Human and climatically induced environmental change in the Mediterranean during the Medieval Climate Anomaly and Little Ice Age: A case from central Italy
Introduction
Global concern over future climate change and its potential impact on society has placed a focus on understanding the relationship between climate and human activity. There is no doubt that climate influences human activities through extremes such as droughts, freezes, and floods, as well as periods of stasis such as prolonged periods of mild or inclement climate Lamb, 1982, Ladurie, 1967, Ladurie, 1971, Pfister and Brázdul, 1999, Pfister and Brázdul, 2006). However, human use of the environment takes place within a local socio-economic context, and while some land use decisions may be constrained by climatic limitations, a broad set of human (e.g. culture and technology) and environmental factors influence land use practices. There is now general recognition that paleoenvironmental change within the Anthropocene is the complex result of both human activity and climate (Dearing et al., 2008, Coombes et al., 2009, Munoz et al., 2010, McCormick et al., 2012), and that unicausal explanations of cultural expansion or collapse are overly simplistic (Dincauze, 2000, O’Sullivan, 2008, Aimers, 2011, Izdebski et al., 2015). Reconstructing human-induced paleoenvironmental change remains a challenge because sources describing human use of the landscape are limited, and distinguishing human impacts from climatic impacts is not a trivial problem. To the extent that we can combine high-resolution physical proxies of paleoenvironmental reconstruction with detailed historical records from the same locality we have the potential to gain new insights into the role of climate and human activities in impacting environmental systems (Berglund, 2003, Dearing et al., 2008, Coombes et al., 2009, Harris, 2013, Izdebski et al., 2015, Kemp et al., 2015). To achieve this we approach local climate changes within an historical framework of longue durée (Leed, 2010).
The Medieval Climate Anomaly (MCA), between ∼900–1350 AD (Graham et al., 2011) and the subsequent Little Ice Age (LIA), between ∼1400 and 1850 AD (Mann, 2002) are arguably the two most important periods of recent climate change that impacted societies, particularly in Europe where the climatic influences have been extensively documented (Lamb, 1982, Ladurie, 1971, Pfister and Brázdul, 1999, Pfister and Brázdul, 2006). The Medieval period was also a time of dramatic socio-economic change with the development of new economic models, expansion of the role of the church through monasteries, and shifting political influences (Hodges, 2012). Europe is one of the few places with extensive written documents for >1000 years, providing an opportunity to compare the historical record of socio-economic activity with the physical proxy record of environmental and climate change. A rich documentary record exists in the Rieti region of central Italy, through monastic writings and community records (Leggio, 1986, Leggio, 1989, Leggio, 1992, Leggio, 1994, Leggio, 1995, Leggio, 2007, Leggio and Marinelli, 1995, Lorenzetti, 1989, Lorenzetti, 1990, Lorenzetti, 1994, Lorenzetti, 2009). In this paper we take advantage of the trove of medieval documents from the Rieti region in central Italy and compare this with a high-resolution paleoenvironmental reconstruction using multiple proxies from sediment cores recovered in the Rieti basin to interpret landscape change within the context of both climatic change and historical development. Our goal is to use this case to document abrupt environmental change in relation to the local history and regional climate in an effort to evaluate the extent to which these changes might be explained by socioeconomic factors, climate change, or the complex interaction of the two.
