15 results on '"Nelson SV"'
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2. Development of a Rhizobium Seed Coating to Establish Lupine Species on Degraded Rangelands.
- Author
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Church BM, Geary B, Griffitts J, Drake CL, Ruebelmann K, Nelson SV, and Madsen MD
- Abstract
Restoring native plant species on degraded landscapes is challenging. Symbiotic partners in the plant rhizosphere can aid in nutrient acquisition, pathogen protection, stress tolerance, and many other processes. However, these microbes are often absent in altered landscapes and need to be re-integrated to improve restoration efforts. We evaluated, within a laboratory setting, the ability of commercial and indigenous rhizobia strains to form nodules on lupine species used for rangeland seedings in the Great Basin region of the Western United States and ascertained if these strains could be applied through a seed coating. We also evaluated if a compost amendment applied via seed coating could further enhance the performance of the rhizobia strains. Our analysis showed that successful nodulation could occur using commercial and wildland-collected indigenous strains through either a liquid culture applied to seedlings or as a dry seed coating. However, the number of root nodules and the presence of a pink color (indicating nitrogen fixation) were typically higher in the commercial product than in the indigenous strains. Compost did not improve nodulation or the performance of the nodules; however, this treatment alone improved shoot growth. Overall, these results suggest that commercial rhizobium may be more effective in improving plant growth, and future research with native rhizobia may want to consider identifying strains compatible with seed-coating delivery. Longer-term studies are now merited for assessing how the rhizobia strains evaluated in this study influence plant growth, particularly in a field setting.
- Published
- 2024
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3. Sr/Ca ratios indicate frugivory versus folivory in primates: a case study using handheld XRF in Kibale National Park, Uganda.
- Author
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Hamilton MI, Drake BL, Dzhinenko E, Galloway A, and Nelson SV
- Subjects
- Animals, Uganda, Fruit, Primates, Diet, Parks, Recreational, Plant Leaves chemistry, Strontium analysis, Calcium analysis
- Abstract
Researchers often use trace element concentrations, including strontium-calcium ratios (Sr/Ca), to reconstruct paleodiets. While most commonly used as a proxy for meat consumption, a more appropriate application may be to differentiate frugivory from folivory. Sr/Ca ratios in animal tissue reflect the Sr/Ca ratios of the highest calcium components of that animal's diet. Because plants have much higher concentrations of calcium than meat, meat consumption signals are often overwhelmed by the variation in Sr/Ca ratios coming from different plant parts. This study uses faunal and plant data from Kibale National Park, a protected forest in southwestern Uganda home to numerous primate species (for example, common chimpanzees and baboons), to assess the reliability of Sr/Ca ratios to differentiate between primate dietary groups. We find that leaves consistently have higher strontium and calcium concentrations than fruits and that this is mirrored in higher Sr/Ca ratios in folivorous primates compared to frugivorous primates. Plant species differ widely in both their overall Sr/Ca ratios and the differences between their fruit and leaf Sr/Ca ratios, but this variation does not overwhelm the dietary signal separating frugivores and folivores. Furthermore, this research demonstrates that non-destructive and portable X-ray florescence (XRF) methods are an effective means of gathering Sr/Ca data from plant and faunal material, increasing the opportunities to apply such methods to fossil material in the future., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)
- Published
- 2024
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4. A reanalysis of strontium isotope ratios as indicators of dispersal in South African hominins.
