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Three-Dimensional Modelling Of A Microcystis Bloom Event In A Western Australian Estuary, Barbara J. Robson, David P. Hamilton Jul 2002

Three-Dimensional Modelling Of A Microcystis Bloom Event In A Western Australian Estuary, Barbara J. Robson, David P. Hamilton

International Congress on Environmental Modelling and Software

In January 2000, there was a record maximum rainfall throughout much of the watershed of the Swan River estuary, leading to the first reported Microcystis aeruginosa bloom in the estuary. Peak cell counts reached over 100,000 cells mL-1. A coupled three-dimensional hydrodynamic-ecological model, ELCOM-CAEDYM, is applied to the period of development and subsequent decline of the bloom. The model, previously calibrated for a more typical year (1995), accurately reproduced the unusual hydrodynamic circumstances and predicted the magnitude and timing of the Microcystis bloom. Salinity and temperature were the primary factors controlling the growth of Microcystis during the period of interest. …

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Modeling And Analysis Of Biofilms Formation And Evolution In Wastewater Treatment Processes Using Multi-Agent Systems, Laurent Lardon, Jean-Philippe Steyer, Nicolas Bernet, Christophe Le Page Jul 2002

Modeling And Analysis Of Biofilms Formation And Evolution In Wastewater Treatment Processes Using Multi-Agent Systems, Laurent Lardon, Jean-Philippe Steyer, Nicolas Bernet, Christophe Le Page

International Congress on Environmental Modelling and Software

Biofilms are complex but omnipresent and industrially important structures. Many studies were devoted to build mathematical models for biofilm analysis but most of them were based on classical continuous approaches. On the other side, only very few studies were directly based on the functional mechanisms to obtain virtual systems which mimic the descriptive observations and allow to predict the state of a biofilm and its possible evolution. This paper will present a non-classical approach based on multi-agent systems for the analysis of biofilm formation. This model shows the spatial repartition of biomass within the biofilm and the impact of the …

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Modelling Contrasted Management Behaviours Of Stakeholders Facing A Pine Encroachment Process: An Agent-Based Simulation Approach, Michel Etienne, Christophe Le Page Jul 2002

Modelling Contrasted Management Behaviours Of Stakeholders Facing A Pine Encroachment Process: An Agent-Based Simulation Approach, Michel Etienne, Christophe Le Page

International Congress on Environmental Modelling and Software

In Southern France, the Causse Méjan is a natural ecosystem of high biological diversity. Sheep farmers, foresters, and a National Park are interacting in this land subject to pine encroachment by Pinus sylvestris and P. nigra at different temporal and spatial scales. The stakeholders are concerned by this global biological process although it affects their management goals (sheep production, timber production, nature conservation) in very different ways. An agent-based model has been built with the Cormas platform. Vegetation changes in terms of structure, composition and productivity were simulated by a cellular automata that was initialised as a spatial grid of …

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The Role Playing Games In An Abm Participatory Modeling Process: Outcomes From Five Different Experiments Carried Out In The Last Five Years, Patrick D’Aquino, Olivier Barreteau, Michel Etienne, Stanislas Boissau, Sigrid Aubert Jul 2002

The Role Playing Games In An Abm Participatory Modeling Process: Outcomes From Five Different Experiments Carried Out In The Last Five Years, Patrick D’Aquino, Olivier Barreteau, Michel Etienne, Stanislas Boissau, Sigrid Aubert

International Congress on Environmental Modelling and Software

Since 1996, we have used Role Playing Games (RPG) with our Multi-Agent System (MAS) platform, CORMAS (Bousquet et al. 1998), in different experiments about local land use management, water management, negotiations between foresters and breeders, and preservation of wild genetic resources by local peasants. Each experiment tested a different sort of coupling between RPG and CORMAS, from a RPG simply explaining the MAS model to a RPG strongly evolving in the different steps of the modeling itself. Each experiment tested also different objectives for this linking, from the improvement of the modeler's knowledge about the issue to the support of …

