Niche-breadth of freshwater macrophytes occurring in tropical southern African rivers predicts species global latitudinal range

摘要: Abstract The study tested the hypothesis that measurement, using multivariate Principal Components Analysis (PCA), of niche-breadth river macrophyte species in southern tropical Africa, may predict their larger-scale biogeographical range. Two measures were calculated for 44 riverine species, from 20 families commonly occurring Zambia, an approach based on PCA ordination with 16 bio-physico-chemical input variables. These included altitude, stream order, flow, pH, conductivity and soluble reactive phosphate concentration (SRP). In absence additional chemical water quality data Zambian rivers, invertebrate-based general also used. benthic macroinvertebrate Average Score per Taxon (ASPT), individual abundance nine differing tolerance, indicated by Sensitivity Weightings within Invertebrate Scoring System (ZISS). Macrophyte large-scale latitudinal range was derived world geopositional records held online databases, authors. two metrics divided into narrow-niche intermediate/broad-niche categories, showing significant variation (from one or both correlation ANOVA test outcomes) conductivity, SRP, pH ASPT, but not order. alpha-diversity (as a measure number niches co-existing habitat) showed no relationship niche-breadth. Narrow-niche higher proportion Afrotropical endemics than did broader niche size. There predictive relationships between target at global scales, Neotropics.