OVERVIEW OF THE LNP COLLARED ELEPHANTS MOVEMENTS

Transcription

1 LIMPOPO NATIONAL PARK MONTHLY REPORT Dry Season 2018: April-September OVERVIEW OF THE LNP COLLARED ELEPHANTS MOVEMENTS Anka Bedetti Elephant Tracking & ID Projects Manager Elephants Alive Hoedspruit South Africa A full dry season has passed (April-Sept), allowing for a broad scale seasonal overview. Elephants tend to stick to certain areas as they are restricted by vegetation and water availability compared to the wet season. This is noticeable in the following report, as we compare elephants movements with the previous wet season. Figure 1: Greater Limpopo Transfrontier Park with a dense forest layer (Limpopo National Park) and probability of surface water occurrence layer (European Commission Copernicus Program) -

2 - Figure 2: Zoom-in of Limpopo National Park as an example, showing the dense forest layer and the probability of surface water occurrence layer Fig.2 s water layer shows the complete history of water detection over the past 32 year period ( ) to calculate water occurrence in an area. As rainfall data is difficult to obtain, this method can be used to describe elephant movement with regards to surface water availibility. The blue and orange circles, as can be seen along the Limpopo River for example, represent areas where water occur (75 to 25% occurrence), other areas are dry. The following table shows the distances travelled as well as home range sizes for the past wet and dry seasons.

3 km Table 1: Summary of distance travelled and alocoh home ranges per elephant for the past wet and dry season LNP Km travelled WET Season Km travelled DRY Season 2018 WET Season % Home Range - alocoh (Km 2 ) DRY Season % WET Season % DRY Season % Dusty Francesca Gemma Max Merlin Nicky Thandi Tinky Winslow The graphs below illustrate Table1: 3500 Distance travelled Dusty Francesca Gemma Max Merlin Nicky Thandi Tinky Winslow Wet Season - Oct 2017-March 2018 Dry Season - Apr-Sept 2018 Figure 3: Distance travelled (km) per elephant during the past wet and dry season Fig.3 shows that 5 elephants out of 9 have travelled further during the wet season compared to the dry season. This could mean that seasonality is not a determining factor for their movements, which is interesting to look into further.

4 % 50% alocoh Home Range 100% alocoh Home Range km km Wet Season - Oct 2017-Mar 2018 Wet Season - Oct 2017-March 2018 Dry Season - Apr-Sept 2018 Dry Season - Apr-Sept 2018 Figure 4: 50% and 100% home range sizes per elephant for the 2 different seasons Fig4. Shows, as expected that elephants have a bigger home range during the wet season than the dry season as they are less restricted by foraging and water availability. Merlin is the exception here as he travelled to Banhine National Park in May and hasn t been back since. We are keeping a close eye on this fascinating exploratory behaviour. Intrestingly, we also had a look at the percentage of distance travelled during the day and night % of distance travelled at night (18:00-06:00) Gemma Thandi Tinky Francesca Max Nicky Winslow Merlin Dusty Wet Season - Oct 2017-Mar 2018 Dry Season - Apr-Sept 2018 Figure 3: Proportion of distance travelled at night during the past wet and dry season The proportion of distance travelled during the day/night seems to be similar regardless of season. Although, LNP elephants have a much higher night percentage compared to other elephants of the Greater Limpopo Transfrontier Park.

5 Time Density Home Range Analysis This methodology quantifies the amount of time spent by an elephant per unit area providing more finescaled insight of elephants spatial and temporal use across a landscape, allowing to focus, protect and manage key areas. The following maps of each individual elephant shows their Time-Density home-range as percent of total hours tracked. The values range from green to red - red representing the most time the elephant has spent in one area. The 50% a-locoh areas have been encircled in black for better visualisation. It is immediately apparent which areas elephant streak through and in which they spend more time whether they are dictated by foraging, water availability, social bonds, rest or fear factors. A more thorough analysis will give more insight to identify the nature of their movements. Dusty s movement are visibility more concentrated around the central river in the dry season. He still visited the Limpopo River but hasn t spend as much time there compared to the wet season. There is more human presence around the Limpopo River and sparse folliage coverage could be the explaination of the less frequent visit/time spent at the available Limpopo River drinking spots.

6 Francesca s movement are similar to Dusty s, where more time is spend along the central river than anywhere else. Gemma s movment are very similar for both seasons.

7 Max has ventured more on the LNP side during the dry season compared to the wet season which is interesting. Merlin has left LNP and ventured all the way to Banhine National Park and South. His movements are very interesting. It would be great to know if he is a leader or a follower of these movements to try and make a bit more sense of it all as this type of exploratory behaviour is more characteristic for wet seasons, unless these movements are not driven by resources.

8 Nicky has clearly focused his movements along the central river during the dry season. Thandi and Tinky have shifted their home range to the LNP side for the dry season.

9 Similar to Dusty and Francesca, Winslow s movement are focused around the central river with less time spend in the Limpopo River area.