20 de febrero de 2021

New desert warthog records for Laikipia County, central Kenya

Yvonne de Jong & Tom Butynski
Lolldaiga Hills Research Programme &
Eastern Africa Primate Diversity and Conservation Program

There are two species of warthog, the well-known common warthog Phacochoerus africanus and the desert warthog Phacochoerus aethiopicus. The latter occupies the Horn of Africa and Kenya but it once occured in South Africa and, perhaps, Namibia, where it was known as the ‘Cape warthog'. The desert warthog, long overlooked by zoologists, is one of Africa’s least studied and most poorly-known large mammals. Although this pig was described in 1766, confusion concerning its taxonomy resulted in the recognition of only one species of warthog, the common warthog.

The desert warthog was ‘rediscovered’ in 1991¹. Ten years later the first distribution map² for this species showed four localities in Kenya. Today, 20 years later, we know that the desert warthog is widespread in Kenya and elsewhere in the Horn of Africa east of the Eastern Rift Valley. In fact, the desert warthog is now known to occur in Laikipia County, central Kenya.

Read here the rest of the blog and see the photos: https://www.wildsolutions.nl/desert-warthog-laikipia/

Publicado el febrero 20, 2021 09:04 MAÑANA por dejong dejong | 0 comentarios | Deja un comentario

01 de diciembre de 2018

Annotated list of large birds extirpated from Laikipia County, Kenya, and some of conservation concern

Thomas M. Butynski & Yvonne A. de Jong, Lolldaiga Hills Research Programme

Introduction
Laikipia County (ca. 9,700 km²), central Kenya, comprises a highly diverse landscape of grassland, bushland, woodland, dry forest, moist forest, riverine forest, wetland, and farmland. Mean annual rainfall ranges from 40 cm in the north to 120 cm in the southeast and southwest. Although mean annual rainfall is >80 cm in the southeast and southwest, about 75% of Laikipia County (hereafter, ‘Laikipia’) is semi-arid. The altitudinal range is 1,260–2,400 m above sea level. In 2013, there were about 43 people/km² and the total population was about 400,000 people. Much of Laikipia’s natural habitat has been degraded, fragmented, or lost as a result of over-grazing and over-browsing by livestock, cutting of trees, conversion to farmland, and over-harvesting of water. Detailed descriptions of the environments of Laikipia, and the threats to these environments, are presented in Georgiadis (2011) and Butynski and De Jong (2014, 2015). In the case of vultures, feeding on poisoned mammal carcasses has probably been the main cause of declines and extirpations (Ogada et al. 2016). Special reference is give here to Lolldaiga Hills Ranch (200 km²) in east Laikipia.

For the full note, please go to http://www.lolldaiga.com/birds-extirpated-laikipia/

Publicado el diciembre 1, 2018 07:21 TARDE por dejong dejong | 0 comentarios | Deja un comentario

23 de marzo de 2018

First record for Gadwall (Mareca strepera) on Lolldaiga Hills Ranch, Laikipia, Kenya

By Tom Butynski, Per Aronsson & Yvonne de Jong, Lolldaiga Hills Research Programme

A solitary adult Gadwall Mareca strepera was observed at Baharini Dam, northern Lolldaiga Hills Ranch (N0.29216; E37.13620; 1830 m asl) by Per Aronsson on 14 December 2017 and spent more than a month at this site. This individual was observed and photographed by Per Aronsson, Yvonne de Jong, Tom Butynski, and Carly Butynski on 4 January 2018. https://www.inaturalist.org/observations/10370332.

Gadwalls are Palearctic migrants that depend on fresh water dams, lakes, and marshes. Although common in many part of its wide geographical range, Gadwall is a rare species in Kenya with only about five records in during the past 15 years (Brian Finch pers. comm.). This appears to be only the second record for Gadwall east of the Eastern Rift Valley, and the first record for the Kenya Highlands.

The Lolldaiga Hills Ranch Bird List now stands at 401 species. To view the bird List go to www.lolldaiga.com.

