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Abstract
There are two cultures in the use of statistical modeling to reach conclusions from data. One assumes that the data are generated by a given stochastic data model. The other uses algorithmic models and treats the data mechanism as unknown. The statistical community has been committed to the almost exclusive use of data models. This commitment has led to irrelevant theory, questionable conclusions, and has kept statisticians from working on a large range of interesting current problems. Algorithmic modeling, both in ...
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Abstract
Climate envelope models (CEMs) have been used to predict the distribution of species under current, past, and future climatic conditions by inferring a species' environmental requirements from localities where it is currently known to occur. CEMs can be evaluated for their ability to predict current species distributions but it is unclear whether models that are successful in predicting current distributions are equally successful in predicting distributions under different climates (i.e. different regions or time periods). We evaluated the ability of CEMs ...
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Abstract
[Highlights] [::] Examines ability of soil losses from a plot to predict those from another [::] Stochastic and systemic variations observed when replicate model used [::] Replicate model tends to perform better that USLE-M when runoff known. [Abstract] It has been proposed that the best physical model of erosion from a plot is provided by a replicate plot (Nearing, 1998). Event data from paired bare fallow plots in the USLE database were used to examine the abilities of replicate plots, the USLE and the USLE-M to ...
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(February 2014)
Abstract
List of indexed keywords within the transdisciplinary set of domains which relate to the Integrated Natural Resources Modelling and Management (INRMM). In particular, the list of keywords maps the semantic tags in the INRMM Meta-information Database (INRMM-MiD). [\n] The INRMM-MiD records providing this list are accessible by the special tag: inrmm-list-of-tags ( http://mfkp.org/INRMM/tag/inrmm-list-of-tags ). ...
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Abstract
[Excerpt] In this article, I give an overview of the recent contribution of Finney et al. (1) to our understanding of how wildfires spread by providing its scientific context and also by putting forward the possible impact on the field. [...] [\n] Wildfires are important to the natural sciences. Since deep time, the top surface of the Earth’s crust has been the interface where abundant plant organic matter meets an atmosphere rich in oxygen. This interface is flammable, especially in dry, windy, ...
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Abstract
[Significance] Wildfires burn millions of hectares per year on every inhabited continent, but the physical mechanism governing spread is not known. Models of wildfire spread are widely used for prediction, firefighter training, and ecological research but have assumed various formulations of known heat transfer processes (radiation and convection) absent a definitive theory of their organization. New experimental evidence reported here reveals how buoyancy generated by the fire induces vorticity and instabilities in the flame zone that control the convective heating needed to ...
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No. LNS0418027. (2003)
Abstract
[Excerpt: Soil Erosion by Water - Extend, Processes and Model for Conservation Planning] In order to develop sustainable systems of agriculture that satisfy the present and the future needs of the mankind, there must be reliable information on the constrains and potential of the land resource. The UNEP Project GLASOD (GLobal Assessment of SOil Degradation) recognized erosion by water as the most important soil degradation type, representing more than a half of all soil degradation (Oldeman et al., 1991). Soil erosion by water refers to a series of ...
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In Proceedings of the 1st Biennial Meeting of the iEMSs "Integrated Assessment and Decision Support" (2002)
Abstract
The paper discusses the problems associated with environmental modelling and the need to develop simple, ‘top-down’, stochastic models that match the information content of the data. It introduces the concept of Data-Based Mechanistic (DBM) modelling and contrasts its inductive approach with the hypothetico-deductive approaches that dominate most environmental modelling research at the present time. The major methodological procedures utilized in DBM modelling are outlined and two practical examples illustrate how it has been applied in a hydrological and water quality context. The use of this same ...
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Abstract
The relative importance of competition vs. environmental filtering in the assembly of communities is commonly inferred from their functional and phylogenetic structure, on the grounds that similar species compete most strongly for resources and are therefore less likely to coexist locally. This approach ignores the possibility that competitive effects can be determined by relative positions of species on a hierarchy of competitive ability. Using growth data, we estimated 275 interaction coefficients between tree species in the French mountains. We show that ...
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Abstract
1. A long-standing hypothesis in ecology and evolutionary biology is that closely related species are more ecologically similar to each other and therefore compete more strongly than distant relatives do. A recent hypothesis posits that evolutionary relatedness may also explain the prevalence of mutualisms, with facilitative interactions being more common among distantly related species. Despite the importance of these hypotheses for understanding the structure and function of ecological communities, experimental tests to determine how evolutionary relatedness influences competition ...
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Abstract
A longstanding concept in community ecology is that closely related species compete more strongly than distant relatives. Ecologists have invoked this “limiting similarity hypothesis” to explain patterns in the structure and function of biological communities and to inform conservation, restoration, and invasive-species management. However, few studies have empirically tested the validity of the limiting similarity hypothesis. Here we report the results of a laboratory microcosm experiment in which we used a model system of 23 common, co-occurring North American freshwater green ...
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Abstract
Natural and anthropogenic changes constantly impact the environment surrounding us. Available moisture and energy change due to variability and shifts in climate, and the separation of precipitation into different pathways on the land surface are altered due to wildfires, beetle infestations, urbanization, deforestation, invasive plant species, etc. Many of these changes can have a significant impact on the hydrological regime of the watershed in which they occur (e.g. DeWalle et al., 2000; Porporato et al., 2004; Milly et al., 2005; Xu et al., 2005; Poff et al., 2006; Oki ...
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Abstract
[Highlights] [::] Methods for estimating various hydrological indices at ungauged sites were compared. [::] Methods included a TopNet rainfall-runoff model and a Random Forest empirical model. [::] TopNet estimates were improved through correction using Random Forest estimates. [::] Random Forests provided the best estimates of all indices except mean flow. [::] Mean flow was best estimated using an already published empirical method. [Summary] Predictions of hydrological regimes at ungauged sites are required for various purposes such as setting environmental flows, assessing availability of water resources or ...
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Abstract
Knowledge of underwater morphology is an essential component of many hydrological and environmental applications such as flood modelling and lotic habitat mapping. Remote sensing allows modelling of bathymetry at spatial scales that are impossible to achieve with traditional methods. However, the use of passive remote sensing for modelling water depth in fluvial environments remains a challenge. Different methods of computing bathymetry models based on remotely sensed imagery combined with ground measurements for calibration were investigated in order to produce a digital bathymetry ...
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