زیست‌بوم و تطور فرهنگی: ارزیابی پدیده اقلیمی 8.2 بر ساختارهای اجتماعی و اقتصادی هزاره هفتم پیش‌از میلاد فارس

تغییرات اقلیمی طی چند دهه گذشته به موضوع نگرانی جهانی تبدیل شده است؛ تحقیق در مورد وقایع اقلیمی گذشته نقش مهمی در تلاش برای به دست آوردن بینش در تحولات اقلیمی آینده ایفا می‌کند و به درک پیامدهای محیطی ناشی از نوسانات ناگهانی و کوتاه مدت آب و هوایی کمک می‌کند. یکی از تغییرات اقلیمی که توجه باستان شناسان را نیز به خود معطوف داشته پدیده اقلیمی 8.2 است که باستان شناسان این پدیده را یکی از عوامل اصلی تغییرات فرهنگی و معیشتی در نیمه دوم هزاره هفتم پیش ازمیلاد دانسته اند. با توجه به مطالعات گسترده ای که در اروپا و دیگر کشورهای خاورمیانه در رابطه با این موضوع صورت گرفته اما تاکنون پژوهش مستقلی درباره ایران صورت نگرفته است. ازاینروی کاوش های صورت گرفته در حوزه فرهنگی فارس نشان می دهد که ساختار اقتصادی و اجتماعی در نیمه اول هزاره هفتم پیش از میلاد بر پایه کشاورزی قرار داشته که این ساختار به‌یک‌باره در نیمه دوم هزاره هفتم پیش‌از میلاد به شکاروزی تغییر نموده و سپس در اوایل هزار ششم پیش‌از میلاد اقتصادی مبتنی به کشاورزی با آبیاری جایگزین می شود. مواد فرهنگی به دست آمده از محوطه های موشکی و هرمنگان در فارس به‌خوبی این تغییرات معیشتی در نیمه دوم هزاره هفتم پیش ازمیلاد را نشان می دهد. با توجه به مطالعات دیرین‌اقلیم‌شناسی و باستان‌شناسی در سراسر خاور نزدیک و خاورمیانه می‌توان این دگرگونی را ناشی از تغییرات اقلیمی موسوم به پدیده 8.2 دانست، هر چند نمی توان عوامل دیگر مثل عوامل انسانی و یا توسعه فرهنگی را در مورد این تغییرات رد نمود.

Ecology and cultural evolution: impacts of 8.2 climate event on economic and social structures at Fars in seventh millennium BCE

