Precipitation and temperature drives ant traits distribution along a altitudinal gradient
Diego Fernando Domínguez Gordillo, John Lattke , Mónica Páez , Elizabeth Gusmán , David Andrés Donoso Vargas
Departamento de Ciencias Naturales, Universidad Técnica Particular de Loja, Loja, Ecuador; Department of Zoology, Universidade Federal do Paraná, Curitiba, Brazil. ; Centro de Investigación de la Biodiversidad y Cambio Climático, Facultad de Ciencias de Medio Ambiente, Universidad Tecnológica Indoamérica, Calle Machala y Sabanilla, Quito, Ecuador. ; Departamento de Ciencias Naturales, Universidad Técnica Particular de Loja, Loja, Ecuador. ; Instituto de Ciencias Biológicas, Escuela Politécnica Nacional, Quito, Ecuador.
A growing body of literature suggests that species survival, and thus community structure, depends on the interactions between ecological traits and environment. Therefore, community functional responses (trait distribution) to ecological gradients can shed light on the mechanisms that govern species assembly at local and regional scales. We investigated the distribution of 17 functional (morphological) traits in 16 ant communities sorted in two forest types (wet and dry) along an 1950 m-altitudinal gradient, in southern Ecuador. We were able to test separately for the effects of ambient temperature and precipitation because they were not correlated, however they both were negatively correlated with altitude. We observe two ant assemblages. We found no evidence of a mid-altitude peak in species richness or abundance, and both ant abundance and species richness decreased at higher elevations. Most traits were positively correlated with temperature and precipitation. Traits related to thermoregulation e.g. ant body color (e.g. head and mesosoma color) were darker (i.e. black at higher temperatures, and browner at higher precipitation) with altitude. These findings show that environmental conditions affect the morphology of ants, with potential impact in their spatial distribution. At the same time, these results also suggest that environmental conditions act at local scales, implying a finer-grained impact in the taxonomic and functional composition of ant communities.