| Autor: |
Gąsiorowski, Michał1 mgasior@twarda.pan.pl, Sienkiewicz, Elwira1 |
| Předmět: |
|
| Zdroj: |
Science of the Total Environment. Jan2019, Vol. 646, p1359-1366. 8p. |
| Abstrakt: |
Abstract Five peat sequences were studied to identify the time the little auk Alle alle colonies originated in the Hornsund area (Spitsbergen). Elemental and stable isotope analysis of nitrogen and carbon was applied as markers for bird activity. The peat sequences were dated with 210Pb and radiocarbon methods. The results showed that peat development related to seabird activity is significantly older (at least 300 years old) in localities closer to the fjord's mouth (west) than those located deeper in the fjord (east), which are ~100 years old. Isotopic signals indicated that bird activity in the western localities decreased simultaneously with the growth of the eastern colonies. Colonization by birds of new localities correlated with the termination of the Little Ice Age and the meaningful decrease in the glacier area of the region. Hence, we suggest that the availability of new localities for nesting in talus cones, nival moraines and lateral moraines on gentle mountain slopes with south-eastern exposition attracted the little auk due to better thermal conditions, isolation from strong westerly winds and better protection from predation by gull Larus hyperboreus. The expansion of little auks to the new localities was fast (20–30 yrs), and there are no records of changes in bird impacts on the tundra environment after 1920. Graphical abstract Unlabelled Image Highlights • Five peat profiles deposited near seabird colony in Spitsbergen were studied. • Peat profiles were dated with radiometric methods. • Bird colonization was recorded in C and N stable isotopes. • Peats located in the western part of the fjord are older than in the eastern part. • Climate changes after the LIA initiated expansion of birds into the fjord. [ABSTRACT FROM AUTHOR] |
| Databáze: |
GreenFILE |
| Externí odkaz: |
|
Full Text from ScienceDirect