Tracking black rhinos in Zambia
Paul Smith, Head of Kew's Millennium Seed Bank, carried out a vegetation survey of the North Luangwa National Park back in the 1990s. Now he's returned to the Park to help with the black rhino reintroduction project. He has been studying the plants and habitats that black rhinos prefer and keeping a daily record of his activities. Read his daily diary below.
Black rhinoceros (Diceros bicornis) (Image courtesy of Save The Rhino International)
Wednesday 27th February
I set off at seven this morning accompanied by two game scouts armed with AK 47s and a rhino tracking device. My assistants are called Chambo and Michael.
Chambo and Michael standing by a shrub, Combretum zeyheri, browsed by black rhino.(Image: Paul Smith)
We find a rhino!
We headed west and then turned south, parallel with the Muchinga escarpment into the territory of a male rhino called Kango. We located Kango with the tracking device (he has a radio transmitter collar), but he caught wind of us when we were about 40 yards away. He took off with quite a hullabaloo – fortunately, downwind and away from us. Rhinos are big, heavy animals and the last thing you want is two tons of irate rhino coming at you through thick bush. As soon as he had crashed away, we were able to pick up his spoor and backtrack the route he had taken in the night. Black rhino tend to do their browsing (eating shrubs and trees) at night and lie up during the day. His tracks were easy to follow in the soft ground, and Chambo (from the Bisa tribe), in particular, is a good tracker.
We followed the rhino's route for a mile or so, and it was clear that he hadn’t been stopping during that part of his journey because there was no sign of any browse bites on the vegetation along the way. He left regular middens to mark his territory until he got to a small stream. There we picked up lots of evidence of what he had been eating.
What was he eating?
We recorded signs of browsing on the following species: Combretum zeyheri (Mufuko – Bisa); Ormocarpum kirkii (Mupulupulu - Bisa); Dichrostachys cinerea cinerea (Lupangala – Bisa, Senga); Argyrolobium sp.; Duosperma crenatum (a favourite); Lannea humilis; Jasminum stenolobum; Commelina bracteosa (blue flower);Ocimum americanum (Lwena – Bisa); Dalbergia melanoxylon; Pterocarpus rotundifolius (Muchalala – Bisa); Acacia tortilis; Markhamia zanzibarica; Feretia aeruginescens; Cissus cornifolia; Siphonochilus sp.; Premna senensis; and Phyllanthus reticulatus.
Tracking radio-collared black rhino from the air. (Image: Paul Smith)
It is interesting that he prefers to eat in the riverine area where most of these species occur. At this time of year with plenty of forage around, he appears to prefer the soft stuff in the understorey near the ground. We got back into camp at lunchtime with some useful, new data.
Thursday 28th February
Up at 5.30 this morning, I flew with Ed across the valley to drop some supplies to game scouts on the other side of the Luangwa river. Beautiful views in the early morning. We saw elephants, zebra, wildebeest, eland and then a pride of 15 lions following a buffalo herd on the Mwaleshi river. Back for breakfast at seven, then out with my companions, the game scouts Chambo and Michael, to do our first rhino browse transect.
Game scouts Chambo and Michael helping with the rhino browse transect (Image: P. Smith)
Trying to estimate how much food is available
Black rhinos are exclusively browsers, meaning they eat only woody plants. White rhinos, in contrast, are grazers, i.e. they prefer grass. Unlike yesterday, where we simply back-tracked a rhino to see what he had been eating, the task before us today was to gather information on the amount of available browse in the rhino sanctuaries. To do this we were driven out to our starting point six or seven kilometres from the camp, and we walked back on a 300 degree bearing, recording the available woody plants in each of the three habitats we passed through, noting some exotic local fauna, like this chameleon.