- Author
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Hamilton MI, Copeland SR, and Nelson SV
- Subjects
- Male, Animals, Female, Pan troglodytes, South Africa, Strontium Isotopes analysis, Ecosystem, Fossils, Hominidae, Tooth Abnormalities
- Abstract
Dispersal patterns in primates have major implications for behavior and sociality but are difficult to reconstruct for fossil species. This study applies novel strontium isotope methodologies that have reliably predicted philopatry and dispersal patterns in chimpanzees and other modern primates to previously published strontium isotope ratios (
87 Sr/86 Sr) of two South African hominins, Australopithecus africanus and Australopithecus robustus. In this study, the difference or 'offset' was calculated between the87 Sr/86 Sr of each fossil tooth compared to local bioavailable87 Sr/86 Sr as defined by cluster analysis of modern plant isotope ratios. Large teeth (presumably belonging to males) have low offsets from local87 Sr/86 Sr proxies, while small teeth (presumably from females) have greater offsets from local87 Sr/86 Sr proxies. This supports previous conclusions of male philopatry and female dispersal in both A. africanus and A. robustus. Furthermore, A. robustus shows more extreme differences between presumed males and females compared to A. africanus. This is analogous to differences seen in modern olive baboons compared to chimpanzees and suggests that A. africanus may have had a larger home range than A. robustus. Neither hominin species has87 Sr/86 Sr consistent with riparian habitat preferences despite the demonstrated presence of riparian habitats in South Africa at the time., (Copyright © 2023 Elsevier Ltd. All rights reserved.)- Published
- 2024
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5. Slow Release of GA 3 Hormone from Polymer Coating Overcomes Seed Dormancy and Improves Germination.
- Author
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Larson AJS, Cartwright MM, Jones WD, Luce K, Chen MY, Petersen K, Nelson SV, Michaelis DJ, and Madsen MD
- Abstract
Seed dormancy often hinders direct seeding efforts that are attempting to restore degraded landscapes. Gibberellic acid (GA
3 ) can be applied to physiologically dormant seeds to induce germination, but this hormone is rarely effective, as it can degrade or be leached from the seed. We tested different polymer matrixes (polylactic acid, polyvinylpyrrolidone, and ethylcellulose) to apply and slowly release GA3 to the seed. These polymers were tested as seed coatings in either a powder, liquid, or a combination of powder and liquid forms. We found that a liquid ethylcellulose/GA3 coating generally outperformed the other polymers and applications methods using our test species Penstemon palmeri . With this top-performing treatment, seed germination was 3.0- and 3.9-fold higher at 15 °C and 25 °C, respectively. We also evaluated the liquid ethylcellulose/GA3 coating on P. comharrenus , P. strictus , P. pachyphyllus , and P. eatonii . Again, the coating had a strong treatment response, with the degree of difference related to the relative level of dormancy of the species. Growth studies were also performed in pots to ensure that the side effects of GA3 overdosing were not present. Here, we found minimal differences in root length, shoot length, or biomass between plants grown from untreated and GA3 -coated seeds.- Published
- 2023
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6. Complete Chloroplast Genome Sequence of the Western Poison Oak, Toxicodendron diversilobum (Anacardiaceae), from California.
- Author
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Huitron Vazquez LI, Aviles PE, Bailon SA, Cabanillas AG, Fernandez A, Galarza JI, Guerrero B, Hernandez AB, Hernandez D, Jarrett K, Li T, Maravillo FJ, Moreno M, Perez A, Rosales NA, Ruegg HF, Valdez J, Bravo KM, Chávez VL, Diaz DI, Enriquez D, Martinez EL, Mendoza Padilla J, Meza J, Nelson SV, Quintero-Ahumada C, Ramirez AM, and Hughey JR
- Abstract
Here, we present the complete chloroplast genome sequence of Toxicodendron diversilobum, western poison oak, from Pacific Grove, California. The genome is 159,543 bp in length, contains 133 genes, and has a high level of gene synteny to other species of Toxicodendron .
- Published
- 2023
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7. Eating-disorder psychopathology in female athletes and non-athletes: A meta-analysis.
