Dark Nature : Responses of humans and ecosystems to rapid environmental changes

Impact of rapid environmental changes on humans and ecosystems An environmental catastrophe is poorly defined, but generally, from the point of view of an earth scientist, is thought to be either a specific brief event (earthquakes, volcanic eruption, tsunamis) or a pervasive evolution at the time scale of the century or less (epidemics, dry periods) over a large area, significant enough to be registered in the sedimentary, chemical or biological earth archives and to have an impact on society. The full scale of rapid environmental changes has not been recorded in the short period covered by the instrumental record. Therefore it is essential to turn to geological and archaeological archives that span a much longer timescale. In some cases of high resolution, they may serve as adequate surrogates for the instrumental record. The societal response (such as collapse, migration) to external forcing (such as strength, frequency of the event) has a non-linear nature. Unless good science is done (robust dating or duration control), it may be difficult to prove a causality. The amplitude of a catastrophe will be larger if it combines the following: 1) rapid onset and long duration, 2) large area, or large proportion of the settlement, 3) inflexible society unable to adapt, and finally 4) an already stressed society or environment. Two special issues of Quaternary International, each containing eleven papers, have been prepared on this topic. This first volume (the present one) concentrates on the impact of rapid and catastrophic environmental changes on humans and ecosystems. These papers present methodologies and case studies as well as a paper more directed to end-users. The second volume (Leroy et al., 2006) focuses on the responses of humans and ecosystems to rapid and catastrophic environmental changes. The investigations presented here explore the past capacity of humans to react to drastic changes affecting significantly their environment. Responses are related to population dynamics (migration), activities (land use, subsistence), societal structure, or belief. Holocene societies changed in depth within the neolithisation process: domestication of animals and plants, and emergence of civilisations are key elements in the study of human adaptation potential. The examples here present evidence of how a drastic change can stimulate social and cultural development, or can be the cause of a culture collapse or emergence. These studies provide caution regarding environmental determinism, and point out that no simple rules seem to govern human evolution. This volume begins with a paper by Walker and Surge on the development of an isotopic method to reconstruct past temperature and salinity from coupled analysis of shells and otoliths found in archaeological sites of southwest Florida dating of the last two millennia. The negative impact of agriculture on human health at the beginning of the Holocene in Europe is reconstructed by Larsen from the analysis of human skeletal remains. Sallares proposes that environmental changes altering mosquito-breeding sites in many southern European coastal wetlands favoured the spread of malaria during the Holocene. Ollive et al. present the results of their investigation of a Gallo-Roman town in the southern Upper Rhine Graben that has been affected by four major floods between AD 20 and AD 145/ 146. Dinis et al. investigated the Holocene infill of three coastal lagoons in central Portugal and their impacts on humans as well as the reverse. A study of pollen and dinoflagellates by Leroy et al., set in the framework of instrumental data and biological surveys, showed the link between fluctuating sea levels of the Karabogaz-Gol/ Caspian Sea system and their rapidly changing environment. Stancikaite et al. found a connection between Holocene vegetational changes and human occupation in the surroundings of a lake in northwest Lithuania. The 4.1 cal. ka BP event seems to have been detected in the Congo deep-sea fan by palynological analyses (Marret et al.). It is expressed by more open vegetation in the lowland regions. Williams and Nottage analysed the synoptic conditions of the 1999 wet year in Sudan as a potential analogue for the environment of Later Stone Age peoples of the early Holocene, who occupied sandy ridges seasonally. Renssen