The impact of giraffe, rhino and elephant on the habitat of a black rhino sanctuary in Kenya

The habitat in an enclosed black rhino sanctuary, the Sweetwaters Game Reserve in Kenya, is being altered as populations of elephant, giraffe and black rhino increase. Height‐specific browse impact data were recorded for 1075 trees of the dominant species, the whistling thorn, Acacia drepanolobium. Rhinos and elephants browsed 18% of these trees in 1 year, including 5% that were killed or removed. The remaining trees were subjected to high levels of giraffe browse and low rainfall and grew by only 7.5 cm in a year. A mathematical model has been constructed that predicts how the number of trees ha^?1 will change with time under different browsing impacts. The model compares recruitment rate with removal rate and estimates that the number of trees ha^?1 will fall by 2% per year under the current browsing impact of black rhino (0.27 per km²), elephant (1.1 per km²) and giraffe (1.9 per km²). In 7 years, if the rhino and elephant populations continue to increase at the current rates, tree density will be falling by 5% per year and nearly one‐third of the trees will have been removed. These conditions are unsustainable and will result in habitat change and may affect rhino breeding. Several ways of alleviating the problem are discussed.     

The impact of elephants on the marula tree Sclerocarya birrea

This study determined the abundance, density and population structure of the marula tree, Sclerocarya birrea, in three game reserves in South Africa, and assessed patterns and amounts of new and cumulative impact of elephants. Elephant feeding was very patchy so several attributes of individual trees, sampled transects and communities that might influence elephant herbivory were investigated. The incidence and type of elephant impact (bark, branch or stem breakage) were significantly related to tree diameter, but not to fruiting nor proximity to roads. At the transect level, elephant impact was influenced by density of marula trees, but was not influenced by proximity to roads, nor proportion of marula trees bearing fruits in the vicinity. At the community level, elephant impact was higher on reserves with higher total marula densities. Fourfold differences in elephant densities (0.08–0.30 elephants km^?2) did not explain marula consumption: the percentage of trees with branch damage was similar across reserves and bark damage was inversely proportional to elephant density. Variation across reserves may reflect local and landscape‐level marula tree abundance, differences in alternative food plants and individual feeding habits. The recorded levels of impact appeared to be sustainable because mortality rates were low, affected trees often recovered, and small trees were not preferentially preyed upon.     

Carbon isotopes as indicators of elephant diets and African environments

Stable carbon isotope ratios have been successfully used to assess modern animal diets and to reconstruct prehistoric diets of animals and humans (Vogel & van der Merwe, 1977; van der Merwe & Vogel, 1978; Burleigh & Brothwell, 1978; Vogel, 1978a; DeNiro & Epstein, 1978; Tieszen et al., 1979; Tieszen & Imbamba, 1980; Chisholm, Nelson & Schwarcz, 1982; Tauber, 1981). We have used ¹³C/¹²C ratio measurements of bone collagen to study the diets of African elephants in twelve wildlife refuges. These represent most of the habitats in which elephants live, including such diverse plant communities as primary rain forest, savanna woodland and desert. The δ¹³C values were found to have a simple linear relationship with tree density in most cases. When translated into relative amounts of dietary browse (C₃ plants) and graze (C₄ plants), the grass content is seen to be systematically under-represented, presumably due to inefficient metabolism. This does not affect the relationship between elephant diet and tree density, which has implications for the study of elephant-woodland interactions, and for reconstructions of past African environments.     

Historical range and movements of the Elephants in Babile Elephant Sanctuary,Ethiopia

A study on historical range and movement patterns of the African savannah elephants (Loxodonta africana africana) in Ethiopia was made from December 2004 to November 2008. Babile Elephant Sanctuary is one of the strongholds of elephants in the country, where it now supports approximately 27% of the elephant population in Ethiopia. Elephant movement routes and ranges were identified based on interviews of local people and by tracking the animals in the field. Elephants of the Sanctuary were categorized into two distinctive groups or clans based on their movement patterns and their associations to each other. Three major valleys, namely Gobele, Erer and Dakata, were crossed by elephants. Elephants in the population had an estimated annual range of 3014 km². Of this, 85.7% (2583 km²) was inside the Sanctuary and 14.3% (430 km²) outside but adjacent to the Sanctuary. Elephant use outside of the Sanctuary included three different areas: Upper Erer Valley (8 km²), Upper Gobele Valley (48 km²) and west of Gobele Valley (374 km²). The extent of range varied seasonally. During the wet season, elephant range was restricted to Erer Valley and its tributaries (1266 km² and a density of approximately 0.25 animal km^?2), or 42% smaller than the dry season range (1417 km², 0.23 elephant km^?2). Range use was smallest (332 km²) in October to November and from April to May. During the dry season, elephants were found in two distinctive groups, one using Gobele Valley and the other Erer Valley.     

