Ecovolontariat en Afrique du Sud /Botswana : Rapport mensuel
Southern Africa Conservation Monthly Update November-December 2013
Further erosion control work has been carried out on the heavily eroded areas in the north of the property, which showed very little growth during the last year indicating poor soil conditions. The hope is that by limiting further erosion and creating banks of fertile soil behind vegetation barriers, seeds of grass and other plants will be left in the area after rain and will be able to germinate in situ rather than being washed out into the rivers. We have constructed 20 barriers across rills in the open area referred to as Serengeti. We have also completed the construction of gabions on the heavily eroded section of river bank along the Limpopo mentioned in the last report. The final touch to this construction was moving 2 tonnes of sand across the river to pack the rear side of the gabions to give extra support to the construction.
Continued observations at the 4 mammal census sites around the property have shown 11 mammal species in the vicinity of the water points. 4 species were recorded drinking from the water sources at the census sites. The most prolific species was Impala (Aepycerosmelampus) recorded on 12 separate occasions with a total of 84 animals observed over the 2 months. Greater Kudu (Tragelaphusstrepsiceros), and Savanna Baboons (Papio cynocephalus ursinus), were each observed 4 and 3 times during censuses with 13 and 39 individuals noted each respectfully. As the rains have started now the numbers of animals using the regularly observed water sources has dropped as they are able to use newly formed water sources across ours and neighbouring properties. Two sessions were recorded during which no animals were observed visiting the waterhole that was being monitored.
We have several strains of bird research running at any given time. The bird census on the reserve carried out along the Limpopo River and at the mammal census sites continues to give us information about the general abundance of certain species and indicates the progress of various avian movements. For example these last two months we have seen the arrival of many summer visitors back to Wild at Tuli, including common species such as Woodland Kingfisher (Halcyon senegalensis) and Violet-Backed Starling (Cinnyricinclusleucogaster) as well as more irregular visitors like Amur Falcon (Falco amurensis) and European Honey-Buzzard (Pernisapivorus).
We also maintain a monthly record of the species observed on the reserve at any point, this includes driving around the reserve to and from activities and species sited on the activities. November and December recorded 174 species with 5 new editions: Cape Sparrow (Passer melanurus), Lesser-Spotted Eagle(Aquila pomarina), Greater Flamingo (Phoenicopterusruber), Bar-throated Apalis (Apalisthoracica), and Red-Breasted Swallow (Hirundosemirufa) bringing the total species count to 251. We are also continuing our work at Thune Dam recording the water bird species which occur there and so monitoring the colonisation of the dam and the progress of any breeding attempts by species now using it.
We have recorded 6 new species using the dam Comb Duck (Sarkidiornismelanotos), Grey Plover (
We will have to wait for those water bodies to start drying up next year to see if they return to the Thune Dam or if they find refuge elsewhere. We have also participated in the November Bird Population Monitoring scheme run by Birdlife Botswana. We have completed 2 bird censuses, one along the river, and the other amongst the mopane. The information gathered here is used by Birdlife Botswana directly to monitoring the movement and population of birds across Botswana from data gathered by volunteer members of the public. We have also reported the presence of several species listed on the Birdlife Botswana Rarities List, the list includes extra-limital species; species of undefined range in Botswana; and species of conservation concern. Some of those species observed over the last year include European Honey-Buzzard (Pernisapivorus) and White-backed Night-Heron (Gorsachiusleuconotus).
Eight vegetation censuses were completed during the two months, most of them aimed at filling in gaps in the coverage of the census across the reserve. The data set for the vegetation census is now complete. The data for mopane woodland shows that 65% of the woody vegetation is Mopane (Colophospermummopane) and 15% being LowveldClusterleaf (Terminaliaprunoides), the other 20% of woody vegetation is made up of 22 species or genus groups contributing between 10% and 0.02%.The mopane woodland substrate census also shows little change having incorporated new land area with 58% of land cover being bare soil, 17% organic matter, 15% non-woody vegetation such as grasses and small flowering plants, and 8% exposed rock. The data for riverine woodland shows that 51% of the woody vegetation is Forest False Nettle (Acalyphaglabrata) and Large Feverberry (Croton megalobotrys) and Raisin Bush (Grewia spp.) contributing 11% each, the other 17% of woody vegetation is made up of 20 species or genus groups contributing between 8% and 0.02%.The riverine woodland substrate census shows quite different results to the mopane woodland with 64% of land cover being bare soil, 29% organic matter, and the other categories only constituting 7% of land cover.
