| 1. |
- Lazarova, Maria, et al.
(författare)
-
A 5000-year pollen and plant macrofossil record from the Osogovo Mountain, Southwestern Bulgaria : Vegetation history and human impact
- 2015
-
Ingår i: Review of Palaeobotany and Palynology. - : Elsevier BV. - 0034-6667 .- 1879-0615. ; 223, s. 1-9
-
Tidskriftsartikel (refereegranskat)abstract
- Pollen and plant macrofossil analyses were performed on a sequence 105 cm deep obtained from a peat bog (1750 m) that is located above the present timber-line in the Osogovo Mountain, Southwestern Bulgaria. The palaeovegetation reconstruction, supported by a radiocarbon chronology, revealed the vegetation dynamics and human impact during the last 5000 years. The peat bog formed when a coniferous belt of Abies alba and Pinus (Pinus sylvestris, Pinus nigra) covered the high mountain slopes. Charcoal fragments indicate the presence of a broad-leaved tree community composed of Quercus, Corylus, Carpinus, Tilia, Acer and Ulmus at lower altitudes. Stands of Fagus sylvatica in places with higher air and soil humidity, like river valleys and deep ravines, became established. The pollen assemblages after c. 3200 cal. BP record an important change in the forest composition that led to the replacement of the conifers, mostly A. alba, by the invading communities of F. sylvatica. The reasons for this replacement included factors related to both climate change and anthropogenic disturbance. During the last centuries a large-scale degradation of the woodlands in the mountain has occurred. On a regional scale the palaeoecological evidence is compared with information from palynological, archaeological and historical sources in Southwestern Bulgaria.
|
|
| 2. |
- Tonkov, Spassimir, et al.
(författare)
-
A NEW LATE HOLOCENE POLLEN DIAGRAM FROM VITOSHA MOUNTAIN. VEGETATION HISTORY AND ANTHROPOGENIC IMPACT
- 2016
-
Ingår i: Comptes Rendus de l'Academie Bulgare des Sciences / Proceedings of the Bulgarian Academy of Sciences. - 1310-1331 .- 2367-5535. ; 69:3, s. 327-336
-
Tidskriftsartikel (refereegranskat)abstract
- Pollen analysis was performed on a core collected from a peat bog near the touristic hut Kumata in Vitosha Mountain. For the first time palynological information from this mountain was combined with a detailed radiocarbon chronology for the last 1400 years and quantitative determination of microcharcoal particles as paleoecological evidence for forest fires. Between 600 and 1200 years AD the surroundings of the peat bog were overgrown by a dense Picea abies forest with an admixture of Pinus and Abies alba. Mixed oak forests with Carpinus betulus and Corylus were distributed at lower altitudes. A large-scale disturbance in the coniferous and deciduous forest belts started after ca. 1500 years AD. The areas occupied by the conifers were considerably reduced and subsequently colonized by grasses and stands of Juniperus. The peak of microcharcoal particles suggests the existence of forest fires caused by humans to enlarge pasture land. The last 300 years marked the strongest intensification of the anthropogenic impact in all vegetation belts.
|
|
| 3. |
|
|
| 4. |
- Tonkov, Spassimir, et al.
(författare)
-
Lateglacial to Holocene vegetation development in the Central Rila Mountains, Bulgaria
- 2016
-
Ingår i: The Holocene. - : SAGE Publications. - 0959-6836 .- 1477-0911. ; 26:1, s. 17-28
-
Tidskriftsartikel (refereegranskat)abstract
- The vegetation history of the Central Rila Mountains for the last 14,000years was reconstructed by means of pollen analysis and radiocarbon chronology of a core retrieved from Lake Manastirsko-2 (2326m). The Lateglacial landscape was dominated by open herb vegetation composed of Artemisia, Chenopodiaceae, Poaceae, and other cold-resistant herbs (14,000-11,700 cal. yr BP). Stands of Pinus, Betula, and Juniperus-Ephedra shrubland partly enlarged during the Lateglacial interstadial. Pioneer forests of Betula with Pinus and Juniperus occupied barren soils in the early Holocene (11,700-7900 cal. yr BP), while mixed oak forests with Tilia, Ulmus, Acer, and later on Corylus spread at lower elevations. A coniferous forest belt with Pinus sylvestris, Pinus peuce, and Abies developed after 7900 cal. yr BP in the conditions of milder winters, cooler summers, and increase in precipitation. The late Holocene dynamic vegetation changes were associated with the invasion of Picea abies after 3400 cal. yr BP, while Fagus communities slightly enlarged in the river valleys. Indications of human activities are visible in the pollen diagram since the Late Bronze Age' (3400-3200 cal. yr BP). The vegetation development in the study area followed a similar pattern when compared with palynological and macrofossil records from other parts of the Rila and the adjacent Northern Pirin Mountains. On a larger geographical scale, the postglacial vegetation history of the Rila Mountains displays common features with sites in the Romanian Carpathians, whereas the differences observed are result of the location of tree refugia, competing abilities, climate changes, and human activities.
|
|
| 5. |
- Tonkov, Spassimir, et al.
(författare)
-
On the Holocene vegetation history of the Central Rila Mountains, Bulgaria : The palaeoecological record of peat bog Vodniza (2113 m)
- 2018
-
Ingår i: Review of Palaeobotany and Palynology. - : ELSEVIER SCIENCE BV. - 0034-6667 .- 1879-0615. ; 250, s. 16-26
-
Tidskriftsartikel (refereegranskat)abstract
- Information on the Holocene vegetation history of the Central Rila Mountains for the last 10,000 years was obtained by means of pollen and fossil stomata analyses of a 500 cm core retrieved from peat bog Vodniza (2113 ma.s.l.), and supported by radiocarbon chronology. The early Holocene afforestation started with an initial Betula phase with stands of Juniperus and Pinus which occupied barren soils (10,000-8300 cal. yrs. BP) while deciduous oak forests with abundant Tilia, Ulmus, Acer, and later on Corylus, spread at lower elevations. During the Holocene climatic optimum (8300-6000 cal. yrs. BP) the conifers Pious (Pious sylvestris, Pinus mugo, Pinus peuce) and Abies expanded at the expense of the birch and oak forests. The tree line was running above 2100 m comparable to the present-day situation and started to descend after ca. 3200 cal. yrs. BP mostly due to human impact. The last tree which penetrated into the coniferous belt after 3400 cal. yrs. BP and reached altitudes of 2000-2100 m, confirmed by the find of fossil stomata, was Picea abies. Its maximal distribution was achieved between 2250 and 1100 cal. yrs. BP, alongside with some enlargement of beech communities. The first indications of stockbreeding and other human activities in the Central Rila Mountains were recorded since 3400-3200 cal. yrs. BP (Late Bronze Age). The vegetation reconstruction during the Holocene followed a pattern coherent with the information from the Northern Pirin and partly from the Western Rhodopes Mountains. The palaeoecological evidence from the Rila Mountains could be compared in broad lines with the high quality data obtained from the Romanian Carpathians by the application of multi-proxy research approach.
|
|
