Theoretical Ecology Lab Tea

The Theoretical Ecology Lab Teas are informal meetings where members of affiliated lab groups give talks on their current research and receive feedback from their audience. Talks are 30 minutes long and are followed by questions and discussion.

Lab Tea typically meets Wednesdays at 12:30 pm during the fall and spring semesters. All talks this semester will be held in Eno 209 unless otherwise stated.

For the spring semester of 2019, the talk schedules and email lists will be maintained by Mari Kawakatsu and Georgios Artavanis. Please contact Mari or Georgios to have your name added to the Lab Tea email list so that you can receive reminders about upcoming meetings.

Spring 2019 schedule

Click on an event to view the talk title and abstract

Date and time Speaker
Luca Rade
Theresa Ong
Renato Pagliara Vasquez
Daniel Cooney
Alex Becker
Laura Elsler
Chris Tokita
Christie Riehl
Alice Lin
Spring break - no Lab Tea
Sarah Drohan
Mari Kawakatsu
Bernat Guillen
John Harte (Visitor from UC Berkeley)
Fernando Santos
Available
Anna Vinton (Visitor from Yale)
Ricardo Martinez-Garcia

Note: Priority is given to graduate students. A symbol next to the speaker's name means that approval is pending for a week and graduate students can still claim the slot.

Titles and abstracts

Towards a general framework of adaptive processesLuca Rade

Any cohesive system in an unpredictably changing environment has an adaptive process to maintain fitness. There must be a mechanism for processing the change in the environment's fitness function, exploring and selecting possible adaptations, maintaining the integrity of the rest of the system, and preventing over-adaptation to transient change. By examining genetic evolution, the immune system, biological learning, and artificial learning as adaptive processes, I am seeking to formalize the underlying principles of adaptive processes and the axes along which such systems differ. This is a work in progress and the talk is primarily aimed at soliciting sources and ideas based on the initial framework.

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Agroecological theory: a complex systems approachTheresa Ong

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Infection and reinfection in epidemic models in networksRenato Pagliara Vasquez

We study the SIRI (Susceptible-Infected-Recovered-Infected) epidemic model for reinfection in which the susceptibility of individuals to first-time infections might be different than their susceptibility to secondary infections. The SIRI model generalizes the basic SIS and SIR models and allows for the study of systems in which the susceptibility of agents changes irreversibly after the first exposure to the infection. Using a mean-field approximation, we derive a set of ODE's describing the spreading dynamics on arbitrary networks. We use the resulting network SIRI model to explore the role of network topology and agent heterogeneity in the transient and long-term dynamics at the level of the group. We show the network SIRI model has four different dynamical regimes, including a bistable regime that takes place when secondary infections are more likely than primary infections, and where there exists a critical manifold of initial conditions that separates solutions where the infection dies out and solutions where the infection spreads through the network. We show that when the infection spreads through the network, solutions exhibit a resurgent epidemic in which the probability of infection across the network initially decreases before ramping up towards an endemic equilibrium.

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Pattern formation in opinion dynamicsDaniel Cooney

We will discuss the Hegselmann-Krause model for opinion dynamics and review recent work on the clustering of opinions in the presence of noisy decision-making. Emphasis will be placed on the potential bistability of patterned and uniform states and on the "spikiness" of clustered opinions.

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Coexisting attractors in the context of cross-scale population dynamics: measles in London as a case studyAlex Becker

Patterns of measles infection in large urban populations have long been considered the paradigm of synchronized nonlinear dynamics. Indeed, recurrent epidemics appear approximately mass-action despite underling heterogeneity. However, using a subset of rich, newly-digitized mortality data (1897-1906), we challenge that proposition. We find that sub regions of London exhibited a mixture of simultaneous annual and biennial dynamics, whilst the aggregate city-level appears firmly annual. Using a simple stochastic epidemic model and maximum likelihood inference methods, we show that we can capture this observed variation in periodicity. We identify strong agreement between theory and data, indicating that both changes in periodicity and phase coupling between regions can follow relatively simple rules. Our analysis underlines that multiple attractors can coexist in a strongly-mixed population, and follow theoretical predictions.

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Oceanographic dynamics drive inequality through critical multi-level links in the Humboldt squid fisheryLaura Elsler

Environmental dynamics can amplify inequality and poverty for fishers dependent on marine species use for their livelihoods. Traders, fishers and other groups in the social system are affected by environmental dynamics. In small-scale fisheries, distribution of benefits is often influenced by relationships between fishers and traders. Those relationships are not included in traditional models for fisheries management. A considerable gap remains in understanding the mechanisms through which benefits are distributed by both trade relationships and environmental dynamics and thus affect inequality and poverty in fisheries. Here we find that driven by oceanographic variability and change the links between target species, traders and fishers, have contradictory effects on income inequality in the Mexican Humboldt squid fishery. We demonstrate that development programs based on models ignoring the multi-level between oceanographic dynamics, fishers and traders may exacerbate already severe income inequality between those groups. In particular, during cold oceanographic conditions fishers benefit from high catches but they are trapped in a traders monopoly that sets low prices. In contrast, catch volumes and trader competition decrease during warming oceanographic conditions. Our quantitative analysis shows that in this context, increasing local market prices, as a management strategy to develop the squid fishery, reinforces existing income inequalities. This research provides an example how to integrate multi-level links in a yet simple modeling framework to improve prediction accuracy and guide contextualised management strategies. We anticipate our model to be a starting point to expand existing fishery models with social and trade relationships that interact with variables relevant to fishery management.

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Chris Tokita

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Christie Riehl

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Alice Lin

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Spring break - no Lab Tea

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Sarah Drohan

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Mari Kawakatsu

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Bernat Guillen

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John Harte (Visitor from UC Berkeley)

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Fernando Santos

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Available

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Anna Vinton (Visitor from Yale)

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Ricardo Martinez-Garcia

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Links to previous schedules

  1. Fall 2000
  2. Spring 2001
  3. Fall 2001
  4. Spring 2002
  5. Fall 2002
  6. Spring 2003
  7. Fall 2003
  8. Spring 2004
  9. Fall 2004
  10. Spring 2005
  11. Fall 2005
  12. Spring 2007
  13. Fall 2007
  14. Spring 2008
  15. Fall 2008
  16. Spring 2009
  17. Fall 2009
  18. Spring 2010
  19. Fall 2010
  20. Spring 2011
  21. Fall 2011
  22. Spring 2012
  23. Fall 2012
  24. Spring 2013
  25. Fall 2013
  26. Spring 2014
  27. Fall 2014
  28. Spring 2015
  29. Fall 2015
  30. Spring 2016
  31. Fall 2016
  32. Spring 2017
  33. Fall 2017
  34. Spring 2018
  35. Fall 2018