Noninvasive genetic analyses for estimating population size and genetic diversity of the remaining Far Eastern leopard (Panthera pardus orientalis) population

Understanding and monitoring the population status of endangered species is vital for developing appropriate management interventions. We used noninvasive genetic analyses to obtain ecological and genetic data on the last remaining Far Eastern leopard population in the world. During seven winters from 2000–2001 to 2007–2008, we collected feces, hair, and saliva from most of the leopard habitat. Of the 239 leopard samples collected during the study period, 155 were successfully genotyped at 13 microsatellite loci and 37 individuals (18 males and 19 females) were identified. Population size estimates based on the Capwire model were 28 (95 % CI 19–38) in 2002–03 and 26 (95 % CI 13–33) in 2007–2008. The leopard population had a low level of genetic diversity (expected and observed heterozygosity = 0.43; average number of alleles per locus = 2.62), and effective population size was estimated to be low (N _e = 7–16) by two genetic-based methods. We observed little improvement in the genetic diversity during the study period and did find an indication of allele loss compared with individuals from the mid-1990s, suggesting that the remaining population will continue to suffer loss of genetic diversity. Given the small population size and the low genetic diversity, with little expectation of replenishment of the genetic variation by natural immigration, successful expansion of available habitat and development of a second population based on captive individuals may be crucial for persistence of this leopard subspecies in the wild.     

How should a clever baboon choose and move rocks?

Chacma baboons (Papio ursinus) intentionally overturn rocks to feed on the invertebrates beneath. However, baboons do not move all the rocks they encounter, with this presumably reflecting cost–benefit (or effort–reward) trade‐offs in their foraging behavior. We ask, how do “clever baboons” choose rock sizes and shapes and move these rocks? Using optimal foraging theory, we predicted that baboons would prefer to move medium‐sized rocks, a trade‐off between moving larger rocks that might require more effort to move, and smaller rocks that likely do not provide enough prey (the reward) to make the effort worthwhile. We also expected baboons to prefer rounded rocks as these will require less energy to move by rolling (rather than being flipped as for flat rocks) and that the effort of rock movement might be offset by moving rocks along the shortest axis. We show that baboons have clear preferences for specific rock sizes (medium‐sized) and shapes (angular and flat when these were medium‐sized), and the way in which rocks are moved (along the shortest axis). Prey occurred infrequently under rocks. The low predictability of prey beneath rocks suggests that such prey, when encountered, is of considerable value to baboons for them to expend the search effort, and also explains the extensive nature of rock movement by baboons in the landscape. Our study provides a novel application of the optimal foraging theory concept and has important implications for understanding and predicting how animals choose to move rocks.     

Book Reviews

Adams, N.J., Kerley, G.I.H. & Watson, J.J. 1999. Disturbance of incubating African Black Oystercatchers: is heating of exposed eggs a problem? Ostrich 70(3&4): 225–228.

We measured temperatures of incubated and exposed eggs of African Black Oystercatchers Haematopus moquini nesting in coastal dunes, Algoa Bay, South Africa through three of the 10 hottest days of summer during the 1994/95 breeding season. Mean incubation temperature was 34.4 ± 0.7°C (range: 32.2–37.0; n=3). The average maximum temperature attained by exposed dummy eggs, averaged higher at 37.4 ± 2.7°C (n=5). The absolute maximum recorded for exposed eggs was 40.1°C. These temperatures are within lethal limits measured for other birds and suggests that heating of exposed eggs after disturbance of incubating was not a direct factor in explaining variation in breeding success of oystercatchers in the Alexandria Dunefield, Algoa Bay.     

Evidence for prey selection by spotted hyaena in the Eastern Cape,South Africa

We tested the widely accepted hypothesis that spotted hyaenas (Crocuta crocuta) are non-selective in their diet. The prey preference of spotted hyaena was studied in the Addo Elephant National Park (AENP), South Africa. Diet (frequency of occurrence of prey items in the diet) was quantified through the analysis of 55 scats, and compared with available prey. A combination of large- and medium-sized mammals (buffalo (Syncerus caffer), red hartebeest (Alcelaphus buselaphus) and common duiker (Sylvicapra grimmia) were the most preferred prey items. The most abundant species, warthog (Phacochoerus africanus) and kudu (Tragelaphus strepsiceros), were ignored and avoided, respectively. These results show that the assumption that hyaena prey on the most abundant available prey species may be overly simplistic. Predation patterns, such as the ones observed in AENP, may have important ramifications for less common species that are selected by hyaena in small enclosed reserves.     