The savanna ecology of Kidepo Valley National Park

(1) Food habits of elephant and giraffe were recorded in short sample periods over several years using the feeding minutes technique. (2) Twelve species of common plants were collected on these occasions, separated into their main parts and analysed chemically. (3) Damage to trees was also recorded at intervals. (4) Fifty-nine species of plant were eaten by elephant. During wet months their diet was predominantly grass but during dry months woody vegetation became more important. Giraffe were observed eating from thirty-nine species of plant which were almost entirely browse throughout the year. At least eighteen of these species were also eaten by elephant. (5) Three of the browse species most important to giraffe were also important to elephant in dry seasons. In the driest month the species eaten by giraffe formed more than two-thirds of the observed diet of elephants. (6) Chemical analyses of plants show that browse leaves had a higher level of protein, fat and minerals than most other plants. (7) The trunk of an elephant and the tongue of a giraffe are highly sensitive organs which permit food selection. Elephant in particular appeared to alter their food habits seasonally and it is suggested that this may be an attempt to obtain a balanced intake of nutrients. (8) Due to the effect of elephant and other agencies there is an accelerating decline in Acacia gerrardii woodlands. Browsing and fire are independently preventing their regeneration. (9) The extensive overlap of food requirements on preferred but diminishing browse resources implies potential if not already existing competition between elephant and giraffe. (See Part III.)     

Growth energetics of juvenile herring,Clupea harengus L.: food conversion efficiency and temperature dependency of metabolic rate

The relationship between rates of food consumption (C) and somatic growth (G) and the effect of temperature (T) on rates of mass lost during food deprivation were examined in 9–10 cm total length (TL) [1.0–1.5 g dry mass (DM)] juvenile Atlantic herring (Clupea harengus L.) in the laboratory. One feeding‐growth trial was conducted at 16°C using groups of herring feeding on known rations of brine shrimp (Artemia spp.) nauplii to quantify gross and net growth efficiency. Rates of mass lost by groups of herring (a proxy for metabolic rate, M) were measured in trials conducted at 9.7, 14.2 and 17.9°C. Gross growth efficiency (GGE = 100*G*C^?1) at 16°C was 25% at the highest rations (5.8–6.6% DM). The maintenance ration (C_main = C at zero G) was equal to 432 J*fish^?1*d^?1 or 2.0% DM*d^?1. At 16°C, net growth efficiency (100*G*(C?C_main)^?1) was 42%. The nucleic acid content (RNA‐DNA ratio, RD) in herring muscle tissue was strongly related to somatic growth (G, % DM*d^?1 = ?0.36*RD² + 3.21*RD ?3.92, r² = 0.90, P < 0.05, n = 8 groups). The effect of T (9.7–17.9°C) on M was described by a second order polynomial equation M = ?1.24*T + 38.2*T ? 218 (J*g DM^?1*d^?1) and M = ?10*T + 310*T ? 1815 (J*fish^?1*d^?1). This was the first study to investigate the influence of temperature on the metabolic rate of juvenile Atlantic herring under stress‐free conditions in the laboratory and provides the first estimates of gross and net growth efficiency for this species feeding on live prey.     

Landscape-scale feeding patterns of African elephant inferred from carbon isotope analysis of feces

The African elephant (Loxodonta africana) is a large-bodied, generalist herbivore that eats both browse and grass. The proportions of browse and grass consumed are largely expected to reflect the relative availability of these resources. We investigated variations in browse (C(3) biomass) and grass (C(4)) intake of the African elephant across seasons and habitats by stable carbon isotope analysis of elephant feces collected from Kruger National Park, South Africa. The results reflect a shift in diet from higher C(4) grass intake during wet season months to more C(3) browse-dominated diets in the dry season. Seasonal trends were correlated with changes in rainfall and with nitrogen (%N) content of available grasses, supporting predictions that grass is favored when its availability and nutritional value increase. However, switches to dry season browsing were significantly smaller in woodland and grassland habitats where tree communities are dominated by mopane (Colophospermum mopane), suggesting that grasses were favored here even in the dry season. Regional differences in diet did not reflect differences in grass biomass, tree density, or canopy cover. There was a consistent relationship between %C(4) intake and tree species diversity, implying that extensive browsing is avoided in habitats characterized by low tree species diversity and strong dominance patterns, i.e., mopane-dominated habitats. Although mopane is known to be a preferred species, maintaining dietary diversity appears to be a constraint to elephants, which they can overcome by supplementing their diets with less abundant resources (dry season grass). Such variations in feeding behavior likely influence the degree of impact on plant communities and can therefore provide key information for managing elephants over large, spatially diverse, areas.     

