Preliminary Analysis of Home Range Structure in the Komodo Monitor, Varanus Komodoensis

We conducted a radio-telemetric study to assess home range size and structure in the Komodo monitor, Varanus komodoensis, using minimum convex polygon (MCP) and kernel statistics. Home ranges calculated by MCP varied from 278 ha to 530 ha, while areas covered by 100% kernel contours ranged from 170 ha to 390 ha. We suggest that these areas probably represent only part of the entire home range of V. komodoensis. Locations recorded during long excursions of up to 5,500 m accounted for most of the difference observed between MCP and kernel-based methods. Home ranges showed different partitioning of core areas of most intensive use, which covered up to 29.5% of kernel utilization distribution and 56% of MCPs. Our results provide preliminary data to develop comprehensive studies on space use patterns of the Komodo monitor as part of management and conservation initiatives for Komodo monitors in Komodo National Park and the island of Flores, southeast Indonesia.

Figure 1

Map of study site. Grey areas show the distribution of Varanus komodoensis in Komodo National Park and West Flores. Hatched line delimits the boundary of Komodo National Park. Frames on Komodo and West Flores represent approximate locations of study areas.

Figure 2

Distribution of location points and home range assessed by minimum convex polygon (left) and kernel method (right) for female 1. Probability contours delineate regions of different intensity of home range use. From the outer border, contour lines represent 100%, 95%, 75%, 50%, and 25% (thick lines) of the kernel probability distribution, respectively. Units of measurement refer to Universal Transverse Mercator (UTM) grid coordinates expressed as a distance in kilometers to the east (easting) of UTM zone 50 and a distance in kilometers to the north (northing) measured from the South Pole.

Figure 3

Distribution of location points and home range for female 2. (A) Minimum convex polygon described by the solid line was calculated with the exclusion of location points recorded during two long excursions (1 and 2). Arrows show direction of movements. Dashed line describes total area of convex polygon. (B) Fixed kernel utilization distribution. Other details as in Fig. 2.

Figure 4

Distribution of location points and home range calculated using minimum convex polygon (A) and kernel approach (B) for male 3. Other details as in Fig. 2.