Middle- to late-Holocene fire history and the impact on Mediterranean pine and oak forests according to the core RF93-30, central Adriatic Sea

The Holocene ◽  
2019 ◽  
Vol 29 (8) ◽  
pp. 1362-1376 ◽  
Author(s):  
Anna Maria Mercuri ◽  
Assunta Florenzano ◽  
Rita Terenziani ◽  
Elisa Furia ◽  
Daniele Dallai ◽  
...  
Keyword(s):  
Bronze Age ◽  
Late Holocene ◽  
Fire History ◽  
Last Millennium ◽  
Terrestrial Vegetation ◽  
Fire Event ◽  
Po River ◽  
Good Correspondence ◽  
Anthropogenic Fire ◽  
The Impact

The high-resolution Adriatic RF93-30 core shows changes in its microcharcoal record, which correlate to terrestrial fires from the last 7000 years. Pollen and microcharcoals were transported by wind and fluvial transport from the sedimentary basin, including the Po River and other rivers flowing into the sea off the Italian east coast. Charcoal particles and pollen were counted in the same samples, and the maximum breadth and length of charcoal particles were measured. Microcharcoals with large dimensions were taken as fire indicators occurring along the near coast, as they probably arrived from short distances, the nearest being in Apulia, in southern Italy. The age–depth model was developed within the multidisciplinary PALICLAS project. Several potential fire activity increases (PFAIs) were visible as peaks in the diagram. The oldest PFAIs occurred at the middle Holocene (approximately dated to c. 6730, 5430, 4150 cal BP), others occurred at the late Holocene ( c. 3760, 2660, 2240, 2030, 1930, 1510 cal BP) and during the last millennium ( c. 900–865, 530, 120–96 cal BP). The two oldest peaks in the diagram, occurring in the 7th–6th millennia, showed the highest contribution of charcoal corresponding to the highest values of arboreal pollen (AP) in the sedimentary record. Although the CHAR peaks did not represent a single fire event, the diagram suggests a good correspondence between paleofire activity and terrestrial vegetation biomass during this early phase. Pollen containing black particles was observed, which suggested some grains were transported in suspension with winds from burned woods. The main unambiguous anthropogenic fire causation would have occurred during the last four millennia. From 4.2 ka, it became hard to disentangle climate and Bronze Age actions. Technology and human activity probably improved the pace of fire events, especially involving oak woods, with evidence of an increase of CHAR during the last millennium.

scholarly journals Holocene Carbon Accumulation, Wetness Shifts and Fire History at Three Threatened Peatlands in Carmarthenshire, SW Wales, UK

2021 ◽  
Author(s):  
◽  
Kristy Holder
Keyword(s):  
Bronze Age ◽  
Environmental History ◽  
Late Holocene ◽  
Fire History ◽  
Developmental Change ◽  
Management Strategies ◽  
Carbon Accumulation ◽  
Public Understanding ◽  
Valuable Insight ◽  
Holocene Thermal Maximum

This project studies three peatlands in Carmarthenshire, SW Wales, UK (Figyn Common, Pyllau Cochion and Mynydd Bach) that are threatened by the impacts of continued human interference and projected climate change. The threat that human and climatic forces pose on peatland carbon storage has become a significant global concern in the fight against greenhouse gas climate forcing. A record of their Holocene environmental and developmental history is obtained via a multi-proxy analysis, including carbon:nitrogen ratio (C:N), humification, charcoal and carbon accumulation. Potential drivers of developmental change and temporal carbon accumulation are also explored. Fen peat inception occurred at ca. 10800, ca. 9730 and ca. 7960 cal yrs. BP at Figyn Common, Pyllau Cochion and Mynydd Bach (respectively). The fen to bog transition (FBT) is dated to ca. 5120 cal yrs. BP at Pyllau Cochion and ca. 4480 cal yrs. BP at Figyn Common. The FBT does not take place at Mynydd Bach. Evidence of regional wet shifts during the late Holocene is found at ca. 2000 and ca. 850 cal yrs. BP and a dry shift is detected at ca. 2400 cal yrs. BP. All three sites demonstrate evidence of burning through the Mesolithic period and on-site burning increases at all sites after ca. 4500 cal yrs. BP. At Mynydd Bach, fire activity is linked to Bronze Age ritual practices. Long-term Apparent Rates of Carbon Accumulation (LARCA) for the three sites are 23.71, 13.09 and 42.55 g C m -2 yr -1 for Pyllau Cochion, Mynydd Bach, and Figyn Common (respectively). Carbon accumulation is high in the early Holocene, likely in response to the faster accumulation rates associated with early fen stages. However, in contrast to other northern peatlands carbon accumulation is lower during the Holocene Thermal Maximum and higher in the late Holocene when neoglacial cooling persisted. This is most likely because they sit close to the bioclimatic threshold of peatland formation in a UK context. Furthermore, an association between shorter-term wet shifts and higher carbon accumulation is found at several points in the Pyllau Cochion and Figyn Common record. The findings imply that the sites accumulate more carbon during wetter/cooler conditions and less when it is warmer/drier. Therefore, it is likely that they will experience reductions in carbon accumulation in response to projected warming during the 21st century. This adds support to the widely reported theory in the literature that peripheral peatlands will be the first to see losses in their carbon sequestration capacity because of predicted warming. This work contributes to the public understanding of the environmental history of these peatlands and the results provide valuable insight for conservation and future management strategies along with an assessment of carbon projections.

