Heavy metal concentrations in two populations of Mopane worms (Imbrasia belina) in the Kruger National Park pose a potential human health risk.

Metal concentrations in Mopane worms from Phalaborwa and Shangoni sites in the Kruger National Park were determined. Metal concentrations were evaluated by inductively coupled plasma optical emission spectroscopy (ICP-OES) and ICP-MS spectrometry after microwave digestion. The results indicate a substantial bioaccumulation of metals in Mopane worms. In Phalaborwa Cd concentrations were 15 times and Cu two times higher than the EU and UK recommended legal limits for human consumption, Zn levels were tolerable. Likewise, Cd, Cu and Zn concentrations at the Shangoni site were 26, 2.5 and 0.4 times over the EU and UK approved limits. Manganese concentrations were 20 and 67 times higher than FDA standards respectively. During the study the condition factor of the worms was determined. No significant difference between the condition factors indicated the worms at both sites are in similar condition. Potential sources of metals in the worms are either from the food they eat or pollution settling on the leaves.

A baseline study of metal contamination along the Namibian coastline for Perna perna and Choromytilus meridionalis.

The use of bivalves such as the brown mussel (Perna perna) and the black mussel (Choromytilus meridionalis) is common in the study of marine pollution and the effect of these pollutants on ecosystems and are important in both economic and ecological roles. Namibian marine ecosystems are threatened by pollution from mining, commercial fishing and population growth. The aims of this study were to determine baseline metal concentrations, spatial variation and variation between species. Metal levels in C. meridionalis from Guano Platform (GP) are the lowest of all the sites. The most polluted sites are Rocky Point (RP), Halifax Island (HIL) and between Walvis Bay and Swakopmund (WS). The bioaccumulation of metals between P. perna and C. meridionalis were not uniform for all metals. Overall the study indicates the condition of the coastline to be mostly normal, with Cd and Pb levels being of concern.

Estimation and management of genetic diversity in small populations of plains zebra (Equus quagga) in KwaZulu-Natal, South Africa.

Plains zebras (Equus quagga antiquorum) occur in few large, but many small, isolated populations in KwaZulu-Natal. Problems identified in small populations include reduced striping patterns on hind quarters, smaller size, elevated mortality rates and high number of still-births. Inbreeding may be implicated. Population viability analysis (PVA) was conducted with a computer model (VORTEX), and DNA and allozyme analyses were conducted to test the findings of the model. Using standard methods, DNA (PCR-RAPD) and allozyme diversity was assessed in blood samples from 72 plains zebra from four KwaZulu-Natal Nature Conservation Services (KZN-NCS) protected areas: Umfolozi Game Reserve (UGR), Albert Falls (AFNR), Vernon Crookes (VCNR) and Harold Johnson (HJNR) Nature Reserves. Populations of the latter three, small-sized (9-110 individuals) populations were seeded from the same source population (UGR: current population of 2000) during the past 25 years. Information from PCR-RAPD and allozyme analyses were compared with each other as well as to that predicted by population genetic modelling (using VORTEX). Allozyme heterozygosities were consistently high in all populations (12.1-12.9%), with no observable losses associated with reduced population size. On the other hand, percentage loss of polymorphism (20-39%) calculated from the PCR-RAPD study appeared to be positively correlated with the loss of heterozygosity predicted by population viability analysis (PVA), and negatively correlated with population size. On the basis of the above results, a policy of translocation was advocated for small, intensely managed populations of zebras, whereby a harem should be translocated every five years for a population size of nine (HJNR), while for a population size of 110 (VCNR) translocations should take place every 15 years if heterozygosity is to be maintained at more than 90% within each population over 100 years.

Allozyme and DNA sequence data support speciation of northern and southern populations of silver catfish, Schilbe intermedius (Rüppel, 1832).

Patterns of genetic variation in Schilbe intermedius were investigated due to morphological differences and taxonomic uncertainties regarding the Southern African schilbeids. A total of three populations, two Southern populations representing the former Eutropius depressirostris and a Northern population representing S. mystus, were electrophoretically analysed to determine the extent of genetic differentiation among these populations. The Northern and Southern populations were fixed for different alleles at the G3PDH-2 protein coding locus and allozyme differentiation between populations, using the 0.95 criterion, were also encountered at the PGDH-2 locus. Genetic distance values indicate greater genetic differentiation between the Northern and Southern populations compared to the two Southern populations. DNA sequence analysis of 900-1000 nucleotides of the cytochrome b gene revealed distances of 3.2-3.5% between the Schilbe/Eutropius complex. This finding, together with ingroup and outgroup analysis of evolutionary relationships, is congruent with the results from the electrophoretic analysis of the taxa. Sufficient differentiation exist between the Northern and Southern populations to regard them as distinct species.

Allozyme divergence among four representatives of the subfamily Alcelaphinae (family: Bovidae).

We used protein gel electrophoresis to study genetic diversity within and between blue wildebeest (Connochaetes taurinus), black wildebeest (C. gnou), red hartebeest (Alcelaphus buselaphus caama) and blesbok (Damaliscus dorcas phillipsi). Twenty-nine protein encoding loci were resolved, average heterozygosity ranged from 3.25-5.36% and between population gene diversity accounted for the major share of the total relative gene diversity (69.34%). Genetic distance values ranged from 0.021 to 0.132 and 0.029 to 0.136, with closest identity between the two wildebeest species (as expected for congeneric species). The results are discussed with specific reference to taxonomic relationships between species within the subfamily where interbreeding is known to have occurred.

Genetic variability in South African blue wildebeest (Connochaetes oaurinus).

1. We use protein gel-electrophoresis to investigate genetic heterogeneity at 33 protein coding loci in a total of 46 blue wildebeest (C. taurinus) kept under different management regimes. 2. Average heterozygosity ranged from 2.14 to 4.3% and within-population differences accounted for 97.2% of total relative gene diversity. 3. Comparatively little divergence was found between animals sampled from populations with very diverse population sizes and management histories, with the largest genetic distance estimated between any two populations being only 0.0021. 4. We discuss our results with particular emphasis on the influence of management history on genetic diversity and divergence in C. taurinus.

Allozyme variation in a wild African elephant (Loxodonta africana) population from the Kruger National Park, South Africa.

1. Blood, liver, heart, testis, skin, eye, muscle and kidney samples were obtained from elephants (Loxodonta africana) in the Kruger National Park during a culling programme in April 1992. 2. Gene products of 25 protein coding loci in L. africana were examined by horizontal starch-gel electrophoresis. 3. Eighteen protein coding loci (72%) displayed monomorphic gel banding patterns whereas only seven (28%) displayed polymorphic gel banding patterns. 4. Average heterozygosity values for adults, youngsters and the total population are respectively 0.058, 0.024 and 0.047. 5. Relative gene diversities within and between populations are 84% and 16% respectively. 6. Two population simulation programmes were utilized to predict the duration of the current variability present in this species, based on current genetic variation and gene transfer from one generation to the next.