Showing papers in "Ecological Modelling in 1981"

TL;DR: In this article, several approaches are presented which permit calculation by computer or hand calculator of solar radiation for any place on Earth, without input of certain measured data for the location of interest, but others permit an approximation even without actual data.

TL;DR: In this article, it is suggested that the simple correlation coefficient derived from analysis of Monte Carlo simulations is a more reasonable way to rank model parameters according to their contribution to prediction uncertainty.

TL;DR: In this article, a reliability index for a model is defined, which is a number k ⩾ 1 which is determined from a set x 1, x 2, x n of model predictions and a corresponding set y 1, y 2,…, y n of observations.

TL;DR: In this article, an ensemble of acceptable parameter vectors for the model is identified by reference to a partly qualitative and somewhat vague definition of system behaviour in terms of allowable ranges, and then used for the simulation of a multitude of future systems behaviour patterns, so that the uncertainty in the initial data and assumptions is preserved, and thus the predicted future systems response can be interpreted in a probabilistic manner.

TL;DR: A spatial simulation model of annual plant interference which employs dispersal and neighborhood effects is developed and implemented with a computer program and results in behavior which is significantly different from that of non-spatial models.

TL;DR: A procedure to estimate parameters for a eutrophication model using an intensive measuring program is described and it is possible to obtain a unique set of parameters, while the calibration method carried out on the basis of bi-monthly measurements gives several solutions to the parameters.

TL;DR: The object of this paper is the complete qualitative study of predator-prey system dynamics with two processes taken into account, namely, the saturation of the predator population, and the competition of predators for prey.

TL;DR: The paper argues, in particular, that there is an intimate relationship between prediction and model calibration, which is especially important in accounting for uncertainty in the development and use of models.

TL;DR: In this article, a generalized bioeconomic simulation model of annual-crop marine fisheries is described and its use in marine fisheries management is demonstrated by evaluating several management alternatives for the pink shrimp (Penaeus duorarum ) fishery on the Tortugas grounds in the Gulf of Mexico.

TL;DR: In the case of complex ecosystems, the modelling process must be executed in different steps as shown in this work, and it is shown that there must be a strong cohesion between model elaboration and data acquisition.

TL;DR: A population dynamic model of D. frontalis within an infestation was developed based on the integration of several component submodels that describe individual life stage processes of the beetle, resulting in a model response which closely follows actual field responses.

TL;DR: In this paper, temperature data obtained from NUC Tower, San Diego, California during May-June 1968 provide input to a three-wave period version of MOVER, a computer model that simulates organism diurnal vertical migration through an internal wave field.

TL;DR: Stability analyses using numerical techniques of digital simulation elucidate relationships among various analytical approaches, indicate some misapplication of analytical mathematics to ecosystem models, and establish a technique suitable for linear or non-linear models which most ecologists can use.

TL;DR: In this paper, a procedure of extended sensitivity analysis for simulation models is developed which is applicable to the situation in which input uncertainties are specified in a multiplicative (rather than an additive) way.

TL;DR: The North Inlet Marsh-Estuarine System Model (NIMES) is a 19-compartment real-time deterministic ecosystem simulation model of intrasystem carbon flow and exchange between an estuary and adjacent coastal water as discussed by the authors.

TL;DR: It is shown that in certain time domains the system may be stiff, thus requiring the use of suitable algorithms, and certain properties of this system, such as the existence of limit cycles, are demonstrated numerically.

TL;DR: A model is described which was used to augment field experiments in substantiating that predator resistance and non-aggressive spatial competition were essential attributes responsible for these observed spatial patterns of Hydractinia echinata.

TL;DR: In this article, a number of statistical phosphorus-retention models described in the literature were applied to two sets of data, one from Lake Paijanne and the other from 85 lakes situated in different parts of the world.

TL;DR: In this paper, a model of the Oregon upwelling ecosystem is used to calculate the complex eddy diffusivity which would have to be included in the model in lieu of realistic advection, although the authors do not recommend such a substitute.

TL;DR: An optimization procedure utilizing stochastic dynamic programming is described, and optimal feedback strategies for a wolf-ungulate system in Alaska are estimated, revealing that stability properties depend on predator search efficiency.

TL;DR: In this paper, a qualitative analysis of a system of autonomous differential equations modelling an ecosystem microcosm is carried out from the point of view of persistence, and sufficient conditions are given that no trajectory with positive initial conditions has a component that tends to zero asymptotically or reaches zero in finite time.

TL;DR: In this article, the root-decomposer system is shown to be asymptotically stable if nitrogen net-mineralization is positive and if net mineralization is negative, the system evolves in time towards the annihilation of the roots.

TL;DR: Models of gallery construction, emergence and re-emergence for use in a general population dynamics model of the southern pine beetle, Dendroctonuc frontalis Zimmermann, are developed to account for fluctuating temperatures and variable attack densities under field conditions.

TL;DR: In this paper, a simulation model representing deposition of SO 2 to a grassland ecosystem was constructed, which provided a fair representation of the accumulation of sulfur on live and dead leaves and soil.

TL;DR: In this paper, the authors examined the stochastic structure of flow data for the upper Delaware River and synthesized autoregressive integrated moving average (ARIMA) models to describe the random components of discharge time series.

TL;DR: Five kinetic models were applied to the data to determine the kinetic parameters governing growth of the organisms and the so-called ‘Haldane function’ was chosen as the best and utilised in the model describing the steady-state behaviour of the chemostat.

TL;DR: In this paper, a model based on the social and territorial behaviour of lions is used to simulate localized lion culling operations in a large game park and the results are compared with culling experiments performed in the Central District of the Kruger National Park, South Africa.

TL;DR: In this article, the effects of the volume of leachate on the quality of the leachates were evaluated using a numerical model of salt transport and field data collected on 63 research plots located in the Grand Valley (Colorado, U.S.A.).