Human Macroecology at AAAS/SWARM

We at human macroecology are proud to announce that we have organized a symposium for this year's SWARM meetings, which will be held here in Albuquerque, New Mexico from the 9th to 12th of April 2008. SWARM is the southwest and rocky mountain regional division of the AAAS, the publishers of the journal Science. The symposium features the work of several authors whose work represents the backbone of the approach we conveyed in our class last semester. They also provide the exemplary examples of what this style of social science research will strive to emulate in the future. We hope that anyone who can travel to the event considers stopping in and enjoying the papers, which will prove to be diverse, exciting, and novel in their perspectives and analyses. Information about registration can be found here and lodging info is here.

The keyword for this year's SWARM meeting is collaboration, thus human macroecology fits the theme very well.

The abstracts for the symposium and each of the papers are presented below. We'll periodically add information about the symposium to this blog so check back in from time to time if you're interested.

The symposium will be held on Thursday April 10th, 2008. Papers should start at 9:00 am but the official schedule has not yet been completed. I'll post new information as it becomes available.

Cheers,
Oskar

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Symposium Schedule:

Thursday, April 10, 2008.

Order	time	Speaker	Affiliation
1	9:00 - 9:20	Oskar Burger and Bill Burnside	University of New Mexico
2	9:20 - 9:40	James H. Brown	University of New Mexico
3	9:40 - 10:00	Bill Burnside and Jordan Okie	University of New Mexico
4	10:00 - 10:20	Larry Todd	Colorado State University
5	10:20 - 10:40	Mary Stiner	University of Arizona
	10:40 - 11:00	break	break
6	11:00 - 11:20	Peter Turchin	University of Connecticut
7	11:20 - 11:40	Alison Boyer	University of New Mexico
8	11:40 - 12:00	Helen Davis et al.	University of New Mexico
	12:00 - 1:00	lunch	lunch
9	1:00 - 1:20	Robert Walker et al.	Max Planck Institute
10	1:20 - 1:40	Paul Hooper	University of New Mexico
11	1:40 - 2:00	Marcus Hamilton	University of New Mexico
12	2:00 - 2:20	Melanie Moses	University of New Mexico
13	2:20 - 2:40	Louis Bettencourt	Los Alamos National Laboratory
	2:40 - 3:00	break	break
	3:00 - 4:00	round table discussion

Each presentation is allotted 20 minutes, 15 for the talk with 5 for questions.

Symposium Title:

Human Macroecology: Emergent Patterns and Processes in Large-Scale Human Ecology

Symposium Abstract:

Through a multidisciplinary team of speakers and a panel discussion, this symposium explores the developing field of human macroecology, the study of emergent patterns in human-environment interactions across scales. This collaborative approach to social science emphasizes law-like generalizations of human dynamics that occur at scales larger than what can be observed in a single study, survey, or field site. Within this framework, we borrow from a diverse range of fields, including evolutionary ecology, statistical mechanics, complex systems, biogeography, and others. The talks are connected by the spirit of the analyses and the nature of the questions asked, and provide examples of studies that human macroecology will strive to emulate in the future. These include studies of life history variation in primates and humans that emphasize emergent features of human evolution and energetic tradeoffs among essential demographic variables. Other presentations explore biogeographic trends and large-scale human-environment interactions. To this end, archaeological and paleobiological perspectives are utilized to explore the dynamic feedbacks of demographic trends, dietary shifts, adaptations and their impacts on the environment. We examine the form and structure of human settlements by analyzing how properties of cities and road networks change with population size and geography. Explicitly considering the flow of energy, materials, and information that power human societies highlights the importance of a metabolic framework for human ecology. In many instances, analogies with biological systems are employed to gain novel insights into human dynamics. By encompassing a wide range of topics and datasets we take a macroscopic view of the complexity and diversity of human systems, identifying underlying regularities, mechanisms, and organizing principles. Our approach bridges historic disciplinary divides while building a perspective that is needed to confront many of our most pressing issues of population growth, energy use, and sustainability.

Organized by Oskar Burger and Bill Burnside

9:00 - 9:20 am

Title: Orientation to the Goals, Motives, and Definition of Human Macroecology

Authors: Oskar Burger¹ and Bill Burnside²

1 Department of Anthropology, University of New Mexico

2 Department of Biology, University of New Mexico

Abstract: We present the definition and rationale behind the developing field of human macroecology. We emphasize the interdisciplinary and collaborative nature of this approach to social science by outlining its connections to a wide range of other areas of research that also focus on big picture dynamics in human systems. In doing so, we present some of the more salient emergent patterns that have been examined empirically and discuss some of their likely underlying mechanisms. Additionally, we provide framework for the symposium by highlighting commonalities in theme and approach among the papers which follow.

