The recent increase of interest in the graph invariant called tree-depth and in its applications in algorithms and logic on graphs led to a natural question: is there an analogously useful “depth” notion also for dense graphs (say; one which is stable under graph complementation)? To this end we introduced, in a 2012 conference paper, the notion of shrub-depth of a graph class which is related ...

* Fire disturbance can mediate the invasion of ecological communities by nonnative species. Nonnative plants that modify existing fire regimes may initiate a positive feedback that can facilitate their continued invasion. Fire-sensitive plants may successfully invade pyrogenic landscapes if they can inhibit fire in the landscape. * Here, we investigated whether the invasive shrub Brazilian pepp...

gmelinoides fasciatus (stebbing, 1899) is a baikal endemic amphipod that has recently become widespread in eurasia. this species accidentally entered the cooling reservoir of the belovo power plant and became successfully naturalised there. this study describes the peculiarities of g. fasciatus distribution in reservoir sites with different thermal regimes and analyses the environmental factors...

Rhazya stricta, an evergreen poisonous shrub, is invading many rangeland areas in Saudi Arabia. A field study was conducted in Raudhat AI-Khafs to assess the relationship between R. stricta and Hammada elegans, a valuable and a dominant saltbush range plant in the area. Only eight perennial species were found in the site of which H. elegans and R. stricta were almost exclusively co-dominating t...

In a recent paper [6], Kwon and Oum claim that every graph of bounded rank-width is a pivot-minor of a graph of bounded tree-width (while the converse has been known true already before). We study the analogous questions for “depth” parameters of graphs, namely for the tree-depth and related new shrub-depth. We show that shrub-depth is monotone under taking vertex-minors, and that every graph c...

Through competition for pollinators, invasive plants may suppress native flora. Community-level studies provide an integrative assessment of invasion impacts and insights into factors that influence the vulnerability of different native species. We investigated effects of the nonnative herb Lythrum salicaria on pollination of native species in 14 fens of the eastern United States. We compared v...

The threat posed by invasive species, in particular weeds, to biodiversity may be exacerbated by climate change. Lantana camara L. (lantana) is a woody shrub that is highly invasive in many countries of the world. It has a profound economic and environmental impact worldwide, including Australia. Knowledge of the likely potential distribution of this invasive species under current and future cl...

In this paper, the researchers investigate the vegetative growth of Chromolaena odorata and the infl uence of light intensity on the understorey environment of Shorea robusta forest at Chitwan in south-central Terai, Nepal. C. odorata is a clonally growing shrub and typically consists of several clones with an underground “cormous organ” (a modifi ed stem to store food reserve; here after “corm...

In arctic tundra, where wind transport of snow is common, shrubs can significantly modify the distribution and physical characteristics of the snow cover. We examined interactions between shrubs and snow by measuring snow depths along three 1-km transects in arctic Alaska and then measuring plant canopy characteristics at the same locations during the following growing season. Snow depths corre...