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Hoofs - A Multi-Scale, Agent-Based Simulation Framework For Studying The Impact Of Grazing Animals On The Environment, J. A. Beecham, S. P. Oom, C. P. D. Birch Jul 2002

Hoofs - A Multi-Scale, Agent-Based Simulation Framework For Studying The Impact Of Grazing Animals On The Environment, J. A. Beecham, S. P. Oom, C. P. D. Birch

International Congress on Environmental Modelling and Software

An agent based system (HOOFS) has been developed in order to examine the interactions between foraging animals and a spatially explicit description of the environment, including vegetation growth processes. HOOFS makes use of the agent-based approach to develop a model of foraging in which animal decision making processes are explicitly modelled. The model has evolved from one where foraging decisions are based on a simple biased random walk model with an information weighting parameter, through one in which animals decide between direct walking towards an object as against continuous foraging, ending with a model where memory is used. The model …

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Comparison Between Water Quality Models For Toxics, C. Gualtieri Jul 2002

Comparison Between Water Quality Models For Toxics, C. Gualtieri

International Congress on Environmental Modelling and Software

Water quality models have been applied increasingly to represent the interaction between pollutants and aquatic environment due to transport and transformation phenomena: These models can be used to better understand pollution phenomena and to choose between different, alternative management strategies. The paper compares the results of two different water quality models, which have been applied to a water column-sediments system of a lake with an inflow contaminant loading. In the former, the system is idealized as well-mixed surface-water underlain by a well-mixed active sediment layer, where the resulting concentrations are attained by direct analytical solutions at the steady-state and in …

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Framework Of A Regional Impacts Assessment Model And Its Application On Arid/Semi-Arid Region, Yinpeng Li, Jinjun Ji Jul 2002

Framework Of A Regional Impacts Assessment Model And Its Application On Arid/Semi-Arid Region, Yinpeng Li, Jinjun Ji

International Congress on Environmental Modelling and Software

Regional impacts assessment model is an indispensable tool for the study on environmental and economical change and the impacts on ecosystems. In this paper a regional impact assessment model AVIMia, which is an extended version of AVIM is designed. AVIMia is consists of two components: original AVIM (Atmosphere- Vegetation Interaction Model) and an impact assessment model. Over past 50 year the arid/semi-arid grassland of North China degraded severely due to the change in Climate and social economy. AVIMia is applied to assess the impacts of climatic changes and human activities on grassland in North China, based on historical data, and …

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Drips – A Dss Estimating The Input Quantity Of Pesticides For German River Basins, B. Röpke, Martin Bach, Hans Georg Frede Jul 2002

Drips – A Dss Estimating The Input Quantity Of Pesticides For German River Basins, B. Röpke, Martin Bach, Hans Georg Frede

International Congress on Environmental Modelling and Software

The development of the GIS Decision Support System (DSS) – Drainage Runoff Input of Pesticides in Surface Water - based on model algorithms describing the major pathways of pesticide entry into surface waters has been initiated by the German Federal Environmental Agency (Umweltbundesamt, UBA) in 2000. The tool estimates the quantity of pesticide input from non-point sources via surface runoff, tile drainage and spraydrift. Furthermore, the resulting predicted environmental concentration of pesticides in surface waters (PECsw) can be retrieved considering the mean daily inputs of substances into various types of river-basins characterized by their daily discharge. A Graphical User Interface …

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Sensitivity Of The Inca Model To N Process Parameters And Hydrological Input, Katri Rankinen, A. Lepistö, Kirsti Granlund Jul 2002

Sensitivity Of The Inca Model To N Process Parameters And Hydrological Input, Katri Rankinen, A. Lepistö, Kirsti Granlund

International Congress on Environmental Modelling and Software

The Integrated Nitrogen in CAtchments (INCA) model simulates nitrogen transport and processes within catchments. It was applied to the Simojoki river basin in northern Finland where major human impacts are forest management and atmospheric nitrogen deposition. In this work the main emphasis is to evaluate the sensitivity of the INCA model to hydrological input. Parameters defining vegetation nitrogen uptake and denitrification rate were also studied. A simple univariate parametric (one-at-a-time) sensitivity analysis was conducted for NO3-N leaching, NH4-N leaching and denitrification in forest cut areas. Mineral nitrogen leaching was mainly influenced by hydrologically effective rainfall (HER). The parameter that controls …

