Researches on weed niche in turf
草坪杂草生态位研究

Niche is an important theoretic problem in studying plant population and community ecology. Niche breadth may be a measure of turfs' using diversity to environmental resource and it is a response of weeds to ecological niche. Niche-overlap is a measure to display the similarity of plant interspecies bionomics. Studies on the important value, niche breadth, and niche overlap of different weeds in turf can reveal the ecological demand similarity of different weeds, and can forecast the trend of reciprocal affect between different kings of weeds. So it can give some guide in using herbicide reasonably and get to a double-aim of dropping cost in maintaining turf and protecting the environment. When turf is identified as a healthy ecosystem, this turf ecosystem remains resistant or resilient to the long-term and unexpected disturbance caused by natural or human activities. Long-term application of a certain herbicide let a variation of weed populations in turf. It increases the difficulty controlling weeds effectively. Therefore, it is a hot problem for us to solve. In this paper, different kinds of turfs in Wuhan region were exemplified systematically. In the turfs in Wuhan region, 20 sites under different ecological condition were surveyed in detail with seven scales by visua- lization of weed dominance to rape to obtain the important value of 20 main weeds. The species niche breadth and niche overlap were calculated on the basis of the investigation. The results show that Alopecurus aequalis (0.559), Stellaria media (0.4341), Avena fatua (0.3214), Gnaphalium multiceps (0.2909), Galium apaine (0.2747), Ranunculus arvensis (0.2686), and Mazus japonicus (Thunb) O. Ltze (0.2474) have bigger value in ecological niche. The bigger value of the weeds showed that they have wider ecological-amplitude, and they can adapt to more kinds of environment. Because different weeds have different ecological annidation, they have different niche overlap value. The more ecological niche overlaps value show that the more same ecological resource can be used, and they must compete more fierily. Different weeds can be classfied according to their overlap value. For example, Galium apaine, Avena fatua, and Veronica persica belong to the same class. Galium apaine and Veronica persica have a bigger overlap value than Avena fatua. Alopecurus aequalis, Stellaria media, Mazus japonicus (Thunb) O. Ltze., Gnaphalium multiceps, Cardamine hirsuta L., Ranunculus arvensis and Poa annual can be classed together. These weeds always occur in similar spaces and have a large number. As compared with those of the other species, the niche overlaps between Galium apaine, Veronica persica, and Avena fatua were higher. The bigger value of weeds showed that they have wider ecological-amplitude, and they can adapt to more kinds of environment.Niche breadth reflects weeds' variety or specialization level in using nature resource. In the ordinary way weeds having a bigger niche breadth immolate th