Fig 1.
(a) topography with major mountain massifs and rivers, (b) major bioclimatic zones (herein called biomes) [47], (c) geographic regions ([48], boundaries based on watersheds ([2], and (d) delimitation of northern Madagascar as used herein including the Sambirano, North, and North East regions (map also shows a few towns and nature reserves discussed in the text).
Fig 2.
Biodiversity measures for reptiles and amphibians.
Species richness (SR), endemicity (corrected weighted endemism, CWE), and turnover as measured by general dissimilarity models (GDM), based on the distribution of 325 species of amphibians and 420 species of reptiles from Madagascar. Species richness scales range from low (blue) to high (red) number of species per hexagon; Local endemism values range from low (blue) to high (red).
Fig 3.
Species richness (SR) calculated separately for different clades and subclades of Malagasy amphibians and reptiles. Microhylidae G1 includes scaphiophrynines whereas G2 includes cophylines.
Fig 4.
Corrected weighted endemism (CWE) calculated separately for different clades and subclades of Malagasy amphibians and reptiles. Microhylidae G1 includes scaphiophrynines whereas G2 includes cophylines.
Fig 5.
Species richness by elevation.
Number of specimens of amphibians and reptiles, predicted by the adjusted SDMs to occur at certain elevations at intervals of 100 m above sea level. Presumably due to over-prediction the inferred elevational ranges probably are larger than the realized ones, giving higher numbers of species than actually occurring in lowlands and high elevations.
Fig 6.
Body size and range sizes correlations.
Correlation of body size with range size in amphibians (black circles and solid line) and reptiles (white squares and dashed line). Both correlations are highly significant (see text).
Fig 7.
Range filling of reptiles and amphibians.
Correlation of range filling (ratio of range sizes of clipped distribution model vs. full distribution model) with SVL, separately for amphibians (black solid circles) and reptiles (squares). Analyses carried out after removing all taxa with 1–2 data points only.
Fig 8.
Species numbers and proportion of amphibians and reptiles recorded during herpetological inventories in Madagascar.
Each pie chart represents one surveyed site (i.e., the area around one campsite at a specific elevation) and thus a community of co-occurring amphibian and reptile species. Pie area is proportional to the number of species; proportion of amphibians vs. reptiles in the community is indicated by colors. See S1 Table for a list of sites and references.
Fig 9.
Results of a Principal Component Analysis of surveyed sites in Madagascar.
Each dot represents the amphibian and reptile community at one site (see Fig 8 for a map of sites). Colors represent major bioclimatic subdivisions. PCA based on species numbers recorded for each of four major amphibian and eight major reptile groups (Table 1).
Table 1.
Results of a Principal Component Analysis of surveyed sites in Madagascar (Fig 8), based on species numbers recorded for each of 4 major amphibian and 8 major reptile groups.
Principal Components with eigenvalues >1 were extracted (PC1-PC3). Component loadings with values >0.5 are in bold.
Fig 10.
Graph showing relative observation probability of main categories of amphibian and reptile species in survey sites across Madagascar.
Bars show the percentage of species of each category found per site, relative to the respective number of species theoretically occurring at these sites based on overlap of clipped SDMs. Low values indicate groups that are either difficult to detect during surveys, or are ecological specialists occurring patchily across their range.