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A model for amphipod (Talitrus saltator) population dynamics
Anastácio, P. M.; Gonçalves, S. C.; Pardal, M. A.; Marques, J. C.This study provides a population dynamics model for one of the most common species (Talitrus saltator) in sandy beaches. Sensitivity analysis showed that in the model the abundance of T. saltator is deeply affected by variations in the minimum recruitment day length, the minimum temperature at recruitment, and the period between recruitments. The mortality rate, as expected, also had a profound effect on model ...
Impact of crayfish densities on wet seeded rice and the inefficiency of a non-i...
Anastácio, P. M.; Frias, A. F.; Marques, J. C.In order to compare the effects of crayfish (Procambarus clarkii) on rice production, with and without the use of a non-ionic surfactant (Genapol OX-80) at a concentration of 0.005%, 12 enclosures at 1 m2 containment area were built in each of two experimental fields. Crayfish densities used in the experiment were: 0, 1, 3, and 5 adult crayfish per m-2. In each field, at harvest time, five randomly chosen areas...
Surfactant (Genapol OX-80) toxicity to Selenastrum capricornutum
Anastácio, P. M.; Holten Lützhøft, H. -C.; Halling-Sørensen, B.; Marques, J. C.A non-ionic surfactant (Genapol OX-80) was proposed as a means of reducing destructive crayfish activity in rice. In order to study the toxicity of this product on algae, a test in accordance to the ISO 8692 protocol (1989) was performed. The growth inhibiting effect of the pure formulation of Genapol OX-80 was studied on Selenastrum capricornutum in the concentration range of 0.01-1.0 mg/l. The result indicate...
CRISP (crayfish and rice integrated system of production): 2. Modelling crayfis...
Anastácio, P. M.; Nielsen, S. N.; Marques, J. C.An ecological sub-model of crayfish (Procambarus clarkii) population dynamics is presented for integration into the CRISP (crayfish and rice integrated system of production) series of models. The present structure is directed towards simulation of crayfish population responses under different human interventions, namely different capture rates. The crayfish population was subdivided into seven age classes of 80...
CRISP (crayfish and rice integrated system of production): 1. Modelling rice (O...
Anastácio, P. M.; Frias, A. F.; Marques, J. C.A ecological sub-model for rice growth, adapted to the culture processes used in the lower Mondego river valley (Portugal), is presented. The structure of the model is based on the production of carbohydrates by the photosynthesis. Parallel structures were used to simulate the development stage of the crop, and the tillering process. The model is composed of 11 state variables, 14 forcing functions, 22 rate pro...
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