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001-es BibID:BIBFORM079875
Első szerző:Orbán Ildikó
Cím:Treeline and timberline dynamics on the northern and southern slopes of the Retezat Mountains (Romania) during the late glacial and the Holocene / Ildikó Orbán, Hilary H. Birks, Ildikó Vincze, Walter Finsinger, Ilona Pál, Elena Marinova, Gusztáv Jakab, Mihály Braun, Katalin Hubay, Tamás Bíró, Enikő K. Magyari
Dátum:2018
ISSN:1040-6182
Megjegyzések:To investigate treeline and timberline dynamics in the Retezat Mountains (Romanian Carpathians), late glacial and Holocene sediment sequences from four lakes were studied. The south and north slopes of the mountain range were compared using two lakes from the north flank (Lake Brazi, 1740 m a.s.l. and Lake Gales, 1990 m a.s.l) and two from the south flank (Lake Lia, 1910 m a.s.l. and Lake Bucura, 2040 m a.s.l.). Macrofossil and stomata analyses were performed to assess changes in the local vegetation, supplemented by pollen, charcoal and loss-on-ignition analyses. Our results show that treeline reached Lake Brazi on the northern side during the late glacial (ca. 14,000 cal yr BP) and then Lake Gales between 11,000 and 10,800 cal yr BP. During the early Holocene the upper limit of closed forest, the timberline, reached and passed Lake Brazi and has stayed above it since, but it has never reached Lake Gales at 1990 m a.s.l. The expansion of Larix decidua in the late glacialand early Holocene around Lake Brazi is unique. Stomata and macrofossils of Abies alba are also more abundant in the northern records. On the southern flank, treeline reached Lake Lia at around 12,000 cal yr BP, and was either very close to or at the elevation of Lake Bucura between ca. 8600 and 3000 cal yr BP. Timberline reached Lake Lia at ca. 8000 cal yr BP, some 3000 years after Lake Brazi, only 170 m lower on the north slope. Local fire events delayed the advance of timberline around Lake Lia in the early Holocene in a dry continental climate. The surrounding forest was dominated by Picea abies with individuals of Pinus cembra and stands of P. mugo until about 3000 cal yr BP when timberline retreated below the lake. Maximum elevation of timberline was attained between ca. 8000 and 3000 cal yr BP, after which it descended in response to climate cooling. Regional climate change appears to be the main driver of treeline dynamics, but it was modified by local climatic differences due to slope aspect. The first signs of human disturbance appeared ca. 4200 cal yr BP, when naturally open areas were used as alpine pastures. Human impact in the treeline ecotone, mainly burning and grazing, was intensified after ca. 2600 cal yr BP, contributing to the widening of the ecotone and the lowering of the timberline.
Tárgyszavak:Természettudományok Környezettudományok idegen nyelvű folyóiratközlemény külföldi lapban
Treeline
Timberline
Macrofossil analysis
Stomata analysis
Retezat mountains
Carpathians
Megjelenés:Quaternary International. - 477 (2018), p. 59-78. -
További szerzők:Birks, Hilary H. Vincze Ildikó Finsinger, Walter Pál Ilona Marinova, Elena Jakab Gusztáv Braun Mihály (1966-) (vegyész, analitikus) Hubay Katalin (1985-) (biológus, környezetkutató) Bíró Tamás Magyari Enikő (1973-) (biológus)
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001-es BibID:BIBFORM080859
Első szerző:Vincze Ildikó
Cím:Holocene treeline and timberline changes in the South Carpathians (Romania): Climatic and anthropogenic drivers on the southern slopes of the Retezat Mountains / Ildikó Vincze, Ildikó Orbán, Hilary H. Birks, Ilona Pál, Walter Finsinger, Katalin Hubay, Elena Marinova, Gusztáv Jakab, Mihály Braun, Tamás Biró, Mónika Tóth, Claudia Dănău, Iosif V. Ferencz, Enikő K. Magyari
Dátum:2017
ISSN:0959-6836
Megjegyzések:Two high-altitude lake-sediment sequences (Lake Lia, 1910 m a.s.l. and Lake Bucura, 2040 m a.s.l.) from the Retezat Mountains (South Carpathians, Romania) were analysed using multi-proxy methods to study responses of treeline, timberline and alpine/subalpine vegetation to climate change and human impact during the past 16,000 years. Woody species (Pinus mugo, Pinus cembra, Picea abies and Juniperus communis) reached Lake Lia between 12,000 and 11,800 cal. yr BP, whereas P. mugo colonised the shores of Lake Bucura at 9600 cal. yr BP. Lake Lia was in the timberline ecotone between 8000 and 3200 cal. yr BP, in semi-open P. cembra and Picea abies woodland, probably mixed with P. mugo on the steeper slopes. Lake Bucura was surrounded by the upper part of the krummholz zone during the mid-Holocene. The increase in P. cembra after c. 6000 cal. yr BP around Lake Lia suggests that the composition of the timberline forest changed. The disappearance of P. cembra and Picea abies around Lake Lia at ~3000 cal. yr BP reflects descent of the timberline. A large mean July temperature decline between 3300 and 2800 cal. yr BP may have driven or at least contributed to the descent of the Picea abies?P. cembra forests. An increase in human indicator pollen types in Lake Bucura around 4200 cal. yr BP may reflect human impact in the naturally open alpine zone in the Late Bronze Age. In contrast, human impact likely appeared considerably later, around 2650 cal. yr BP (Early Iron Age) around Lake Lia in the upper subalpine zone. Human impact likely intensified after 2200 cal. yr BP at both sites that resulted in the lowering of the krummholz zone. We conclude that climate change and human impact both played an important role in the lowering of the treeline and timberline in the late-Holocene.
Tárgyszavak:Természettudományok Földtudományok idegen nyelvű folyóiratközlemény külföldi lapban
Holocene climate
human impact
plant macrofossils
Retezat Mountains
timberline
treeline
Megjelenés:Holocene. - 27 : 11 (2017), p. 1613-1630. -
További szerzők:Orbán Ildikó Birks, Hilary H. Pál Ilona Finsinger, Walter Hubay Katalin (1985-) (biológus, környezetkutató) Marinova, Elena Jakab Gusztáv Braun Mihály (1966-) (vegyész, analitikus) Biró Tamás Tóth Mónika (1983-) Dănău, Claudia Ferencz, Iosif V. Magyari Enikő (1973-) (biológus)
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