Social support correlates with glucocorticoid concentrations in wild African elephant orphans.

Social relationships have physiological impacts. Here, we investigate whether loss of the mother/offspring relationship has lasting effects on fecal glucocorticoid metabolite (fGCM) concentrations in wild African elephant orphans several years following their mothers' deaths. We find no difference in fGCM concentrations between orphans and nonorphans, but find lower fGCM concentrations in elephants with more age mates in their family. We also unexpectedly identify lower concentrations in orphans without their natal family versus nonorphans and natal orphans, which we speculate may be due to the development of hypocortisolism following a prolonged period without familial support. An index of plant productivity (i.e. food) shows the largest correlation with fGCM concentrations. Our findings indicate no lasting differences in glucocorticoid concentrations of surviving orphan elephants who are with their family, suggest the presence of age mates may reduce glucocorticoid concentrations in elephants, and emphasize that basic survival needs are the primary regulators of the stress response.

Conserving large populations of lions - the argument for fences has holes.

Packer et al. reported that fenced lion populations attain densities closer to carrying capacity than unfenced populations. However, fenced populations are often maintained above carrying capacity, and most are small. Many more lions are conserved per dollar invested in unfenced ecosystems, which avoid the ecological and economic costs of fencing.

Feasibility study on the spatial and temporal movement of Samburu's cattle and wildlife in Kenya using GPS radio-tracking, remote sensing and GIS.

The study was conducted to assess the technical feasibility of studying the spatial and temporal interaction of traditionally herded livestock and wildlife using global positioning system (GPS) tracking technology in Northern Kenya. Two types of collars were used on nine cows: radio frequency and global system for mobile communications (GSM) collars and GPS-satellite (SAT) collars. Full results of cattle tracking were available for eight cows (3 GSM and 5 SAT) tracked between July 2008 and September 2010. A cumulative total of 1556 tracking days was recorded over the 17 month period. On average cows walked 10,203 m/day (average total monthly distance walked was 234 km). Significant seasonal differences were found; on average cows walked 9.607 m and 10,392 m per day in the rainy and the dry seasons, respectively. This difference was also significant for total monthly and daily distance walked between the dry and the rainy season. On average cows walked daily 9607 m and 10,392 m on the rainy and the dry season respectively. During the dry months a 48 h cycle was observed with cows walking 15-25 km to water every 2nd day but only 5-8 km/day between watering days. There was a 24% overlap of cattle range with both elephants and zebras. This study demonstrated the feasibility of tracking cattle using radio collars. It shows the complexity of spatial use by cattle and wildlife. Such information can be used to understand the dynamics of disease transmission between livestock and wildlife.

Effective population size dynamics reveal impacts of historic climatic events and recent anthropogenic pressure in African elephants.

Two hundred years of elephant hunting for ivory, peaking in 1970-1980s, caused local extirpations and massive population declines across Africa. The resulting genetic impacts on surviving populations have not been studied, despite the importance of understanding the evolutionary repercussions of such human-mediated events on this keystone species. Using Bayesian coalescent-based genetic methods to evaluate time-specific changes in effective population size, we analysed genetic variation in 20 highly polymorphic microsatellite loci from 400 elephants inhabiting the greater Samburu-Laikipia region of northern Kenya. This area experienced a decline of between 80% and 90% in the last few decades when ivory harvesting was rampant. The most significant change in effective population size, however, occurred approximately 2500 years ago during a mid-Holocene period of climatic drying in tropical Africa. Contrary to expectations, detailed analyses of four contemporary age-based cohorts showed that the peak poaching epidemic in the 1970s caused detectable temporary genetic impacts, with genetic diversity rebounding as juveniles surviving the poaching era became reproductively mature. This study demonstrates the importance of climatic history in shaping the distribution and genetic history of a keystone species and highlights the utility of coalescent-based demographic approaches in unravelling ancestral demographic events despite a lack of ancient samples. Unique insights into the genetic signature of mid-Holocene climatic change in Africa and effects of recent poaching pressure on elephants are discussed.

Noninvasive genotyping and Mendelian analysis of microsatellites in African savannah elephants.

We obtained fresh dung samples from 202 (133 mother-offspring pairs) savannah elephants (Loxodonta africana) in Samburu, Kenya, and genotyped them at 20 microsatellite loci to assess genotyping success and errors. A total of 98.6% consensus genotypes was successfully obtained, with allelic dropout and false allele rates at 1.6% (n = 46) and 0.9% (n = 37) of heterozygous and total consensus genotypes, respectively, and an overall genotyping error rate of 2.5% based on repeat typing. Mendelian analysis revealed consistent inheritance in all but 38 allelic pairs from mother-offspring, giving an average mismatch error rate of 2.06%, a possible result of null alleles, mutations, genotyping errors, or inaccuracy in maternity assignment. We detected no evidence for large allele dropout, stuttering, or scoring error in the dataset and significant Hardy-Weinberg deviations at only two loci due to heterozygosity deficiency. Across loci, null allele frequencies were low (range: 0.000-0.042) and below the 0.20 threshold that would significantly bias individual-based studies. The high genotyping success and low errors observed in this study demonstrate reliability of the method employed and underscore the application of simple pedigrees in noninvasive studies. Since none of the sires were included in this study, the error rates presented are just estimates.

Movements and corridors of African elephants in relation to protected areas.

Understanding how mammals satisfy their need for space in fragmenting ecosystems is crucial for ecosystem conservation. Using state-of-the-art global positioning system (GPS) technology we tracked 11 focal African elephants (Loxodonta africana) in Kenya at 3-hourly fix intervals and collected between 34 and 406 days per individual. Our recordings gave a high spatio-temporal resolution compared to previous studies and allowed novel insights into range use. The actual ranges of the tracked elephants are smaller than usually represented. Moreover, the ranges in our sample were complex and not confined to officially designated protected areas, except where fenced. All the unfenced elephants in our sample had distinct 'home sectors' linked by 'travel' corridors. Within each home sector the elephants concentrated in favourite 'core zones'. Such core zones tended to lie in protected areas whereas corridors typically crossed unprotected range. Elephants moved significantly faster along corridors than elsewhere in their range, which suggests awareness of danger outside the protected area. We conclude that understanding the complex use of an animal's range is crucial for conservation planning aiming to balance animal interests with those of human beings that co-habit in their range.

Stability in a multi-species assemblage of large herbivores in East Africa.

Animal census data from Lake Manyara National Park in northern Tanzania are presented. The data refer to large mammalian herbivores, that is individually heavier than twenty kg, of which the numbers were counted in nine different years between 1959 and 1984. The total biomass of these herbivores was comprised mainly of African buffalo and African elephant. Five functional groups of herbivores were distinguished (buffalo, "elephant-as-grazer", "elephant-as-browser", "other grazers", and "other browsers"). The pressures of all these groups were constant over time with the exception of that by buffalo. Buffalo numbers increased since the last outbreak of rinderpest in 1959. There was no correlation between herbivore biomass and rainfall fluctuations. Individual species showed large fluctuations in their numbers but within the total herbivore assemblage the different species compensated the fluctuations of the other species. This resulted in an overall constancy of herbivore biomass, and, thus, the carrying capacity of the system has to be viewed on the level of all species combined and not on that of the individual species. This view is supported by the result that size of the stability index showed that the system of herbivore species was stable.