The vanished Alnus-dominated forests along the Tyrrhenian coast

Folia Geobotanica, 2000

Vegetation development in the lowland floodplain aider carr "Na bahnt" (eastern Bohemia, the Czech Republic) has been studied by means of pollen and macrofossil analyses and combined with vegetation analysis performed over the last 70 years. Local successional changes started with an oxbow lake (160 cai BC) which has later terrestrialised (630 cai AD). Then it changed from a typical alluvial fen into a Sphagnum--dominated spring mire (950 cal AD) supplied by water arising from a river terrace surrounding the locality from three sites. In the centre of this wetland a small patch of alder carr developed (100 cal. AD), showing some tendency towards cyclic succession. The alder carr alternated several times with an open Carex fen (1100 cal AD to recenO. The last fen-to-aider carr transition has been documented by direct observation during this century. Possible autogenic and ailogenic factors driving the succession are discussed. The model of autogenic cyclic succession corresponds well with direct field observations and can be used to interpret aider cart structure, its dynamics, and function.

Applied Vegetation Science, 2015

Aim: Formalized classifications synthesizing vegetation data at the continental scale are being attempted only now, although they are of key importance for nature conservation planning. Therefore, we aim to provide a vegetation classification and to describe the main biogeographical patterns of floodplain forests and alder carrs in Europe.

Quaternary International, 2016

Pollen analysis and radiocarbon dating of a core from northern Iran enable reconstructing the past three millennia of vegetation dynamics of the Caspian lowlands and Alborz foothills of central northern Iran as a function of Caspian Sea level oscillations, climate change and human impact. The high values of ALNUS pollen and a diverse assemblage of non-pollen palynomorphs indicate that during most of the time span covered by the record a wet eutrophic to mesotrophic alder (Alnus cf. glutinosa) carr was present at the coring site. Only at the onset of the 2600-BP highstand event tree growth was hampered because of inundation. Our findings (including calcareous gyttja with remains of Charophytes; remnants of molluscs, freshwater snails, Foraminifera, Ostracoda, Algae and sponges) indicate that the highstand extended to and culminated in the period 2100 to 1900 calBP. Wingnut (Pterocarya fraxinifolia), which was a major component in the vegetation composition of the Caspian lowland from the beginning of the record, strongly decreased after ca. 1200 calBP, most probably due to a drier or colder climate. ARTEMISIA and CHENOPODIACEAE and AMARANTHACEAE (C-A) show fluctuating and largely parallel values throughout the record, suggesting the natural co-occurrence and similar ecology of their corresponding plants in the coastal areas under the influence of Caspian Sea transgressions. The steep slopes south of the mire were probably most of the time covered by a species-rich deciduous forest predominated by hornbeam (Carpinus betulus) and beech (Fagus orientalis) accompanied by oak (Quercus castaneifolia), elms (Ulmus glabra/U. carpinifolia), Persian ironwood (Parrotia persica), maples (Acer velutinum/A. cappadocicum), box tree (Buxus hyrcana), grape (Vitis vinifera), ash (Fraxinus excelsior), and lime (Tilia platyphyllos). However, climate change and human impact triggered significant vegetational changes both in the lowland and the hilly upland. The first signal of human activity in the area can be inferred from findings of pollen of Juglans regia at ca. 2350 calBP and slightly later of Fagopyrum esculentum. A dramatic decline of tree pollen over the last centuries suggests that tree cover of both the lowland and upland landscape surrounding the mire declined and forests were increasingly replaced by open vegetation most likely as a result of intensified human activities.

