Martina Trinkel

INBREEDING DEPRESSION INCREASES SUSCEPTIBILITY TO BOVINE TUBERCULOSIS IN LIONS: AN EXPERIMENTAL TEST USING AN INBRED–OUTBRED CONTRAST THROUGH TRANSLOCATION

Disease can dramatically influence the dynamics of endangered wildlife populations, especially when they are small and isolated, with increased risk of inbreeding. In Hluhluwe-iMfolozi Park (HiP), a small, enclosed reserve in South Africa, a large lion (Panthera leo) population arose from a small founder group in the 1960s and started showing conspicuous signs of inbreeding. To restore the health status of the HiP lion population, outbred lions were translocated into the existing population. In this study, we determined the susceptibility to bovine tuberculosis (bTB), and the prevalence of antibody to feline viruses of native lions, and compared the findings with those from translocated outbred lions and their offspring. Antibodies to feline herpesvirus, feline calicivirus, feline parvovirus, and feline coronavirus were present in the lion population, but there was no significant difference in antibody prevalence between native and translocated lions and their offspring, and these feline viruses did not appear to have an effect on the clinical health of HiP lions. However, feline immunodeficiency virus (FIV), which was previously absent from HiP, appears to have been introduced into the lion population through translocation. Within 7 yr, the prevalence of antibody to FIV increased up to 42%. Bovine tuberculosis posed a major threat to the inbred native lion population, but not to translocated lions and their offspring. More than 30% of the native lion population died from bTB or malnutrition compared with <2% of the translocated lions and their offspring. We have demonstrated that management of population genetics through supplementation can successfully combat a disease that threatens population persistence. However, great care must be taken not to introduce new diseases into populations through translocation.

Spotted hyenas (Crocuta crocuta) follow migratory prey. Seasonal expansion of a clan territory in Etosha, Namibia

The spatial organization of one clan of spotted hyenas Crocuta crocuta in the centre of the Etosha National Park, Namibia, is described during the dry and the wet seasons. The clan comprised 11 adults and sub-adults and occupied a territory of 160 km2 in the dry season and 320 km2 in the wet season. The dry season territory contained a low density (one animal/km2) of resident herbivores, such as gemsbok Oryx gazella, kudu Tragelaphus strepsiceros, giraffe Giraffa camelopardis, steenbok Raphicerus campestris and ostrich Struthio camelus, and a higher density of migratory species (12 animals/km2), principally springbok Antidorcas marsupialis, zebra Equus burchelli and wildebeest Connochaetes taurinus. These migratory species were the main prey of clan members. At the start of the wet season, the migratory herbivores migrated to the north-west, resulting in a considerable decline in the density of prey in the area used by clan members during the dry season. In response to this decline in prey, clan members followed the migratory herds and shifted the focus of their activities to an area grazed by migratory herbivores during the wet season. There existed a strong spatial relationship between the hyena density and the migratory prey density in both the dry and wet season. We postulate that the considerable enlargement of the clan territory in the wet season is a response to both the migratory movements of prey and an increase in the dispersion of prey during the wet season.

Prey selection and prey preferences of spotted hyenas Crocuta crocuta in the Etosha National Park, Namibia

The feeding ecology of the spotted hyena Crocuta crocuta was studied in the central and eastern part of the Etosha National Park, Namibia. Hyenas mainly hunted migratory ungulates such as springbok Antidorcas marsupialis, zebra Equus burchelli, and blue wildebeest Connochaetes taurinus, but also resident species such as the greater kudu Tragelaphus strepsiceros and gemsbok Oryx gazella. There were, however, major differences in the species most frequently killed by hyenas in central and eastern Etosha. The preferred prey species of spotted hyenas in central Etosha was springbok, whereas regarding the abundance of zebra and wildebeest, these two species were rather avoided. In contrast, the prey species preferred by hyenas in eastern Etosha was kudu. Zebra and gemsbok were taken in proportion to their abundance, whereas wildebeest and springbok seemed to be rather avoided. Differences in prey selection and preferences were also reflected in differences in hunting group sizes. In eastern Etosha, where spotted hyenas frequently hunted larger prey, hunting group sizes were significantly larger compared to those in the center of the park.

Keto-enol tautomerism in β-tricarbonyl compounds: infrared spectroscopy, molecular mechanics and semiempirical (AM1) molecular orbital calculations

Abstract A combination of experimental (infrared spectroscopy) and theoretical (molecular mechanics, semiempirical) AM1 molecular orbital calculations) methods is used to investigate the keto—enol tautomeric equilibria and the conformational preferences in the β-tricarbonyls, 2,2-dibenzoyl-N-alkoxycarbonyl acetamides. In CCl4 only the enol form is present, whereas in CHCl3 both the triketo and the enol tautomers can be observed. In both solvents enolization of the benzoyl but not the amide carbonyl group occurs. E-enols are found to be more stable than their Z isomers. The AM1 method yields quite reliable tautomerization and conformational energies and is, therefore, a useful complement to experimental studies. In contrast, molecular mechanics calculations using the TRIPOS force field do not give reasonable keto-enol energy differences but are essential in generating a sufficient number of different starting conformations in highly flexible molecules for more advanced computations.

The Decline in the Lion Population in Africa and Possible Mitigation Measures

The African lion Panthera leo is under threat. Over the last century the lion has lost about 82 % of its former distribution range, and recent estimates suggest that there are 23,000–38,000 free-ranging lions living in 68 mostly geographically isolated areas. Approximately 24,000 lions are in strongholds, but about 6000 lions are living in populations with a high risk of local extinction, of which about 3000 are in West and Central Africa. Particularly critical is the situation in West Africa, with perhaps only 400 individuals, of which less than 250 are adults. Main threats for lions are habitat loss through agricultural development and human settlement, depletion of prey populations, human–wildlife conflict, epidemics and diseases and trade of lion parts. Conflict mitigation between humans and lions, mainly investigated in rural areas in West and East Africa, have successfully reduced livestock losses and subsequently reduced the number of lions killed. However, mitigation measures alone might fail to secure the critically endangered lion population in West Africa, where translocations and reintroductions might be necessary to counteract genetic impoverishment. Despite encouraging human wildlife coexistence, other approaches for effective long-term conservation of African lions, and the lions’ prey species, favor the separation of land used by humans and conservation areas through the erection of fences. Fences have already been erected in many areas in southern Africa, where lion populations are still viable. Ecotourism and trophy hunting can also be beneficial for lion conservation. However, revenues and user rights over wildlife have to be devolved to local people. This has been successfully implemented in Namibia, which is one of the few countries where lion populations are currently increasing. Although trophy hunting can be a useful conservation tool for conserving lions, it can also be a threat. Therefore, improved regulations and management of lion hunting to prevent negative impacts on hunted lion populations is necessary in many countries. If the downwards trend in lion numbers continues, it is questionable if there will be still lions around in the next century.