Introduction Past climate and environmental change is of longstanding and fundamental interest to archaeologists. a number of recent syntheses have examined the role of climate change and environmental modiication in understanding the rise, spread, and in some instances collapse of early complex societies. One of the most pronounced and abrupt climatic events of the Holocene occurred around 8200 years ago (Alley et al., 1997). Numerous proxy data as well as climate models indicate colder and more arid conditions throughout the Northern Hemisphere (Alley and Agustsdottir, 2005). The effects of the 8.2 ka event on societies in Southwest Asia are under discussion, and interpretations vary from collapse and abandonment of sites, largescale migration, to continuation of occupation (Flohr et al. 2016). in an Iranian context, various scholars have highlighted the role of humanenvironment interactions in the expansion of Neolithic communities (e.g. Hole 1994, 1998). Also the eastward expansion of the Neolithic, into Central and Eastern Iran, and especially in the Southern Zagros province of Fars, may be contemporaneous with the 8.2 ka event. In the Southern Zagros, cultural changes (the more mobile ‘Mushki’ during the event, and ‘Jari’ farming villages after) may also be associated with the 8.2 ka event (Nishiaki, 2010, Weeks, 2013) but dates from other sites are crucially needed to ascertain if the difference between these two sites is generally applicable to the region. Here we review proxy evidence of climatic and environmental conditions to provide an independent background to societal development in Iran during the seventh millennium BC. Method and Material The materials of this study are the result of excavations in the Hormangan site and also the use of publications by other researchers in this field. An attempt is made to analyze the role of environmental factors on the formation of human settlements in the second half of the seventh millennium BC based on cultural materials obtained from excavation. The site is located on the west of Jeshnian village, situated on the southern basin of Bavanat River, on eastern Fars province in Iran. which was identified in 2015 and then it was excavated  2016. Three trenches were dug for excavation, During excavations in these trenches, two phases of the settlement were identified; in the old phase, the lack of architecture, as well as the existence of multiple ovens and ash dispersion, indicate a lack of sedentary and possibly nomadism. On these deposits, a stratiform architectural structure, including several rooms and spaces, was identified that walls were coated. According to the survey, one coal sample from an older phase showed a date about 63736236 B.C and coal samples that were taken from a later phase show a date between 60006200 B.C. According to the excavation results and C14 dating, it can be concluded that the Hormangan region had been occupied seasonally in about 6450/6350 B.C and later after 6200 B.C, had been occupied permanently by inhabitants with the same culture. Changes observed in archeaological records The earliest evidence agricultural village comes from PrePottery Neolithic (PPN) layers of Tepe Rahamat Abad, which is dated to late 8th or early 7th millennium BC (Azizi Kharanaghi et al. 2014). Cultivation and herding of goats/sheep had already begun in this period, however, Pottery Neolithic (PN) farmers came back to rely on hunting to large extent in following Mushki phase. Cultural findings indicate complex of socialeconomic changes from late half Seventh in Fars ragion. The stereography and architectural remains as well as geometrical stone tools, wild animals’ bones, Gazelle and equid bones, are all indicating the existence of a seasonal settlement based on hunting in Hormangan Site and Tole Mushki. These artifacts indicate tendency toward local stone mines whereas exploitation of obsidian is very limited. Regarding technology of stone tools, more extensive exploitation of geometrical stone tools may reflects significance of hunting at Hormangan Site and Mushki. The changes in subsistence are also visible on the stone tools, like the increase in geometric microlithes with the society’s transition into hunting style of livelihood. The emergence of geometrical arrows is not a local phenomenon, yet it is widespread all over the Middle East and it needs a transregional approach, considering global climatic factors (Nishiaki et al. 2015). bulk of equid bones from the site have been identified as onager, Equus hemionus, as well as Tale Mushki. The large number of gazelle bones (Gazella cf. subgutturosa; goitered gazelle) has been found at Hormangan, indicating that hunting activity on the dry steppe environment must have played an important role for the habitants. Biometric data suggests that most of goat bones belong to domestic (Capra hircus). Considering that it had already been introduced to this region in early 7th millennium BC, the absence of sheep bone in Hormangan assemblage seems to be curious (Arai, unpublished). One explanation for the exclusive reliance on goat may attribute it to climatic reason: adaptation to drier condition during the 8.2 ka. Therefore, due to the changes in livelihoods and the absolute dates of the Hormangan and the Mushki(Nishiaki 2010), it issue could be resualt of climate change of 8.2 ka. Probably Neolithic communities of Fars, have adopted new strategies for livelihood such as hunting and gathering food instead of farming, That Hormangan site was provider a part of these livelihoods needs. This unclear economic phenomenon has been stopped at the beginning of the sixth millennium BC, when the economy based on agriculture was fully integrated. So, given the prevalence of Das blades for reaping as well as the reduction of wildlife and hunting in the 6th millennium, Jeri period can be considered as an economic reliant on agriculture.   Conclusion Archaeological excavations in Fars, illustrate the consequences of climate change on the social and economic structures. It seems that due to climate change in the middle of the seventh millennium BCE and its improvement in 6200 BC, we are witnessing changes in subsistence patterns of this period. The cultural materials of the Mushki and Hormangan sites show that the Neolithic people of Fars in this period to adapt to the new conditions choose changes in subsistence and settlement patterns. During this period, due to the cold weather and agricultural constraints, the people to provide part of their subsistence needs, change their life based on agriculture and turn to the social structure based on hunting.