et al. have examined the climate of the end of the African Humid period with a coupled atmosphere–ocean–vegetation model. The decrease of precipitation seems to be due to an orbitally forced reduction of summer insolation. In the western Sahara the transition is not linear but has frequent fluctuations back to more humidity. This volume ends with a paper of Schmidt-Thome´ et al. who introduce maps of economic risks of floods and earthquakes in Europe with the aim of facilitating targeted responses and policies. The papers assembled in these two special issues of Quaternary International are derived from three conferences ARTICLE IN PRESS 1040-6182/$ - see front matter r 2006 Elsevier Ltd and INQUA. All rights reserved. doi:10.1016/j.quaint.2006.01.003 on the theme of catastrophic and other rapid environmental changes and human response. The first one, ‘‘Environmental catastrophes and recoveries in the Holocene’’, was held at Brunel University (UK) in August– September 2002 organised by S. Leroy and I. Stewart (abstracts available in Leroy and Stewart 2002). The second meeting, ‘‘Rapid and catastrophic environmental changes in the Holocene and human response’’, was a joint activity of INQUA, ICSU-Dark Nature and IGCP 490 and was held in Mauritania in January 2004 (organised by S. Leroy, www.mun.ca/canqua/igcp490/mauritania.html; abstracts available in Leroy and Costa, 2004). The final one was the result of two special sessions at the 32nd IGC congress in Florence in August 2004 (M. Cremaschi and S. Leroy on ‘‘Geoarchaeology for climatic changes and catastrophic events in human history’’; and A. Berger and S. Leroy, ‘‘Rapid and catastrophic geological changes and societal response’’ (www.32igc.info/igc32/search/). The first of these reunions was particularly important because it lead to the establishment of two important international projects which stimulated discussion and provided synergy for these special issues: ICSU ‘‘Dark nature: rapid natural change and human response’’ (www.mun.ca/canqua/ ICSU-DN/ICSU-DN_aims.htm) (2004 and 2005) and IGCP 490 ‘‘The role of Holocene environmental catastrophes in human history’’ (www.mun.ca/canqua/igcp490/) (2003 to 2007). The Dark Nature project ran from 2004 to 2005 with funding from the International Council for Sciences (ICSU), the International Scientific Union (IUGS), the International Quaternary Association (INQUA) and several other organisations. The aim was to refine the record of rapid environmental changes affecting physical environments and ecosystems during the Holocene, and to examine how past societies and communities reacted in the face of harmful change. Under the Dark Nature project, six interdisciplinary meetings were organised: Mauritania (January 2004), Mozambique (November 2004) and in 2005: Argentina, Iran, Canada and Italy. These focussed on arid, fluvial, lacustrine, coastal, circum- Arctic, mountainous and other environments where major natural changes have had profound effects on people and ecosystems. We are grateful to the individuals who encouraged this project, especially Prof. Tony Berger (Canada) and to the many funding bodies, large and small, who financed it. References Leroy, S., Costa P. (Eds.), 2004. Environmental catastrophes in Mauritania, the desert and the coast. In: Volume of abstracts and field guide. ICSU Dark Nature-IGCP490, First joint meeting, 4–18 January 2004 Mauritania. 198pp. http://atlas-conferences.com/cgi-bin/ abstract/camu-01 Leroy, S., Stewart, I. (Eds.), 2002. Environmental catastrophes and recovery in the Holocene. In: volume of abstracts, Conference held at Brunel University, West London, 28 August–2 September 2002. 90pp. http://atlas-conferences.com/c/a/i/q/01.htm Leroy, S.A.G., Jousse, H., Cremaschi, M., 2006. Dark nature: responses of humans and ecosystems to rapid environmental changes. Quaternary International 153. S.A.G. Leroy Department of Geography and Earth Sciences and Institute for the Environment, Brunel University (West London), Uxbridge UB8 3PH, UK E-mail address: suzanne.leroy@brunel.ac.uk H. Jousse Institu¨t fu¨r Pala¨oanatomie, Domestikationsforschung und Geschichte der Tiermedezin, 37 Kaulbachstrasse, D-80539 Mu¨nchen, Germany M. Cremaschi University of Milan, CNR-IDPA, Dipartimento di Scienze della Terra ‘‘A. Desio,’’ Via Mangiagalli 34, Milano, 1-20132, Italy ARTICLE IN PRESS 2 Editorial / Quaternary International 150 (2006) 1–2