راهبردهای سازشی گروه های شکارگر - گردآورنده ی پلیئستوسن در زیست بوم های گوناگون

معیشت تمام گروه های انسانی و انسان ریخت کره ی زمین تا پیش از دوره ی هلوسن، شکارگردآوری بوده است. در طول دوره ی پلیئستوسن، شکارگرگردآورندگان در زیست بوم ها و محیط های معیشتی گوناگون زیسته و با آن به سازش رسید ه اند؛ از این رو، راهبردهای معیشتی این گروه ها، راهبردهای سازشی خوانده می شوند.برای مطالعه ی راهبردهای سازشیِ گروه های انسانیِ حاضر در دوره ی پلیئستوسن، ابتدا می بایست چارچوبی براساس مدل های انسان شناختی و بوم شناسی تحولی ارایه شده و سپس، بر این اساس، یافته های باستان شناختی تحلیل شوند. در این نوشتار، بیشتر به چارچوب های کلیِ موجود در بوم شناسی رفتاری انسان برای مطالعه ی گروه های شکارگرگردآورنده ی پلیئستوسن پرداخته می شود؛چارچوب هایی که جز با مشاهده ی رفتارهای گروه های شکارگرگردآورنده ی امروزی و مطالعه ی مآخذ موجود صد سال اخیر در مورد آن ها به دست نخواهد آمد. پس از انجام بررسی ها،به نظر می رسد که در دید کلی و در مقیاس های بزرگ (مکانی و زمانی)، ویژگی های گوناگون محیط های معیشتی و زیست بوم ها بر راهبردهای سازشی گروه های شکارگرگردآورنده ی پلیئستوسن اثراتی عمیق گذارده اند و وابستگی این گروه ها به ویژگی های چشم انداز پیرامون زندگی بسیار شدیدتر از کشاورزان هلوسن یا حتی شکارگرگردآورندگان دوره های سپسین بوده است. دو دیگر آن که احتمالاً اثرات ویژگی های زیست بوم های گوناگون بر گروه های انسانی به صورت تفاوت در یافته های باستان شناختیِ متعلق به دوره ی پلیئستوسن در گوشه و کنار کره ی زمین قابل پیگیری است. از جمله ی این ها، تفاوت در اندازه و پیچیدگی ساختارهای محوطه های باستان شناختی و نیز تفاوت های گهگاه عمیق در بقایای جانوری و دست ساخته هاست.

Hunter-Gatherers’ Adaptive Strategies in different Biomes during Pleistocene

Before the advent of Holocene, the subsistence of all hominins was hunting and gathering. Different biomes have been occupied by Homo sapiens during late Pleistocene. Due to the fact that subsistencerelated activities in a given patch are aimed at adapting to a pack of specific characteristics, the ways to reach this goal could be called adaptive strategies. There is ample evidence supporting the assumption that interbiome (or interpatch) differences had had dramatic impacts on huntergatherers rsquo; various ways of life, generally speaking, and the dependence of Pleistocene foragers upon local environmental characteristics was heavier than horticulturalists or even huntergatherers of later periods. Some models in the framework of human behavioral ecology have been developed in order to grasp different foragers rsquo; behaviors (decision making). These models are based upon optimality for the most part. Foragers could decide which way to choose to acquire a resource among other options, each with its costs and returns. The optimal way is the one with the least cost and the most benefit (return). Finally, foraging optimally would increase individual or group fitness.MATHERIALS AND METHODSFor investigating on subsistence strategies of Pleistocene huntergatherers, a framework should be constructed based upon anthropological and evolutionary ecological models and then, in this light, archaeological finds could be analyzed and explained. Generalized models, built upon the studies of contemporary huntergatherer bands from the ecological viewpoint are analyzed in this paper. The degree to which these models are consistent with data recovered from Pleistocene archaeological sites is equivocal and under scrutiny. To answer such questions more and more archaeological study is needed. In this paper, bibliographic analysis has adopted to assess the relationship between foragers and the natural environment. FINDSStatistical works of researches on contemporary huntergatherers and some inadequate archaeological evidence imply that foragers rsquo; subsistencerelated activities have been regularly related to the environmental parameters with a good accuracy. Pioneers such as Binford have pointed at insolation, effective temperature, and the distribution of solar heat as the ultimate causes (and the most important one) of diversity in biomes and consequently, in foragers rsquo; subsistence; but one should keep in mind that absorbing more solar heat, higher temperatures, and higher net primary productivity (NPP) will not necessarily result in more accessible food to the human foragers, especially the prehistoric ones.In biomes with higher NPP, such as tropical rainforests, a great deal of energy will be invested in structural maintenance (tree trunks) and the capture of sunlight (taller and taller trunks), therefore, the food available to foragers is not that much; whereas in some regions with lower NPP (e.g. African savannah) more energy will be dedicated to reproductive or storage organs of plants which are widely edible for human foragers. Based on this, human foragers tended to live on the edges of dense forests (ecotones) and not the jungles themselves. Therefore, estimation of the availability of food in different biomes is not possible solely based on NPP comparisons. One of the most important aspects of foragers rsquo; life is mobility. It is as much important as that it can explain the variability in archaeological sites to some degree. Based on bibliographic work in this paper, mobility is dependent upon the availability and distribution of resources among other things. For instance, when resources are evenly distributed in space, high residential mobility is practiced in order to decrease the risks associated with local depletion of resources. As a result, archaeological sites associated with foragers with high residential mobility should be smaller and less complex (less intrasite variability) compared to collectors rsquo; settlements (high logistical mobility). On the contrary, when resources are clumped (highly unpredictable environments), logistical mobility would be higher and consequently, associated archaeological sites would be different from the first example. These are some ecological rationales behind the variabilities observed among Pleistocene archaeological sites. DISCUSSION AND CONCLUSIONIt seems that at least part of the differences which have been observed among the archaeological remains of the Pleistocene settlements around the globe (e.g. differences in size, complexity, faunal remains, and artifacts) could be interpreted in the light of different subsistence strategies. For instance, logistical mobility results in archaeological finds and associations which are most probably different from archaeological sites belong to foragers with residential mobility. But one should keep in mind that this variability has an ultimate cause which is characteristics of biomes (such as climatic regimes, the distribution and abundance of critical resources, and as such). In other words, optimal strategy in landscape A differs from landscape B mostly due to the environmental characteristics. In addition, in unpredictable environments (spatially and temporally), optimal strategy may change during time, with other things held constant (e.g. ideology, or historyrelated inertia). Finally, it should be noted that all models discussed in the paper are developed just based on physical properties of environments. Therefore, they cannot explain all the variabilities observed among foragers and their associated archaeological sites. Things such as ideology and worldviews, inertia of history, sexual selection, individual decisions and so on can play vital roles in the formation of foragers rsquo; strategies and then, their archaeological remains.