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Although corridors have been the subject of extensive research in the recent years, the probable correlation between structural and functional corridors have not been addressed to date. To fill this scientific gap, we compared structural and functional corridors of wild sheep (Ovis orientalis) as a threatened species in a semi-arid area of central Iran. We first used Maximum-Entropy to develop wild sheep habitat suitability map. We then used Morphological-Spatial-Pattern-Analysis (MSPA) and circuit theory to map structural and functional corridors of wild sheep respectively. Bootstrapping techniques then were used to compare structural and functional corridors. We found that structural corridor is a concept which is dependent on the scale of observation. By changing edge-width from 600 to 1200 m, the total area of structural corridors increased by 63%. We also only found very small differences in the functional connectivity role of different MSPA categories (including structural corridors). All MSPA categories together accounted for only 20% of the functional connectivity. Although, in some cases functional corridors had a better performance in showing migration path of wild sheep between reserves, other cases showed that for effective conservation, both structural and functional corridors should be identified and considered in the planning step.

Studying the concentration distribution of metals is necessary for soil pollution monitoring and maintaining environmental quality. To date, very little large-scale research has been performed to investigate metal contamination in developing countries. In this study, the content and spatial distributions of five metals (cadmium [Cd], copper [Cu], nickel [Ni], lead [Pb], and zinc [Zn]) were quantified based on 346 topsoil samples from 12 districts in the province of Golestan (northeast [NE] Iran). The concentration levels (mg/kg) of Cd, Cu, Pb, Ni and Zn varied from 0.02 to 0.36, 9.3 to 93.7, 6.8 to 44, 9.5 to 85.35, and 25 to 417.4, respectively. The average concentrations (mg/kg) obtained were as follows Cd 0.12 ± 0.07, Cu 23.9 ± 9.07, Ni 34.88 ± 11.59, Pb 15.42 ± 5.81 and Zn 82.08 ± 30.87. Significant differences in the distribution of trace elements among districts were detected. The AzadShahr and BandarGaz districts displayed the highest metal concentrations. Greater metal values were obtained in the central, south, west, and NE areas, although Zn concentration was also high to the north of the province. Values of contamination factor and contamination degree indicated that the metal pollution level was on the order of Zn > Cd > Pb > Cu > Ni and that all of the metals belonged to a low or moderate pollution category. Ni and Cu levels derived from natural sources, whereas Cd, Pb, and Zn derived from anthropogenic activities with greater mean concentrations than reference concentrations. © 2014 Springer Science+Business Media New York.