176 research outputs found
Reply to Ellis et al.: human niche construction and evolutionary theory
We are pleased Ellis et al. found value in our recent synthesis of the deep history of human impacts on
global ecosystems and agree that our paper should influence the current debate on if and how an Anthropocene epoch is defined. We also agree that the ecological consequences of human niche construction have profound and growing effects on the evolutionary trajectories of humans and other species living within human-altered ecosystems. Niche construction theory (NCT) provides an explicit framework for linking evolutionary and ecological processes into a coherent theory of biological evolution. Of special appeal to us as archaeologists is that NCT bridges biological and cultural evolution by including human culture and social learning within the mechanisms of evolutionary change, allowing scientists to address issues at the interface of human and natural systems. Some of us have contributed significantly to human NCT, addressing some of the very issues raised by Ellis et al. Finally, we agree that human transformations of ecosystems are inherently social processesâclearly humans are intensely social organismsâand that such processes result from long-term melding of biological and cultural evolution
Reply to Westaway and Lyman: emus, dingoes, and archaeologyâs role in conservation biology
In a curious comment on our PNAS Perspective, Westaway and Lyman offer two Australian zooarchaeological case studiesâone involving eggshells and the other dingoesâthat they argue undercut one of our main points: that archaeological data and deep time perspectives have much to offer conservation biology. Neither example provides a specific substantive critique of our perspective: there are no dingoes in our article, no eggshells, and we mention the long and rich record of human management and alteration of Australian environments only briefly. Nor do we suggest that all archaeological assemblages can effectively inform current conservation biology efforts. Such datasets obviously vary in their quality and potential applicability to modern situations. When considered more closely, both of Westaway and Lymanâs case studies underscore rather than undercut the importance of archaeological and paleoecological data in conservation biology initiatives
Oregon 2100: projected climatic and ecological changes
Greenhouse climatic warming is underway and exacerbated by human activities. Future outcomes of these processes can be projected using computer models checked against climatic changes during comparable past atmospheric compositions. This study gives concise quantitative predictions for future climate, landscapes, soils, vegetation, and marine and terrestrial animals of Oregon. Fossil fuel burning and other human activities by the year 2100 are projected to yield atmospheric CO2 levels of about 600-850 ppm (SRES A1B and B1), well above current levels of 400 ppm and preindustrial levels of 280 ppm. Such a greenhouse climate was last recorded in Oregon during the middle Miocene, some 16 million years ago. Oregonâs future may be guided by fossil records of the middle Miocene, as well as ongoing studies on the environmental tolerances of Oregon plants and animals, and experiments on the biological effects of global warming. As carbon dioxide levels increase, Oregonâs climate will move toward warm temperate, humid in the west and semiarid to subhumid to the east, with increased summer and winter drought in the west. Western Oregon lowlands will become less suitable for temperate fruits and nuts and Pinot Noir grapes, but its hills will remain a productive softwood forest resource. Improved pasture and winter wheat crops will become more widespread in eastern Oregon. Tsunamis and stronger storms will exacerbate marine erosion along the Oregon Coast, with significant damage to coastal properties and cultural resources
Wildfire and Abrupt Ecosystem Disruption on California\u27s Northern Channel Islands at the Allerod-Younger Dryas Boundary (13.0-12.9 ka)
Sedimentary records from California\u27s Northern Channel Islands and the adjacent Santa Barbara Basin (SBB) indicate intense regional biomass burning (wildfire) at the Ă
llerĂždâYounger Dryas boundary (~13.0â12.9 ka) (All age ranges in this paper are expressed in thousands of calendar years before present [ka]. Radiocarbon ages will be identified and clearly marked â14C yearsâ.). Multiproxy records in SBB Ocean Drilling Project (ODP) Site 893 indicate that these wildfires coincided with the onset of regional cooling and an abrupt vegetational shift from closed montane forest to more open habitats. Abrupt ecosystem disruption is evident on the Northern Channel Islands at the Ă
