Effects of Organic Farming on Winter Plant Composition, Cover and Diversity in Olive Grove Ecosystems in Central Greece

Abstract

The present study aimed to assess the effects of organic farming in comparison with conventional on plant composition, plant cover (%), diversity [species richness, Shannon, Simpson, and evenness (Pielou's) indexes] and investigate and describe the relations among plant species richness, plant cover, indexes, and soil parameters (pH and temperature) in olive grove ecosystems during the winter. Organic olive groves had significantly greater values of cover, species richness, and Shannon and Simpson indexes than the conventional ones. Plant species richness was positively correlated to plant cover and Shannon and Simpson indexes but negatively correlated to evenness index for both farming system. Finally, plant cover was positively correlated to the Shannon and Simpson indexes for both farming systems. According to principal component analysis (PCA), for axis 1, positive correlation was detected among the plant species richness, soil temperature, and Shannon and Simpson diversity indexes, whereas for axis 2, negative correlation was detected between plant cover and soil pH. It can be concluded that the organic management system enhances herbaceous plant cover and diversity (species richness, Shannon and Simpson indexes) in olive grove ecosystems during the winter.