Population Census of Thornicroft's Giraffe Giraffa Camelopardalis Thornicrofti in Zambia, 1973−2003: Conservation Reassessment Required

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Population census of Thornicroft's giraffe Giraffa camelopardalis thornicrofti in Zambia, 1973−2003: conservation reassessment required

P HILIP S. M. BERRY and F RED B. BERCOVITCH

Abstract Thornicroft’s giraffe Giraffa camelopardalis thor- southern limit is unknown but reaches the confluence of nicrofti is limited in distribution to a single population resi- the Msanzara and Luangwa Rivers (c. °′S). Individuals dent in the Luangwa Valley, Zambia. During − range primarily along the Luangwa River, usually within regular counts were recorded along the Luangwa River in – km, although occasionally up to  km away (Berry, the core section of the subspecies’ range. In  we con- ). Areas further from the Luangwa River are mostly ducted a count in the same region for comparison with unsuitable, especially the miombo (Brachystegia and the earlier survey results. During the -year period Julbernardia) woodland, where the giraffes’ main food − the giraffe index (no. of individuals per km sur- plants are scarce or non-existent. veyed) was relatively stable, with an increase in  and The habitat most favoured by the giraffe is riparian forest  coinciding with an influx of giraffes to the west bank containing a number of large tree species that feature prom- following an exceptionally reduced flow of the Luangwa inently in their diet (e.g. Trichilia emetica, Tamarindus in- River. The mean giraffe index during this period was dica, Diospyros mespiliformis, Faidherbia albida, Kigelia − . km , whereas the  count yielded an index of africana). Other habitats include mopane Colophospermum − . km . Given the limited range of the Thornicroft’s gir- mopane and munga (Acacia, Combretum, Terminalia) affe, we estimate that the population comprises c. – woodland, thickets, scrub brush and open grassland (Astle individuals. et al., ; Fanshawe, ; Berry, ). Giraffes subsist on a varied diet, consuming flowers, leaves, stems and fruits Keywords Giraffe, Giraffa camelopardalis, population cen- from  plant species in the Luangwa Valley (Berry, ; sus, Thornicroft’s giraffe, Zambia P.S.M. Berry & F.B. Bercovitch, unpubl. data). In  hornicroft’s giraffe Giraffa camelopardalis thornicrofti their core area was given protection with the gazetting of is an isolated subspecies (Dagg, ; but see Groves the South and North Luangwa Game Reserves, both of T  & Grubb, ) found only in the Luangwa Valley, in eastern which were designated National Parks in .  Zambia. Current information regarding their mitochondrial In the early s the population was estimated to com- – DNA profile indicates that the Thornicroft’s giraffe is more prise only individuals, mostly ranging on the eastern similar to the Masai giraffe G. camelopardalis tippelskirchi bank of the Luangwa River in small herds, but the methods than to any of the other subspecies (Fennessy et al., ). used to determine these estimates are unknown and prob- However, the Masai giraffe is found at least  km north ably reflected the impressions of the early British administra-  .   of the Thornicroft’s giraffe and there are no records of tors (Berry, ). One report of giraffes in the s movement between the two populations. appears to be inaccurate, based on subsequent information   – The Luangwa Valley is traversed along a north−south (Berry, ). Darling ( ) estimated a population of  axis by the Luangwa River, a meandering waterway charac- individuals along the eastern bank of the river at − ‘ ’ terized by numerous oxbow lakes, or lagoons, and deli- c. °S, although he also recorded a few vagrants on the  neated on the western side by the Muchinga Escarpment. western bank. By the end of the s the range of the ’ The northern limits of the Thornicroft’s giraffe are uncer- Thornicroft s giraffe had expanded in both northerly and   tain but its range extends at least to the confluence of the southerly directions (Berry, ). Berry ( ) noted that a Chibembe and Luangwa Rivers (c. °′S). Similarly, the few individuals were present on the western bank but most of the population lived on the eastern bank. The greatest north−south distance between sightings of Thornicroft’sgir- affe was between °′Sand°′S, but these were often ei- PHILIP S. M. BERRY P.O. Box 33, Mfuwe, Zambia ther lone bulls or small herds. In  Berry ()estimateda FRED B. BERCOVITCH (Corresponding author) Primate Research Institute and population size of –,withDagg&Foster() concur- Wildlife Research Centre, Kyoto University, Inuyama, Japan  E-mail [email protected] ring that the maximum population size was c. individuals.  Received  June . Revision requested  September . Systematic population surveys were initiated in by Accepted  October . First published online  January . PSMB. Giraffes have distinctive coat patterns that remain

