Abstract
The opposite slopes of lower Nahal Oren, Mount Carmel, Israel, designated 'Evolution Canyon', display physical and biotic contrasts, although both are cut in Upper Cenomanian calcareous limestone. The three-fold greater solar radiation makes the south-facing slope warmer, drier and more variable than the north-facing slope and valley bottom. Consequently, biodiversity is greater. Microclimate (mesic-xeric) is a major force driving adaptive evolution, and causing soil divergence. The soils on both slopes are Terra Rossas in the Israeli classification system (Rhodoxeralfs in US taxonomy). However, selected properties (pH, humus content, NH4-N content, cation exchange capacity and others) display greater interslope than intraslope differences. The north-facing Terra Rossas have a dark-coloured A1 humic horizon, which is better developed than in south-facing Terra Rossas. Differences in soil morphology, moisture regime and microfabric between the north- and south-facing soils suggest that they belong to different taxonomic classes. These differences probably result in part from the forested ecosystem of the north-facing slope versus the savanna-like ecosystem of the opposite slope.
Original language | English |
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Pages (from-to) | 241-254 |
Number of pages | 14 |
Journal | Catena |
Volume | 33 |
Issue number | 3-4 |
DOIs | |
State | Published - Nov 1998 |
Bibliographical note
Funding Information:Discussions with Prof. Dan H. Yaalon and Prof. M. Evron were very useful. Noah Moskin and Ohad Zackheim helped to identify the archaeological finds. We also thank Prof. A. Korol for providing the computer facilities for statistical analysis of the chemical data. This work was supported by the Israeli Ministry of Science, grants nos. 1426 and 4147, the Israeli Discount Bank Chair of Evolutionary Biology, and the Ancell-Teicher Research Foundation for Genetics and Molecular Evolution.
Keywords
- Biotic divergence
- Israel
- Microclimate differentiation
- Mount Carmel
- Slope-soil differentiation
- Terra Rossa
ASJC Scopus subject areas
- Earth-Surface Processes