Lewin, A. & Feldman, A. & Bauer, A.M. & Belmaker, J. & Broadley, D.G. & Chirio, L. & Itescu, Y. & LeBreton, M. & Maza, E. & Meirte, D. & Nagy, Z.T. & Novosolov, M. & Roll, U. & Tallowin, O. & Trape, J.-F. & Vidan, E. & Meiri, S. (2016) - Patterns of species richness, endemism and environmental gradients of African reptiles. - Journal of Biogeography, 43 (12): 2380-2390.
× Aim To map and assess the richness patterns of reptiles (and included groups:
amphisbaenians, crocodiles, lizards, snakes and turtles) in Africa, quantify the
overlap in species richness of reptiles (and included groups) with the other terrestrial
vertebrate classes, investigate the environmental correlates underlying
these patterns, and evaluate the role of range size on richness patterns.
Location Africa.
Methods We assembled a data set of distributions of all African reptile species.
We tested the spatial congruence of reptile richness with that of amphibians,
birds and mammals. We further tested the relative importance of
temperature, precipitation, elevation range and net primary productivity for
species richness over two spatial scales (ecoregions and 1° grids). We arranged
reptile and vertebrate groups into range-size quartiles in order to evaluate the
role of range size in producing richness patterns.
Results Reptile, amphibian, bird and mammal richness are largely congruent
(r = 0.79–0.86) and respond similarly to environmental variables (mainly productivity
and precipitation). Ecoregion size accounts for more variation in the
richness of reptiles than in that of other groups. Lizard distributions are distinct
with several areas of high species richness where other vertebrate groups
(including snakes) are species-poor, especially in arid ecoregions. Habitat
heterogeneity is the best predictor of narrow-ranging species, but remains relatively
important in explaining lizard richness even for species with large range
sizes.
Main conclusions Reptile richness varies with similar environmental variables
as the other vertebrates in Africa, reflecting the disproportionate influence of
snakes on reptile richness, a result of their large ranges. Richness gradients of
narrow-ranged vertebrates differ from those of widespread taxa, which may
demonstrate different centres of endemism for reptile subclades in Africa.
Lizard richness varies mostly with habitat heterogeneity independent of range
size, which suggests that the difference in response of lizards is due to their
ecological characteristics. These results, over two spatial scales and multiple
range-size quartiles, allow us to reliably interpret the influence of environmental
variables on patterns of reptile richness and congruency.