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An Application Of Queuing Theory To Waterfowl Migration, Richard S. Sojda, John E. Cornely, Leigh H. Fredrickson Jul 2002

An Application Of Queuing Theory To Waterfowl Migration, Richard S. Sojda, John E. Cornely, Leigh H. Fredrickson

International Congress on Environmental Modelling and Software

There has always been great interest in the migration of waterfowl and other birds. We have applied queuing theory to modelling waterfowl migration, beginning with a prototype system for the Rocky Mountain Population of trumpeter swans (Cygnus buccinator) in Western North America. The queuing model can be classified as a D/BB/28 system, and we describe the input sources, service mechanism, and network configuration of queues and servers. The intrinsic nature of queuing theory is to represent the spatial and temporal characteristics of entities and how they move, are placed in queues, and are serviced. The service mechanism in our system …

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Comparing Basal Area Growth Models, Consistency Of Parameters, And Accuracy Of Prediction, J. J. Colbert, Michael Schuckers, Desta Fekedulegn Jul 2002

Comparing Basal Area Growth Models, Consistency Of Parameters, And Accuracy Of Prediction, J. J. Colbert, Michael Schuckers, Desta Fekedulegn

International Congress on Environmental Modelling and Software

We fit alternative sigmoid growth models to sample tree basal area historical data derived fromincrement cores and disks taken at breast height. We examine and compare the estimated parameters forthese models across a range of sample sites. Models are rated on consistency of parameters and on theirability to fit growth data from four sites that are located across a longitudinal gradient across the states ofDelaware, Pennsylvania, West Virginia, and Ohio in the USA. We then examine the differences among thesemodels in their abilities to predict short-term (decade) and longer-term growth of trees. Accuracy andpotential effects of bias are discussed relative …

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Plant Disease Models. Critical Issues In Development And Use, A. Susi, A. Perini, E. Olivetti Jul 2002

Plant Disease Models. Critical Issues In Development And Use, A. Susi, A. Perini, E. Olivetti

International Congress on Environmental Modelling and Software

Models which simulate the evolution of a plant disease during the season give important informationto assess the seriousness of the situation. This activity precedes the choice of an appropriate action to be implementedfor reducing the economical damage. Having effective models is a critical issue in modern agriculture,especially in Integrated Protection and Organic Farming, which rest on a set of plant disease managementpractices with low environmental impact.Considerable effort has gone in the study of models for the simulation of plant diseases evolution. Phenologymodels, population and epidemiological models have been developed for several, diffused diseases. Problemsare still open, especially when the aim …

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Integrated Modelling And Decision Support Tools: A Mediterranean Example, T. Oxley, N. Winder, Brian Mcintosh, M. Mulligan, Guy Engelen Jul 2002

Integrated Modelling And Decision Support Tools: A Mediterranean Example, T. Oxley, N. Winder, Brian Mcintosh, M. Mulligan, Guy Engelen

International Congress on Environmental Modelling and Software

A great deal of new knowledge and research material has been generated from research carried out under the auspices of the EU. However, only a small amount has been made available as practical policysupport tools. In this paper we describe how EU funded research models and understanding has been integrated into an interactive Decision Support System addressing physical, economic and social aspects of land degradation in the Mediterranean. We summarise the 10 constituent models that simulate hydrology, human influences, crops, natural vegetation and climatic conditions. The models operate on very different spatial and temporal scales and utilise different modelling techniques …

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Sensitivity Analysis Of Velfeem –Venice Lagoon Finite Element Ecological Model- To The Macro-Nutrient Input Regime, D. M. Canu, Cosimo Solidoro, Georg Umgiesser Jul 2002

