Leiden University Scholarly Publications

Law, S.J.; Kort, S.R. de; Bennett, D.; Weerd, M. van (2018)

Diet and Habitat Requirements of the Philippine Endemic Frugivorous Monitor Lizard Varanus bitatawa

Article / Letter to editor

Little is known about the ecology and diet of Varanus bitatawa, a recently discovered monitor lizard endemic to the Sierra Madre Mountains of Northern Luzon. Here we present data that show that it has a seasonal omnivorous diet comparable to its southern congener Varanus olivaceus. Consumption of fruits from Pandanus sp., Canarium sp. and Microcos stylocarpa was evident in fecal samples, from spool and line tracking observations, and from camera trap images. The frugivorous diet was supplemented with snails and insects belonging to the orders Orthoptera, Phasmatodea and Coleoptera. Habitat of V. bitatawa was studied in lowland disturbed dipterocarp forest at an elevation below 300 m. In three sampled sites basal area of dipterocarp trees ranged from 16.23 to 84.14 m2 ha-1, total tree density from 624.6 to 1021.4 trees per ha-1 and density of Pandanus from 115.15 to 222.30 trees per ha-1. Predominantly arboreal, V. bitatawa showed reliance on large sentinel trees. Of trees...Show moreLittle is known about the ecology and diet of Varanus bitatawa, a recently discovered monitor lizard endemic to the Sierra Madre Mountains of Northern Luzon. Here we present data that show that it has a seasonal omnivorous diet comparable to its southern congener Varanus olivaceus. Consumption of fruits from Pandanus sp., Canarium sp. and Microcos stylocarpa was evident in fecal samples, from spool and line tracking observations, and from camera trap images. The frugivorous diet was supplemented with snails and insects belonging to the orders Orthoptera, Phasmatodea and Coleoptera. Habitat of V. bitatawa was studied in lowland disturbed dipterocarp forest at an elevation below 300 m. In three sampled sites basal area of dipterocarp trees ranged from 16.23 to 84.14 m2 ha-1, total tree density from 624.6 to 1021.4 trees per ha-1 and density of Pandanus from 115.15 to 222.30 trees per ha-1. Predominantly arboreal, V. bitatawa showed reliance on large sentinel trees. Of trees utilized, 47.4% were estimated at over 30 m tall with a mean circumference at breast height (CBH) of 176.28 cm and were significantly larger than the mean CBH of trees in sampled habitats. Shy and reclusive, V. bitatawa is likely to be vulnerable to disturbance. Illegal selective logging further degrades remaining habitat threatening the large dipterocarp trees on which they rely. Continued and improved protection of the forests within the Sierra Madre Mountain Range is imperative to safeguard the future of this restricted range species.Show less

All authors

Law, S.J.; Kort, S.R. de; Bennett, D.; Weerd, M. van

Date

2018

Journal

Biawak

Volume

12

Issue

1

Pages

12 - 22