Niche-breadth of freshwater macrophytes occurring in tropical Southern African rivers predicts species global latitudinal range
Date
2016
Authors
Sichingabula, Henry
Journal Title
Journal ISSN
Volume Title
Publisher
Elsevier
Abstract
The study tested the hypothesis that measurement, using multivariate Principal Components Analysis
(PCA), of the niche-breadth of river macrophyte species in southern tropical Africa, may predict
their larger-scale biogeographical range. Two measures of niche-breadth were calculated for 44 riverine
macrophyte species, from 20 families commonly occurring in Zambia, using an approach based on PCA
ordination with 16 bio-physico-chemical input variables. These included altitude, stream order, stream
flow, pH, conductivity and soluble reactive phosphate concentration (SRP). In the absence of additional
chemical water quality data for Zambian rivers, invertebrate-based measures of general water quality
were also used. These were benthic macroinvertebrate Average Score per Taxon (ASPT), and individual
abundance of nine macroinvertebrate families with differing water quality tolerance, indicated by their
Sensitivity Weightings within the Zambian Invertebrate Scoring System (ZISS). Macrophyte large-scale
latitudinal range was derived from world geopositional records held by online databases, and additional
records held by the authors. The two niche-breadth metrics divided the species into narrow-niche and
intermediate/broad-niche categories, showing significant variation (from one or both of correlation and
ANOVA test outcomes) in altitude, stream flow, conductivity, SRP, pH and ASPT, but not stream order.
Macrophyte alpha-diversity (as a measure of number of individual niches co-existing per habitat) showed
no significant relationship with individual species niche-breadth. Narrow-niche species included a higher
proportion of Afrotropical endemics than did species with broader niche size. There were significant predictive
relationships between macrophyte niche-breadth and latitudinal range of the target species at global and Afrotropical scales, but not for the Neotropics
Keywords:
Africa
Aquatic plants
Benthic macroinvertebrates
Freshwater ecology
Latitudinal distribution
Niche analysis
Rivers.
Description
Journal Article
Keywords
Benthic macroinvertebrates , Latitudinal distribution