Sensitivity Analysis Of Velfeem –Venice Lagoon Finite Element Ecological Model- To The Macro-Nutrient Input Regime, D. M. Canu, Cosimo Solidoro, Georg Umgiesser

International Congress on Environmental Modelling and Software

A sensitivity analysis of VELFEEM, the Finite Element Ecological Model for the lagoon of Venice, has been performed in order to test the responses of the model to changes in external input regimes. The model is obtained by internally coupling a hydrodynamic model, an energetic model, and an ecological model. The hydrodynamics are simulated using SHYFEM, a barotropic bi-dimensional model based on a finite element discretization of the spatial domain, which allows for a very good spatial resolution of the lagoon morphology while keeping at a low level the computational demand. Using a standard heat fluxes formulation, the energetic module …

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The Control Of Algal Bloom Damages To Clam Yield In A North Adriatic Coastal Lagoon (Sacca Di Goro, Italy), F. Cellina, G. A. De Leo, M. Bartoli, P. Viaroli Jul 2002

The Control Of Algal Bloom Damages To Clam Yield In A North Adriatic Coastal Lagoon (Sacca Di Goro, Italy), F. Cellina, G. A. De Leo, M. Bartoli, P. Viaroli

International Congress on Environmental Modelling and Software

During the last twenty years the economic activity of clams exploitation has been intensively developed in the southernmost coastal lagoon of the Italian Po river delta, Sacca di Goro. Still, clam breeding is in danger because of frequent summer algal blooms, due to Ulva rigida macroalgae. These blooms cause anoxic crises leading clams to collapse, with a consequent deep impact on the whole economic sector of clams exploitation. Several strategies have been developed to avoid the loss of commercial production, yet none of them has been assessed on a mathematical basis. In this work we develop a simple stochastic mathematical …

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A Step-By Step Approach To Build-Up Land Management Scenarios Based On Multiple Viewpoints On Multi-Agent System Simulations, Michel Etienne, M. Cohen, Christophe Le Page Jul 2002

A Step-By Step Approach To Build-Up Land Management Scenarios Based On Multiple Viewpoints On Multi-Agent System Simulations, Michel Etienne, M. Cohen, Christophe Le Page

International Congress on Environmental Modelling and Software

A multi-agent system was developed to simulate strategies of natural resources management in the remarkable site of the Causse Méjan, a limestone plateau dominated by a rare pseudo-steppe endangered by pine encroachment. To stimulate the emergence of alternative long-term management strategies of the sheep farms and of the woodlands, contrasting dynamic viewpoints on land resources were designed at different space scales. In a first step, they were individually used to validate the model with each main stakeholder (foresters, farmers and the National Park of Cévennes rangers), to improve it and to propose individual scenarios of natural resources management. Once the …

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Ontowedss: An Ontology-Underpinned Decision-Support System For Wastewater Management, Luigi Ceccaroni, Ulises Cortés, Miquel Sànchez-Marrè Jul 2002

Ontowedss: An Ontology-Underpinned Decision-Support System For Wastewater Management, Luigi Ceccaroni, Ulises Cortés, Miquel Sànchez-Marrè

International Congress on Environmental Modelling and Software

This paper characterizes part of an interdisciplinary research on arti cial intelligence techniques applied to environmental decision-support systems. The architecture's design of OntoWEDSS, a decision support system for wastewater management, is presented. This system augments classic rule-based reasoning and casebased reasoning with a domain ontology. The integration of the newly createdWaWO ontology provides a more exible management capability to OntoWEDSS. The construction of the decision support system is based on a speci c case study but the system is also of general interest, given that its ontology-underpinned architecture can be applied to any wastewater treatment plant and, at an appropriate …

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Avenues Of Spatially Explicit Population Dynamics Modeling — A Par Excellence Example For Mathematical Heterogeneity In Ecological Models?, Ralf Seppelt Jul 2002

Avenues Of Spatially Explicit Population Dynamics Modeling — A Par Excellence Example For Mathematical Heterogeneity In Ecological Models?, Ralf Seppelt

