in order to study the effect of afforestation in reduction oil pollution, one planted area in dezful, affected by pollutions from kuwaiti oil-wells burning was employed. six species, eucalyptus camaldulensis, eucalyptus microtheca, dalbegia sissoo, acacia salicina, acacia stenophylla, populus euphratica were selected. growth parameters, leaf samples and soil samples from different depths (0-30,...

How interactions between exotic species affect invasion impact is a fundamental issue on both theoretical and applied grounds. Exotics can facilitate establishment and invasion of other exotics (invasional meltdown) or they can restrict them by re-establishing natural population control (as predicted by the enemyrelease hypothesis). We studied forest invasion on an Argentinean island where 43 s...

Parker et al. (Reports, 10 March 2006, p. 1459) showed that native herbivores suppress exotic plants more than native plants. Further analysis reveals that the effect of native herbivores is reduced on exotic plant species that are closely related to native species in the invaded region. Exotic plants may share traits with native congeners that confer similar resistance to resident herbivores.

This study investigated the isotopic niches of two fish species, one exotic and one native. It was hypothesized that these species would show little or no isotopic niche overlap. This hypothesis was tested with the isotopic niche concept and the trophic Layman's metrics. A considerable isotopic niche overlap was observed between the species, mainly for the exotic that showed the greater percent...

While small-scale studies show that more diverse native communities are less invasible by exotics, studies at large spatial scales often find positive correlations between native and exotic diversity. This large-scale pattern is thought to arise because landscapes with favorable conditions for native species also have favorable conditions for exotic species. From theory, we proposed an alternat...

-The effect of exogenous Namalva interferon (IF) on the natural killer (NK) cell activity of human blood lymphocytes was examined against 5 target cell lines (K562, CCRF/CEM, Molt 4, Raji and Bri8) using the 51Cr-release assay. Addition of IF to the test significantly increased the cytotoxicity, though not as much as when effector cells were treated with IF before the test. Augmentation of cyto...

Fewer than 200 fish species are found in freshwater habitats in Australia, of which 144 are confined exclusively to freshwater. At least 22 species of exotic freshwater fish have been introduced into Australia, and 19 of these have established selfsustaining populations. However, the parasite fauna of both native and exotic freshwater fishes in Australia is poorly known. This is particularly th...

The question of whether species' origins influence invasion outcomes has been a point of substantial debate in invasion ecology. Theoretically, colonization outcomes can be predicted based on how species' traits interact with community filters, a process presumably blind to species' origins. Yet, exotic plant introductions commonly result in monospecific plant densities not commonly seen in nat...

A survey of exotic beetles that attack trees or shrubs in New Zealand found 51 species of mainly Australian (58%) and European (25%) origin. In addition, three biological control agents have been released against woody adventive plant pests. The host range of most species is restricted to exotic crop and ornamental plants in New Zealand. Nine polyphagous borers sometimes attack dead wood of ind...

Human land use tends to decrease the diversity of native plant species and facilitate the invasion and establishment of exotic ones. Such changes in land use and plant community composition usually have negative impacts on the assemblages of native herbivorous insects. Highly specialized herbivores are expected to be especially sensitive to land use intensification and the presence of exotic pl...