Late Holocene vegetation and environments of the Mersey Valley, Tasmania

2007 ◽  
Vol 55 (1) ◽  
pp. 74 ◽  
Author(s):  
Patrick T. Moss ◽  
Ian Thomas ◽  
Michael Macphail
Keyword(s):  
Late Holocene ◽  
Fire History ◽  
Climatic Factors ◽  
Regional Climate ◽  
Sedimentation Rates ◽  
Exotic Plant ◽  
Charcoal Analysis ◽  
Climate Signal ◽  
The Past ◽  
The Impact

A record of vegetation and environmental change over the past 3000 years was obtained through pollen and charcoal analysis of sediments from a grassy plain in the Mersey Valley, Tasmania. The results tentatively suggest that Aborigines had an impact on the environment of the Mersey Valley, although the scale of the impact is difficult to quantify owing to complexities associated with the fire history and sedimentary processes. In addition, a strong regional climate signal (drier late Holocene environments) was observed, suggesting that both anthropogenic and climatic factors are required to explain pre-European environments. The study also showed the dramatic impact European settlers had on the Australian environment, with massive land clearance, introduction of exotic plant types and increased sedimentation rates.

Postglacial Vegetation and Fire History in the Chirripó Páramo of Costa Rica

1993 ◽  
Vol 40 (1) ◽  
pp. 107-116 ◽  
Author(s):  
Sally P. Horn
Keyword(s):  
Costa Rica ◽  
Late Holocene ◽  
Fire History ◽  
Charcoal Analysis ◽  
Climatic Warming ◽  
Lowland Forest ◽  
Fire Activity ◽  
Ice Retreat ◽  
The Impact ◽  
Cordillera De Talamanca

AbstractPollen and charcoal analysis of a 5.6-m sediment core from Lago de las Morrenas (9°29′N, 83°29′W; 3480 m) provides evidence of postglacial vegetation and fire history in the highlands of the Cordillera de Talamanca, Costa Rica. The site is presently surrounded by treeless páramo vegetation and apparently has been so since deglaciation about 10,000 yr B.P. Pollen spectra suggest no pronounced changes in vegetation since ice retreat. Fires set by people or lightning have burned the páramo repeatedly, with fire activity probably highest during the late Holocene, but these fires have not carved páramo from forest. Pollen percentages for Gramineae and other páramo taxa decline upward, whereas percentages for certain subalpine, lower montane, and lowland forest taxa increase slightly; these changes may reflect the impact of prehistoric human activity or slight upslope migrations of forest taxa owing to climatic warming. There is no clear evidence of higher timberlines during the mid-Holocene.

Investigating Burnt Mounds in Clydesdale during Motorway Construction

1998 ◽  
Vol 21 (1) ◽  
pp. 1-28
Author(s):  
John A Atkinson ◽  
Camilla Dickson ◽  
Jane Downes ◽  
Paul Robins ◽  
David Sanderson
Keyword(s):  
Bronze Age ◽  
Research Strategy ◽  
Archaeological Evidence ◽  
Radiocarbon Dates ◽  
Short Account ◽  
And Function ◽  
The Impact ◽  
The Bronze Age

Summary Two small burnt mounds were excavated as part of the programme to mitigate the impact of motorway construction in the Crawford area. The excavations followed a research strategy designed to address questions of date and function. This paper surveys the various competing theories about burnt mounds and how the archaeological evidence was evaluated against those theories. Both sites produced radiocarbon dates from the Bronze Age and evidence to suggest that they were cooking places. In addition, a short account is presented of two further burnt mounds discovered during the construction of the motorway in Annandale.