Quaternary International, 2017

Due to the scarcity of reliable palaeoecological and climatic proxy records from the Eastern Baltic covering the Holocene, there has been increased interest for multi-proxy studies in the region to detect local to regional environmental changes. The Cepkeliai wetland complex, SE Lithuania, provides an uninterrupted Holocene sediment sequence, which is used here to reconstruct palaeoenvironmental history in the southern part of the Eastern Baltic. High-resolution lithological (LOI, magnetic susceptibility), palaeobotanical (pollen, plant macrofossil, tree rings), isotopic (14 C) and geochemical data were employed to reconstruct the peculiarities of vegetation and hydroclimate dynamics, as well as to discuss results in a local to regional context. Temporal lags of environmental reactions to Holocene climatic warming were recorded both in lithostratigraphical and biostratigraphical data, thus confirming regional significance of this phenomenon. A deep meso-to eutrophic basin e influenced by high surface runoff and surrounded by early boreal forest e existed at the site until about 11,300 cal BP. Thereafter, immigration of thermophylous taxa such as Ulmus (since 10,700e10,800 cal BP), Corylus (since 10,400 e10,300 cal BP), Tilia and Quercus (after 9500 cal BP) as well as changes in the limnic environment point to an amelioration of the environmental situation, i.e. to a predominance of a warm and dry climatic regime. Instability of palaeobotanical and lithological records suggests that environmental anomalies of the Early Holocene occurred at about 11,200e11,000 cal BP, 10,600e10,300 cal BP, and 8200-7800 cal BP. These anomalies are thus contemporaneous with the pronounced climatic shifts (i.e. dry and cool intervals) known at the continental scale. An expansion of Picea was facilitated by the 8200-7800 cal BP climatic shift whereas early establishment of Alnus glutinosa suggests an onset of a wet interval (10,200 cal BP) which was previously unknown in the area. The stepwise lowering of the water table noted at about 7300e7200 and 6600e6700 cal BP, with the termination of the lake-phase and change to telmatic environment after 6100 cal BP, proves the positive reaction of the site to the dry climatic reversals of the Middle Holocene. Following the decay of the broad-leaved thermophilous forest after 4500 cal BP, a cold climatic reversal favored the formation of a diverse mosaic-like vegetation which was then replaced by homogenous Pinus-Picea vegetation after 3400 cal BP. The climatic and site-specific factors have been playing a leading role in the development of the site whereas signals of human interference remain negligible.

International Journal of Earth Sciences

Here, we present a palaeoecological study from the Valdai Hills to examine the Holocene dynamics of forest and lake ecosystems as apparent from the isolated Lake Chernoye, which developed on an island within the greater Lake Seliger middle of the East European Plain, Russia. Palaeobotanical (plant macrofossils and pollen), geochemical and quartz grains analyses, complemented with radiocarbon dating, were carried out on a 370-cm-long sediment core. Our study involves a period between ca. 11,000 and 2100 cal. yr BP, with four main results: (1) The development of Lake Chernoye began in ca. 11,000 cal. yr BP, after the melting of buried dead-ice blocks intensified by the Early Holocene warming. As pioneer plants, Chara sp., Isöetes and C. demersum, appeared in the water with a high Ca and Mg content. High values of Pinus, Artemisia, Betula nana and Chenopodiaceae pollen may indicate the remains of cold flora that have occurred in the Younger Drays in this region. (2) Between 8000 and 6500 cal. yr BP, water level decreased as apparent from a sediment hiatus. This may be connected with the Holocene thermal maximum and final melting of the buried dead-ice block. Lower water level at that time is documented by the spreading of Najas marina, N. flexilis and Potamogeton pusillus, which are all submerged plants growing in eutrophic shallow water. Significant changes in the forest ecosystem also took place in this time frame: an increase of Quercus, Corylus and Alnus was accompanied by a decrease of Pinus. (3) A decrease in deciduous tree pollen (Ulmus, Quercus, Tilia) and an increase in coniferous tree pollen (Picea and Pinus) at ca. 4200 cal. yr BP and ca. 2700 cal. yr BP are associated with the climate cooling documented by multiproxy records in many sites in Europe. (4) Location of the lakeon the isolated island did not lead to different vegetation pattern development, since this latter is similar to the other sites in the East European Plain.

Quaternary International, 2009

Multiproxy data (pollen, diatoms, plant macrofossils, 14 C and loss on ignition measurements) obtained from two cores (Petraši unai and Juodonys) were used to reconstruct the pattern of Lateglacial and early Holocene environmental changes in NE Lithuania.

