نتایج جستجو برای: willow
تعداد نتایج: 2089 فیلتر نتایج به سال:
Shrubs have expanded in Arctic ecosystems over the past century, resulting in significant changes to albedo, ecosystem function, and plant community composition. Willow and rock ptarmigan (Lagopus lagopus, L. muta) and moose (Alces alces) extensively browse Arctic shrubs, and may influence their architecture, growth, and reproduction. Furthermore, these herbivores may alter forage plants in suc...
During the years 2006 and 2007 the phytoextraction ability of maize (Zea mays), willow-tree (Salix smithiana) and poplar (Populus nigra × P. maximowiczii) to accumulate cadmium, copper, mercury and zinc was investigated. Small scale field experiment was carried out on soil contaminated with chemicals from the waste incineration plant in Hradec Kralové (Czech republic). Screening of this allotme...
1. We examined the effects of browsing by moose and snowshoe hares on vegetation structure, species composition, plant demography and element cycling in 25 riparian (willow) vegetation stands along the Tanana River, interior Alaska, across a 250-km gradient that represented a fivefold range in moose densities (0.2–1.0 km –2 ). 2. Browsing frequency was much greater in areas with high moose dens...
Free mechanosensory neuromasts of larval fishes have been described as playing a complementary role to vision in feeding behaviour (Disler, 1971; Iwai, 1972a,b). In certain species or under limited conditions, free neuromasts play a major role in detecting prey. The larvae of mottled sculpin Cottus bairdi can feed on Artemia in the dark by using free neuromasts (Jones and Janssen, 1992). Artifi...
Willow has been used for nearly 200 years as the main material in blades of cricket bats, whilst application bamboo sport declined. In this work, laminated was characterised to assess if it could be a viable alternative willow. Bamboo matures much more quickly than willow and is prevalent countries, such India, where there large interest cricket. Using lead increased participation new products ...
The cultivation of bioenergy crops (BECs) represents a significant land-use change in agrienvironments, but their deployment has raised important issues globally regarding possible impacts on biodiversity. Few studies however, have systematically examined the effect of commercial scale bioenergy plantations on biodiversity in agri-ecosystems. In this study we investigate how the abundance and d...
Mitochondrial DNA sequences were used to study the phylogeny, population structure and colonisation history of Parus species. The phylogenetic relationships of seven European and three American species were examined by sequencing a part of the cytochrome b gene. Phylogenetically the closest species were the great tit (Parus major) and the blue tit (P. caeruleus). Subgenus Poecile was divided in...
We present DARRT, a sampling-based algorithm for planning with multiple types of manipulation. Given a robot, a set of movable objects, and a set of actions for manipulating the objects, DARRT returns a sequence of manipulation actions that move the robot and objects from an initial configuration to a final configuration. The manipulation actions may be non-prehensile, meaning that the object i...
One of the major goals in speciation research is to understand which isolation mechanisms form the first barriers to gene flow. This requires examining lineages that are still in the process of divergence or incipient species. Here, we investigate the presence of behavioral and several cryptic barriers between the sympatric willow and birch host races of Lochmaea capreae. Behavioral isolation d...
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