scholarly journals 8,000 years of climate, vegetation, fire and land-use dynamics in the thermo-mediterranean vegetation belt of northern Sardinia (Italy)

2021 ◽  
Author(s):  
Tiziana Pedrotta ◽  
Erika Gobet ◽  
Christoph Schwörer ◽  
Giorgia Beffa ◽  
Christoph Butz ◽  
...  
Keyword(s):  
Land Use ◽  
Bronze Age ◽  
Fire History ◽  
Vegetation History ◽  
Juglans Regia ◽  
Fire Disturbance ◽  
Lake Productivity ◽  
The Past ◽  
Evergreen Oak ◽  
The Bronze Age

AbstractKnowledge about the vegetation history of Sardinia, the second largest island of the Mediterranean, is scanty. Here, we present a new sedimentary record covering the past ~ 8,000 years from Lago di Baratz, north-west Sardinia. Vegetation and fire history are reconstructed by pollen, spores, macrofossils and charcoal analyses and environmental dynamics by high-resolution element geochemistry together with pigment analyses. During the period 8,100–7,500 cal bp, when seasonality was high and fire and erosion were frequent, Erica arborea and E. scoparia woodlands dominated the coastal landscape. Subsequently, between 7,500 and 5,500 cal bp, seasonality gradually declined and thermo-mediterranean woodlands with Pistacia and Quercus ilex partially replaced Erica communities under diminished incidence of fire. After 5,500 cal bp, evergreen oak forests expanded markedly, erosion declined and lake levels increased, likely in response to increasing (summer) moisture availability. Increased anthropogenic fire disturbance triggered shrubland expansions (e.g. Tamarix and Pistacia) around 5,000–4,500 cal bp. Subsequently around 4,000–3,500 cal bp evergreen oak-olive forests expanded massively when fire activity declined and lake productivity and anoxia reached Holocene maxima. Land-use activities during the past 4,000 years (since the Bronze Age) gradually disrupted coastal forests, but relict stands persisted under rather stable environmental conditions until ca. 200 cal bp, when agricultural activities intensified and Pinus and Eucalyptus were planted to stabilize the sand dunes. Pervasive prehistoric land-use activities since at least the Bronze Age Nuraghi period included the cultivation of Prunus, Olea europaea and Juglans regia after 3,500–3,300 cal bp, and Quercus suber after 2,500 cal bp. We conclude that restoring less flammable native Q. ilex and O. europaea forest communities would markedly reduce fire risk and erodibility compared to recent forest plantations with flammable non-native trees (e.g. Pinus, Eucalyptus) and xerophytic shrubland (e.g. Cistus, Erica).

scholarly journals Late-Holocene forest resilience in the central Pyrenean highlands as deduced from pollen analysis of Lake Sant Maurici sediments

The Holocene ◽  
2021 ◽  
pp. 095968362110332
Author(s):  
Valentí Rull ◽  
Núria Cañellas-Boltà ◽  
Teresa Vegas-Vilarrúbia
Keyword(s):  
Bronze Age ◽  
Middle Ages ◽  
Iron Age ◽  
Late Holocene ◽  
High Elevation ◽  
Roman Period ◽  
High Mountain ◽  
Southern Central ◽  
Central Pyrenees ◽  
The Middle Ages

Palynological analysis of the last ca. 4300 cal year BP using a sediment core taken from high mountain (ca. 1900 m elevation) Lake Sant Maurici sediments (southern-central Pyrenees) showed remarkable vegetation constancy during the Bronze Age and the Middle Ages. Records of the Iron Age and the Roman period were missing due to a major sedimentary gap. During the studied periods, the vegetation around the lake was largely dominated by pine ( Pinus) forests with birch ( Betula), oak ( Quercus) and hazel ( Corylus) trees, as is the case today. The composition of these forests and the abundance of their components remained quite stable, despite the occurrence of temperature and moisture shifts. The degree of human disturbance, notably that of pastoralism and cereal cultivation by scattered and temporary settlements, was very low and had little or no effect on the dominant forests. This situation contrasts with most high-elevation (subalpine and alpine) environments of the central Pyrenees that were massively anthropized during the Middle Ages. Further research should be aimed at finding sediments corresponding to the Iron Age and the Roman period to verify whether the vegetation constancy can be extended throughout the Late-Holocene. Past records of this type may allow the estimation of natural and anthropogenic thresholds for irreversible forest changes, which would be useful for conservation purposes.