Turkish Journal of Earth Sciences

During the Oligocene, in addition to mangrove pollen, new pollen types such as Alnus (morpho-species Polyvestibulopollenites verus), Carya (morpho-species Subtriporopollenites simplex), Calamus (morpho-species Dicolpopollis kockelii), Elaeagnaceae (morpho-species Boehlensipollis hohli) and Hipophae (morpho-species Slowakipollis hippophaëoides) appeared (Akkiraz &Akgün 2005; İslamoğlu et al. 2010; Kayseri 2009; Akkiraz et al. 2011). In contrast most Eocene species disappeared in the Oligocene. This study is focused on the Oligocene Thrace Basin, situated between the Tethyan and Paratethyan realms (Rögl 1998; İslamoğlu et al. 2010). From Palaeocene to Middle Eocene times, much of the marine Thrace Basin was filled with thick olistostrome complexes (Özcan et al. 2010). According to Görür and Okay (1996), the Thrace Basin developed as a fore-arc basin during the Middle Eocene and Oligocene. During the Early Oligocene the closure of seaways between the Eastern Paratethys and Mediterranean is marked in Thrace by the deposition of dark shales with fish remains (Rögl 1998) (Figure 1). During the middle Oligocene the Paratethys returned to open marine conditions (Rögl 1999) (Figure 1). Up to the end of Rupelian the Thrace Basin was still part of the Tethys Sea. The regression started during the late Oligocene (mammal zone MP 26) (Bozukov et al. 2009; İslamoğlu et al. 2010). With regression, marine coastal swamps should

Quaternary …, 2012

This paper presents a fresh examination of a pollen profile from Ustków (central Poland), which after preliminary results was thought to span a period between the Early Eemian (MIS 5e) and the upper Pleni-Weichselian (MIS 3). The newly obtained results confirmed the age assessment of the bottom series, but revealed a much older age for the uppermost part of the profile as far back as the Rederstall stadial (MIS 5b). Palynological research showed slightly different patterns of vegetation in comparison to other sites located in Central Europe. Among them were an early Ulmus maximum coinciding with the Betula optimum in the Early Eemian, a relatively late optimum of Taxus baccata during the decline of the Middle Eemian, and a distinct division of the older part of the Late Eemian into phases of Abies-Picea and Picea-Pinus forest domination. The Herning stadial (MIS 5d) falls into a typical bipartition reflected by heathland domination during its older part and the prevalence of Juniperus thickets and Artemisia-Poaceae steppe during its younger part, which makes this succession similar to those from northern Germany. The pollen spectra reflecting the Brørup interstadial (MIS 5c) distinctly revealed an intra-Brørup cold oscillation rarely detected in profiles from Central Europe and a period of Larix dominated forests during the latest part of the interstadial (extraordinarily high percentages exceeding 15% of the total pollen sum). Local pollen taxa, together with the lithological composition of deposits, revealed that there was a water body in the area during the periods of the Late Saalian/Early Eemian transitioneMiddle Eemian (the decline of the Tilia phase), the Herning stadial (MIS 5d), the early Brørup interstadial (MIS 5c), and the Rederstall stadial (MIS 5b). Between these time-intervals a poor and/or rich fen and/or bog functioned.

Philippika - Marburger altertumskundliche Abhandlungen, 2009

Palynological investigations on Holocene profiles from Lake Voulkaria and Katouna Fen, Western Greece, show that deciduous oak species dominated the natural vegetation of the coastal area of northern Akarnania in the Holocene. The profile from Lake Voulkaria shows that until ca. 7000 BC. Pistacia occurred abundantly, other evergreen woody species were rare. At ca. 6300 cal. BC an expansion of Carpinus orientalis/Ostrya can be observed. Around ca. 5300 cal. BC spreading of Erica indicates a change to a drier climate and/or first human impact. Since ca. 3450 cal. BC an increase of evergreen shrubs clearly indicates land-use. Both sites show a distinct period of prevailing Phillyrea maquis, which can be attributed to human impact in the Classical period. At the same time, brackish molluscs indicate the construction of a connection between the Ionian sea and Lake Voulkaria. The deciduous Quercus woodland recovered as human impact decreased in the area and prevailed until the large deforestation in modern times.

Journal of Quaternary Science, 2017

We report pollen-stratigraphical evidence for an abrupt, episodic and widespread population decline of alder (Alnus), one of the most common boreal tree genera, during the medieval period in northern Europe. Decline of alder pollen values was observed both in forest hollow pollen records reflecting local vegetation of pristine forests and in pollen percentage and pollen accumulation data from lake sediments. The event began roughly at AD 600 and the recovery took place at AD 1000. Human impact is an unlikely cause because the decline is specific to alder and there is no evidence for a concurrent episode of human impact. It is possible that the decline was caused or influenced by a severe drought. Another potential cause is a sudden, widespread pathogen outbreak, especially as alder is known to be sensitive to the impacts of fungal pathogens such as the oomycete Phytophthora.