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Treeline and timberline dynamics on the northern and southern slopes of the Retezat Mountains (Romania) during the late glacial and the Holocene
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Abstract 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.
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RBINS Staff Publications 2017
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The pan-and-tilt hyperspectral radiometer system (PANTHYR) for autonomous satellite validation measurements – prototype design and testing
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RBINS Staff Publications 2019
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Pterosaur melanosomes support signalling functions for early feathers
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RBINS Staff Publications 2022
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Radial porosity profiles: a new bone histological method for comparative developmental analysis of diametric limb bone growth
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RBINS Staff Publications 2022
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Endocranial morphology of Liaoceratops yanzigouensis (Dinosauria: Ceratopsia) from Early Cretaceous Jehol Biota of Liaoning in China
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RBINS Staff Publications 2022
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Reassessment of the morphology and taxonomic status of the varanid lizard Saniwa orsmaelensis from the early Eocene of Northwest Europe
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Saniwa is an extinct genus of varanid lizard from the Eocene of North America and Europe. It is the sister taxon to the crown-group Varanus. Up to now, only one poorly known species is recognized from Europe, Saniwa orsmaelensis from the earliest Eocene of Dormaal, Belgium. This species originally named by Louis Dollo nearly a century ago, is the earliest varanid of Europe. Unfortunately, the material was limited to vertebrae with only preliminary description and no figure provided, except for one dorsal vertebra that later has been designated as the lectotype. Here we describe and illustrate new fossil specimens collected from Dormaal and other early Eocene localities of the Paris Basin, France, including dentary and maxilla fragments as well as skull material, allowing to reassess the validity of the European taxon. These fossils allow further comparisons with the type-species, Saniwa ensidens, from the late early Eocene Bridger and Green River formations of Wyoming and to propose a new diagnosis for S. orsmaelensis. The occurrence of S. orsmaelensis is restricted to the early Eocene of Northwest Europe and its geographic origin is unresolved because the earliest record of Saniwa in North America is also from the earliest Eocene. The brief presence of varanid lizards in the European Paleogene could result from two major climatic events. At the Paleocene Eocene Thermal Maximum, large biotic interchanges occurred in the northern hemisphere allowing new dispersals into Europe. However, at the end of the Eocene, thermophilic lizards disappeared due to cooler conditions. Another hypothesis for their disappearance could be the competition that occurred with other anguimorph lizards. Grant Information: This abstract is a contribution to the Belspo Brain network project BR/121/A3/PalEurAfrica funded by the Belgian Science Policy Office.
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RBINS Staff Publications 2018
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New data on the Early Eocene Mammals and other vertebrates from the Cambay Shale Formation exposed in Lignite Mines of Gujarat, Western India
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Excavations since 2004 in the early Eocene Cambay Shale Formation at Vastan, Mangrol, and Tadkeshwar open-cast lignite mines in Gujarat, western India, have yielded thousands of vertebrate specimens of terrestrial mammals, lizards, snakes, frogs, and birds as well as elasmobranch and teleost fishes. Here we report new fossils from the currently active Tadkeshwar mine discovered from several layers intercalated at different heights between the two major lignite seams. Most of them belong to taxa already described from the nearby Vastan and Mangrol mines, such as the adapoid primate Marcgodinotius indicus, the hyaenodontan Indohyaenodon raoi, the tillodont Anthraconyx hypsomylus, the perissodactyl-like mammal Cambaytherium thewissi, the agamid lizard Tinosaurus indicus, the palaeophiid snake Palaeophis vastaniensis, the caenophidian snakes Procerophis and Thaumastophis, and the bird Vastanavis. The presence of these taxa in the three mines and at different levels suggests that the deposits between the two major lignite seams represent a relatively short time span and a single mammal age. Among the new specimens from Tadkeshwar are well-preserved jaws of a new condylarth-like mammal, a new adapoid primate, and a small tapiroid perissodactyl. Most vertebrate taxa of the Cambay Shale Formation are of west European affinities; some of them seem to be endemic to India, and a few are of Gondwanan affinities, such as mesoeucrocodylians and the giant madtsoiid snake Platyspondylophis, attesting that the early Eocene was an important period in India during which Laurasian taxa coexisted with relict taxa from Gondwana before the India-Asia collision. Grant Information: Funded by Leakey Foundation, National Geographic Society, Wadia Institute of Himalayan Geology, and Belgian Science Policy Office (project BR/121/A3/PalEurAfrica)
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RBINS Staff Publications 2018
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Supposedly lost syntype of the rough-toothed dolphin (Steno bredanensis (Lesson, 1828)) traced back at the Ghent University Museum
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RBINS Staff Publications 2016
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Towards a cross-border hydrogeological model: harmonized data integration within the H3O-projects
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RBINS Staff Publications
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PSI analysis of TSX archive data for urban geohazard risk management: preliminary results from Brussels
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RBINS Staff Publications
