Population and distribution parameters of arthropods of wet paddy ecosystem and their fits to distribution models

Hassan S.T.S., . Population and distribution parameters of arthropods of wet paddy ecosystem and their fits to distribution models. pp. 61-68. ISSN 0126-8643

Population parameters (with one hill as the sampling unit) such as mean density variance and proportion of infested hills were used to test for types of between-plant distribution or dispersion of 22 arthropod categories of wet paddy arthropods through examining variance to mean rations Morisita's index of dispersion Iwao's index of crowding and Tatlor's coefficients. The populaton and distribution parameters were then fitted to four types of binomial models to further confirm the distribution patterns. Variance to mean ratios and Taylor's power law detected only 15 and 13 arthropod categories with clumped distribution respectively. In contrast Morisita's index of dispersion Iwao's index of crowding and binomial models detected 21 21 and 17 clumping respectively. In the analysis of variance of r strength 2 generated from regressing proportions of infestation (P(I)) obtained from the four binomial models on observed P(I) the effects of arthropod category and model type are significant (P less than 0.05) but not their interactions. Thus the majority of arthropod categories examinded indicated higher fits to the model derived from negative binomial distribution conforming to clumped dispersion followed by the Poisson models which indicated random dispersion. The relative variation (RV) of mean population densities and distribution parameters are relatively low none exceeding 21 percent thus indicating acceptable sampling precision of these field studies. Each arthropod category then can be characterised by specific distribution parameters describing certain dispersion patterns

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Abstract

Population parameters (with one hill as the sampling unit) such as mean density variance and proportion of infested hills were used to test for types of between-plant distribution or dispersion of 22 arthropod categories of wet paddy arthropods through examining variance to mean rations Morisita's index of dispersion Iwao's index of crowding and Tatlor's coefficients. The populaton and distribution parameters were then fitted to four types of binomial models to further confirm the distribution patterns. Variance to mean ratios and Taylor's power law detected only 15 and 13 arthropod categories with clumped distribution respectively. In contrast Morisita's index of dispersion Iwao's index of crowding and binomial models detected 21 21 and 17 clumping respectively. In the analysis of variance of r strength 2 generated from regressing proportions of infestation (P(I)) obtained from the four binomial models on observed P(I) the effects of arthropod category and model type are significant (P less than 0.05) but not their interactions. Thus the majority of arthropod categories examinded indicated higher fits to the model derived from negative binomial distribution conforming to clumped dispersion followed by the Poisson models which indicated random dispersion. The relative variation (RV) of mean population densities and distribution parameters are relatively low none exceeding 21 percent thus indicating acceptable sampling precision of these field studies. Each arthropod category then can be characterised by specific distribution parameters describing certain dispersion patterns

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Item Type:	Article
Additional Information:	Summaries (En Ms)
AGROVOC Term:	ARTHROPODA
AGROVOC Term:	PLAGAS DE PLANTAS
AGROVOC Term:	DISTRIBUCION DE LA POBLACION
AGROVOC Term:	ORYZA
AGROVOC Term:	ECOSISTEMA
AGROVOC Term:	MUESTREO
AGROVOC Term:	DISPERSION
AGROVOC Term:	MALASIA
Depositing User:	Ms. Norfaezah Khomsan
Last Modified:	24 Apr 2025 05:52
URI:	http://webagris.upm.edu.my/id/eprint/17346

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