9:20 - 9:40 am

Title: Toward a Metabolic Theory of Human Ecology

Author: James H. Brown

Department of Biology University of New Mexico

Abstract: The developing metabolic theory of ecology (MTE) uses metabolism – the uptake, transformation, and allocation of energy and materials by organisms – to conceptualize, synthesize, and unify diverse environmental sciences. Since ecological interactions involve exchanges of energy, matter, and information, it is possible to use first principles (e.g., conservation of mass and energy, second law of thermodynamics, chemical stoichiometry) and biological processes (e.g., scaling of metabolic rate with body size and temperature, and dependence of resource use, life history, demography, and species diversity on metabolic rate) to build models and test their predictions. The principles, models, and approaches of MTE are directly applicable to human ecology. In collaborations among colleagues and students in biology and anthropology, we have begun to compile ‘macroecological’ data and to apply MTE. Our goal is to understand how energy and material resources are acquired, transformed, and allocated by aboriginal hunter–gatherers and modern technological societies. Preliminary results highlight the potential to use metabolism as well as genetics to cross the interdisciplinary interfaces between the natural and social sciences.

9:40 - 10:00 am

Title: Ecology of Range Size among Traditional Human Foragers: Macroecological Implications for Cultural Diversity Patterns

Authors: Bill Burnside and Jordan Okie

Department of Biology, University of New Mexico

Abstract: Indigenous human cultures display consistent geographic patterns of ethnic and linguistic diversity and group and territory size. As with biological species, cultural groups are more concentrated in the tropics. In species and populations generally, the geographic range reflects foraging ecology and energy requirements. We hypothesize that similar forces constrain range sizes of human societies: 1) environmental productivity will decrease territory size by supporting given populations with less land, while 2) reliance on hunting will increase territory size because energy is lost ascending food chains. Using a database of 339 traditional foraging societies, we used OLS regressions to test correlations between range size and climate; range size and mobility; and range size and foraging mode (gathering, hunting, fishing). We develop mathematical theory to explain the resulting macroecological patterns, guided by the effects of temperature on productivity and kinetics, or the rates of biological reactions and ecological interactions. Analyses of datasets on both traditional foraging societies and global indigenous cultural diversity support our theory. Combining macroecological analyses of ethnographic data with mechanistic ecological theory helps explain general patterns of human foraging ecology and cultural diversity.

10:00 - 10:20 am

Title: Scale, Boundaries, and Bridges: Human Dimensions in Paleoecology

Author: Lawrence C. Todd

Colorado State University

Abstract: One of the more difficult hurdles for research that examines multi-scale, transdisciplinary ecological processes can be the widespread perception that human actions and cultural transmission of information preclude inclusion of our species. One approach that makes this partition more permeable uses human paleoecology and archaeology as a basis for placing human behaviors within a framework of macroecological analysis. Fundamental to this approach is the effort to refocus archaeological research toward an integrated study of landscapes in which human actions are approached in ways that can be investigated in concert with other biological and physical processes. This approach emphasizes that only the most reductionist of research programs can investigate ecological relationships that do not consider aspects of all three domains of landscape formation and evolution (i.e., the cultural, the biological, and the physical). Examples for the Greybull River Sustainable Landscape Ecology project (GRSLE) in northwester Wyoming’s Greater Yellowstone Ecosystem are used to illustrate the basic components of this approach, which is referred to as “landscape taphonomy.” Investigations of this sort help bridge the unfortunate gap between research in the social and natural sciences.

10:20 - 10:40 am

Title: Changes in the ‘Connectedness’ and Resilience of Paleolithic Societies in Mediterranean Ecosystems

Author: Mary C. Stiner

Department of Anthropology, University of Arizona

Abstract: Human predator-prey relationships changed dramatically in the Mediterranean Basin between 250,000 to 9,000 years ago. Many of these changes can be linked to increases in Paleolithic human population densities. Small game species are particularly diagnostic of increases in human hunting pressure and are a major source of evidence for demographic change after 40-45,000 years ago. Biomass-corrected data on prey choice also indicate increasing use of those species that possess higher reproductive efficiencies. Step-wise, apparently irreversible shifts in human predatory niche are apparent in the Mediterranean Basin, beginning with the earliest Upper Paleolithic in the east and spreading westward. Evidence of demographic pressure and greater use of resiliant prey populations is followed by technological innovations to exploit these animals more efficiently. The zooarchaeological findings suggest that Middle and Lower Paleolithic reproductive units probably were not robust at the micropopulation scale, due to the rather narrow set of behavioral responses that characterized social groups at the time, and that localized extinctions at the micropopulation level were likely to have been common. Upper Paleolithic groups were the quintessential colonizers and, in addition, uniquely good at holding on to habitat gained. Upper Paleolithic archaeological “cultures” have shorter histories of existence than those of earlier periods, but they were even more widespread geographically. The demographic robustness of the Upper Paleolithic systems may stem from wholesale strategies for evening-out or sharing risk and volatility in technology. Micropopulations were larger and often denser on landscapes, more connected via cooperative ties, and thus more robust.

