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Author

Rohlf Fj

Bio: Rohlf Fj is an academic researcher. The author has an hindex of 1, co-authored 1 publications receiving 4080 citations.

Papers
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TL;DR: The book aims to instill in students an ability to think through biological research problems in such a way as to grasp the essentials of the experimental or analytical setup to know which types of statistical tests to apply in a given case and to carry out the computations required.
Abstract: This text develops the science of biometry from an elementary introduction up to the advanced methods necessary for biological research and for an understanding of the published literature. This text is aimed primarily at the academic biologist including general zoologists botanists microbiologists geneticists and physiologists in universities research institutes and museums. This book while furnishing ample directions for the analysis of experimental works also stresses the descriptive and analytical statistical study of biological phenomena. It is intended both as a text to accompany a lecture course and as a complete course for self-study. The book aims to instill in students an ability to think through biological research problems in such a way as to grasp the essentials of the experimental or analytical setup to know which types of statistical tests to apply in a given case and to carry out the computations required. Chapters cover biological data data handling descriptive statistics probability estimation and hupothesis testing analysis of variance linear regression correlation multiple and curvilinear regression analysis of frequencies and miscellaneous methods.

4,145 citations


Cited by
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Journal ArticleDOI
22 Apr 2004-Nature
TL;DR: Reliable quantification of the leaf economics spectrum and its interaction with climate will prove valuable for modelling nutrient fluxes and vegetation boundaries under changing land-use and climate.
Abstract: Bringing together leaf trait data spanning 2,548 species and 175 sites we describe, for the first time at global scale, a universal spectrum of leaf economics consisting of key chemical, structural and physiological properties. The spectrum runs from quick to slow return on investments of nutrients and dry mass in leaves, and operates largely independently of growth form, plant functional type or biome. Categories along the spectrum would, in general, describe leaf economic variation at the global scale better than plant functional types, because functional types overlap substantially in their leaf traits. Overall, modulation of leaf traits and trait relationships by climate is surprisingly modest, although some striking and significant patterns can be seen. Reliable quantification of the leaf economics spectrum and its interaction with climate will prove valuable for modelling nutrient fluxes and vegetation boundaries under changing land-use and climate.

6,360 citations

Book
01 Jan 2004
TL;DR: The second edition of "Geometric Morphometrics for Biologists" represents the current state of the art and adds new examples and summarizes recent literature, as well as provides an overview of new software and step-by-step guidance through details of carrying out the analyses.
Abstract: The first edition of "Geometric Morphometrics for Biologists" has been the primary resource for teaching modern geometric methods of shape analysis to biologists who have a stronger background in biology than in multivariate statistics and matrix algebra. These geometric methods are appealing to biologists who approach the study of shape from a variety of perspectives, from clinical to evolutionary, because they incorporate the geometry of organisms throughout the data analysis. The second edition of this book retains the emphasis on accessible explanations, and the copious illustrations and examples of the first, updating the treatment of both theory and practice. The second edition represents the current state-of-the-art and adds new examples and summarizes recent literature, as well as provides an overview of new software and step-by-step guidance through details of carrying out the analyses. This title contains updated coverage of methods, especially for sampling complex curves and 3D forms and a new chapter on applications of geometric morphometrics to forensics. It offers a reorganization of chapters to streamline learning basic concepts. It presents detailed instructions for conducting analyses with freely available, easy to use software. It provides numerous illustrations, including graphical presentations of important theoretical concepts and demonstrations of alternative approaches to presenting results.

2,733 citations

Journal ArticleDOI
TL;DR: Global-scale quantification of relationships between plant traits gives insight into the evolution of the world's vegetation, and is crucial for parameterizing vegetation-climate models.
Abstract: Summary • Global-scale quantification of relationships between plant traits gives insight into the evolution of the world’s vegetation, and is crucial for parameterizing vegetation‐ climate models. • A database was compiled, comprising data for hundreds to thousands of species for the core ‘leaf economics’ traits leaf lifespan, leaf mass per area, photosynthetic capacity, dark respiration, and leaf nitrogen and phosphorus concentrations, as well as leaf potassium, photosynthetic N-use efficiency (PNUE), and leaf N : P ratio. • While mean trait values differed between plant functional types, the range found within groups was often larger than differences among them. Future vegetation‐ climate models could incorporate this knowledge. • The core leaf traits were intercorrelated, both globally and within plant functional types, forming a ‘leaf economics spectrum’. While these relationships are very general, they are not universal, as significant heterogeneity exists between relationships fitted to individual sites. Much, but not all, heterogeneity can be explained by variation in sample size alone. PNUE can also be considered as part of this trait spectrum, whereas leaf K and N : P ratios are only loosely related.

1,606 citations

Journal ArticleDOI
TL;DR: Case studies re-evaluating three different types of biodiversity experiments demonstrate that the increases found in such ecosystem properties as productivity, nutrient use efficiency, and stability were actually caused by “hidden treatments” that altered plant biomass and productivity.
Abstract: Interactions between biotic and abiotic pro- cesses complicate the design and interpretation of eco- logical experiments. Separating causality from simple correlation requires distinguishing among experimental treatments, experimental responses, and the many pro- cesses and properties that are correlated with either the treatments or the responses, or both. When an experi- mental manipulation has multiple components, but only one of them is identified as the experimental treatment, erroneous conclusions about cause and eAect relation- ships are likely because the actual cause of any observed response may be ignored in the interpretation of the experimental results. This unrecognized cause of an observed response can be considered a ''hidden treat- ment.'' Three types of hidden treatments are potential problems in biodiversity experiments: (1) abiotic condi- tions, such as resource levels, or biotic conditions, such as predation, which are intentionally or unintentionally altered in order to create diAerences in species numbers for ''diversity'' treatments; (2) non-random selection of species with particular attributes that produce treatment diAerences that exceed those due to ''diversity'' alone; and (3) the increased statistical probability of including a species with a dominant negative or positive eAect (e.g., dense shade, or nitrogen fixation) in randomly selected groups of species of increasing number or ''diversity.'' In each of these cases, treatment responses that are actually the result of the ''hidden treatment'' may be inadver- tently attributed to variation in species diversity. Case studies re-evaluating three diAerent types of biodiversity experiments demonstrate that the increases found in such ecosystem properties as productivity, nutrient use eAciency, and stability (all of which were attributed to higher levels of species diversity) were actually caused by ''hidden treatments'' that altered plant biomass and productivity.

1,601 citations

Journal ArticleDOI
Alban Ramette1
TL;DR: Here, well-established exploratory and hypothesis-driven approaches are reviewed, so as to foster their addition to the microbial ecologist toolbox.

1,550 citations