Publicado el marzo 23, 2018 05:17 MAÑANA por dejong dejong | 0 comentarios | Deja un comentario

25 de enero de 2018

New survey reveals… Laikipia’s patas monkey in decline

De Jong, Y.A. & Butynski, T.M. (2017). Survey of eastern patas monkey Erythrocebus patas pyrrhonotus, other primates, warthogs, dik-diks, and waterbuck in Laikipia County, central Kenya.
Read the full report here: http://www.lolldaiga.com/wp-content/uploads/DeJongButynski-2017-patasELaikipia.pdf

Abstract: The eastern patas monkey Erythrocebus patas pyrrhonotus is a subspecies whose abundance and geographic range are in decline. Laikipia County, central Kenya, supports a small, isolated, population which forms the stronghold and eastern limit of Kenya’s patas population. This report presents the results of the third survey of the abundance and distribution of patas in eastern Laikipia. Additional aims of this survey were to: (1) answer, or contribute towards answering, several questions important to primate conservation, both in eastern Laikipia and globally; (2) stimulate further interest in primate research and conservation in eastern Laikipia; (3) improve on the information available for the IUCN Red List assessments of the primate species and subspecies of eastern Laikipia; and (4) obtain information on the biogeography and taxonomic status of the region’s warthogs, dik-diks, and waterbucks.
The finding presented here are based on field surveys, questionnaires and communications with long-term residents and property managers/owners.

Eastern Laikipia appears to hold 145–155 patas. These occur in about 13 groups (mean group size = c. 12 individuals). Twenty of the 60 properties (33%) surveyed in eastern Laikipia County supported patas during 2010–2017. No property has more than two groups and most groups use at least two properties. Groups range in size from two to 25 individuals. There are at least four solitary individuals (all probably adult males) in this region.

The extent of occurrence of patas in eastern Laikipia is c. 1,750 km². The north and northwest limit of the geographic range of patas in Laikipia is Loisaba Conservancy were solitary individuals (but no groups) are occasionally observed. Borana Conservancy represents the east and southeast limit. Central Solio Ranch is the south and southeast limit. The west and southwest limit may be ADC Mutara Ranch, but a survey of patas in western Laikipia County is required to confirm this.

Comparisons with earlier studies show that the number of patas in eastern Laikipia has declined. This decline has occurred mainly through reduction in group size rather than through a reduction in the number of groups. Patas have been extirpated, or groups sizes reduced, in areas affect by habitat degradation, loss, and fragmentation, loss of perennial water sources, and severe competition with livestock over access to water. Habitat degradation, loss, and fragmentation are predominantly caused by over-grazing and over-browsing by livestock, conversion of large areas to agriculture, uncontrolled logging, charcoal production, high concentrations of savanna elephant Loxodonta africana, and spread of invasive plants, particularly prickly pears Opuntia spp. Damage is most severe in and around rural and communal areas---where the human population is most dense and where the extraction of natural resources is most intense and unsustainable.

With the fast-growing human and livestock populations it is increasingly difficult for patas and other wildlife to find suitable habitat and to access water outside well-managed ranches. During the time of this study, eastern Laikipia experienced a drought and many, if not most, dams and rivers were dry for several months. In addition, pastoralist illegally brought very large numbers of livestock onto well-managed ranches for most of 2017. As a result, water on these ranches became difficult or impossible for patas and other wildlife to access.

In order to assess the abundance and distribution of patas for all of Laikipia County, a survey in western Laikipia is needed. Additional recommendations for patas research and conservation action in Laikipia are provided in this report.

Fifty-nine groups of diurnal primates, belonging to four genera and four species, were encountered during this survey (olive baboon Papio anubis , Hilgert’s vervet monkey Chlorocebus pygerythrus hilgerti , Kolb’s monkey Cercopithecus mitis kolbi , Mount Kenya guereza colobus Colobus guereza kikuyuensis ). Only one species of nocturnal primate was observed--- Kenya lesser galago Galago senegalensis braccatus . Somali lesser galago Galago gallarum was encountered in Samburu County during this survey.

Both species of warthog Phacochoerus (common warthog Phacochoerus africanus and desert warthog Phacochoerus aethiopicus ) and two species of dik-dik (Smith’s dik-dik Madoqua smithi and Kirk’s dik-dik Madoqua kirkii ) were found in northeast Laikipia (Lekurruki Conservancy and Il ‘Ngwesi Conservancy). These are the first records of desert warthog and Kirk’s dik-dik for Laikipia County.