11:00 - 11:20 am

Title: Dynamical Feedbacks between Population Growth and Sociopolitical Instability

Author: Peter Turchin

Department of Ecology and Evolutionary Biology, University of Connecticut

Abstract: Most preindustrial states experienced recurrent waves of political collapse and internal warfare. One possible explanation of this pattern, the demographic-structural theory, suggests that population growth beyond the means of subsistence leads to state instability and breakdown, which in turn causes population decline. In several cases (e.g., early modern England and ancient China) we have data on both population dynamics and sociopolitical instability that can be analyzed using standard time-series approaches. Such analyses confirm that periods of sustained and vigorous population growth are followed, with a time lag, by waves of instability. Industrialization was made possible by rapid gains of agricultural productivity, and the general expectation is that the Malthusian component of the demographic-structural theory should lose relevance. Nevertheless, a survey of industrializing states (Western Europe, the U.S., Russia, and Japan) shows that periods of popular immiseration (proxied by declines in the average body height) were also followed, after a time lag, by waves of instability.

11:20 - 11:40 am

Title: Human Colonization and Pacific Island Biodiversity

Author: Alison G. Boyer

Department of Biology, University of New Mexico

Abstract: Human arrival on every landmass around the world has been associated with elevated extinction probability in the native fauna, which has been a major contributor to biodiversity loss and global change. Human impacts, through direct predation, habitat change and the introduction of exotic species, have been implicated as extinction drivers, but aside from one or two well-analyzed locations, the relative roles of these environmental impacts are much debated. Regression trees built on zooarcheological data from over 40 islands were used to assess the relative importance of these extinction drivers in island bird extinctions across the tropical Pacific. Prehistoric extinctions showed a strong bias toward larger body sizes and flightless, ground-nesting species, even after accounting for preservation bias, indicating a significant human predation component. In many cases endemism was also associated with extinction, possibly through impacts of exotic predators and habitat destruction. Human societies on small, isolated islands can be thought of as replicated microcosms which provide crucial information on the dynamic interplay between humans and biodiversity in natural communities.

11:40 am - 12:00 pm

Title: People as Islands: The Theory of Island Biogeography and Patterns of Disease across Human Populations.

Authors: Helen Elizabeth Davis¹, Oskar Burger¹, and Michael Gurven², and Hillard Kaplan¹.

1 Department of Anthropology, University of New Mexico,

2 Department of Anthropology, University of California- Santa Barbara,

Abstract: Infectious disease plays a major role in human population dynamics. Here we investigate host-parasite interactions across space and time using data collected among the Tsimane, a traditional forager-horticulturalist society in lowland Bolivia. Community ecology and human macroecology models are used to address the co-evolution of hosts and disease with respect to parasite virulence and spread, and human infection and re-infection rates. GIS mapping provides a spatial distribution pattern for 17 helminth and protozoa infections across the population (n=3,000). Application of MacArthur and Wilson’s (1967) theory of island biogeography allows us to identify disease reservoirs and analyze their contribution to population dynamics and disease spread. Counter-intuitively, higher population density (nodes) did not correlate with parasite density, suggesting that other factors such as wealth and immune system integrity are important. Particular attention is given to children’s health, with cognitive performance correlating significantly with parasitic burden and a measure of immune system integrity (IgE). Finally, we discuss the relationship of pathogen load across human populations and how these patterns have global significance.

1:00 - 1:20 pm

Title: The Tradeoff between Number and Size of Offspring in Humans and other Primates

Authors: Robert Walker¹, Michael Gurven², Oskar Burger³, Marcus Hamilton³

1 Max Planck Institute for Evolutionary Anthropology

2 Department of Anthropology, University of California- Santa Barbara,

3 Department of Anthropology, University of New Mexico

Abstract: Life-history theory posits a fundamental trade-off between number and size of offspring that structures the variability in parental investment across and within species. We investigate this ‘quantity–quality’ trade-off across primates and present evidence that a similar trade-off is also found across natural-fertility human societies. Restating the classic Smith–Fretwell model in terms of allometric scaling of resource supply and offspring investment predicts an inverse scaling relation between birthrate and offspring size and a -1/4 power scaling between birth rate and body size. We show that these theoretically predicted relationships, in particular the inverse scaling between number and size of offspring, tend to hold across increasingly finer scales of analyses (i.e. from mammals to primates to apes to humans). The advantage of this approach is that the quantity–quality trade-off in humans is placed into a general framework of parental investment that follows directly from first principles of energetic allocation.

