69 research outputs found
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Documentation for a combined carbon-water flow stand level coniferous forest model
The following report Introduces a documentation scheme for flow
oriented ecosystem models and shows its application to a carbon-water
model developed within the coniferous biome. This documentation scheme
has remained operative through revision of this model and expansion of
It to include nutrient flows. This model and subsequent versions are
operative simulations on the CDC 6400 at the University of Washington
using SIMCOMP (Gustafson S Innis (1971)).and give reasonable output.
The purpose of this report is mainly to introduce the reader to
the documentation scheme which we have found so effective in maintaining
a running history of the modeling process for large scale models.
We hope that it will lead to the adoption of this or a similar documentation
scheme as a standard for ecological modeling
Recommended from our members
Conifer : a model of carbon and water flow through a coniferous forest : revised documentation
CONIFER simulates water, carbon, and energy dynamics of a coniferous forest. The model consists of 29 nonlinear difference equations. Measured driving variables include air temperature, dew point temperature, precipitation, solar radiation, and wind speed. Water and energy variables are updated
daily; carbon variables are updated weekly. This report contains a detailed description of the model including all equations, parameter values, and initial conditions. Cross-reference tables list the equations in which each variable and parameter appear. Listings of the driving variable data,
computer implementation, and corresponding output are also provided. Information sources and model behavior are discussed elsewhere
Oxygen: A Fundamental Property Regulating Pelagic Ecosystem Structure in the Coastal Southeastern Tropical Pacific
Background: In the southeastern tropical Pacific anchovy (Engraulis ringens) and sardine (Sardinops sagax) abundance have recently fluctuated on multidecadal scales and food and temperature have been proposed as the key parameters explaining these changes. However, ecological and paleoecological studies, and the fact that anchovies and sardines are favored differently in other regions, raise questions about the role of temperature. Here we investigate the role of oxygen in structuring fish populations in the Peruvian upwelling ecosystem that has evolved over anoxic conditions and is one of the world's most productive ecosystems in terms of forage fish. This study is particularly relevant given that the distribution of oxygen in the ocean is changing with uncertain consequences. Methodology/Principal Findings: A comprehensive data set is used to show how oxygen concentration and oxycline depth affect the abundance and distribution of pelagic fish. We show that the effects of oxygen on anchovy and sardine are opposite. Anchovy flourishes under relatively low oxygen conditions while sardine avoid periods/areas with low oxygen concentration and restricted habitat. Oxygen consumption, trophic structure and habitat compression play a fundamental role in fish dynamics in this important ecosystem. Conclusions/Significance: For the ocean off Peru we suggest that a key process, the need to breathe, has been neglected previously. Inclusion of this missing piece allows the development of a comprehensive conceptual model of pelagic fish populations and change in an ocean ecosystem impacted by low oxygen. Should current trends in oxygen in the ocean continue similar effects may be evident in other coastal upwelling ecosystems
Preliminary bird population dynamics and biomass model, A
In this paper a preliminary model for the population and biomass change over time is given for bird populations. The interaction between biologist and modeler in the development of the model and its parameters is emphasized. The model consists of two constant coefficient differential equations. The output of the model, applied to the lark bunting, is compared with results of field experiments. Discussions of further extensions of the model as well as present difficulties are also included
Preliminary model for consumer predation, A
July 1971.On cover: Grassland Biome, Ecosystem analysis studies, U.S. International Biological Program.Includes bibliographical references
Predicting mortality from HIV-associated Pneumocystis pneumonia at illness presentation: an observational cohort study
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