The Final stage of the vegetation census was to complete the tree species list by further investigation in mopane and riverine woodlands as well as targeted assessments of the kopje vegetation. The standard vegetation census was not used on the kopjes as the terrain is too difficult to follow that method. It can be assumed that the large majority of the substrate on the kopjes is also bare rock with varying amounts of soil, organic matter and non-woody vegetation making up the rest. Amongst the kopjes it was found the major vegetation species were Bell Bean Tree (Markhamiazanzibarica) on the northern kopjes and Wild Camphor Bush (Tarchonanthuscamphoratus) on the southern kopjes.
There were also significant numbers of species commonly found in the mopane woodland including Mopane and Raisin Bush. In total 25 tree species were recorded on the kopjes which included several species not recorded elsewhere on the property such as Carrot Tree (SteganotaeniaaraliaceaI) and Transvaal Candelabra Tree (Euphorbia cooperi). In all, 58 species of tree have been identified on the property. We have also recommenced flower identification sessions as the rains have allowed the flowers to start blooming. At the end of the last season we had identified 64 species of flower in 32 families. Since the beginning of November we have increased this to 123 species in 39 families.
Over the last 2 months we have conducted 2 crocodile censuses and recorded 10 crocodiles on those censuses. The largest number recorded in any given day was 8 individuals, and crocodiles observed have ranged in size from 0.5m to 4m, a large proportion of the1.5m to 2.5m crocodiles observed are still almost certainly captive breed crocodiles escaped from a crocodile farm in South Africa during the January floods.
Spoor ID and Predator Database
Only 5 species of predator were recorded as being present at Wild at Tuli during the last two months, these were Leopard, African Civet (Civettictiscivetta), Genet (Genetta spp.), Banded Mongoose (Mungosmungo) and Spotted Hyena. Sightings of all predator species have decreased markedly with only 2 sightings of Leopard in 2 months and a few Spotted Hyena sightings. The bush has become very thick limiting visibility to only a few tens of metres in some areas. Lion (Pantheraleo) were heard roaring on a couple of nights but they were probably on a neighboring property and so were not counted in the total for these months.
We continue to regularly patrol areas which are high risk targets for poachers. Following Septembers discovery of drying racks near the veterinary fence we have focused all anti-poaching efforts in this area. The time around Christmas is a very high risk time in terms of poaching as family members working away from home return to their families; this increases the human populations in remote wilderness areas as we have here. This increases the demand for meat which is often met through supplying villages and butcheries with illegally caught meat from snaring operations on private land.
After finding the drying rack, we have proceeded to regularly patrol the area around that site and have found removed a total of 78 snares from an area of 0.2km2 on 3 separate visits to the site. Nearly all the snares found were fresh and would have been placed after the discovery of the drying rack in September. The area is located between two fences on a neighbouring property and situated around 2 major drainage lines. The fences and drainage lines make it a perfect area for attempting to catch animals as they are drawn to water in the area but the area has limited access routes so it is very easy to cover all the options the animals have with snares so maximising their catch.
All the volunteers over the last two months have had the opportunity to spend the day at a wilderness reserve situated about 50km from Wild at Tuli where they have a resident population of 7 White Rhinoceros (Ceratotheriumsimum). The volunteers were able to track the rhino on foot and on all occasions found them with relative ease and were able to approach them to within 20m. Part of the experience is aimed at raising awareness of the fact that rhinos throughout Southern Africa are in a very precarious position as poaching for their horn is at epidemic proportions. These visits sadly may be the last time any of these volunteers will ever see a rhino in the wild. It should be noted that as at end December 2013 almost 1,000 rhino have been poached in South Africa alone!
As part of our social program we also took some of the volunteers in to Solomon’s Wall. This is a natural feature consisting of a broken basalt dyke which cut across the Motloutse River. The Dyke broke millennia ago leaving an impressive free-standing wall jutting into the usually dry river bed. The volunteers were able to experience first-hand some of the difficulties of living and working in remote conditions when one of the vehicles we were crossing the newly flowing river in got stuck in soft sand. After 50 mins of digging, lifting and rocking the vehicle in knee deep water we succeeded in freeing the vehicle.