Rieti (Reate in Latin) was settled by the Sabini in the Early Iron Age ∼2800 years ago, although archaeological evidence indicates that the region was largely abandoned towards the end of the period with virtually no occupation by the time the Romans established a presence ∼300 BC (Cifani, 2003). The Rieti Basin is an intermontane depression in the Central Apennines (Fig. 1) connected with Rome by the ancient Via Salaria (Coccia et al., 1992). Water level in the basin was controlled by the elevation of a travertine sill at Marmore where the Velino River exits the basin (Calderoni et al., 1994) and local hydrologic engineering efforts have played a major role in environmental changes in the valley. During pre-Roman times the basin held one large lake, Lacus Velinus, though by early Roman time it is thought that the basin was an expansive wetland dotted with lakes (Lorenzetti, 1990, Calderoni et al., 1994). Written documents suggest that the Romans cut a channel through the travertine sill ∼270 BC to drain the basin for pasture and agriculture (Coccia et al., 1992). The basin has been continuously utilized for farming and pasture since then although maintaining drainage in the basin has been a continuous challenge. Following Roman occupation, the basin was controlled by the Ostrogoth until it fell to the Lombards in 590 AD. Monasteries have been important from an early time with the founding of the Farfa Monastery by the Benedictine Order between 550 and 560 AD and foundation of San Salvatore Maggiore Monastery within the Rieti basin in 735 AD (Leggio, 1992, Leggio, 1995). The monasteries controlled use of the lakes including fishing and shrimp production (Coccia et al., 1992). During this period the governance of the region was established through the Duchy of Spoleto (Leggio, 1992). In 774 AD Charlemagne conquered northern Italy and Rieti became the southern frontier of the Carolingian Empire. An important period of urbanization began about 1000 AD with the chartering of multiple fortified hill towns around the basin (Coccia et al., 1992). Throughout the Medieval period, community records and historic maps dating from the 16th century describe the successive phases of drainage works critical to preventing the basin from becoming a marsh (Leggio, 1992, Leggio, 1995, Leggio, 2007, Lorenzetti, 1990, Lorenzetti, 1994).
Today, four remnant lakes persist, Lago Lungo, Ripasottile, Ventina and Pieidiluco (Fig. 1). Our site, Lago Lungo, (369 a.m.s.l.) has a maximum depth of up to 7 m with a surface area of 0.78 km2 (Riccardi, 2006). The basin is cultivated for maize and cereals and the hillsides and the surrounding hill slopes are covered in coppiced stands of mixed deciduous forest dominated by oaks and hop-hornbeam. Sedimentation rates in the Apennines are among the highest across Europe (Panagos et al., 2015), averaging 10–20 tons ha−1 yr−1. Detailed description of local vegetation and geology are published in Mensing et al. (2015). The area has a Mediterranean precipitation pattern with 1117 mm annually falling predominantly in winter. Mean annual temperature varies between 4 °C in January and 21 °C in July (Fig. 4 29 in Leone, 2004). The temperature and precipitation regime is strongly controlled by the North Atlantic Oscillation (NAO) with warm dry climate predominating during positive phases of the NAO, and cool wet climate during negative phases (Hurrell, 1995, López-Moreno et al., 2011).
Section snippets
Methods
Sediment cores were recovered in 2009 and 2012 using a hand operated square-rod Livingstone corer from a floating platform anchored in the deepest part of the lake. Surface sediments were recovered with a plastic tube core specially fitted with a piston to produce minimal disturbance of the sediment-water interface. The unconsolidated surface sediments were stabilized with Zorbitrol (sodium polyacrylate absorbent powder) while the core was still in an upright position. Three overlapping cores
Results
Ninety different pollen types, nine non-pollen palynomorphs (NPP) and eleven algae types (not shown) were identified. Cluster analysis (Fig. 2) identified three eco-functional groups: Grassland and disturbance taxa; forest taxa; and cultivated plants and early pioneer forest taxa. Pinus grouped with grassland and disturbance taxa, possibly because it is not a common constituent of the local forest and appears in disturbed habitats through long-distance transport. Selected pollen and NPP are
Independent climate change reconstructions
There are no millennial-length high resolution temperature or precipitation reconstructions from peninsular Italy, therefore we rely on reconstructions from the western Mediterranean, Alps and northern Europe for independent climate records (Fig. 4). The longest precipitation series available comes from a tree-ring reconstruction of the Palmer Drought Severity Index—(PDSI) in Morocco using Cedrus atlantica (Endl. Carrière; Esper et al., 2007). A reconstructions of the NAO from speleothems in
Conclusions
Our study demonstrates that within the Anthropocene, paleoenvironmental change may be the result of the complex interaction between human activity and climatic variation. The MCA and LIA provide an important climatic backdrop to environmental change in the Rieti basin of central Italy, but examination of the socioeconomic context within which land use change took place demonstrates that the timing and magnitude of environmental impacts was closely linked to local activities. There are three
Acknowledgements
We appreciate two anonymous reviews that significantly improved the quality of the manuscript. We are grateful to the many people who helped make this study possible. Chronology development was done by Leonardo Sagnotti, Fabio Florindo and Francisco-Javier Pavón-Carrasco of the Istituto Nazionale di Geofisica e Vulcanologia, Rome, Italy and Susan Zimmerman of the Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory. Cores were processed at LACORE, Minneapolis with
References (89)
Human impact and climate changes—synchronous events and a causal link?