Chameleon on Brachystegia shrub in the miombo woodland (Image: P. Smith)
We started in miombo woodland which is very dense, recording all browse in touching distance of our path (a metre each side), estimating the volume of woody plant material available under two metres, i.e. in reach of a rhino. After recording five pages of miombo browse (around 200 plants) we were interrupted by a herd of elephants, and decided to move on to the next habitat - Combretum-Terminalia wooded grassland. From there we came to riverine woodland and grassland, recording all species within rhino range as we passed. We eventually got back to camp at one o’clock. The same procedure was followed this afternoon in a different part of the park. We got back in at about 5.30, having recorded some 800 individual plants, ready for a cold beer.
Bauhinia petersiana, thicket species favoured by rhino, in flower (Image: P. Smith)
Planning for the future
Our two transects today were marked with orange spray paint on occasional trees along our route, and as waypoints on the GPS. This means that these transects can be walked again in October at the end of the dry season to compare the amounts of available browse. This is when the rhinos are likely to be most hungry, and the data we are gathering will help the park managers to measure the carrying capacity of the current rhino sanctuaries. This, in turn will help ensure that stocking levels are appropriate. If this seems like a lot of trouble to go to, it is worth remembering that black rhinos are critically endangered. In South Africa alone, it is estimated that a rhino is poached every 14 hours for their horns. According to TRAFFIC, the major market is the far east where the horns are used as a hangover cure amongst other things.
Friday 1st March
No flight this morning. We headed out by car south, and then west along the Mwaleshi river. The riverine vegetation here is very productive, being associated with deep, alluvial soils. The result is plenty of vegetative biomass. It is very green at this time of year.
Transect team above the Mwaleshi after a morning's work (Photo: Ed Sayer)
Near the river, on the flood plains is mainly grassland, interspersed with a few shrubs and trees such as Acacia sieberiana and Kigelia africana (the sausage tree). Then, as you move away from the river, you come into the thicket, dominated by Combretum obovatum and then Combretum fragrans and the ‘monkeybread’ Piliostigma thonningii. As you gain higher ground, Terminalia and Combretum zeyheri start to appear. You also see Phyllanthus reticulatus – the ‘baked potato bush’, the tiny flowers of which produce a smell like baking potatoes during the evenings in May through to September. This is one of the evocative smells of the Luangwa valley.
We get scared!
We sampled around 300 plants on our narrow transect, covering perhaps a couple of kilometres up the riverine catena. We finished at about 11 am, and headed back up to the car with Ed Sayer (Chief Technical Adviser in North Luangwa) leading the way, Chambo and Michael behind him and me bringing up the rear. Ed stepped over a Mocambique spitting cobra without noticing it, but Chambo coming second jumped a foot in the air as it raised its head and inflated its hood. We rapidly retreated, and it went on its way. I got a fuzzy photo on full zoom!
A glimpse of a Mocambique spitting cobra. Neither party was pleased to see each other. (Photo: P.Smith)
Back for lunch and then out again this afternoon. I got to try out the newest vehicle in camp – the aptly named Yamaha Rhino, a kind of quad bike but with a steering wheel and a gear stick. Great fun, and seems to be able to go anywhere.
Trying out the latest in off-road vehicles - the aptly named Yamaha 'Rhino'.(Photo: Ed Sayer)
We did another riverine transect this afternoon without encountering anything more dangerous than a herd of zebra. Roughly a thousand plants sampled in our transects so far. It will be interesting to see how heavily they have been browsed by the end of the dry season.
Saturday 2nd March - I get covered in insects!
This morning we headed out to the east of the park into Combretum-Terminalia woodland and thicket. We were on the trail of two rhinos: Londekeni, whose name means ‘Lost but found’ in Bemba; and Mwaiseni (‘Welcome’). We travelled out to the thicket in the Yamaha Rhino, which you will recall from yesterday has no windscreen. While I was prepared to take a lot of grass seed on board, I was less prepared for the wide range of spiders, stick insects, beetles and caterpillars that live on the tall grass stems in the middle of the road.
At one point we had to stop to let a golden orb spider out – 10cm across and with a nasty bite. Apart from this minor drawback the vehicle did very well – no terrain was too difficult to cross. We arrived in the rhino’s territory at about 9am, and climbed an observation tower to scan for rhinos. We found Londekeni first, and tracked him to where he was hiding in some thick vegetation. I caught sight of his broad back as he beat a retreat when he heard us coming. We were able to track his movements back into the thicket, though - from where he had slept to his forays for food.
