There are two species of warthog (Kiswahili name ‘ngiri’) and both occur in Kenya; the common warthog (Phacochoerus africanus) and the desert warthog (Phacochoerus aethiopicus). As mentioned in our earlier blogs (e.g., ‘Quest for Kenya´s Desert Warthog‘), our mission during this project is to better understand the biogeography and ecology of the desert warthog, one of Africa’s least known large mammals. During this project we also, opportunistically, collected data on other large mammals—particularly the primates.
In early October 2013 we surveyed warthogs in the Meru Conservation Area (MCA; ca 5,000 km²), north-east of Mount Kenya, central Kenya. The MCA is comprised of Meru National Park, Kora National Park, Bisanadi National Reserve, and Mwingi National Reserve. The Tana River forms the southern boundary of Meru NP and Bisanadi NR, seperating them from Kora NP and Mwingi NR on the right (south) bank.
The MCA ranges in altitude from 200 m above sea level in the south (Kora NP) to 1040 m asl in the north (Meru NP). Mean annual rainfall ranges from ca. 300 mm in the south (Kora NP) to 700 mm in the north-west (Meru NP). The main habitats of nothern MCA are acacia (Acacia spp.) wooded grassland intermixed with acacia bushland, and combretum (Combretum spp.) wooded grassland. Commiphora (Commiphora spp.) bushland and woodland are the main habitats in the south. No fewer than 13 permanent water courses drain Meru NP. These, and the Tana River, support riverine vegetation dominated by acacias, doum palm (Hyphaene thebaica), and raffia palm (Raphia farinifera).
This was not the first time that we have undertaken ecological surveys in the MCA. Over the past 10 years we have conducted several surveys of the primates of Meru NP and Kora NP (see below). It was in Meru NP that we found the Somali lesser galago (Galago gallarum) and the Kenya lesser galago (Galago senegalensis braccatus) at the same sites, and documented that these two galagos have very different loud (advertisement) calls. These findings put to rest any doubts that these two galagos are of different species. We also observed Pousargues’s monkey (Cercopithecus mitis albotorquatus) in the riverine forest along the Tana River, all the way up river to Mwingi NR. These observations greatly extends the known distributional range of this subspecies, and indicate that this monkey is not as threatened as previously reported. Our findings, and those of others, indicate that the MCA has a complex, interesting, and important biogeography. As such, we wanted to see what the MCA had to reveal in terms of its warthogs.
A ‘new’ warthog for Meru National Park
Warthogs are typically shy, and those of Meru NP were no exception. Nonetheless, we observed 21 individuals, during six encounters in 5 days. All encounters were with common warthogs. Density was highest in the relatively wet north-west corner of the Park. The lack of encounters with desert warthogs was a surprise. This is because, exactly 2 years earlier (October 2011), YDJ observed four sounders of common warthog and four sounders of desert warthog here. Not only was that the first time that the desert warthog was recognized as a species present in Meru NP, that finding yielded yet another site where the common warthog and desert warthog co-occur (i.e., are ‘sympatric’).
The results of our 2013 survey made us wonder if the population of desert warthog in Meru NP had severely declined over the past 2 years, or whether our lack of encounters with desert warthogs was simply a matter of chance. A month later (November 2013), YDJ visited Meru NP again, this time for 3 days. She observed eight common warthogs during two encounters. One of the encounters was with an adult female common warthog that had just been killed by a lioness (Panthera leo; see next photograph). A day later, at the same site, YDJ observed four desert warthogs fleeing out of a narrow strip of tall, dense, riverine forest. This encounter confirmed the continued presence of desert warthogs in Meru NP.
A good understanding of the biogeography of the desert warthog is of great importance to the design of effective conservation and management plans for this species. The findings of this 7-year project, together with locality and abundance data collected by others, are now present in ‘WarthogBase’—the electronic database that we maintain with Jean-Pierre d’Huart. We now know that desert warthog and common warthog are sympatric in at least three regions of Kenya; (1) central Kenya (which includes Samburu National Reserve, Namunyak Wildlife Conservancy, and Meru NP) in an area of ca. 8700 km²; (2) central-south Kenya (which includes Tsavo West National Park and Tsavo East National Park) in an area of ca. 7000 km²; and (3) south-east Kenya (south-west of the Lamu Archipelago) in an area of ca. 4000 km². The total known area of sympatry in Kenya is ca. 19,700 km². Meru NP would be a good study site at which to conduct ecological and behavioral research on both species of warthog, as would Samburu NR, Tsavo West NP, and Tsavo East NP.