BEYOND BUTRINT: THE ‘MURSI SURVEY’, 2008

2016 ◽  
Vol 111 ◽  
pp. 269-297
Author(s):  
Richard Hodges ◽  
Erika Carr ◽  
Alessandro Sebastiani ◽  
Emanuele Vaccaro
Keyword(s):  
Bronze Age ◽  
Late Antiquity ◽  
Short Report ◽  
Mediterranean Landscapes ◽  
Ancient City ◽  
History Of ◽  
Byzantine Period ◽  
The Creation ◽  
The Impact ◽  
The Town

This article provides a short report on a survey of the region to the east of the ancient city of Butrint, in south-west Albania. Centred on the modern villages of Mursi and Xarra, the field survey provides information on over 80 sites (including standing monuments). Previous surveys close to Butrint have brought to light the impact of Roman Imperial colonisation on its hinterland. This new survey confirms that the density of Imperial Roman sites extends well to the east of Butrint. As in the previous surveys, pre-Roman and post-Roman sites are remarkably scarce. As a result, taking the results of the Butrint Foundation's archaeological excavations in Butrint to show the urban history of the place from the Bronze Age to the Ottoman period, the authors challenge the central theme of urban continuity and impact upon Mediterranean landscapes posited by Horden and Purcell, inThe Corrupting Sea(2000). Instead, the hinterland of Butrint, on the evidence of this and previous field surveys, appears to have had intense engagement with the town in the Early Roman period following the creation of the Roman colony. Significant engagement with Butrint continued in Late Antiquity, but subsequently in the Byzantine period, as before the creation of the colony, the relationship between the town and its hinterland was limited and has left a modest impact upon the archaeological record.

scholarly journals Implementation of the biogenic emission model MEGAN(v2.1) into the ECHAM6-HAMMOZ chemistry climate model. Basic results and sensitivity tests

2016 ◽  
Author(s):  
Alexandra-Jane Henrot ◽  
Tanja Stanelle ◽  
Sabine Schröder ◽  
Colombe Siegenthaler ◽  
Domenico Taraborrelli ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Climate Model ◽  
High Sensitivity ◽  
Emission Model ◽  
Terrestrial Vegetation ◽  
Biogenic Emission ◽  
Tropical Regions ◽  
Global Emission ◽  
Empirical Coefficients ◽  
The Impact

Abstract. A biogenic emission scheme based on the Model of Emissions of Gases and Aerosols from Nature (MEGAN) version 2.1 (Guenther et al., 2012) has been integrated into the ECHAM6-HAMMOZ chemistry climate model in order to calculate the emissions from terrestrial vegetation of 32 compounds. The estimated annual global total for the simulation period (2000–2012) is 634 Tg C yr−1. Isoprene is the main contributor to the average emission total accounting for 66 % (417 Tg C yr−1), followed by several monoterpenes (12 %), methanol (7 %), acetone (3.6 %) and ethene (3.6 %). Regionally, most of the high annual emissions are found to be associated to tropical regions and tropical vegetation types. In order to evaluate the implementation of the biogenic model in ECHAM-HAMMOZ, global and regional BVOC emissions of the reference simulation were compared to previous published experiment results with the MEGAN model. Several sensitivity simulations were performed to study the impact of different model input and parameters related to the vegetation cover and the ECHAM6 climate. BVOC emissions obtained with the biogenic model are within the range of previous published estimates. The large range of emission estimates can be attributed to the use of different input data and empirical coefficients within different setups of the MEGAN model. The biogenic model shows a high sensitivity to the changes in plant functional type (PFT) distributions and associated emission factors for most of the compounds. The global emission impact for isoprene is about −9 %, but reaches +75 % for α-pinene when switching to PFT-dependent emission factor distributions. Isoprene emissions show the highest sensitivity to soil moisture impact, with a global decrease of 12.5 % when the soil moisture activity factor is included in the model parameterization. Nudging ECHAM6 climate towards ERA-Interim reanalysis has impact on the biogenic emissions, slightly lowering the global total emissions and their interannual variability.