International Congress on Environmental Modelling and Software

This contribution discusses different approaches to spatially explicit modeling of population dynamics of the intrusion of non-endemic species into patched habitats. Different modeling approaches such as cellular automata, partial differential equations and hybrid Petri nets are summarized. An application of a meta–population model for the Galapagos archipelago is described using a partial differential equation and a Petri net model. A detailed comparison of both models in terms of simulation results and methodology shows how different building blocks of ecological models can be. And the question is raised, how far the integration of models is at all possible and should be …

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Integrating Mechanistic Modelling And Statistical Learning Theoretic-Methods: Initial Steps Toward A Strategy For Model Evaluation And Structure Selection, A. Guergachi Jul 2002

Integrating Mechanistic Modelling And Statistical Learning Theoretic-Methods: Initial Steps Toward A Strategy For Model Evaluation And Structure Selection, A. Guergachi

International Congress on Environmental Modelling and Software

The traditional model validation procedure has been criticized in many areas of environmentalengineering. In this paper, it is suggested to replace it by a more reasonable procedure: “model evaluation”.A framework for model evaluation and structure selection (FMESS) is presented. Based on statisticallearning theory, this framework considers the model identification step as a learning problem. The modelevaluation process is based on one single criterion: model performance. The latter is measured by amathematical deviation between the model prediction and reality. Although it is an exact measure of modelperformance, this deviation cannot be computed, but can be related to the empirical measure that …

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Integrating Structural Changes In Future Research And Modelling On The Seine River Basin, H. Kieken Jul 2002

Integrating Structural Changes In Future Research And Modelling On The Seine River Basin, H. Kieken

International Congress on Environmental Modelling and Software

For years policy makers and researchers involved in the management of the Seine river basin haveshared a common representation of the system's structure and behaviour: Paris, in the centre, divides thewatershed into two very unequal parts, a "clean" upstream and the downstream where environmentalproblems occur due to Paris sewage. This representation resulted in both (1) a focus of the attention and theefforts of policy makers on the downstream area and (2) the structuring of scientific research on the SeineRiver in a very dissymmetric way, including the features of the models developed within the 12-year old andstill ongoing research programme dedicated …

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Optimisation Of Artificial Neural Network (Ann) Model Design For Prediction Of Macroinvertebrate Communities In The Zwalm River Basin (Flanders, Belgium), A. Dedecker, Peter L. M. Goethals, W. Gabriels, N. De Pauw Jul 2002

Optimisation Of Artificial Neural Network (Ann) Model Design For Prediction Of Macroinvertebrate Communities In The Zwalm River Basin (Flanders, Belgium), A. Dedecker, Peter L. M. Goethals, W. Gabriels, N. De Pauw

International Congress on Environmental Modelling and Software

To meet the requirements of the EU Water Framework Directive, models are useful to predict communities in watercourses based on the abiotic characteristics of their aquatic environment. For that purpose back-propagation artificial neural network algorithms were used to induce predictive models on a dataset of the Zwalm river basin (Flanders, Belgium). This dataset consisted of 120 samples, collected over a two year period. Fifteen environmental variables including temperature, percentage of dissolved oxygen, water depth, stream velocity, presence/absence of hollow beds, … were measured at each site, as well as the abundance of the aquatic macroinvertebrate taxa. Different neural networks were …

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Use Of Genetic Algorithms To Select Input Variables In Artificial Neural Network Models For The Prediction Of Benthic Macroinvertebrates, T. D’Heygere, Peter L. M. Goethals, N. De Pauw Jul 2002

Use Of Genetic Algorithms To Select Input Variables In Artificial Neural Network Models For The Prediction Of Benthic Macroinvertebrates, T. D’Heygere, Peter L. M. Goethals, N. De Pauw

International Congress on Environmental Modelling and Software

The first consideration in predictive ecological modelling is the selection of appropriate input variables. Numerous variables can however be involved and most of them cannot be omitted without a significant loss of information. The collection of field data on the other hand is both time-consuming and expensive. Therefore, rigorous methods are needed to detect which variables are essential and those which are not. Appropriate selection of input variables is not only important for modelling objectives as such, but also to ensure reliable decision-support in river management and policy-making. In this paper, the use of genetic algorithms is explored to automatically …