ELEPHANT ECOLOGY IN THE QUEEN ELIZABETH NATIONAL PARK, UGANDA

1. Aerial and ground counts in the Queen Elizabeth National Park from 1963 to 1969 indicate that the number of elephants has more than doubled. The increase appears to be the result of immigration rather than reproduction. 2. Elephant food habits were studied for 10 months in two areas of the Park. In the short-grass/thicket area, browse intake rose markedly whenever the rainfall fell below 50 mm/month. In the tall-grass area without thicket, herbs were eaten frequently during the rains and Cymbopogon grass bases in the dry season. 3. Food availability had an important influence on the diet of elephants. Sometimes, however, elephant were very selective, e.g. for Panicum maximum, Azima tetracantha, Securinega virosa, and Tribulus terrestris. Certain grass inflorescences were selected during the rains, and bases in the dry season. 4. Most browse was consumed in the thicket area during the dry season and most grass was eaten in the tall-grass area of the Park. 5. Stomach and faecal samples gave a similar result and indicated that the diet in the tall-grass area was comparable to that of elephant in Murchison Falls National Park. 6. Analyses of important plant species showed that, in general, tall-grass had a lower crude protein content than short-grass, herbs and browse. Browse leaves had a relatively high crude-protein content in the dry season. Differences were less marked in the rains. 7. Ether extract, or fat content, was high in browse leaves and in Cymbopogon, in particular its bases. These may have been selected in the dry season for this reason. 8. Grass and browse stems were very fibrous and this may have contributed to their being avoided. 9. High carbohydrate levels probably enhanced the palatability of grass bases and browse leaves. 10. Grasses were very siliceous, in particular their bases when contaminated with soil. Elephant took considerable trouble to remove soil. Browse leaves had little silica but were rich in other minerals, and this may have contributed to their greater palatability. 11. Studies of woodland dynamics show a decline in large trees which corresponds to the increase in elephants. In some cases trees have been almost eliminated. Damage to trees indicates that a most important factor in their decline is the elephant. There is some evidence that the trees are eliminated selectively. 12. In the tall-grass area there has been an increase of 46.3% in elephant numbers, but a decline of 80.3 % in buffalo, over the past 15 years. An overall decline in combined biomass of 36.9 % is calculated. Estimates of energy utilization of the annual vegetation production by elephant and buffalo indicates a decline from 6.1 % to 3.9% over this period.     

Spatial distribution and effects of Lantana camara invasion on soil properties and native vegetation community composition in Tugwi-Mukosi Recreational Park,Masvingo, Zimbabwe

This study investigated spatial distribution and effects of Lantana camara invasion on soil properties and vegetation composition in Tugwi-Mukosi Recreational Park. Supervised classification with the Random Forest classifier was used to map L. camara in the park. The study area was stratified into two categories based on soil type and the extent of L. camara invasion. Stratified random sampling was used in data collection to assess differences in species diversity and soil properties in the park. Results revealed that L. camara covered an area of 1772 ha. Using Random Forest classification, the study obtained an accuracy score of 92.1% and an F1 score of 86.25%. Two-way ANOVA showed significant effect of L. camara invasion on soil moisture (F = 28.143, p = 0.000), organic matter (F = 13.377, p = 0.003), pH (F = 1272.369, p = 0.000), total nitrogen (F = 51.762, p = 0.000), total phosphorus (F = 5.000, p = 0.045), woody species density (F = 4.987, p = 0.027), basal area (F = 10.393, p = 0.001), grass species richness (F = 196.258, p = 0.000) and grass cover (F = 3.637, p = 0.042). These results suggest that L. camara was modifying the soil and vegetation properties of the ecosystem which has implications on biodiversity.     

