Space Pattern of Forest Species and Its Relationship With Agricultural Factors Agroflorestal System

Abstract

The objective of this work was to describe the spatial distribution pattern of the arboreal and regenerating forest stratum and its relationship with edaphic factors in a multistratified agroforestry system without management. The data were obtained by means of a census of the arboreal and regenerating plants, in which the variables diameter were measured at 1.30m of the soil and total height, besides the botanical identification. The plants of the arboreal stratum were grouped in diameter and height classes and the regenerating plants in height classes. In both strata, the horizontal structure indicators were estimated and the species of higher Importance Value Index (IVI) were selected to perform the spatial analysis. The K Ripley function was applied in the univariate case to test the hypothesis of complete randomness in the groups and in the arboreal and regenerating species of higher IVI. In the bivariate case, the Ripley K function was applied to test the hypothesis of complete spatial independence between groups or aggregate pattern species, with edaphic attributes. The results indicated random spatial pattern for most of the tested groups, with only the species Gliricidia sepium and Archontophoenix alexandrae with aggregate spatial pattern, up to 30m distance, in the arboreal and regenerating strata, respectively. However, no spatial relationship was observed between the pattern of distribution of the species and the soil factors of agroforestry system (SAF). In general, it is concluded that edaphic factors were fundamental in the development of plants, but not for the formation of aggregates. Resumo Padrão espacial de espécies florestais e sua relação com fatores edáficos em sistema agroflorestal. O objetivo deste trabalho foi descrever o padrão de distribuição espacial do estrato florestal arbóreo e regenerante e sua relação com fatores edáficos em um sistema agroflorestal multiestratificado. Os dados foram obtidos por meio de censo das plantas arbóreas e regenerantes, no qual foram mensuradas as variáveis diâmetro a 1,30m do solo e altura total, além da identificação botânica. As plantas do estrato arbóreo foram agrupadas em classes de diâmetro e de altura e as plantas regenerantes em classes de altura. Nos dois estratos, foram estimados os indicadores da estrutura horizontal e as espécies de maior Índice de Valor de Importância (IVI) foram selecionadas para realizar a análise espacial. Aplicou-se a função K Ripley, no caso univariado, para testar a hipótese de completa aleatoriedade nos grupos e nas espécies arbóreas e regenerantes de maior IVI. No caso bivariado, a função K de Ripley foi aplicada para testar a hipótese de completa independência espacial entre os grupos ou espécies de padrão agregado, com atributos edáficos. Os resultados indicaram padrão espacial aleatório para a maioria dos grupos testados, sendo apenas as espécies Gliricidia sepium e Archontophoenix alexandrae com padrão espacial agregado, até 30m de distância, nos estratos arbóreo e regenerante, respectivamente. Contudo, não foi o...

Fine-Scale Distribution Patterns of Phragmites australis Populations Across an Environmental Gradient in the Salt Marsh Wetland of Dunhuang, China

“…On the one hand, the spatial distribution pattern of a plant population is closely related to the biological characteristics of the plant species itself [58,59], including the diversity characteristics of a plant population and community, life history strategies, regeneration and reproduction patterns, intermediate and intraspecific competition, and inter-clonal trade-off. On the other hand, the spatial distribution pattern of a population is also deeply affected by external environmental factors [60,61], including the soil temperature, humidity, salinity, nutrition, and so on.…”