- Author
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Chapa DAN, Johnson SN, Richson BN, Bjorlie K, Won YQ, Nelson SV, Ayres J, Jun D, Forbush KT, Christensen KA, and Perko VL
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- Athletes, Female, Humans, Psychopathology, Thinness, Feeding and Eating Disorders diagnosis, Sports
- Abstract
Objective: There is ongoing discussion about whether sports participation is a risk or protective factor for eating disorders (EDs). Research is mixed, with some studies suggesting that athletes have higher mean levels of ED psychopathology compared to nonathletes, while other studies suggest the opposite effect or no differences. The purpose of the current meta-analysis was to identify whether female athletes reported higher mean levels of ED psychopathology compared to nonathletes., Method: Following PRISMA guidelines, we identified 56 studies that reported ED psychopathology for female athletes and nonathletes. A three-level random-effects model of between- and within-study variance was completed for the following outcome variables: overall ED psychopathology, body dissatisfaction, drive for thinness, restricting, and loss-of-control eating., Results: Athletes reported lower levels of body dissatisfaction compared to nonathletes (g = -.21, p < .0001). Athletes and nonathletes reported similar levels of overall ED psychopathology, drive for thinness, restricting, and loss-of-control eating on average. Sport type significantly moderated standardized mean difference effect sizes of ED psychopathology in athletes versus nonathletes. Effect sizes comparing levels of drive for thinness, restricting, and loss-of-control eating in athletes versus nonathletes were larger for studies with athletes participating in aesthetic/lean sports compared to nonaesthetic/nonlean sports., Discussion: Findings from this meta-analysis could inform future ED prevention and treatment in female athletes by providing further evidence that athletes in aesthetic/lean sports may report higher levels of ED psychopathology. Participating in nonaesthetic/nonlean sports may be a protective factor for experiencing less body dissatisfaction., Public Significance Statement: The current meta-analysis summarized findings from 56 studies that assessed levels of disordered eating, body dissatisfaction, dietary restricting, and loss-of-control eating in female athletes and nonathletes. Athletes reported lower levels of body dissatisfaction compared to nonathletes, highlighting that participation in sport could have some protective factors. Athletes participating in sports that require weight categories (e.g., judo) and sports that emphasize thinness/leanness (e.g., gymnastics and distance running) had higher levels of disordered eating relative to athletes participating in other types of sports that do not emphasize thinness/leanness (e.g., volleyball and basketball)., (© 2022 Wiley Periodicals LLC.)
- Published
- 2022
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8. Using strontium isotopes to determine philopatry and dispersal in primates: a case study from Kibale National Park.
- Author
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Hamilton MI, Fernandez DP, and Nelson SV
- Abstract
Strontium isotope ratios (
87 Sr/86 Sr) allow researchers to track changes in mobility throughout an animal's life and could theoretically be used to reconstruct sex-biases in philopatry and dispersal patterns in primates. Dispersal patterns are a life-history variable that correlate with numerous aspects of behaviour and socio-ecology that are elusive in the fossil record. The present study demonstrates that the standard archaeological method used to differentiate between 'local' and 'non-local' individuals, which involves comparing faunal isotopic ratios with environmental isotopic minima and maxima, is not always reliable; aspects of primate behaviour, local environments, geologic heterogeneity and the availability of detailed geologic maps may compromise its utility in certain situations. This study instead introduces a different methodological approach: calculating offset values to compare87 Sr/86 Sr of teeth with that of bone or local environments. We demonstrate this method's effectiveness using data from five species of primates, including chimpanzees, from Kibale National Park, Uganda. Tooth-to-bone offsets reliably indicate sex-biases in dispersal for primates with small home ranges while tooth-to-environment offset comparisons are more reliable for primates with larger home ranges. Overall, tooth-to-environment offsets yield the most reliable predictions of species' sex-biases in dispersal., (© 2021 The Authors.)- Published
- 2021
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9. Detecting riparian habitat preferences in "savanna" chimpanzees and associated Fauna with strontium isotope ratios: Implications for reconstructing habitat use by the chimpanzee-human last common ancestor.