Analyses of African elephant (Loxodonta africana) diet with various browse and pellet inclusion levels

To more closely simulate the diet of free-ranging elephants, the diet of six (2.4) African elephants (Loxodonta africana) was altered to include more browse and less pelleted complete feed (5% total diet). Dietary proximate compounds, minerals, vitamins A (and carotenoids), D and E, and fatty acids were analyzed on pelleted diet items and forages including hay, grass, and browse. A total of 42 browse species were offered over 1 year with an average total diet inclusion of 5.2% (dry matter basis) per day. Dietary Na and Se were low while Fe and Mn were high compared to published intake levels for elephants. Analyzed nutrients within browse varied widely among seasons and species. Ingredient analyses were used to create predicted elephant nutrient intake for (a) the current diet, (b) a diet excluding pellets, and (c) a diet excluding pellets and providing browse at doubled levels. Formulated diets excluding pellets had lower mineral levels than the current diet and doubled browse did not alter mineral inclusions of concern. This study provides seasonal data on the nutrient levels of Southeastern browse species important for various pachyderm and herbivorous species. Predicted nutrient intake with new diet scenarios does not support the exclusion of pellets in the diets of African elephants without greater browse quantity availability, strict diet management, or additional supplements.     

Diet and distribution of elephant in the Maputo Elephant Reserve, Mozambique

The distribution and diet of the elephants of the Maputo Elephant Reserve were studied using dung counts, satellite tracking and faecal analysis. The results were compared with earlier data from before the civil war in Mozambique. The elephant population decreased during the civil war, but 180 animals still remain. Earlier studies described the elephants as preferring the grass plains. Currently, the elephants prefer the dense forest patches over the high quality forage found in the grass plains. Water salinity affected distribution; elephant dung piles were found closer to fresh water in the dry season. A total of 95 different plant species were identified in the faeces. The percentage of grass was relatively low compared with other studies, increasing at the beginning of the rainy season. At the end of the dry season, elephants concentrated on the few available browse species with young leaves, but generally preferred grass species to browse species. Diet composition was mainly affected by season and less by habitat. The elephants have changed their habitat preference in reaction to poaching, and probably increased the contribution of browse species in the diet. The presence of forest patches has been vital for the survival of the elephants.     

Assessing the effects of elephant foraging on the structure and diversity of an Afrotropical forest

African forest elephants (Loxodonta cyclotis) are ecosystem engineers that browse and damage large quantities of vegetation during their foraging and movement. Though elephant trail networks and clearings are conspicuous features of many African forests, the consequences of elephant foraging for forest structure and diversity are poorly documented. In this study in northeastern Gabon, we compare stem size, stem density, proportional damage, species diversity, and species relative abundance of seedlings and saplings in the vicinity of seven tree species that produce elephant-preferred fruits (“elephant trees”) relative to control trees that do not. Across 34 survey trees, with a combined census area of 2.04 ha, we recorded data on 26,128 woody stems in three sizes classes. Compared with control trees, the area around elephant trees had the following: (a) a significantly greater proportion of damaged seedlings and a marginally greater proportion of damaged saplings (with 82% and 24% greater odds of damage, respectively); (b) no significant difference in stem density or species diversity; and (c) a significantly greater relative abundance of seedlings of elephant tree species. Increasing distance away from focal elephant trees was associated with significantly reduced sapling stem damage, significantly increased sapling stem density, and significantly increased sapling species diversity. Considered in sum, our results suggest that elephants can affect the structure and diversity of Afrotropical forests through their foraging activities, with some variation based on location and plant size class. Developing a more complete understanding of elephants’ ecological effects will require continued research, ideally with manipulative experiments.     

Continuous multistep versus fed‐batch production of ethanol and xylitol in a simulated medium of sugarcane bagasse hydrolyzates

Co‐cultures for simultaneous production of ethanol and xylitol were studied under different operation bioreactor modes using Candida tropicalis IEC5‐ITV and Saccharomyces cerevisiae ITV01‐RD in a simulated medium of sugarcane bagasse hydrolyzates. Xylitol and ethanol tolerance by S. cerevisiae and C. tropicalis, respectively, was evaluated. The results showed that C. tropicalis was sensitive to ethanol concentrations up to 30 g/L, while xylitol had no effect on S. cerevisiae viability and metabolism. The best condition found for simultaneous culture was S. cerevisiae co‐culture and C. tropicalis sequential cultivation at 24 h. Under these conditions, productivity and yield for ethanol were Q_EtOH = 0.72 g L^?1 h^?1 and Y_EtOH/s = 0.37 g/g, and for xylitol, Q_XylOH = 0.10 g L^?1 h^?1 and Y_XylOH/S = 0.31 g/g, respectively; using fed‐batch culture, the results were Q_EtOH = 0.87 g L^?1 h^?1 and Y_EtOH/s = 0.44 g L^?1 h^?1, and Q_EtOH = 0.27 g L^?1 h^?1 and Y_EtOH/s = 0.57 g/g, respectively. Maximum volumetric productivity in continuous multistep cultures of ethanol and xylitol was at dilution rates of 0.131 and 0.074 h^?1, respectively. Continuous multistep production, Q_EtOH increased up to 50% more than in fed‐batch culture, even though xylitol yield remained unchanged.     

