The species richness-elevation relationship: globalpatterns of variation in chironomid richness inmountain lakes

MOTTA, LUCIANA; RUGGIERO, ADRIANA; DE MENDOZA, GUILLERMO; MASSAFERRO, JULIETA

INSECT CONSERVATION AND DIVERSITY

WILEY-LISS, DIV JOHN WILEY & SONS INC

Lugar: New York; Año: 2019 vol. 12 p. 339 - 350

1752-458X

1. The species richness-elevation relationship (SRE) is predominantlyhump-shaped along terrestrial gradients, but has been less explored in aquaticenvironments. Chironomids were used to evaluate the generality of the SRE inmountain lakes, and the role of methodological and biological factors indetermining its shape.2. The shape of 39 chironomid SREs distributed worldwide was identified byconsensus between statistical and visual methods. A ?coefficient of methodologicalintegrity? (Cin) was developed to combine information on sampling effortand homogeneity, and elevational extent in order to quantify the adherence ofeach dataset to methodological standards known to influence the SRE. Differencesin the shape of the SRE between biogeographical regions, biomes and climaticregions were tested using Fisher?s exact tests. A formal meta-analysis wasconducted to quantify the overall strength of the SRE, and its association withgeographical extent, sampling technique, biogeography, biomes and climate.3. The SRE presented multiple forms, with considerable variation betweenidentification methods. The most satisfactory datasets (i.e. lowest Cin values),showed predominance of non-linear (low-plateau and hump-shaped) patterns.The Cin explained ~21% of pattern variation. Neither biogeography, nor biomesor climatic regions accounted for differences in the shape of the SRE.4. The global predominance of non-linear SRE suggests that chironomidrichness generally remains high in lakes at mid-elevations, decreasing sharplytowards high elevations. As previously known for terrestrial environments, identificationof SRE shape is influenced by analytical method. Whenever possible,tailoring the sampling design to increase methodological integrity will reduceuncertainty in the identification of SRE shape in mountain lakes.