- Author
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Hamilton M, Nelson SV, Fernandez DP, and Hunt KD
- Subjects
- Animals, Biological Availability, Bone and Bones chemistry, Humans, Mammals, Plants chemistry, Rivers chemistry, Strontium Isotopes metabolism, Uganda, Animal Distribution, Anthropology methods, Biological Evolution, Forests, Grassland, Pan troglodytes, Strontium Isotopes analysis
- Abstract
Objectives: Riparian or gallery forests are critical habitats for numerous plants and animals today. Paleoanthropologically, reliance on such habitats informs behavioral and ecological reconstructions; for example, gallery forest habitats likely played a critical role in the transition from ape to hominin in the early Pliocene and may represent a preferred habitat for the last common ancestor of chimpanzees and humans. Direct indicators for gallery forest habitats preference are lacking. The objective of this article is to assess whether strontium isotope ratios are a reliable indicator of habitat preference for fauna living in and around gallery forests., Materials and Methods: We report bioavailable strontium isotope ratios from the Mugiri River, its tributaries, and its gallery forest (Toro-Semliki Wildlife Reserve, southwestern Uganda), and compare them to surrounding savanna-grassland values. We compare these environmental values to strontium isotopes ratios in faunal tooth enamel to determine if habitat preferences are accurately reflected., Results: Gallery forest and savanna-grassland vegetations have significantly different strontium isotope ratio profiles. We trace these isotopic differences to the influence of the Mugiri tributaries, which originate on Paleoproterozoic gneiss deposits on top of the surrounding escarpments. These isotopic differences in vegetation are mirrored in the tissues of fauna with habitat preferences for either the gallery forest or the surrounding grasslands., Discussion: This research demonstrates the potential of strontium isotope ratios to identify habitat preferences in modern or fossil fauna under proper geologic variability. It provides a methodological model for future studies seeking to reconstruct habitat preferences in early hominins., (© 2019 Wiley Periodicals, Inc.)
- Published
- 2019
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10. Isotopic reconstructions of habitat change surrounding the extinction of Oreopithecus, the last European ape.
- Author
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Nelson SV and Rook L
- Subjects
- Animals, Diet history, Extinction, Biological, Fossils, History, Ancient, Italy, Paleontology, Carbon Isotopes analysis, Ecosystem, Hominidae physiology, Oxygen Isotopes analysis
- Abstract
Objective: Oreopithecus bambolii was the last hominoid to survive in Europe. The purpose of this investigation was to reconstruct, through stable isotope analyses, Oreopithecus' habitat, subsistence behavior, and changes in habitat that may have led to its extinction., Methods: Carbon and oxygen stable isotopes from inorganic carbonate in tooth enamel from Oreopithecus and its contemporaneous faunas from localities in Tuscany and Sardinia were sampled. Also the fauna from localities in Tuscany shortly after Oreopithecus went extinct were sampled., Results: Results indicated that Oreopithecus, compared with most modern hominoids, inhabited forests that probably had a more open canopy. At Tuscan localities, Oreopithecus yields some of the highest carbon isotope values but some of the lowest oxygen, suggesting a diet that may have included tubers or aquatic vegetation. Relatively higher oxygen values in Sardinia suggested that its diet included arboreal foods as well. Among modern and fossil hominoids, Oreopithecus only resembled chimpanzees living outside of rainforests. It also resembled Ardipithecus in carbon isotope values, suggesting possible similarities in feeding strategies concordant with shared skeletal features between Oreopithecus and early hominins. Isotope values from post-Oreopithecus faunas indicated a shift to more forested conditions, unlike other hominoid extinctions associated with loss of forest., Conclusions: Isotopic reconstructions of Oreopithecus' habitat and changes associated with its extinction indicated that its paleoecology was unique among hominoids. However, these reconstructions also suggested that like other hominoids, Oreopithecus was susceptible to changes in seasonality of precipitation, and it may have used wetlands as a buffer to seasonal regimes. Am J Phys Anthropol 160:254-271, 2016. © 2016 Wiley Periodicals, Inc., (© 2016 Wiley Periodicals, Inc.)
