scholarly journals A biophysical model of population dynamics of the autotrophic dinoflagellate Gymnodinium breve

2001 ◽  
Vol 210 ◽  
pp. 101-124 ◽  
Author(s):  
G Liu ◽  
GS Janowitz ◽  
D Kamykowski
Keyword(s):  
Population Dynamics ◽  
Biophysical Model ◽  
Gymnodinium Breve

A biophysical model of the interaction between vertical migration of crustacean zooplankton and circulation in the Lower St. Lawrence Estuary

1999 ◽  
Vol 56 (12) ◽  
pp. 2420-2432 ◽  
Author(s):  
Bruno A Zakardjian ◽  
Jeffrey A Runge ◽  
Stephane Plourde ◽  
Yves Gratton
Keyword(s):  
Population Dynamics ◽  
Vertical Migration ◽  
Horizontal Distribution ◽  
Calanus Finmarchicus ◽  
Biophysical Model ◽  
Crustacean Zooplankton ◽  
Simple Formulation ◽  
Lawrence Estuary ◽  
Circulation Patterns ◽  
St Lawrence Estuary

As an essential step in modeling the influence of circulation on the population dynamics of marine planktonic copepods, we define a simple formulation of swimming behavior that can be used in both Eulerian and Lagrangian models. This formulation forces aggregation of the population toward a preferential depth and can be stage specific and time varying, thus allowing description of either diurnal or seasonal vertical migration. We use the formulation to examine the interaction between the circulation and vertical distribution in controlling horizontal distribution of the common planktonic copepod Calanus finmarchicus in the Lower St. Lawrence Estuary, Canada. We first introduce diel migration into a simple one-dimensional model and then into a model of residual two-dimensional circulation patterns representative of conditions encountered in the Lower St. Lawrence Estuary. Results from the latter indicate that interactions between circulation and stage-specific swimming behaviors are the main mechanisms for aggregation of planktonic crustaceans at the head of the Laurentian Channel and highlight the implications of flushing of the surface-dwelling young stages for the population dynamics of C. finmarchicus in the Lower St. Lawrence Estuary.

scholarly journals Population dynamics of Eldana saccharina Walker (Lepidoptera: Pyralidae): application of a biophysical model to understand phenological variation in an agricultural pest

2017 ◽  
Vol 108 (3) ◽  
pp. 283-294 ◽  
Author(s):  
E. Kleynhans ◽  
M.G. Barton ◽  
D.E. Conlong ◽  
J.S. Terblanche
Keyword(s):  
South Africa ◽  
Population Dynamics ◽  
Integrated Pest Management ◽  
Pest Management ◽  
Life Stage ◽  
Management Strategies ◽  
Biophysical Model ◽  
Eldana Saccharina ◽  
Pest Population ◽  
Model Predictions

AbstractUnderstanding pest population dynamics and seasonal phenology is a critical component of modern integrated pest-management programs. Accurate forecasting allows timely, cost-effective interventions, including maximum efficacy of, for example, biological control and/or sterile insect technique. Due to the variation in life stage-related sensitivity toward climate, insect pest population abundance models are often not easily interpreted or lack direct relevance to management strategies in the field. Here we apply a process-based (biophysical) model that incorporates climate data with life stage-dependent physiology and life history to attempt to predict Eldana saccharina life stage and generation turnover in sugarcane fields. Fitness traits are modelled at two agricultural locations in South Africa that differ in average temperature (hereafter a cold and a warm site). We test whether the life stage population structures in the field entering winter and local climate during winter directly affect development rates, and therefore interact to determine the population dynamics and phenological responses of E. saccharina in subsequent spring and summer seasons. The model predicts that: (1) E. saccharina can cycle through more generations at the warm site where fewer hours of cold and heat stress are endured, and (2) at the cold site, overwintering as pupae (rather than larvae) confer higher relative fitness and fecundity in the subsequent summer adult moths. The model predictions were compared with a large dataset of field observations from scouting records. Model predictions for larval presence (or absence) generally overlapped well with positive (or negative) scout records. These results are important for integrated pest management strategies by providing a useful foundation for future population dynamics models, and are applicable to a variety of agricultural landscapes, but especially the sugarcane industry of South Africa.

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