scispace - formally typeset
Search or ask a question
Author

Adrian C. Newton

Bio: Adrian C. Newton is an academic researcher from James Hutton Institute. The author has contributed to research in topics: Hordeum vulgare & Biodiversity. The author has an hindex of 74, co-authored 453 publications receiving 21814 citations. Previous affiliations of Adrian C. Newton include Seattle Children's Research Institute & University of Peradeniya.


Papers
More filters
Journal ArticleDOI
TL;DR: It is suggested that an unexpectedly high degree of genetic variation exists within Mexican beech, and this variation should be considered in developing the conservation strategy that is urgently required if extinction of this taxon is to be prevented.
Abstract: Fagus grandifolia var. mexicana(Fagaceae) is a Mexican endemic tree, currently threatened with extinction. In order to assess the level and structure of genetic variation in four remaining populations, leaf samples were analysed using random amplified polymorphic DNA (RAPD) and cpDNA PCR-RFLP markers. A sample of the more widespread congener, F. grandifoliavar. grandifolia from the USA was also analysed for comparison. Thirty-three polymorphic RAPD bands were produced using 18 10-mer primers. AMOVA of RAPD data indicated significant (P < 0.002) population differentiation, with 15.6% of variation recorded between Mexican populations. PCR-RFLP analysis enabled three cpDNA haplotypes to be identified, denoted types A, B, and C. Types A and B were each restricted to an individual Mexican population, whereas Type C was fixed for two Mexican populations, and the population from the USA. Within-population genetic variation, quantified as percentage polymorphic bands, Shannon's Diversity Index and Nei's gene diversity measure, was found to be lower in Mexican populations than in that from the USA, and was positively related to population size. These results suggest that an unexpectedly high degree of genetic variation exists within Mexican beech, and this variation should be considered in developing the conservation strategy that is urgently required if extinction of this taxon is to be prevented.

42 citations

Journal ArticleDOI
TL;DR: It is shown that hundreds of springs currently distributed across East Africa could function as persistent groundwater hydro-refugia through orbital-scale climate cycles, providing a new environmental framework in which to understand how patterns of taxonomic diversity in hominins may have developed.
Abstract: Water is a fundamental resource, yet its spatiotemporal availability in East Africa is poorly understood. This is the area where most hominin first occurrences are located, and consequently the potential role of water in hominin evolution and dispersal remains unresolved. Here, we show that hundreds of springs currently distributed across East Africa could function as persistent groundwater hydro-refugia through orbital-scale climate cycles. Groundwater buffers climate variability according to spatially variable groundwater response times determined by geology and topography. Using an agent-based model, grounded on the present day landscape, we show that groundwater availability would have been critical to supporting isolated networks of hydro-refugia during dry periods when potable surface water was scarce. This may have facilitated unexpected variations in isolation and dispersal of hominin populations in the past. Our results therefore provide a new environmental framework in which to understand how patterns of taxonomic diversity in hominins may have developed.

41 citations

Journal ArticleDOI
TL;DR: Results suggest that disturbance produced by human activities (trail use, selective cutting of trees, livestock, livestock) may influence the size and composition of the soil seed bank in forest fragments.
Abstract: The density and floristic composition of the soil seed bank was assessed in six cloud forest fragments with different levels of human disturbance in central Veracruz, Mexico. A total of 8416 seeds germinated in 60 soil samples, at 5-cm depth, corresponding to 107 species, 85 genera, and 48 families. Significant differences were found among study sites in seed densities with values ranging from 873 to 3632/m 2 . Tree species contributed 20 percent of the total soil seed bank in four sites and herbs accounted for the majority of the species in each site. Among tree species, Trema micrantha displayed the highest seed density, accounting for 84 percent of the germinated seeds. In general, the tree species composition of the soil seed bank did not closely reflect the composition of the tree community. Results suggest that disturbance produced by human activities (trail use, selective cutting of trees, livestock) may influence the size and composition of the soil seed bank in forest fragments. Sites where human activity has been reduced showed the highest proportion of dormant seeds.

41 citations

Journal ArticleDOI
TL;DR: In this article, four inventory protocols (one ad hoc, one fixed count and two fixed area methods) are tested for their efficiency and statistical robustness when applied to the woody floras of a Mexican seasonally dry tropical forest.

40 citations


Cited by
More filters
Journal ArticleDOI
TL;DR: Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols used xiii 1.
Abstract: Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols Used xiii 1. The Importance of Islands 3 2. Area and Number of Speicies 8 3. Further Explanations of the Area-Diversity Pattern 19 4. The Strategy of Colonization 68 5. Invasibility and the Variable Niche 94 6. Stepping Stones and Biotic Exchange 123 7. Evolutionary Changes Following Colonization 145 8. Prospect 181 Glossary 185 References 193 Index 201

14,171 citations

Journal Article
TL;DR: This book by a teacher of statistics (as well as a consultant for "experimenters") is a comprehensive study of the philosophical background for the statistical design of experiment.
Abstract: THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

13,333 citations

Journal ArticleDOI

7,335 citations

Book
24 Nov 2003
TL;DR: The Millennium Ecosystem Assessment (MEA) as discussed by the authors is a conceptual framework for analysis and decision-making of ecosystems and human well-being that was developed through interactions among the experts involved in the MA as well as stakeholders who will use its findings.
Abstract: This first report of the Millennium Ecosystem Assessment describes the conceptual framework that is being used in the MA. It is not a formal assessment of the literature, but rather a scientifically informed presentation of the choices made by the assessment team in structuring the analysis and framing the issues. The conceptual framework elaborated in this report describes the approach and assumptions that will underlie the analysis conducted in the Millennium Ecosystem Assessment. The framework was developed through interactions among the experts involved in the MA as well as stakeholders who will use its findings. It represents one means of examining the linkages between ecosystems and human well-being that is both scientifically credible and relevant to decision-makers. This framework for analysis and decision-making should be of use to a wide array of individuals and institutions in government, the private sector, and civil society that seek to incorporate considerations of ecosystem services in their assessments, plans, and actions.

2,427 citations