Oryx, 2016, 50(4), 721–723 © 2016 Fauna & Flora International doi:10.1017/S003060531500126X Downloaded from https://www.cambridge.org/core. IP address: 170.106.202.8, on 24 Sep 2021 at 14:23:34, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1017/S003060531500126X 722 P. S. M. Berry and F. B. Bercovitch

unchanged throughout their lifetime and facilitate identifi- cation of individuals. Here we present giraffe population trends that cover a -year span (–), as well as results from a follow-up survey in .During− surveys were conducted annually on foot and/or in avehicle. Each time a giraffe was observed its identity, if known, was recorded, along with location, herd composition, time and activ- ity. As identical methods were used throughout this period, the population counts are comparable across years, although they may not be directly comparable with those at other sites where alternative methods were used. The counts were conducted along both the east and west banks of the Luangwa River but for consistency across years we restrict our analysis to the west bank, as those surveys were undertaken on a more regular basis. In  and  the Luangwa River stopped flowing in some places and giraffes of both sexes and all ages were able to cross dry sections of the river bed from the east to the west bank. This resulted in an influx of new giraffes into the study area. Prior to that time only mature bulls were FIG. 1 The area within South Luangwa National Park, Zambia, capable of wading across the Luangwa River. ’  surveyed for the Thornicroft s giraffe Giraffa camelopardalis For purposes of analysis we subdivided the -year study thornicrofti, and the presumed range of the subspecies The into -year time blocks. The total number of giraffes counted southern limit of the Masai giraffe G. camelopardalis during each survey year analysed included both recognized tippelskirchi, the nearest subspecies, is indicated by the dashed and unknown individuals. For each year we calculated the line on the inset. mean number of sightings of known individuals. We then divided the number of counts of unknown individuals by this mean to estimate the total number of unrecognized gir- concentrated on the roads in the vicinity of Mfuwe Lodge. affes observed in the survey area. We added the numbers of This survey covered . km and we counted a minimum − identified and unrecognized giraffes to yield a total count. of  individual giraffes, yielding an index of . km . For example, in  we recorded  unique individuals On  September  we identified  individuals during on  occasions, or a mean of . observations per individ- a systematic survey that covered  km of road not in the ual. The same year we counted unknown giraffes on  oc- vicinity of Mfuwe Lodge. This survey yielded a giraffe − casions, which we estimate represented  individuals (/ index of . km . The last count was conducted on  . = .). Combining these numbers yields a total count September  during a drive of . km. Seven individuals of  giraffes along the  km survey. Given that we have were sighted during this survey, yielding a giraffe index of − no estimate of distance from the survey track to the giraffes, . km . Hence, during the -day survey the giraffe − − we cannot estimate density and therefore we refer to our va- index was .−. km , with a mean of . km . lues as a giraffe index. Figure  charts the giraffe index within the Luangwa The survey distance was determined by measuring the River Valley during −. Because of the relatively length of travel during each of the survey years on maps small population size, demographic changes have a signifi- of scale  : , produced by the Department of Surveys cant impact on density estimates. The dip in  was prob- of the Republic of Zambia. The maps used in our assessment ably a result of the deaths of two mature males in August, were  B (Manze),  B (Mfuwe),  B (Lusangazi), one of whom was the victim of lion Panthera leo predation.  C (Chasera) and  D (Lion Plain). Figure  shows Over the -year period the mean giraffe index was . ± SE − the location of the survey region, the approximate range of . km . Omitting the two unusual years of  and  − the Thornicroft’s giraffe and the distance to the closest sub- gives a mean index of . ± SE . km . The giraffe index − species of giraffe. in  (. km ) was essentially the same as in  − In September  a more directed and focused system- (. km ). − atic count was conducted by PSMB, FBB and colleagues in With an estimated giraffe index in  of . km the South Luangwa National Park. Over a -day period, along the Luangwa River, and given an approximate length teams of – trained observers drove along tracks in the of  km for the Luangwa River between the confluence Park and recorded the number of giraffes observed, as with the Chibembe River and the confluence with the well as specific coat patterns for recognition of individuals. Msanzara River, we can reasonably assume that at least During a -day period (– September )we  Thornicroft’s giraffes reside in their core area along

of the Government of Zambia. Our examination of the lon- gitudinal database was triggered by extensive communica- tion with Kerryn Carter, Julian Fennessy and Andy Tutchings, all of whom provided insightful input.

