Ecological importance and sociological characters of fourteen widespread weeds and their contribution to the observed (dis)similarity between weed communities

Abstract

Widespread weeds are a serious nuisance to farmers in any country whether they are growing agricultural or horticultural crops for the great damage they cause to the economy, human health and environment loss. Thus, it is important to measure their ecological importance, sociological characters, their contribution to the observed (dis)similarity between weed communities associated with agronomic and horticulture crops, as well as performing time series analysis and forecasting for their cumulative records. Hopefully with the aforementioned information available, it will be possible to determine the most detrimental which deserve resistance priority within a successful weed control plan, which is the aim of the current study. Depending on species records 2018–2020, fourteen weeds assigned widespread out of the 537-species recorded. Their values in the Importance Value Index (IVI) suggested that Sonchus oleraceus had the highest ecological importance among winter weeds (IVI = 50.5), whereas Bassia indica had the highest IVI among summer weeds (IVI = 42.7) and Cynodon dactylon showed the highest value in the observed competition throughout the year (IVI = 46.2). Analysis of Similarities (ANOSIM) indicates that the weed community structure is significantly affected by widespread weeds and the mean of ranked dissimilarities in floristic composition between groups (weed communities associated with crop categories) is greater than within groups. Similarity Percentage analysis (SIMPER) based on Bray-Curtis as a distance dissimilarity measure, revealed that Cyperus rotundus, Melilotus indicus and Beta vulgaris were the most discriminant species in creating the observed pattern of (dis)similarity between the weed community structure associated with agronomic and horticultural crops during the winter half of the year, while Aster squamatus and Echinochloa colona were the most discriminant during the summer half. It is prominent from the results of the current study and the implemented time-series analysis and forecasting that no-decline is expected in the cumulative records of the 14-widespread weeds when the same current weed management strategy is applied.