Elevational surveys of Sulawesi herpetofauna 1: Gunung Galang, Gunung Dako Nature Reserve

Abstract

The Indonesian island of Sulawesi has a unique geology and geography, which have produced an astoundingly diverse and endemic flora and fauna and a fascinating biogeographic history. Much biodiversity research has focused on the regional endemism in the island's Central Core and on its four peninsulas, but the biodiversity of the island's many upland regions is still poorly understood for most taxa, including amphibians and reptiles. Here, we report the first of several planned full-mountain checklists from a series of herpetological surveys of Sulawesi's mountains conducted by our team. In more than 3 weeks of work on Gunung Galang, a 2,254 m peak west of the city of Tolitoli, Sulawesi Tengah Province, on Sulawesi's Northern Peninsula, we recovered nearly fifty species of reptiles and amphibians, more than a dozen of which are either new to science or known but undescribed. The incompleteness of our sampling suggests that many more species remain to be discovered on and around this mountain.

Keywords: Altitudinal gradient; Biodiversity; Biodiversity survey; Herpetology; Reptiles and amphibians; Southeast Asia; Transect survey; Wallacea.

Figure 1. Maps showing (A) location of Gunung Galang on Sulawesi and (B) detail of Tolitoli and the Western Gunung Dako Preserve with sampling points indicated.

Points less than 700 m elevation in light blue, points from 700–1,400 m elevation in medium blue, points above 1,400 m elevation in dark blue.

Figure 2. Photos of habitats present on Gunung Galang.

(A) Rice paddies at ~50 m elevation with views of Gunung Galang and Gunung Dako in the background. (B) Forest at mid camp ~1,100 m. (C) Forest at high camp ~1,650 m. (D) Stunted mossy forest at the summit ~2,250 m. (E) A landslide provided a rare view out of the forest eastwards, photo taken along the ridge near the summit ~2,000 m. Photos by B. Karin.

Figure 3. All frog (green; upright triangles), lizard (light blue; circles), and snake (dark blue; inverted triangles) species and specimens found on Gunung Dako, arranged by maximum elevation.

The upper line plot tallies species richness in 10 m intervals under a range-through assumption. Vertical dashed lines at 700 and 1,400 m demarcate the elevational bands (Table 2). The green, long-dashed line represents frogs; the light blue, short-dashed line represents lizards; the dark blue, dotted line represents snakes. Total richness is represented by the solid gray line.

Figure 4. Species accumulation over the course of the field survey.

(A) Accumulation of frog (green, long dashes), lizard (light blue, medium dashes), and snake (dark blue, dotted) species over the length of the survey period, plus the cumulative species count (gray, solid); (B) accumulation of all frog, lizard, and snake species found below 700 m (solid line), from 700 to 1,400 m (long dashes), and above 1,400 m (dot-dashes) elevation over the number of days during which specimens were collected in that band.