Stefani Crabtree (Washington State U) Cognitive Webs and Long Term Sustainability

STUDYING ARCHAEOLOGICAL FOOD-WEBS IN ANCESTRAL

PUEBLOAN SOCIETY

Stefani Crabtree, Washington State University

Monday, October 22, 2012

WHAT IS A FOOD-WEB?A network of interactions between producers and consumers

The graphical representation of trophic interactions

directional, shows community structure, stability, and nutrient flow

Basically, who eats whom.


PREVIOUS FOOD-WEB STUDIES

Estes et al. 1998; a look at killer whale predation on sea otters.

First study linking oceanic and near shore systems.

Yodzis and Inness’s producer/consumer functional response model.


HUMAN SPECIFIC MODELS

Studies usually focus on negative consequences of human involvement--i.e. exploitation.

Deer predation in U.S. Southwest--human overhunting destroyed big game by Pueblo II times.

Exception: work by Jennifer Dunne’s lab

Collaboration with Herb Maschner looking at long-term human interaction/management in Alaska


THIS STUDY:

Looks at human/environment interactions in a novel environment

The Mesa Verde Cuesta and Great Sage Plain

Attempts to understand human/environment interactions within an agricultural society.

Decouples humans from direct causation; looks at humans as actors (and reactors) in a complex system.

Tests vulnerability of humans in their environment.


Occupied 1250-1274 AD.

Well-excavated by Crow Canyon Archaeological Center.

Oral history linking surviving descendants to the site.

Well-recorded, high resolution of utilized plants and animals.

WHY CASTLE ROCK?


METHODS

Combed the grey literature to compile information on all animals and plants living in our study area in Southwest Colorado.

Data easily located for plants and mammals. Difficult for invertebrates.

Invertebrates were aggregated according to types.

Human consumption patterns were taken from Castle Rock Pueblo Archaeological site and data on ethnographic consumption from Crow Canyon Archaeological Center.


THE FOOD-WEBS

Overall Food Web

Human-Specific Food Web

Trophic Level

Trophic Level


DISCUSSION

Humans directly predate few species on the landscape.

When we take into account what the species that humans prey on eat, web gets more complicated.

Humans are connected to all species in the landscape through secondary, tertiary and quaternary connections.


VULNERABILITY WEB

Humans are not especially vulnerable because of their omnivory.

However, the species that humans rely on most have few species they eat.

Human vulnerability is related to the vulnerability of their prey.

Vulnerability


DISCUSSION

Humans did affect the survival of their prey through hunting. However, because high-ranked game rely on few species for preferred browse, high-ranked prey would be affected by small climatic changes.

If deer rely on a shrub for a majority of their diet, but it is affected by long term growth cycles of invertebrates, deer abundance will go down when invertebrates get more abundant.

Humans reacted not only to hunting-induced depletion but also the resiliency of the system as a whole


CONCLUSIONS

These data are preliminary; it’s being refined daily.

Working to include percents of diets to look at “nodal knockout” of key species

However, there are important implications for worldwide ecosystems.

Seemingly “invisible” forces may have dramatic effects on an ecosystem.

Resiliency of ancestral population is in the choices they had; what is our resiliency now?


ACKNOWLEDGEMENTSThis work was produced under the Village Ecodynamics Project (VEP), funded by NSF DEB-0816400

Individual support provided by the NSF grfp program at Washington State University.

Initial project produced at the Santa Fe Institute Complex Systems Summer School.


THANKS...Lydia Smith, MA student at UC Berkeley

Santa Fe Institute, especially Jennifer Dunne for invaluable advice on this project;

Rick Williams and Neo Martinez for their help with the use of Networks 3D;

Mark Varien, Scott Ortman and Donna Glowacki for advice on how to proceed with archaeological literature;

Thomas Lewinsohn and the faculty at the Sao Paulo Advanced Science School on Ecological Networks for critiques of an earlier draft of this project;

David Krakauer and Cormac McCarthy for evaluating and judging a previous version of this work


Stefani Crabtree (Washington State U) Cognitive Webs and Long Term Sustainability

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