1. Parameter uncertainty challenges the use of matrix models because it violates key assumptions underlying elasticity analyses. We have developed a matrix model to compare Monte Carlo methods with elasticity analyses for estimation of the relative importance of factors in the asymptotic population growth rate, λ, of Cirsium vulgare (spear thistle) in Nebraska, USA. 2. We calculated λ for a bas...

Cirsium semzinanicumsp. nov. (Asteraceae) is described as a new species from Hakkâri, Turkey. The new species is a part of the sect. Epitrachys (Cardueae) and similar to Cirsium karduchorum, from which it differs in morphological characters such as leaves, involucre, phyllaries, corolla, achens and pollen morphology. Geographical distribution, habitat and IUCN conservation status of this specie...

The current situation of global environmental degradation as a result anthropogenic activities makes it necessary to open new research lines focused on the causes and effects main alterations caused in ecosystems. One most relevant is how niche dynamics invasive species change between different geographical areas, since its understanding key early detection control future invasions. In this reg...

Background: High concentrations of various heavy metals of mine tailings can easily contaminate the environment. Such materials need monitoring and remediation to prevent them from polluting the environment and food chain. Materials & Methods: The concentrations of certain metals were evaluated in the soil samples at Sorkheh and Mazraeh copper mining areas in northwestern Iran, using three r...

Postrelease studies can provide data with which to evaluate expectations based on prerelease tests of biological control insects. In 2004, we observed Trichosirocalus horridus Panzer (Coleoptera: Curculionidae), the rosette weevil introduced into North America against Eurasian thistles, feeding on native tall thistle, Cirsium altissimum L. Spreng., in tallgrass prairie. In this study, we examin...