scholarly journals An improved glyoxal retrieval from OMI measurements

2014 ◽  
Vol 7 (12) ◽  
pp. 4133-4150 ◽  
Author(s):  
L. M. A. Alvarado ◽  
A. Richter ◽  
M. Vrekoussis ◽  
F. Wittrock ◽  
A. Hilboll ◽  
...  
Keyword(s):  
Cross Sections ◽  
Anthropogenic Activities ◽  
Absorption Cross ◽  
Fire Event ◽  
Data Set ◽  
Polynomial Degree ◽  
Temperature Boundary ◽  
Sensitivity Tests ◽  
Radiative Power ◽  
The Impact

Abstract. Satellite observations from the SCIAMACHY, GOME-2 and OMI spectrometers have been used to retrieve atmospheric columns of glyoxal (CHOCHO) with the DOAS method. High CHOCHO levels were found over regions with large biogenic and pyrogenic emissions, and hot-spots have been identified over areas of anthropogenic activities. This study focuses on the development of an improved retrieval for CHOCHO from measurements by the OMI instrument. From sensitivity tests, a fitting window and a polynomial degree are determined. Two different approaches to reduce the interference of liquid water absorption over oceanic regions are evaluated, achieving significant reduction of the number of negative columns over clear water regions. The impact of using different absorption cross-sections for water vapour is evaluated and only small differences are found. Finally, a high-temperature (boundary layer ambient: 294 K) absorption cross-section of nitrogen dioxide (NO2) is introduced in the DOAS retrieval to account for potential interferences of NO2 over regions with large anthropogenic emissions, leading to improved fit quality over these areas. A comparison with vertical CHOCHO columns retrieved from GOME-2 and SCIAMACHY measurements over continental regions is performed, showing overall good consistency. However, SCIAMACHY CHOCHO columns are systematically higher than those obtained from the other instruments. Using the new OMI CHOCHO data set, the link between fires and glyoxal columns is investigated for two selected regions in Africa. In addition, mapped averages are computed for a fire event in Russia between mid-July and mid-August 2010. In both cases, enhanced CHOCHO levels are found in close spatial and temporal proximity to elevated levels of MODIS fire radiative power, demonstrating that pyrogenic emissions can be clearly identified in the new OMI CHOCHO product.

scholarly journals Numerical modelling of sediment transport in the Adriatic Sea

2014 ◽  
Vol 11 (3) ◽  
pp. 1391-1433 ◽  
Author(s):  
A. Guarnieri ◽  
A. J. Souza ◽  
N. Pinardi ◽  
P. Traykovski
Keyword(s):  
Sediment Transport ◽  
Adriatic Sea ◽  
Transport Model ◽  
Data Availability ◽  
Western Coast ◽  
Po River ◽  
Northern Adriatic ◽  
Coastal Belt ◽  
Italian Coasts ◽  
The Impact

Abstract. A new sediment transport model, considering currents, tides and waves is presented for the Adriatic Sea basin. The simulations concentrate on the winter of 2002–2003 because of field data availability and interesting intermittent processes occurrence. A process oriented analysis is performed to investigate the impact that Sirocco and Bora wind regimes have on sediment transport. The comparisons of the simulations with the observed data show that the model is capable to capture the main dynamics of sediment transport along the Italian coasts and the sediment concentration within the water column. This latter can reach values up to several g L−1, especially within the first centimetres above the bottom. The sediments are transported mainly southwards along the Italian coasts, consistently with the known literature results, except during Sirocco wind events, which can be responsible for reversing the coastal circulation in the northern area of the basin, and consequently the sediment transport. The resuspension of sediments is also related to the specific wave regimes induced by Bora and Sirocco, the former inducing resuspension events near the coasts while the latter causing a more diffused resuspension regime in the Northern Adriatic basin. Beside the realistic representation of short timescales resuspension/deposition events due to storms, the model was also used to investigate persistent erosion or deposition areas in the Adriatic Sea. Two main depocenters were identified: one, very pronounced, in the surroundings of the Po river delta, and another one a few kilometres off the coast in front of the Ancona promontory. A third region of accumulation, even if less intense, was found to be offshore the southernmost limit of the Gargano region. On the contrary the whole western coast within a distance of a few kilometres from the shore was found to be subject to prevailing erosion. The comparison with observed accumulation and erosion data shows that the model captures well the main depocenters in the domain and the erosion within the very coastal belt of the western side of the basin, but seems to be too erosive in a few areas, in particular those where the contribution of sediment inflow to the sea of some minor but intermittently important rivers is not considered in a realistic way as input to the model.

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