The decline of Kora National Park
On 9 October 2013, upon completion of our warthog survey in Meru NP, we entered Mwingi NR and Kora NP. From the equator it is only ca. 11 km (straight line distance) to Adamson’s Falls Bridge on the Tana River. This impressive (and noisy) metal bridge connects Meru NP with Mwingi NR and Kora NP…and offers a good opportunity to see large (>4 m long) Nile crocodiles (Crocodylus niloticus) basking on the banks.
Kora NP is well-known for its impressive diversity and abundance of commiphora trees. These spiny, often bare, trees give the area a dramatic arid vibe.
No warthogs were encountered during our 2 days in Kora NP. Indeed, we encountered almost no large wild mammals in Kora NP. We did, however, observe thousands of goats, sheep, camels (dromedaris) and cattle, and many herders. The few elephant footprints and dropping that we came across were small, indicating that they were produced by young individuals. The yellow baboons (Papio cynocephalus) and Hilgert’s vervet monkeys (Chlorocebus pygerythrus hilgerti) here were atypically shy. The number of people and livestock, and the level of habitat degradation, increased as we travelled eastward through Kora NP and down-stream along the Tana River. Our observations indicate that the history of the MCA is repeating itself in Kora NP.
During the 1970s and 1980s, the MCA went through rough times after it was invaded by heavily armed Somali bandits (called ´Shifta´ in Kenya). Dramatically, the MCA lost almost all its larger mammals to the Shifta. The black rhino (Diceros bicornis) was extirpated and 90% of the elephants were removed. As a result, the conservation values of the Area were greatly reduced, tourism was no longer a viable activity, and degazettement of Meru NP was considered.
All was not lost, however. During the 1990s, under the directorship of Dr. Richard Leaky, the newly formed Kenya Wildlife Service (KWS) re-established security and infrastructure in Meru NP. In addition, several translocations of large mammals were conducted (e.g., elephants, giraffe, Grevy’s zebra, black rhino). These complex and expensive operations were successful as, today, Meru NP is, again, one of East Africa’s premier protected areas. Unfortunately, the same cannot be said about Kora NP.
Kora NP became famous for the conservation work of George Adamson and his team when they released captive lions into the area during the 1960s. To make a sad and long story short, ‘Baba ya Simba’ (George’s nick name which means ‘Father of lions’ in Kiswahili), together with two members of his team, lost their lives in Kora NP to Shifta bullets in 1989. The release camp, ‘Kampi ya Simba’ (Kiswahili for ‘Camp of the Lions’), was raided and destroyed after the dramatic murders. With these acts, the future of Kora NP appeared bleak.
George and his assistant, Tony Fitzjohn, founded the George Adamson Wildlife Preservation Trust in 1979. The Trust, keen to continue its work in Kora NP, recently reconstructed Kampi ya Simba as a memorial site. The Trust joined forces with KWS to protect Kora’s wildlife and re-establish the Park’s infrastructure. Nonetheless, despite these efforts, Kora NP has, once again, fallen to a heavy wave of illegal activities, including poaching, human and livestock encroachment, and cutting of trees.
Jamie Manwell, The Trust’s representative at Kampi ya Simba, told us that Kora NP no longer holds any zebra, impala or adult elephants. Indeed, we observed none of these species during our visit, nor did we encounter warthogs or large predators.
The harsh reality is that Kora NP has now lost almost all of its larger-bodied mammals and that natural habitats have been severely degraded. Amazingly, the conservation community of Kenya seems to be largely unaware of the present situation in Kora NP. KWS, The George Adamson Wildlife Preservation Trust, and WildlifeNOW are working to alleviate the present problems but it is clear that much additional help, political will, and action are required to reverse present trends at Kora NP.