A pragmatic approach to estimating the distributions and spatial requirements of the medium- to large-sized mammals in the Cape Floristic Region, South Africa

Conservation planning in the Cape Floristic Region, a recognized world plant diversity hotspot, required systematic information on the estimated distributions and spatial requirements of the medium- to large-sized mammals within each of 102 Broad Habitat Units delineated according to key biophysical parameters. As a consequence of a general lack of data, we derived a pragmatic approach for obtaining estimates of these two parameters. Distribution estimates were based on a combination of a literature survey (with emphasis on early texts) and the ecological requirements of the species. Spatial requirement estimates were derived from a simple spreadsheet model that is based on forage availability estimates and the metabolic requirements of the mammals in question. Our analysis incorporated adaptations of the agriculture-based Large Stock Unit or Animal Unit approach. The predictions of the model were tested by comparing them with actual density data. The outcomes provided realistic estimates of the two parameters. However, they should be considered as testable hypotheses and the concept of adaptive management — or management by hypothesis — must apply. Examples of the outcomes are provided in the form of maps and tables.     

Elephant both Increase and Decrease Availability of Browse Resources for Black Rhinoceros

Despite the apparent dual role of elephant Loxodonta africana in shaping the food niches of large herbivores, empirical studies focus on their role in facilitating foraging opportunities, while declining resource opportunities (a necessary requirement for competition) are rarely quantified. Our study investigates the relative importance of elephant in these processes by quantifying potential browsing opportunities (using total and preferred biomass, between‐bite distances and bite mass) for black rhinoceros Diceros bicornis along a gradient of elephant utilization in the succulent thickets of the Addo Elephant National Park, South Africa. We show that browse biomass and potential between‐bite harvest rates initially increase with the intensity of elephant utilization through the formation and spread of elephant pathways in otherwise impenetrable thicket. At the maximum, modeled estimates of total and preferred biomass are on average 223 percent and 254 percent higher, respectively, than that recorded in the absence of elephant (Exclosures); potential between‐bite harvest rates are 75 percent higher. With continued elephant utilization, however, browse biomass declines and between‐bite distances increase as the pathways expand and coalesce and canopy height declines. Our model of the change in potential browsing opportunities for rhinoceros reflects the accumulated effects of elephant over time, i.e., the effects accumulate until the relationship switches from increased to reduced availability. With this we demonstrate the key role of elephant for rhinoceros foraging, linked to a potential loss of this role at higher levels of utilization.     

QTLs associated with dry matter intake,metabolic mid-test weight,growth and feed efficiency have little overlap across 4 beef cattle studies

Background

The identification of genetic markers associated with complex traits that are expensive to record such as feed intake or feed efficiency would allow these traits to be included in selection programs. To identify large-effect QTL, we performed a series of genome-wide association studies and functional analyses using 50 K and 770 K SNP genotypes scored in 5,133 animals from 4 independent beef cattle populations (Cycle VII, Angus, Hereford and Simmental × Angus) with phenotypes for average daily gain, dry matter intake, metabolic mid-test body weight and residual feed intake.

Results

A total of 5, 6, 11 and 10 significant QTL (defined as 1-Mb genome windows with Bonferroni-corrected P-value <0.05) were identified for average daily gain, dry matter intake, metabolic mid-test body weight and residual feed intake, respectively. The identified QTL were population-specific and had little overlap across the 4 populations. The pleiotropic or closely linked QTL on BTA 7 at 23 Mb identified in the Angus population harbours a promising candidate gene ACSL6 (acyl-CoA synthetase long-chain family member 6), and was the largest effect QTL associated with dry matter intake and mid-test body weight explaining 10.39% and 14.25% of the additive genetic variance, respectively. Pleiotropic or closely linked QTL associated with average daily gain and mid-test body weight were detected on BTA 6 at 38 Mb and BTA 7 at 93 Mb confirming previous reports. No QTL for residual feed intake explained more than 2.5% of the additive genetic variance in any population. Marker-based estimates of heritability ranged from 0.21 to 0.49 for residual feed intake across the 4 populations.

Conclusions

This GWAS study, which is the largest performed for feed efficiency and its component traits in beef cattle to date, identified several large-effect QTL that cumulatively explained a significant percentage of additive genetic variance within each population. Differences in the QTL identified among the different populations may be due to differences in power to detect QTL, environmental variation, or differences in the genetic architecture of trait variation among breeds. These results enhance our understanding of the biology of growth, feed intake and utilisation in beef cattle.     

Nutritional skewing of conceptus sex in sheep: effects of a maternal diet enriched in rumen-protected polyunsaturated fatty acids (PUFA)

Background  

Evolutionary theory suggests that in polygynous mammalian species females in better body condition should produce more sons than daughters. Few controlled studies have however tested this hypothesis and controversy exists as to whether body condition score or maternal diet is in fact the determining factor of offspring sex. Here, we examined whether maternal diet, specifically increased n-6 polyunsaturated fatty acid (PUFA) intake, of ewes with a constant body condition score around the time of conception influenced sex ratio.