Abstract
D.Phil.
The main objective of this study was to describe the population genetic structure of African
Whitebacked Vultures (Pseudogyps africanus) and to compare values to those previously
documented for the Cape Griffon Vulture (Gyps coprotheres). The percentage of polymorphic .loci
(P = 34.15%, 0.99 criterion) and average heterozygosity (17 = 0.108, ±0.032) calculated for P.
africanus, confirm low levels of genetic -variation as reported for G. coprotheres. Blood samples'
obtained from Lappetfaced (Torgos, tracheliotos) and Egyptian (Neophron percnopterus) Vultures
enabled an evaluation of the genetic differentiation among the four southern African vulture species
from allele frequency data assessed at 19 presumptive gene loci. Six (31.58%) of the 19 shared loci
were polymorphic. Values of 1.26 (10.1), 26.32% and 0.076 (±0.047) for P.'africanus, 1.21 (±0.1),
21.05% and 0.097 (±0.045) for T. tracheliotos, 1.11 (±0.7), 21.05%. and 0.053 .(±0.053) for N:
percnopterus and 1.05 (±0.5), 5.26% and 0.044 (±0.047) for G. coprotheres were obtained for the
mean number of alleles per locus, P and Ti respectively. An average between-population fixigion
index (FsT) value of 0.322 was obtained, which is indicative of significant (P < 0.01) differentiation
between the four accipitrid species studied.
Reference values for some haematological and plasma chemical parameters were established
in 33 apparently normal, free-living, African Whitebacked Vulture nestlings. This .information can
be. used in future ornithological research. A total of 27 variables . were examined, which include:
leucocyte and erythrocyte counts, haemoglobin concentration, .haematocrit, haematimetric indices,
glucose, creatinine, urea, total prOtein, albumin, globulin, albumin/globulin ratio, cholesterol, total
lipids, triglycerides, aspartate aminotransferase, cholinesterase, lactate dehydrogenase, alkaline
phosphatase, calcium, phosphorus, chloride, potassium, sodium and osmolarity. Only five
parameters exhibited statistically significant (p < 0.05) differences between the two populations
assayed. The Sandveld population showed elevated mean corpuscular haemoglobin concentration
and alkaline phosphatase levels relative to the Dronfield population, whereas, the latter group
displayed higher erythrocyte counts and potassium and sodium values than birds from the Sandveld
community.
Gaschromatography was used to establish the presence of quantifiable . residues .of 14
persistent chlorinated hydrocarbon pollutants in whole blood, clotted blood, heart, kidney, liver,
bone, fat and muscle samples obtained from individual African Whitebacked, Cape. Griffon and
Lappetfaced Vultures from different localities in South Africa. Concentrations of seven essential
elements (Ca, Co, Cr, Cu, Fe, Mn and Zn) and four toxic metals (Al, Ni, Pb and Sr) were,
furthermore, measured. The levels of pollutants measured in whole blood samples of live specimens
were compared between nestlings from two natural breeding colonies, adults from a wildlife area
and birds held in captivity. Statistically significant differences between populations were detected in
geometric means calculated for y-BHC, a-chlordane and a-endosulfan. Five of the organochlorine
contaminants displayed significant variations between concentrations detected in the clotted blood,
organs and muscles excised from vulture carcasses. This includes residues ofy-BHC, a-chlordane,
dieldrin, ,8-endosulfan and heptachlor epoxide. Values of the respective organochlorines obtained in vulture samples were generally low in comparison to results documented for a number of avian
species.
Levels of the , majority of metals analysed differed significantly- between two or more of the
sampling localities, between adults and nestlings, and between captive and wild individuals. Metals
which did not occur in such distinctly defining concentrations were Sr, Cu and Fe. Birds from
Moholoholo maintained the highest overall blood metal burden, while nestlings from Dronfield
were the least contaminated Significant differences were present between two or more tissues types
for all the metals. The predominant sites for metal accumulation in vultures were the fatty tissues
and bones. Most of the levels of metals measured in vultures compared well with concentrations
reported for other avian species, and were generally within the range documented for species
devoid of deleterious symptoms induced from heavy metal poisoning. However; certain individuals
exhibited potentially toxic concentrations of specific metals such as Cu, Fe, Ni, and Pb. Continual
monitoring of breeding colonies is recommended. The suitability of African Whitebacked Vulture
nestlings as basic bioindicatori is highly advocated.
The genetic data from this study can be used to compare levels of genetic diversity remaining
in captive and wild vulture populations. An assessment of the amount and pattern of genetic
variation of current populations of vulture species is an essential step towards ensuring the longterm
survival of these birds. The phylogenetic conclusions found in. this study through allozyme
electrophoresis correspond to results obtained from nucleotide sequence studies of the
mitochondrial cytochrome b. gene. This points to an extent of positive corroboration between the
two techniques. The haematological profile established for African Whitebacked Vulture nestlings
constitutes a set of reference values that was previously unavailable for southern African vulture
species. This data can assist in diagnosing and monitoring pathological and clinical' incidents
detected in vultures. Values for a number of organochlo?ine pesticides and heavy metals, which
have not been analysed in vulture species in the past, are documented. These values can serve as
guidelines for future research, as well as control values for monitoring the occurrence and
distribution of these contaminants within the habitats of vulture species. This study, therefore,
presents information for research fields directly related to the survival of vulture populations. These
factors must be included in future vulture management and reintroduction programmes as they will
serve to enhance the success of conservation attempts.