Quat. Int.
(2003)- et al.
The Northwest European Pollen Flora: 65. Betulaceae and Corylaceae
Rev. Palaeob. Palynol.
(2003) Middle to late Holocene glacial variations, periglacial processes, and alluvial sedimentation on the higher Apennine massifs (Italy)
Quat. Res.
(2005)- et al.
Effects of the North Atlantic Oscillation (NAO) on combined temperature and precipitation winter modes in the Mediterranean mountains: observed relationships and projections for the 21st century
Global Planet. Change
(2011) - et al.
2700 years of Mediterranean environmental change in central Italy: a synthesis of sedimentary and cultural records to interpret past impacts of climate on society
Quat. Sci. Rev.
(2015) - et al.
The new assessment of soil loss by water erosion in Europe
Environ. Sci. Policy
(2015) - et al.
The Northwest European pollen flora 31. Cannabaceae, Moraceae and Urticaceae
Rev. Palaeobot. Palynol.
(1984) - et al.
The Northwest European Pollen Flora, 45 Oleaceae
Rev. Palaeobot. Palynol.
(1991) - et al.
Climatic change and contemporaneaous land-use phases north and south of the Alps 2300 BC to 800 AD
Quat. Sci. Rev.
(2003) - et al.
Multi-archive summer temperature reconstruction for the European Alps, AD 1053–1996
Quat. Sci. Rev.
(2012)
The Northwest European pollen flora, 33. Fagaceae
Rev. Palaeobot. Palynol.
Diversity and ecology of tropical African fungal spores from a 25,000-year palaeoenviromental record in southeastern Kenya
Rev. Palaeobot. Palynol.
Drought and the Maya; the story of artefacts
Nature
Donationes pro anima: gift and countergift in the early Medieval liturgy
A composite annual-resolution stalagmite record of North Atlantic climate over the last three millennia
Nature Sci. Rep.
2500 years of European climate variability and human susceptibility
Science
Popolamento e agricoltura: aspetti della politica territoriale del comune di Rieti nel Duecento
Palaeoenvironmental, palaeoclimatic and chronological interpretations of a late Quaternary sediment core from Piana di Rieti (central Apennines, Italy)
Giorn. Geol.
Gli insediamenti di età protostorica individuati nell'alveo dell'antico Lacus Velinus: dati e considerazioni
Quaderni di Protostoria
Dionisi
Pollen and spore keys for Quaternary deposits in the northern Pindos Mountains
Greece.G rana
The extra-tropical Northern Hemisphere temperature in the last two millenia: reconstructions of low-frequency variability
Clim. Past
Settlement History, Environment and Human Exploitation of an Intermontane Basin in the Central Apennines: The Rieti Survey 1988-1991, Part I
Pap. Br. Sch. Rome
Settlement History, Environment and Human Exploitation of an Intermontane Basin in theCentral Apennines: the Rieti Survey 1988–1991, Part II Land-Use Patterns and Gazetteer
Pap. Br. Sch. Rome
A high-resolution pollen and geochemical analysis of late Holocene human impact and vegetation history in southern Cumbria, England
J.Quat. Sci.
Modern and fossil non-pollen palynomorphs from the Basque mounatains (western Pyrenees: France): the use of coprophilous fungi to reconstruct pastoral activity
Veg. Hist. Archaeobot.
Using multiple archives to understand past and present climate-human-environmental interaction: the lake Erhai catchment, Yunnan Province, China
J. Paleolimnol.
A virtual water network of the Roman World
Hydrol. and Earth Syst. Sci
A seesaw in Mediterranean precipitation during the Roman Period linked to millennial-scale changes in the North Atlantic
Clim. Past
Long-term drought severity variations in Morocco
Geophys. Res. Lett.
Textbook of Pollen Analysis
Farming in the First Millennium AD: British Agriculture between Julius Caesar and William the Conqueror
Can economic, land use and climatic stresses lead to famine, disease, warfare and death? Using Europe’s calamitous 14th century as a parable for the modern age
Ecol. Econ.
Support for global climate reorganization during the ‘Medieval Climate Anomaly’
Clim. Dyn.
PAST: paleontological statistics software package for education and data analysis
Palaeontol. Electronica
San Vincenzo al Volturno 1: The 1980-86 Excavations part 1
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