Characterization of 26 new microsatellite loci in the dugong (Dugong dugon)

Twenty‐six microsatellite loci have been isolated from a dugong (Dugong dugon). The average heterozygosity was 0.52 with two to 10 alleles per locus surveyed from 50 individuals. The markers are suitable for genetic mark–recapture (P_ID = 5 × 10^?16) in dugongs and they could also be used to quantify physical tag loss, estimate relatedness, assign paternity, elucidate population structure and identify migrants. The loci also amplified in Florida manatees (22/26) and Asian elephants (6/26).     

Humans and elephants as treefall drivers in African savannas

Humans have played a major role in altering savanna structure and function, and growing land‐use pressure will only increase their influence on woody cover. Yet humans are often overlooked as ecological components. Both humans and the African elephant Loxodonta africana alter woody vegetation in savannas through removal of large trees and activities that may increase shrub cover. Interactive effects of both humans and elephants with fire may also alter vegetation structure and composition. Here we capitalize on a macroscale experimental opportunity – brought about by the juxtaposition of an elephant‐mediated landscape, human‐utilized communal harvesting lands and a nature reserve fenced off from both humans and elephants – to investigate the influence of humans and elephants on height‐specific treefall dynamics. We surveyed 6812 ha using repeat, airborne high resolution Light Detection and Ranging (LiDAR) to track the fate of 453 685 tree canopies over two years. Human‐mediated biennial treefall rates were 2–3.5 fold higher than the background treefall rate of 1.5% treefall ha^–1, while elephant‐mediated treefall rates were 5 times higher at 7.6% treefall ha^–1 than the control site. Model predictors of treefall revealed that human or elephant presence was the most important variable, followed by the interaction between geology and fire frequency. Treefall patterns were spatially heterogeneous with elephant‐driven treefall associated with geology and surface water, while human patterns were related to perceived ease of access to wood harvesting areas and settlement expansion. Our results show humans and elephants utilize all height classes of woody vegetation, and that large tree shortages in a heavily utilized communal land has transferred treefall occurrence to shorter vegetation. Elephant‐ and human‐dominated landscapes are tied to interactive effects that may hinder tree seedling survival which, combined with tree loss in the landscape, may compromise woodland sustainability.     

EFFECTS OF ENVIRONMENTAL VARIATION ON SINKING RATES OF MARINE PHYTOPLANKTON1

The effects of environmental variables, particularly irradiance, on the sinking rates of phytoplankton were investigated using cultures of Chaetoceros gracilis Schütt and C. flexuosum Mangin in laboratory experiments; these data were compared with results from assemblages in the open ocean and marginal ice zone of the Greenland Sea. In culture experiments both the irradiance under which the diatom was grown and culture growth rate were positively correlated with sinking rates. Sinking rates (ψ) in the Greenland Sea were smallest when determined from chlorophyll (mean ψ_chl= 0.14 m · d^?1) and biogenic silica (ψ_si= 0.14 m · d^?1) and greatest when determined from particulate carbon (ψ_c= 0.55 m · d^?1) and nitrogen (ψ_N= 0.64 m · d^?1). Field measurements indicated that variations in sinking may be associated with changes in irradiance and nitrate concentrations. Because these factors do not directly affect water density, they must be inducing physiological changes in the cell which affect buoyancy. Although a direct response to a single environmental variable was not always evident, sinking rates were positively correlated with growth rates in the marginal ice zone, further indicating a connection to physiological processes. Estimats of carbon flux at stations with vertically mixed euphotic zones indicated that approximately 30% of the daily primary production sank from the euphotic zone in the form of small particulates. Calculated carbon flux tended to increase with primary productivity.     

