Home Range Size and Patterns of Movement in Bornean Earless Monitors, Lanthanotus Borneensis, in Sarawak, Borneo
Lanthanotus borneensis, Bornean Earless Monitors, are a species of conservation concern, categorized as Endangered in the International Union for Conservation of Nature Red List, and under the list of Totally Protected species in both Kalimantan and Sarawak. We applied radiotelemetry to a study of spatial ecology of nine adults of L. borneensis in Central Sarawak (four males, five females). Minimum convex polygons (100%) were generated for individuals to assess home range sizes. Home range sizes averaged 500.8 ± 300.9 m2, and only a slight overlap of space use was observed between sexes. L. borneensis are apparently sedentary for an average of 3 d, with intervening spikes of high movement, highest daily movement being 74 m. Our research demonstrates space use requirements of L. borneensis, which can be applied to conservation management efforts of this and similar tropical herpetofaunal species in Borneo.Abstract
Lanthanotus borneensis equipped with a radio transmitter on a harness.
Minimum convex polygons (100%) of tracked Lanthanotus borneensis from two sites (A and B), in the drainages of Upper Baleh, Sarawak. Colored polygons differentiating home ranges between sexes, blue representing males, and pink, females.
Boxplots showing distribution of home range sizes (A), daily displacement rates (B) and cumulative distances (C) between sexes in Lanthanotus borneensis (males, n = 4 and females, n = 5).
Scatterplot demonstrating relationship between the log10 values of mean body mass (kg) and mean home range size (100% MCP in ha) for selected species from the Varanidae and Lanthanotus borneensis (Varanus varius, Pascoe et al., 2019; V. tristis, Thompson et al., 1999; V. mertensi, Smith and Griffiths, 2009; V. indicus, Smith and Griffiths, 2009; V. gouldii, Green and King, 1978; V. olivaceus, Auffenberg, 1988; V. griseus, Ibrahim, 2002; V. bittatawa, Law et al., 2016; V. panoptes, Blamires, 2004; V. glauerti, Sweet, 1999; V. glebopalma, Sweet, 1999; V. salvator, Guerrero-Sanchez et al., 2022; V. bengalensis, Auffenberg et al., 1991). Closed circles indicate 100% MCP, open squares indicate 95% home ranges, open circles indicate reported occupancy areas and closed triangles indicate reported activity ranges. Single asterisks indicate males, and double asterisks indicate females. (Pearson's correlation coefficient (r = 0.667, P = 0.02))
Scatterplot of displacement in free-ranging Lanthanotus borneensis against days of tracking.
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