Tracking rhinos from an observation tower
The species we recorded with rhino bites were: Baphia massiensis, Maerua pritwitzii, Phyllanthus sp., Combretum molle, Catunaregum spinosa, Aneilema nicholsonii, Commelina africana, Holarrhena pubescens, Boscia angustifolia, Strychnos potatorum, Excoecaria bussei (a favourite), Barleria prionitis and one other Acanthaceae as yet unidentified. We then carried out a browse availability transect in the thicket area.
Morgan with rhino-browsed Holarrhena
Lots of interesting species around at this time of year, and I was able to take some good photographs for a book on the trees and shrubs of the Luangwa valley that I am working on. We also found two new species for the park’s checklist – the Strychnos potatorum mentioned above, and Philenoptera bussei, another shrub/small tree with signs of elephant browse damage. Back at 1pm for lunch, and then out again to do a riverine transect on the Lubanga river.
Sunday 3rd March
Out with my team again at 8am this morning, this time on the trail of a rhino called Bukwele (‘rhino’ in Bemba). We set out in the Landcruiser today because the river has risen a couple of feet, and we would have drowned the Yamaha had we tried to cross in it. The added bonus was no flies in the face today. Bukwele still receives some supplementary feed, so we started at his trough, which is out in the scrub savanna vegetation about 10 km from the camp. According to his radio collar signal, Bukwele was a long way to the south, so we didn’t see him. Instead, we turned north, and put a long transect in through mopane scrub, Combretum-Terminalia-Diospyros wooded grassland and a riverine gully that a large herd of buffalo had recently vacated. Lots of mud and cowpats to avoid.
Elephant on the Lubanga river
Early March is a great time to be in the valley. Everything is very green with many species in flower. Gladiolus dalenii (orange) and Gladiolus gregorius (purple) dot the landscape along with many pink Ipomoea (morning glory), and Hibiscus species of various colours. Bukwele had been eating Duosperma crenatum, a small but abundant herb, which we had noted as a favourite of Kango’s on day one.
My game scout assistants have a detailed knowledge of their local flora and we have been comparing local and Latin names. The one that has flummoxed them is Pseudolachnostylis maprouneifolia, a tree that is simply known as ‘Msolo’ in these parts. You can guess which name we have been using on the transect forms.
Hot and humid today, with storms gathering over the escarpment. We were glad to head for home at lunchtime. This afternoon was spent writing up the data of the past few days.
Monday 4th March - the final day
Today marks my last day in the valley, so my time was spent tying up loose ends.
My home for the past week
This morning Michael, Chambo and I went back to a couple of our transect sites to identify some of the ground cover species. During my time here in the early 1990s I made photocopies of my herbarium collections. These are still here, and a very useful reference library. We started in the mopane scrub where the main ground cover species are Indigofera schimperi (pink flowers), Cyphostemma gigantophyllum, Ampelocissus africana and Jasminum stenolobum (a rhino favourite). We also found two Vigna climbers in abundance – Vigna vexillata and Vigna frutescens.
From the mopane we went on to the thicket nearer the river and were able to find a couple of early flowering individuals of Hygrophila auriculata (rhino thistle) and Spermacoce princeae, which are both eaten by the rhinos. There we found a beautiful lagoon with a family of Egyptian Geese on it. We counted seven goslings.
Lagoon with Egyptian goose just disappearing out of sight
Then back to camp for an afternoon of data crunching. We have collected data on about 3000 individual trees and shrubs, and that is going to take some time to put on the computer. The whole thing will have to be done again in September/October but at least we have worked out the methodology, so this should be relatively straightforward. The contrast between available browse in the rainy season (now) and the dry season (then) will be very interesting – and will vary between the habitats we have sampled.
Finally, a big thank you to my hosts Ed Sayer and Claire Lewis. It has been great to be back in the Luangwa valley in such good company.
- Paul -