During this survey, the geographic ranges of defassa waterbuck Kobis ellipsiprymnus defassa and of common waterbuck K. e. ellipsiprymnus in Laikipia, Isiolo, and Samburu Counties were better defined, as was their ‘hybrid zone’.

Publicado el enero 25, 2018 08:47 MAÑANA por dejong dejong | 0 comentarios | Deja un comentario

14 de noviembre de 2017

Two additions to the Laikipia Mammal List; desert warthog (Phacochoerus aethiopicus) and Kirk’s dik-dik (Madoqua kirkii)

By Yvonne de Jong & Tom Butynski, Lolldaiga Hills Research Programme & Eastern Africa Primate Diversity and Conservation Program.

Laikipia County, ca. 9,700 km², probably holds the highest diversity of larger mammal species of any region of its size in the world. Most of Laikipia County is covered by the Laikipia Plateau (ca. 1,600–2,400 m asl), an area composed of a mix of flat ground, undulating plains, rolling hills, steep hills, and scattered granitic inselbergs (or ’kopjes’). There are several small perennial rivers—the largest being the Ewaso N’yiro— and many seasonally dry stream channels and gullies, some of considerable size. Within Laikipia County (hereafter referred to as ‘Laikipia’) there is considerable variation in geography, altitude, rainfall, soil, flora, fauna, human population density, and land use.

Yvonne de Jong and Tom Butynski are currently undertaking a primate survey in eastern Laikipia, with a focus on the patas monkey Erythrocebus patas. Beyond the primates, there are several other species groups that we gather ‘opportunistic’ taxonomic, abundance, distribution, and conservation data for during these surveys. Two of these are the warthogs Phacochoerus spp. and the dik-diks Madoqua spp.

During November 2016, we conducted surveys in northeast Laikipia, below the Laikipia Plateau (<1,600 m asl). Two large mammals, not yet listed for Laikipia County (Laikipia Wildlife Forum, 2011. Laikipia – A Natural History Guide) were encountered on Lekurruki Conservancy and Il’Ngwesi Conservancy; the desert warthog Phacochoerus aethiopicus and Kirk’s dik-dik Madoqua kirkii.  

Read the whole blog here: http://www.lolldaiga.com/additions-laikipia-mammallist/

Publicado el noviembre 14, 2017 11:25 MAÑANA por dejong dejong | 0 comentarios | Deja un comentario

13 de noviembre de 2017

Waterbuck (Kobus ellipsiprymnus) of Laikipia County

By Yvonne de Jong and Tom Butynski, Eastern Africa Primate Diversity and Conservation Program, Lolldaiga Hills Research Programme

Waterbuck Kobus ellipsiprymnus, one of biggest antelopes on Lolldaiga Hills Ranch (Laikipia County, central Kenya), are found throughout the Ranch but prefer the higher grasslands and vegetation along the streams and dams of central and south Lolldaiga. Waterbucks are, as their name indicates, highly water-depended. They are limited in their ability to conserve water and are unable to endure dry periods in hot environments. 

Two Waterbuck taxa occur in Kenya: Defassa Waterbuck Kobus (ellipsiprymnus) defassa and Common (or Ellipsen) Waterbuck Kobus (ellipsiprymnus) ellipsiprymnus. Their taxonomic arrangement is debated; some authors (e.g., Lorenzen et al. 2006, Spinage 2013, Kingdon 1982, 2015) treat these taxa as subspecies, while others (e.g, Stewart & Stewart 1963, Groves & Grubb 2011) consider them species. Generally, Defassa Waterbuck occur in Kenya and Tanzania west of the Eastern Rift Valley, and Common Waterbuck east of the Rift. Their ranges overlap in north Tanzania (e.g., Lake Manyara) and in south and central Kenya (Stewart & Stewart 1963, Lorenzen et al. 2006, Spinage 2013). Defassa Waterbuck occur on Lolldaiga Hills Ranch while Common Waterbuck are present ca. 50 km to the northeast in Samburu National Reserve and ca. 100 km to the east in Meru National Park. It is not known where Defassa Waterbuck gives way to Common Waterbuck in this region, or whether Common Waterbuck are present in Laikipia County.

Read the full blog on: http://www.lolldaiga.com/waterbuck-kobus-ellipsiprymnus-laikipia-county/

Publicado el noviembre 13, 2017 05:00 TARDE por dejong dejong | 0 comentarios | Deja un comentario