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A Model For Urban Stormwater Improvement Conceptualisationq, T. H. F. Wong, D. Fletcher, H. P. Duncan, J. R. Coleman, G. A. Jenkins Jul 2002

A Model For Urban Stormwater Improvement Conceptualisationq, T. H. F. Wong, D. Fletcher, H. P. Duncan, J. R. Coleman, G. A. Jenkins

International Congress on Environmental Modelling and Software

Catchment urbanisation leads to increased hydraulic and pollutant loadings into receiving waterbodies. Issues concerning pollution that endangers the sustainable utilisation of water resources have focused government authorities towards integrated catchment management, where both causes and effects of pollution are addressed. Recent research has provided a platform for improving urban stormwater management. The CRC for Catchment Hydrology (CRCCH) has recently developed a Model for Urban Stormwater Improvement Conceptualisation (MUSIC), which serves as a decision support system (DSS) that packages the results of many research activities undertaken at the CRCCH and other organisations into an easily used tool. MUSIC enables urban catchment …

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The Facilitator - An Open Source Effort To Support Multiobjective Decision Making, P. Heilman, Greg Davis, Paul Lawrence, Jerry L. Hatfield, John Huddleston Jul 2002

The Facilitator - An Open Source Effort To Support Multiobjective Decision Making, P. Heilman, Greg Davis, Paul Lawrence, Jerry L. Hatfield, John Huddleston

International Congress on Environmental Modelling and Software

Multiobjective Decision Support technology has matured to the point where new efforts should incorporate components of existing systems, rather than build everything from scratch. To help such efforts, the Java source code to a multiobjective decision support system called “The Facilitator” has been revised and released under the Mozilla Public License. This open source effort will be of interest to three groups. First, anyone needing a tool for multiobjective decision support can use the Facilitator. Users familiar with Java can now see how actions in the Facilitator are implemented or modify the user interface. Second, the open source approach might …

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Quality Attributes Of Dried Milk Products Packaged For Long-Term Storage, Michelle A. Lloyd, J. Zou, H. Farnsworth, Oscar A. Pike Jun 2002

Quality Attributes Of Dried Milk Products Packaged For Long-Term Storage, Michelle A. Lloyd, J. Zou, H. Farnsworth, Oscar A. Pike

Faculty Publications

There is a market for dehydrated foods, such as nonfat dry milk (NFDM), that are packaged for long-term storage in case of natural disasters or other emergencies. To maintain quality and optimize shelf-life, NFDM must be properly processed from good quality milk, well-packaged (minimizing moisture, light and oxygen), and stored appropriately. Research is needed to determine the variation in quality that exists in dried milk products intended for retail sale. The objective of this research was to evaluate and compare the quality of several types of dried milk products packaged for long-term storage. Ten brands of dried milk products (5 …

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Optimization By Varied Beam Search In Hopfield Networks, Tony R. Martinez, Xinchuan Zeng May 2002

Optimization By Varied Beam Search In Hopfield Networks, Tony R. Martinez, Xinchuan Zeng

Faculty Publications

This paper shows that the performance of the Hopfield network for solving optimization problems can be improved by a varied beam search algorithm. The algorithm varies the beam search size and beam intensity during the network relaxation process. It consists of two stages: increasing the beam search parameters in the flrst stage and then decreasing them in the second stage. The purpose of using such a scheme is to provide the network with a better chance to find more and better solutions. A large number of simulation results based on 200 randomly generated city distributions of the 10-city traveling salesman …

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Late Pleistocene Mollusks From The Southern Black Hills, South Dakota, Christopher N. Jass, Jim I. Mead, Amy D. Morrison, Larry D. Agenbroad May 2002

Late Pleistocene Mollusks From The Southern Black Hills, South Dakota, Christopher N. Jass, Jim I. Mead, Amy D. Morrison, Larry D. Agenbroad