A .pdf of a paper that this talk is based on can be found here.

1:20 - 1:40 pm

Title: Understanding the Effects of Braininess on Primate and Human Lifespan Evolution

Author: Paul Hooper

Department of Anthropology, University of New Mexico

Abstract: Explaining variation in animal lifespans is a central goal in life history theory and the metabolic theory of ecology. Understanding why primates in general, and humans in particular, are especially long-lived for their body size is a particularly relevant problem in this area. While previous life history approaches have taken adult mortality rates (and thus adult lifespan) as given, it has become apparent that lifespan should be treated as a partially endogenous decision variable, mediated by investments in mortality reduction throughout life (e.g. cellular maintenance and repair). The goal of this paper is to evaluate the conceptual continuity between two life history models—Kaplan & Robson 2002 and Charnov 2001—in which investment in survival is an endogenous decision variable. I show that Kaplan & Robson's result—that a more learning-intensive niche leads to greater investment in longevity—can be replicated within Charnov's framework using a numerical example. I then briefly discuss these results with respect to the allometry of mammalian and primate life history variables.

1:40 - 2:00 pm

Title: Scaling the Metabolism of Human Socio-Economies from Hunter-Gatherers to Nation States

Author: Marcus J. Hamilton

Department of Anthropology, University of New Mexico

Abstract: Like all biological species, human socio-economies are embedded within complex ecosystems that are structured by the fluxes and flows of energy and information between organisms and their environments. To meet energy demands, humans harvest resources from their environments by tapping into these flows thus creating nonlinear feedbacks between human and ecological systems. In this paper I use scaling theory to quantify the rate at which humans extract, distribute, and expend energy and information within different socio-economies, from hunter-gatherers to nation states. Preliminary data from over 1,030 human cultures show that human energy use scales at approximately the same sublinear rate across the range of human socio-economies. These results suggest a potential scaling law for human energy use, and the implications for understanding human evolution and ecology are discussed.

2:00 - 2:20 pm

Title: Cities as Organisms: Allometric Scaling of Urban Road Networks
Authors: Melanie E. Moses and Horacio Samaniego

Computer Science Department, University of New Mexico

Abstract: Just as the cardiovascular network distributes energy and materials to cells in an organism, urban road networks distribute energy, materials and people to locations in cities. Understanding the topology of urban networks that connect people and places leads to insights into how cities are organized. We study statistics of road networks and traffic patterns across 425 US cities and show that urban road networks are much less centralized than biological vascular networks. As a result, per capita road capacity is independent of the spatial extent of cities. In contrast, driving distances depend on city area, although not as much as is predicted by a completely centralized model. This intermediate pattern between centralized and decentralized extremes may reflect a mixture of different travel behaviors. The approach presented here offers a novel macroscopic perspective on the differences between small and large cities and on how road infrastructure and traffic might change as cities grow.

2:20 - 2:40 pm

Title: Urbanization, Social Adaptation and Sustainable Development

Author: Luís Bettencourt

Theoretical Division, Los Alamos National Laboratory

Abstract: The problem of creating solutions for sustainable development is increasingly predicated on the management of the resource demands of social economic life in cities. Urbanization is the most conspicuous social force at play worldwide today. Developing countries such as China and India are less that 50% urban, but are expected to reach the levels observed in developed nations (80-90%) in the next 3-4 decades. The consequences of urbanization for human demands on natural ecosystems is somewhat ambivalent. While certain forms of consumption (energy, changes in diet) per capita certainly increase on average, urbanization can partially liberate land from human occupation while increasing the efficiency with which a dense population can be serviced. Quantifying these potentially contradictory trends has been a challenge in the past. We show however that scaling, i.e. the analysis of the systematic variation of urban properties with population size reveals scale invariant statistical regularities that capture systematically and predict the course of cities as their population sizes change. We use these insights to frame the discussion of a transition to sustainability in terms of the consumption of several resources used to quantify human footprint, and show how urbanization may be compatible, and even accelerate, the achievement of continued economic growth that is compatible with the preservation of the Earth's support systems.