- Published
- 2016
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11. The paleoecology of early Pleistocene Gigantopithecus blacki inferred from isotopic analyses.
- Author
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Nelson SV
- Subjects
- Animals, Dental Enamel chemistry, Fossils, Tooth chemistry, Carbon Isotopes analysis, Ecology, Hominidae physiology, Oxygen Isotopes analysis, Paleontology
- Abstract
This study presents isotopic analyses of Gigantopithecus blacki and contemporaneous fauna from Early Pleistocene southern China cave localities with a view to reconstructing the paleoecology of this large extinct ape. Carbon and oxygen stable isotope compositions were determined using tooth enamel carbonate of Gigantopithecus and eight other taxa from Longgudong Cave and additional Gigantopithecus specimens from Juyuandong Cave. Carbon isotopic values of Gigantopithecus fauna reflect a densely forested habitat rarely preserved in the fossil record. These values overlap with those of other ape habitats including Miocene Sivapithecus faunas in the Siwaliks of Pakistan and modern chimpanzee faunas at Kibale National Park, Uganda, and the Ituri Forest, Democratic Republic of the Congo. Despite the overlap, Gigantopithecus fauna carbon values are significantly lower than those of the Siwaliks and Kibale, likely reflecting a more continuous canopy or more humid forest. Carbon isotope values suggest the habitat consisted of vegetation similar to current subtropical monsoon forests of southern China. Ranges of carbon and oxygen isotopic values for Gigantopithecus suggest a broad diet comprising both terrestrial and canopy plants., (© 2014 Wiley Periodicals, Inc.)
- Published
- 2014
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12. Chimpanzee fauna isotopes provide new interpretations of fossil ape and hominin ecologies.
- Author
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Nelson SV
- Subjects
- Animals, Carbon Isotopes analysis, Dental Enamel chemistry, Diet, Ecology, Ecosystem, Feeding Behavior, Hominidae metabolism, Oxygen Isotopes analysis, Pakistan, Pan troglodytes metabolism, Trees, Uganda, Fossils, Hominidae physiology, Pan troglodytes physiology
- Abstract
Carbon and oxygen stable isotopes within modern and fossil tooth enamel record the aspects of an animal's diet and habitat use. This investigation reports the first isotopic analyses of enamel from a large chimpanzee community and associated fauna, thus providing a means of comparing fossil ape and early hominin palaeoecologies with those of a modern ape. Within Kibale National Park forest, oxygen isotopes differentiate primate niches, allowing for the first isotopic reconstructions of degree of frugivory versus folivory as well as use of arboreal versus terrestrial resources. In a comparison of modern and fossil community isotopic profiles, results indicate that Sivapithecus, a Miocene ape from Pakistan, fed in the forest canopy, as do chimpanzees, but inhabited a forest with less continuous canopy or fed more on leaves. Ardipithecus, an early hominin from Ethiopia, fed both arboreally and terrestrially in a more open habitat than inhabited by chimpanzees.
- Published
- 2013
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13. Tomorrow's educators … today? Implementing near-peer teaching for medical students.
- Author
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Nelson AJ, Nelson SV, Linn AM, Raw LE, Kildea HB, and Tonkin AL
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- Clinical Competence, Group Processes, Humans, Learning, Problem-Based Learning, Education, Medical, Undergraduate organization & administration, Peer Group, Students, Medical, Teaching organization & administration
- Abstract
Background: The University of Adelaide offers a six-year undergraduate medical degree with a focus on small group learning. Senior medical students had previously received limited formal training in education skills, and were identified as an underutilised teaching resource., Aims: To devise a programme in which senior students are exposed to the various facets of university teaching responsibilities and to evaluate its impact on both the tutors and the students., Methods: A six week rotation in medical education for final year medical students was designed and implemented in 2010 to involve them in the development, delivery and assessment of the 1st and 2nd year medical programme as near-peer tutors (NPTs)., Results: Two years after the rotation's implementation, voluntary evaluation of both the junior students and NPTs was undertaken through a mixed methods approach of survey and focus group. Junior students (n=358) revealed the NPTs provided non-threatening learning environments, provided helpful feedback and acted as role models. Additionally, the NPTs (n=24) reported they had consolidated prior knowledge, developed their teaching skills and expressed a desire to be more involved in teaching in the future., Conclusions: The implementation of NPTs in the teaching of junior medical students appears to benefit both students and their near-peer colleagues. Involvement of NPTs in all facets of medical education through this rotation stands to not only foster potential interest in an academic pathway but also equip them with a variety of transferable skills which they can draw on as future educators in their profession.
