نتایج جستجو برای: invader species
تعداد نتایج: 548714 فیلتر نتایج به سال:
Invasions of non-native species represent a global problem of great scientific interest. Here we study in detail the response in population and life history characteristics of closely related native species, with divergent habitat preferences, that are impacted by an invading species over a sufficient time period to allow a new stable state to become established. A time series of 20 years start...
—The blue-spotted salamander (Ambystoma laterale) has the northern-most distribution of any North American salamander and primarily occurs in areas that were once covered by the southern Laurentide Ice Sheet during the last glacial maximum. We examine the phylogeography of this primary post-glacial invader of northern North America. Mitochondrial DNA sequence data indicate a clade comprised of ...
Invasive plants can inflict great harm, yet drivers of successful invasion remain unclear. Many invaders of North American deciduous forests exhibit extended leaf phenology (ELP), or longer growing season relative to natives. ELP may grant invaders competitive advantages, but we argue that ELP more potently drives invasion in the presence of herbivores. ELP invaders can support herbivores by le...
We used molecular genetic methods to test two hypotheses, (i) that host plant specificity among ectomycorrhizal fungi would be common in a closed-canopy, mixed Pinus contorta-Picea engelmannii forest in Yellowstone National Park and (ii) that specificity would be more common in the early successional tree species, P. contorta, than in the invader, P. engelmannii. We identified 28 ectomycorrhiza...
We study the kinetics of infiltration in which contaminant particles, which are suspended in a flowing carrier fluid, penetrate a porous medium. The progress of the "invader" particles is impeded by their trapping on active "defender" sites which are on the surfaces of the medium. As the defenders are used up, the invader penetrates further and ultimately breaks through. We study this process i...
While invasive species often threaten biodiversity and human well-being, their potential to enhance functioning by offsetting the loss of native habitat has rarely been considered. We manipulated the abundance of the nonnative, habitat-forming seaweed Gracilaria vermiculophylla in large plots (25 m2) on southeastern US intertidal landscapes to assess impacts on multiple ecosystem functions unde...
Invasive species may undergo rapid change as they invade. Native species persisting in invaded areas may also experience rapid change over this short timescale relative to native populations in uninvaded areas. We investigated the response of the native Achillea millefolium to soil from Holcus lanatus-invaded and uninvaded areas, and we sought to determine whether differential responses between...
This paper proposes a vision-based fuzzy 8051 surveillance system which emphasizes on designing the image processing function to detect the invaded states and the 8051 fuzzy servomotors controller to track the invader region. The techniques include discrete wavelet transformation (DWT) image data reducing, edge detection, motion detection, and fuzzy servomotor control. In this paper, image proc...
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