llerĂždâYounger Dryas boundary with the onset of biomass burning and resulting mass sediment wasting of the landscape. These wildfires coincide with the extinction of Mammuthus exilis [pygmy mammoth]. The earliest evidence for human presence on these islands at 13.1â12.9 ka (~11,000â10,900 14C years) is followed by an apparent 600â800 year gap in the archaeological record, which is followed by indications of a larger-scale colonization after 12.2 ka. Although a number of processes could have contributed to a post 18 ka decline in M. exilis populations (e.g., reduction of habitat due to sea-level rise and human exploitation of limited insular populations), we argue that the ultimate demise of M. exilis was more likely a result of continental scale ecosystem disruption that registered across North America at the onset of the Younger Dryas cooling episode, contemporaneous with the extinction of other megafaunal taxa. Evidence for ecosystem disruption at 13â12.9 ka on these offshore islands is consistent with the Younger Dryas boundary cosmic impact hypothesis [Firestone, R.B., West, A., Kennett, J.P., Becker, L., Bunch, T.E., Revay, Z.S., Schultz, P.H., Belgya, T., Kennett, D.J., Erlandson, J.M., Dickenson, O.J., Goodyear, A.A., Harris, R.S., Howard, G.A., Kloosterman, J.B., Lechler, P., Mayewski, P.A., Montgomery, J., Poreda, R., Darrah, T., Que Hee, S.S., Smith, A.R., Stich, A., Topping, W., Wittke, J.H. Wolbach, W.S., 2007. Evidence for an extraterrestrial impact 12,900 years ago that contributed to the megafaunal extinctions and Younger Dryas cooling. Proceedings of the National Academy of Sciences 104, 16016â16021.]
An Anthropocene Without ArchaeologyâShould We Care?
For more than a decade, a movement has been gathering steam among geoscientists to designate an Anthropocene Epoch and formally recognize that we have entered a new geological age in which Earthâs systems are dominated by humans. Chemists, climatologists, and other scientists have entered the discussion, and there is a growing consensus that we are living in the Anthropocene. Nobel Prize-winning atmospheric chemist Paul Crutzen (2002a, 2002b; Crutzen and Stoermer 2000) coined the term, but the idea that humans are a driver of our planetâs climate and ecosystems has much deeper roots. Italian geologist Antonio Stoppani wrote of the âanthropozoic eraâ in 1873 (Crutzen 2002a), and many others have proposed similar ideas, including journalist Andrew Revkinâs (1992) reference to the âAnthroceneâ and Vitousek and colleagues (1997) article about human domination of earthâs ecosystems. It was not until Crutzen (2002a, 2002b) proposed that the Anthropocene began with increased atmospheric carbon levels caused by the Industrial Revolution in the late eighteenth century (including the invention of the steam engine in A.D. 1784), however, that the concept began to gain serious traction among scientists and inspire debate
Extraordinary Biomass-Burning Episode and Impact Winter Triggered by the Younger Dryas Cosmic Impact âŒ12,800 Years Ago. 2. Lake, Marine, and Terrestrial Sediments
Part 1 of this study investigated evidence of biomass burning in global ice records, and here we continue to test the
hypothesis that an impact event at the Younger Dryas boundary (YDB) caused an anomalously intense episode of
biomass burning at âŒ12.8 ka on a multicontinental scale (North and South America, Europe, and Asia). Quantitative
analyses of charcoal and soot records from 152 lakes, marine cores, and terrestrial sequences reveal a major peak in
biomass burning at the Younger Dryas (YD) onset that appears to be the highest during the latest Quaternary. For the
Cretaceous-Tertiary boundary (K-Pg) impact event, concentrations of soot were previously utilized to estimate the
global amount of biomass burned, and similar measurements suggest that wildfires at the YD onset rapidly consumed
âŒ10 million km2 of Earthâs surface, or âŒ9% of Earthâs biomass, considerably more than for the K-Pg impact. Bayesian
analyses and age regressions demonstrate that ages for YDB peaks in charcoal and soot across four continents are
synchronous with the ages of an abundance peak in platinum in the Greenland Ice Sheet Project 2 (GISP2) ice core and
of the YDB impact event (12,835â12,735 cal BP). Thus, existing evidence indicates that the YDB impact event caused
an anomalously large episode of biomass burning, resulting in extensive atmospheric soot/dust loading that triggered
an âimpact winter.â This, in turn, triggered abrupt YD cooling and other climate changes, reinforced by climatic
