous and epizoochorous. Differences among the remaining groups are not significant neither for niche fill nor for niche size.

Main Conclusions: Although endozoochorous species track their niche more efficiently at small-scales than other dispersal syndromes, the differences between dispersal syndromes are not consistent. The ability of a species to track its niche at small-scales is not tightly related to its dispersal syndrome. Although intuitively appealing, dispersal syndrome classifications might not be the most appropriate tools for understanding dispersal processes at small-scales.

Data collection and processing are described in detail in the article. R scripts are available at https://github.com/neckera/niche-Azores.

CONTENTS:

BD_Azores_dryad.csv         <---  Species occurrences dataset

table_climate_dryad.csv    <---  Environmental values of the species occurrences at their respective coordinates

Leo_Dispersal syndromes and climatic niche differences in the Azorean seed plants_README.txt    <---  README describing the dataset