Northwestern Sites Research Articles

Habitat and niche determinants of the organization of two bird communities in northern Italy

Abstract The organization of two birds communities (passeriformes and piriformes) has been studied at two sites in northwestern Italy in order to identify better those factors that, at different ecological levels, may afford interspecific coexistence. Apart from minor differences between the two communities mostly due to the different vegetation structure and composition of the two study areas, it has been shown that the ecological organization of these bird communities depends on common niche and habitat factors. The former mainly work to discriminate, especially in the autumn and winter, several groups of species which are both ecological and systematic assemblages, whereas the latter, independently of the above‐mentioned groups of species, further increase segregation according to habitat gradients. With regard to niche, foraging seems to discriminate groups better than do singing and resting activities.

Submarine Current Measurements, Northwest Gulf of Mexico: ABSTRACT

In February 1966, Exxon Corporation undertook a geophysical and geologic survey of the continental slope of the Gulf of Mexico from Texas to Florida. They were joined in May by Standard Oil Company of California and in August by Gulf and Mobil Oil Companies. As part of this survey the Caldrill 1 was to drill 42 coreholes at 36 sites. Submarine current measurements were to be recorded while the vessel was on station. Because of technical difficulties, submarine-current records were obtained at only 6 northwestern sites. Vertical current profiles at 5 of the 6 stations show two prevailing directions which may represent distinct water masses. The upper current flows generally east or northeast, increasing from about 0.2 knots in the west to about 0.4 knots in the east. Below this system is a current that flows west or northwest at similar rates. The interface between these water masses deepens End_Page 1834------------------------------ westward, from about 400 to about 600 m. The deeper mass may be related to the Yucatan Current. At 5 sites the meter was maintained for up to 9 hours a short distance off the sea floor to determine the sustaining nature of the currents. Records obtained at 3 locations are consistent in both velocity and direction with the short-term measurements. These few scattered measurements would not seem to warrant broad conclusions regarding the movement and structure of the water masses over the upper continental slope. However, the data clearly document certain water movements in the spring of 1966. Most of these data are internally consistent, and the velocities are sufficient at times to transport fine to medium sand. End_of_Article - Last_Page 1835------------

The Indus Civilization: Supplementary Volume to the Cambridge History of India.

Notes 1. Climate 2. Towns and villages of hill and plain 3. The Indus civilization 4. Mohenjo-daro and Harappa: general layout 5. Harappa 6. Mohenjo-daro 7. Chanhu-daro 8. Sutkagen-dor and other north-western sites 8. Lothal and other southern and eastern sites 9. Burials and skeletal types 9. Military aspects of the Indus civilization 10. Commerce and transport 11. Farming and fauna 12. Arts and crafts 13. The Indus script 14. The Indus religions 15. Dating 16. The end of the Indus civilization Conclusion Appendix Bibliography Index.