References

ASTLE, W.L., WEBSTER,R.&LAWRANCE, C.J. () Land classification for management planning in the Luangwa Valley of Zambia. Journal of Applied Ecology, , –. BERRY, P.S.M. () The Luangwa Valley giraffe. Puku, , –. IG ’ F . 2 The population trend of the Thornicroft s giraffe in its BERRY, P.S.M. () Range movements of giraffe in the Luangwa  core range in the Luangwa Valley, Zambia (Fig. ), during Valley, Zambia. African Journal of Ecology, , –. − . DAGG, A.I. () Giraffe: Biology, Behaviour, and Conservation. Cambridge University Press, Cambridge, UK. DAGG, A.I. & FOSTER, J.B. () The Giraffe: Its Biology, Behavior and the tracks near the Luangwa River. Given that giraffes rarely Ecology, nd edition. Krieger Publishing Co., Malabar, USA. range outside of the alluvial zone or .  km from a river DARLING,F.F.() Wild Life in an African Territory. Oxford (Berry, ), a maximum of  Thornicroft’s giraffes University Press, Oxford, UK. FANSHAWE, D.B. () The Vegetation of Zambia. Forest can be estimated to live in their core range within the Research Bulletin, Publication No. . Government Printers, Luangwa River Valley. However, giraffe distribution is not Lusaka, Zambia. uniform along the river, suggesting that the total population FENNESSY, J., BOCK, F., TUTCHINGS, A., BRENNEMAN,R.&JANKE,A. size is probably somewhat less than our estimates. We there- () Mitochondrial DNA analyses show that Zambia’s South fore conclude that the total population is probably Luangwa Valley giraffe (Giraffa camelopardalis thornicrofti) are genetically isolated. African Journal of Ecology, , –. −. FENNESSY,J.&BROWN,D.() Giraffa camelopardalis ssp. peralta. The size of the Thornicroft’s giraffe population in the In The IUCN Red List of Threatened Species :e. Luangwa River Valley has been reasonably stable over the TA. Http://dx.doi.org/./IUCN.UK..RLTS. past  years. Giraffes are concentrated on the west bank, TA.en [accessed  November ].  with changes in population distribution coinciding with FENNESSY,J.&BRENNEMAN,R.( ) Giraffa camelopardalis ssp. rothschildi.InThe IUCN Red List of Threatened Species :e. the extent of water flow in the Luangwa River. Currently TA. Http://dx.doi.org/./IUCN.UK.-. G. camelopardalis is categorized as a species of Least RLTS.TA.en [accessed  November ]. Concern on the IUCN Red List (Fennessy & Brown, FENNESSY,J.&BROWN,D.() Giraffa camelopardalis.InThe ), although two subspecies (G. camelopardalis peralta IUCN Red List of Threatened Species : e.TA. Http://       and G. camelopardalis rothschildi) are categorized as dx.doi.org/ . /IUCN.UK. - .RLTS.T A .en  [accessed  August ]. Endangered (Fennessy & Brown, ; Fennessy &   ’ GROVES,C.&GRUBB,P.( ) Ungulate Taxonomy. Johns Hopkins Brenneman, ). Given that the Thornicroft s giraffe is University Press, Baltimore, USA. confined to a single location in a protected area of Zambia, with the total population size estimated to be  or fewer, we strongly recommend a reassessment of the conservation status of G. camelopardalis thornicrofti, and urge Biographical sketches that conservation monitoring of this distinctive subspecies P HILIP B ERRY has been studying the natural history of Zambia for be implemented for its continued protection. over  years. He was the Chief Ranger for the Department of Wildlife, Fisheries and National Parks, led anti-poaching patrols for Save the Rhino Trust, and has been a safari guide in the Luangwa Acknowledgements Valley for decades. F RED B ERCOVITCH specializes in wildlife biology and has conducted research on baboons in Kenya, rhesus monkeys in Our work has been supported by Andy Hogg (Bushcamp Puerto Rico, elephants in Botswana, and koalas in Australia, as well as Company), and giraffe data were collected with the support giraffe in Zambia.