Original Research
Movement and Home Range of Nile Crocodiles in Ndumo Game Reserve, South Africa
Koedoe | Vol 57, No 1 | a1234 |
DOI: https://doi.org/10.4102/koedoe.v57i1.1234
| © 2015 Peter M. Calverley, Colleen T. Downs
| This work is licensed under CC Attribution 4.0
Submitted: 14 May 2014 | Published: 16 September 2015
Submitted: 14 May 2014 | Published: 16 September 2015
About the author(s)
Peter M. Calverley, School of Life Sciences, University of KwaZulu-Natal, South AfricaColleen T. Downs, School of Life Sciences, University of KwaZulu-Natal, South Africa
Abstract
The study of movement patterns and home range is fundamental in understanding the spatial requirements of animals and is important in generating information for the conservation and management of threatened species. Ndumo Game Reserve, in north-eastern KwaZulu-Natal, bordering Mozambique, has the third largest Nile crocodile (Crocodylus niloticus) population in South Africa. Movement patterns of 50 Nile crocodiles with a total length of between 202 cm and 472 cm were followed over a period of 18 months, using mark-resight, radio and satellite telemetry. The duration of radio transmitter attachment (131 ± 11.4 days) was significantly and negatively related to total length and reproductive status. Satellite transmitters failed after an average of 15 ± 12.5 days. Home range was calculated for individuals with 10 or more radio locations, spanning a period of at least 6 months. There was a significant relationship between home range size and total length, with sub-adults (1.5 m – 2.5 m) occupying smaller, more localised home ranges than adults (> 2.5 m). The largest home ranges were for adults (> 2.5 m). Home ranges overlapped extensively, suggesting that territoriality, if present, does not result in spatially discrete home ranges of Nile crocodiles in Ndumo Game Reserve during the dry season. Larger crocodiles moved farther and more frequently than smaller crocodiles. The reserve acts as a winter refuge and spring breeding site for an estimated 846 crocodiles, which also inhabit the Rio Maputo during the summer months. Nile crocodile movement out of the reserve and into the Rio Maputo starts in November and crocodiles return to the reserve as water levels in the floodplain recede in May.
Conservation implications: Movement patterns of Nile crocodiles show the important role the reserve plays in the conservation of Nile crocodile populations within the greater Ndumo Game Reserve–Rio Maputo area.
Conservation implications: Movement patterns of Nile crocodiles show the important role the reserve plays in the conservation of Nile crocodile populations within the greater Ndumo Game Reserve–Rio Maputo area.
Keywords
habitat use, home range, movement, Nile crocodile, South Africa, spatial ecology
Metrics
Total abstract views: 4968Total article views: 8839
Crossref Citations
1. Nematodes found in Nile crocodiles in the Kruger National Park, South Africa, with redescriptions of Multicaecum agile (Wedl, 1861) (Heterocheilidae) and Camallanus kaapstaadi Southwell & Kirshner, 1937 (Camallanidae)
Kerstin Junker, Joop Boomker, Danny Govender, Yasen Mutafchiev
Systematic Parasitology vol: 96 issue: 4-5 first page: 381 year: 2019
doi: 10.1007/s11230-019-09856-w