Local and landscape-level influences on wetland bird communities of the prairie pothole region of Iowa, USA
摘要:
Bird species richness and individual species densities were measured in wetland complexes in 1998. These values were then related to habitat variables within the complexes and to area of wetland habitat in the surrounding landscape. The percentage of wetland area within a complex that was covered with emergent vegetation and the total area of wetland habitat in the 3 km surrounding each complex were significant predictors of species richness. A perimeter-to-area ratio was the most frequently selected variable for inclusion in species-density models, being selected for 8 of 15 models. Five species' densities were related to the percentage of the wetland area that was covered by emergent vegetation, and 4 densities were related to the area covered by weak-stemmed wet-meadow vegetation. Densities of 5 species, as well as the overall species richness, were associated with a measure of the amount of wetland habitat within a 3-km buffer surrounding the wetland complexes. This indicates that the presence and abundance of some wetland bird species may be influenced by the amount of wetland habitat nearby. Thus, programs that encourage restoration of tracts of land that contain multiple wetland basins should be emphasized to maximize benefits to the wetland bird community.
Copper(II) catalyzed allylic amination of terpenic chlorides in water
作者:Brahim Boualy、Mohamed Anouar Harrad、Soufiane El Houssame、Larbi El Firdoussi、Mustapha Ait Ali、Abdallah Karim
DOI:10.1016/j.catcom.2011.12.019
日期:2012.3
A highly efficient method for the synthesis of allylic amines from terpenic chlorides by cheap copper (II) as catalyst in water has been developed. Allylicchlorides react with high regioselectivity in the presence of secondary amines, under mild conditions to give N-allylic amines in excellent yields.