- Published
- 2013
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14. Effect of colostral volume, interval between calving and first milking, and photoperiod on colostral IgG concentrations in dairy cows.
- Author
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Morin DE, Nelson SV, Reid ED, Nagy DW, Dahl GE, and Constable PD
- Subjects
- Animals, Cattle, Colostrum physiology, Dairying, Female, Lactation, Parturition, Time Factors, Colostrum chemistry, Immunoglobulin G analysis, Photoperiod
- Abstract
Objective: To identify cow and management factors associated with colostral IgG concentration in dairy cows., Design: Prospective observational study., Animals: 81 multiparous Holstein-Friesian cows from a single herd., Procedures: Serum was obtained at the start of the nonlactating period, and cows were assigned to 1 of 4 photoperiod groups: natural day length (n = 22 cows), long days (16 h of light/d [21]) or short days (8 h of light/d [20]) for the entire nonlactating period, or natural day length followed by short days for the last 21 days of the nonlactating period (18). Serum and colostrum were collected at the first milking after calving. Regression analysis was used to investigate associations between colostral IgG concentration and the interval between calving and first milking, colostral volume, photoperiod, length of the nonlactating period, and season of calving., Results: Colostral IgG concentration decreased by 3.7% during each subsequent hour after calving because of postparturient secretion by the mammary glands. The interval between calving and first milking and the colostral volume were significantly and negatively associated with colostral IgG concentration, with the former effect predominating. Photoperiod had no effect on colostral IgG concentration or volume. Serum protein concentration at calving correlated poorly with colostral IgG concentration., Conclusions and Clinical Relevance: Dairy producers should harvest colostrum as soon as possible after calving to optimize transfer of passive immunity in neonatal calves. Photoperiod can be manipulated without adversely affecting colostral IgG concentration.
- Published
- 2010
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15. Ecological changes in Miocene mammalian record show impact of prolonged climatic forcing.
- Author
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Badgley C, Barry JC, Morgan ME, Nelson SV, Behrensmeyer AK, Cerling TE, and Pilbeam D
- Subjects
- Animals, Asia, Biodiversity, Carbon Isotopes, Diet, Vegetarian, Oxygen Isotopes, Paleontology methods, Tooth, Biological Evolution, Climate, Ecosystem, Mammals, Plants, Edible
- Abstract
Geohistorical records reveal the long-term impacts of climate change on ecosystem structure. A 5-myr record of mammalian faunas from floodplain ecosystems of South Asia shows substantial change in species richness and ecological structure in relation to vegetation change as documented by stable isotopes of C and O from paleosols. Between 8.5 and 6.0 Ma, C(4) savannah replaced C(3) forest and woodland. Isotopic historical trends for 27 mammalian herbivore species, in combination with ecomorphological data from teeth, show three patterns of response. Most forest frugivores and browsers maintained their dietary habits and disappeared. Other herbivores altered their dietary habits to include increasing amounts of C(4) plants and persisted for >1 myr during the vegetation transition. The few lineages that persisted through the vegetation transition show isotopic enrichment of delta(13)C values over time. These results are evidence for long-term climatic forcing of vegetation structure and mammalian ecological diversity at the subcontinental scale.
- Published
- 2008
- Full Text
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