Western North American Naturalist

Pleistocene-age mollusks recovered from the Nelson-Wittenberg Site and Mammoth Site provide information on paleoenvironments of the southern Black Hills, South Dakota. New mollusk records for the Mammoth Site include Vertigo modesta, Catinella sp., and Gyraulus parvus. The presence of V. modesta, Columella columella alticola, and Pupilla muscorum at the Nelson-Wittenberg Site suggests cooler than modern conditions in the Black Hills during the Pleistocene. Although the majority of identified taxa are consistent with previous interpretations of an arid, shrubsteppe environment for the Black Hills during the Wisconsin Glaciation, V. modesta and C. c. alticola suggest the presence of at least …

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Movements And Home Ranges Of San Joaquin Kit Foxes (Vulpes Macrotis Mutica) Relative To Oil-Field Development, Bruce W. Zoellick, Charles E. Harris, Brian T. Kelly, Thomas P. O'Farrell, Thomas T. Kato, Marni E. Koopman May 2002

Movements And Home Ranges Of San Joaquin Kit Foxes (Vulpes Macrotis Mutica) Relative To Oil-Field Development, Bruce W. Zoellick, Charles E. Harris, Brian T. Kelly, Thomas P. O'Farrell, Thomas T. Kato, Marni E. Koopman

Western North American Naturalist

We examined the effect of oil-field development on movements and patterns of spatial use of San Joaquin kit foxes (Vulpes macrotis mutica) on the Naval Petroleum Reserves in California (NPRC) in the San Joaquin Valley. To do this, we compared movements and home ranges of kit foxes from June 1984 to September 1985 in areas developed for petroleum production (30% of native habitat lost to production facilities) and areas with little development (3%). Distances traveled nightly by kit foxes did not differ between levels of petroleum development or between sexes (P > 0.2). Mean length of nightly movements …

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Patterns Of Energy Allocation Within Foragers Of Formica Planipilis And Pogonomyrmex Salinus, Peter Nonacs May 2002

Patterns Of Energy Allocation Within Foragers Of Formica Planipilis And Pogonomyrmex Salinus, Peter Nonacs

Western North American Naturalist

Foraging workers of Formica planipilis and Pogonomyrmex salinus were collected at various distances from their colony by pitfall traps in the former species and by catching workers recruited to food at known locations in the latter. In F. planipilis the number of larger workers increased in proportional representation to distance from the nest. Larger workers also weighed relatively less with distance from the nest, indicating that energy or water allocated for maintaining all foragers is patterned such that resource loss with forager mortality is minimized. However, the smallest size class involved in foraging shows the opposite pattern, with heavier individuals …

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Helminth Parasites Of Seven Anuran Species From Northwestern Mexico, Stephen R. Goldberg, Charles R. Bursey May 2002

Helminth Parasites Of Seven Anuran Species From Northwestern Mexico, Stephen R. Goldberg, Charles R. Bursey

Western North American Naturalist

One hundred eighty-three specimens representing 7 anuran species were examined for helminth parasites: Bufo kelloggi, B. mazatlanensis, Leptodactylus melanonotus, Pachymedusa dacnicolor, Rana forreri, R. magnaocularis, Smilisca baudini. The following species were found: 8 species of Trematoda, Cephalogonimus americanus, Clinostomum attenuatum (larva), Glypthelmins poncedeleoni, G. quieta, Gorgoderina attenuata, Haematoloechus complexus, H. longiplexus, and Megalodiscus temperatus; 2 species of Cestoda, Cylindrotaenia americana and Nematotaenia dispar; 13 species of Nematoda, Aplectana incerta, A. itzocanensis, Cosmocerca podicipinus, Cosmocercella haberi, Cosmocercoides variabilis, Foleyellides striatus, Oswaldocruzia pipiens, Rhabdias americanus, R. ranae, Subulascaris falcaustriformis, Physaloptera sp. (larva), Physocephalus sp. (larva), and Spiroxys sp. (larva); …

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