feedback mechanisms, including Arctic sea ice expansion, rerouting of North American continental runoff, and subsequent ocean circulation changes
More than competition: exploring stakeholder identities at a grassroots cause-related sporting event
The purpose of this paper is to (a) explore stakeholder identities of a grassroots cause-related sporting event; and (b) gain a better understanding of how identities are related to stakeholder development, support of the event, and future intentions. We used a mixed methods research design that consisted of two studies: qualitative followed by quantitative. Study 1 explored stakeholder identities and how they are related to stakeholder development and support of the event, and Study 2 examined how future intentions regarding attendance, donations, and sponsor support differ based on levels of stakeholder identity. Sports marketing and non-profit management literature streams as well as identity theory and social capital theory informed our studies. The National Kidney Foundation Surf Festival was selected because it is a grassroots cause-related sporting event with financial success over the last two decades. In addition, a surf contest, an action sport, is a unique sport setting in the nonprofit sector, which offers insight to marketers seeking to target subcultures. The findings of the qualitative study revealed three identities relevant to participants: sport subculture, community, and cause. A framework emerged from the data that illustrated how these identities unite together to generate social capital, which is linked to effective volunteer and sponsorship management. Quantitative analysis through survey data provided further evidence of the impact of identification with a cause-related sport activity on consumer outcomes. Results indicated attendees with high surf-related identity are more likely to attend future Surf Festivals, have higher intentions to donate to the cause, and have higher sponsor purchase intentions compared to those with low self-identity with the sport subculture. The conclusion discusses implications, framing the findings through the intersection of the sports marketing and non-profit sector industries, and provides suggestions for future research.Ye
Coastal Foraging at Otter Cave: A 6600-Year-Old Shell Midden on San Miguel Island, California
Test excavations at a small rock shelter near Otter Point on San Miguel Island produced an assemblage of well-preserved artifacts and faunal remains from buried midden deposits dated to approximately 6600 years ago. Along with an unusual assemblage of 40 Dentalium shell artifacts, faunal remains from Otter Cave (CA-SMI-605) provide valuable information on the nature of San Miguel Island environments and the adaptations of its maritime peoples during the early Middle Holocene. Here we summarize the context, chronology, nature, and implications of the Otter Cave materials. Shellfish from rocky intertidal habitats (turban snails, mussels, owl limpets, etc.) dominate the faunal assemblage, but fishing and marine mammal hunting also contributed to the subsistence of the cave occupants. We also discuss the Otter Cave data in the context of a long sequence of shell midden strata at Otter Point that span much of the past 7500 years, as well as general models for the evolution of maritime adaptations in the Santa Barbara Channel region
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In Search of a White Bear: An Eccentric Crescent from Sudden Ranch (CA-SBA-208), Northern Santa Barbara County, California
Over the years, there has been considerable interest among archaeologists in the distribution, function, and chronology of chipped stone crescents in California and the western United States. Questions about their chronology and function have yet to be fully resolved, but such crescents are widely considered to be Early Holocene or terminal Pleistocene time markers. More than a thousand crescents have been identified from California archaeological sites, but a relatively small percentage have zoomorphic attributes, including a rare âbear-shapedâ specimen now listed as Californiaâs of cial prehistoric artifact. About 20 years ago another bear- shaped crescent in the Lompoc Museum was brought to my attention, a specimen not described in previous syntheses of crescents in California and the Far West. The location of that crescent is now uncertain, but I recently found additional data on the provenience and context of this crescent in two unpublished manuscripts by Clarence Ruth. This rare artifact has an unusual history that sheds light on the development of California archaeology
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