Identifying growth parameters for two endemic species [Capoeta antalyensis (Battalgil, 1943) and Pseudophoxinus antalyae Bogutskaya, 1992] in Duden Creek,Antalya, Turkey

It is hypothesized that Capoeta antalyensis (Battalgil, 1943) and Pseudophoxinus antalyae (Bogutskaya, 1992) might display specific growth characteristics that differ from other species of their genus. Age and growth were described for species from Duden Creek (Antalya, Turkey) from February 2008 to January 2009. The length–weight relationship for all individuals were described by the parameters: a = 0.0143 and b = 2.946 for C. antalyensis and a = 0.0084 and b = 3.251 for P. antalyae. The von Bertalanffy growth parameters based on data from scales were L∞ = 35.78 cm, k = 0.251 year^?1 and t₀ = ?0.30 for C. antalyensis and L∞ = 22.59 cm, k = 0.232 year^?1 and t₀ = ?0.78 for P. antalyae. The growth characteristics for these two species are not much different from those of closely related species from the same genus.     

Contribution of biological nitrogen fixation to Elephant grass (Pennisetum purpureum Schum.)

Aims

Because of its high dry matter (DM) productivity, elephant grass (Pennisetum purpureum) is an ideal candidate for biomass production for biofuel production if low N fertilizer rates are used to avoid high fossil fuel inputs. The objective of this study was to investigate the potential of different elephant grass genotypes to obtain contributions of plant-associated biological N₂ fixation (BNF).

Methods

Three field experiments with 4 or 5 different genotypes were conducted on low-fertility Acrisols, two in Rio de Janeiro State and one in Espirito Santo for the evaluation of DM and N accumulation and ¹⁵N abundance.

Results

DM and N accumulation rates of four genotypes in the two experiments in Rio State stabilized at high levels after 2?years of growth. In all experiments the spontaneously-occurring weeds in the plots were significantly higher in ¹⁵N abundance than the elephant grass genotypes. The lower ¹⁵N abundance of the elephant grass was shown not to be due to lower δ¹⁵N abundance at depth in the soil.

Conclusions

Four of the grass genotypes obtained between 18 and 70% of their N from BNF amounting to inputs of between 36 and 132?kg N ha^?1?yr^?1.     

Working with mahouts to explore the diet of work elephants in Myanmar (Burma)

At an elephant camp in central Myanmar (Burma), we interviewed mahouts and veterinarians to describe the diet of Asian elephants (Elephas maximus) in a mixed-deciduous forest. Elephants showed a broad dietary breadth (103 plant species from 42 families); consumed mostly browse (94% of plant species); and were very selective about plant parts [e.g., many trees were eaten exclusively for their bark (22%) or fruits (14%)]. The fruits from 29 plant species were recorded to be eaten by elephants. Several of these were found as fruit remains, seeds, or seedlings in elephant dung, suggesting a role of Asian elephants in seed dispersal. Work elephants and their mahouts prove to be a rich source of information to understand wild elephant ecology.     

Uncoupling associations of risk alleles with endophenotypes and phenotypes: insights from the ApoB locus and heart‐related traits

Traditionally, genomewide association studies (GWAS) have emphasized the benefits of large samples in the analyses of age‐related traits rather than their specific properties. We adopted a realistic concept of genetic susceptibility to inherently heterogeneous, age‐related traits driven by the elusive role of evolution in their properties. We analyzed in detail the associations of rs693 and rs562338 polymorphisms representing the Apolipoprotein B locus with endophenotypes (total cholesterol [TC] and high‐density lipoprotein cholesterol) and phenotypes (myocardial infarction [MI] and survival) in four large‐scale studies, which include 20 748 individuals with 2357 MI events. We showed that a strong, robust predisposition of rs693 and rs562338 to TC (β = 0.72, P = 7.7 × 10^?30 for rs693 and β = ?1.08, P = 9.8 × 10^?42 for rs562338) is not translated into a predisposition to MI and survival. The rs693_A allele influences risks of MI and mortality after MI additively with lipids. This allele shows antagonistic effects—protecting against MI risks (β = ?0.18, P = 1.1 × 10^?5) or increasing MI risks (β = 0.15, P = 2.8 × 10^?3) and mortality after MI, in different populations. Paradoxically, increased TC concentrations can be protective against MI for the rs693_A allele carriers. Our results uncouple the influences of the same alleles on endophenotypes and phenotypes despite potential causal relationships among the latter. Our strategy reveals virtually genomewide significance for the associations of rs693 with MI (P = 5.5 × 10^?8) that is contrasted with a weak estimate following the traditional, sample‐size‐centered GWAS strategy (P = 0.16) in the same sample. These results caution against the use of the traditional GWAS strategy for gaining profound insights into genetic predisposition to healthspan and lifespan.