Primate biogeography in the Meru Conservation Area
We have, since 2003, gathered information on the taxonomy, distribution and abundance of the six species of primates that occur in the MCA. During the course of our research on the warthogs of the MCA we obtained additional data on the Area’s primates. Not surprisingly, we found that the diversity and distribution of the primates of the MCA have been greatly affected by the Tana River (which varies in width from 20 m to 200 m) and by the Area’s considerable altitudinal range and habitat diversity (see above).
Three species of galago occur in the MCA; Somali lesser galago, Kenya lesser galago, and Kikuyu small-eared galago (Otolemur garnettii kikyuensis). The Somali lesser galago occupies Meru NP and the Kenya lesser galago occupies both Meru NP (left, or north, bank of the Tana River) and Kora NP (right, or south, bank of the Tana River). Despite numerous nocturnal surveys in what appears to be suitable habitat for the the Somali lesser galago, we did not record this species in Kora NP or, indeed, at any site on the right bank of the Tana. The lack of sightings and museum specimens strongly suggests that the Tana River represents the southern limit for the Somali lesser galago.
Beyond the MCA, we have found the Somali lesser galago at several other new sites in Kenya, thereby, considerably extending the known geographic range of this species [e.g., 100 km farther west of the Chalbi Desert than previously reported (Blog: ‘New Population of Bushbabies Discovered in Northern Kenya’), and 80 km farther west along the Kenya-Ethiopa border than previously reported (Blog: ‘Biodiversity of Northern Kenya´s Huri Hills and Mount Forole’)].
The baboons (Papio spp.) and gentle monkeys (Cercopithecus mitis) of the MCA provide other interesting examples of primate diversification and distribution. Meru NP has baboons that, in hair color and length, most ‘resemble’ olive baboon (Papio anubis), and gentle monkeys that most resemble Kolb’s monkey (Cercopithecus mitis kolbi). In contrast, across the Tana River, in Kora NP and Mwingi NR, the baboons most resemble yellow baboon (Papio cynocephalus) and the gentle monkeys most resemble Pousargues’s monkey (Cercopithecus mitis albotorquatus).
We noticed that the ‘olive baboons’ of Meru NP exhibit some of the pelage traits of yellow baboon, and that the ‘yellow baboons’ of Kora NP and Mwingi NR exhibit some of the pelage traits of olive baboon. This is not a surprise to us as, a decade ago, we identified the presence of an extensive ‘phenotypic cline’ from ‘good’ olive baboons in the highlands of central Kenya south-eastwards to ‘good’ yellow baboons along the Kenya coast into north-eastern Tanzania. That there is a gradual gradation from ‘olive baboon’ to ‘yellow baboon’ raises serious questions as concerns the validity of the species Papio anubis and Papio cynocephalus.
Similarly, Kolb’s monkeys of western Meru NP exhibit some of the pelage traits of Pousargues’s monkey, and Pousargues’s monkeys of northern Mwingi NR and Kora NP exhibit some of the pelage traits of Kolb’s monkey. It appears that this phenotypic cline begins in the Nyambeni Hills (north-east Mt Kenya, west of Meru NP), extends south-eastwards via the riverine forests of the larger rivers of Meru NP, then through the riverine forest of the Tana River to the coast.
We have been studying the diversity and distribution of the primates of Kenya and Tanzania since 2003. During this time we have observed a phenotypic cline among the several currently recognized subspecies of gentle monkey in this region. This phenotypic cline runs from the Kenya Highlands, then along the Tana River to the Kenya’ coast, then south-westwards into north-eastern Tanzania…and beyond. This finding calls into question the validity of the subspecies of gentle monkey that occur along this cline and raises questions related to their conservation status and conservation.
Although our National Geographic-supported project on desert warthogs in Kenya has now come to an end, we will continue to investigate the distribution and conservation status of the warthogs, primates and other species in Kenya. Our field research focus over the next few years will, however, shift to Uganda where we are about to begin another National Geographic-supported project, ‘Biogeography, Taxonomy, Abundance, and Conservation Status of the Primates of Uganda’. While this new project is focused on primates, we will also gather data on warthogs and other large mammals and, again, report our more significant findings through this blog.
For more photographs of warthogs and primates, please visit: www.wildsolutions.nl