A Holocene fossil coleopteran (beetle) assemblage from the Central Swiss Alps: Climate and ecology

Citation
M. Jost-stauffer, A Holocene fossil coleopteran (beetle) assemblage from the Central Swiss Alps: Climate and ecology, ECLOG GEOL, 93(3), 2000, pp. 481-490
Citations number
45
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Earth Sciences
Journal title
ECLOGAE GEOLOGICAE HELVETIAE
ISSN journal
0012-9402 → ACNP
Volume
93
Issue
3
Year of publication
2000
Pages
481 - 490
Database
ISI
SICI code
0012-9402(2000)93:3<481:AHFC(A>2.0.ZU;2-5
Abstract
The beetle fauna of a fen peat melted out in pieces from below the retreati ng Unteraar Glacier was examined. The sediment (12 kg of peat) yielded more than 5000 insect fragments. Identification of the fossils provided a detai led picture about palaeoenvironment in the Gletschervorfeld 3600-3800 yr BP ago. Coleopterans living in marshy alpine areas near lakes and running wat er associated with reeds and moss dominate the assemblage. Species indicati ng persisting snow patches even during summer months are Helophorus glacial is and Nebria castanea. Many of the specimens reported live in flowering me adows and shrubs (often Rhododendron, Alnus, Salix). There are several spec ies in the assemblage which are not known to live in the alpine zone (e.g. Stenus bifoveolatus, Gymnusa brevicollis). Those observations and the total absence of tree-dependent species suggest that the ancient Cyperaceae fen peal was growing in the subalpine dwarf-shrub, heath - above the forest lim it but below the treeline. From the finding of wood fragments in the same d eposits, the presence of isolated trees can bs inferred, probably on the sl opes where the conditions were locally more favourable. Reconstructed July temperatures based on the beetle assemblage yielded a mean value similar to today's temperature measured 5.5 km east from the site at Grimsel Hospiz.