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Current research

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  Phenological mismatches between resources and consumers

   Global warming is causing the [6]phenology of many species to advance towards
   earlier dates, but at different rates. Thus, some interactions can weaken and
   others can intensify. Consumer-resource interactions involve feedbacks that can
   affect the abundances of the resources (top-down effects) and the consumers
   (bottom-up effects). I considered these feedbacks in a model where consumers and
   resources recruit during specific seasons of the year, interact, and produce the
   propagules (seed and/or eggs) that will recruit in the next year.

                                   [FIG: Phenology]

   If consumers recruit too early or too late relative to the resources, sure they
   will go extinct. If they recruit very close in time with the resources, they
   avoid extinction, but they will not attain high densities. This is because
   increased temporal overlap between consumers and resources causes
   overexploitation and scarcity in future times.

                             [FIG: Abundance vs mismatch]

   Higher consumer abundances occur when recruitment happens few weeks before or
   after the resource. This result also applies, with appropriate modifications, in
   community modules of three species. For example, two consumers can coexist with a
   single common resource if one recruits before, and the other recruits after the
   resource, but the earliest recruiter becomes more numerous because it can eat
   during more days. Thus, predictions about future consequences of phenological
   changes due climate change must consider top-down controls in addition to
   seasonal availability of food (bottom-up control).

  Phenological shifts and habitat destruction in mutualistic networks

   Phenology is an important structuring factor of [7]mutualistic networks. There is
   concern that global climate change will disrupt the temporal schedules of
   interactions between plants and their pollinators and/or seed dispersers, making
   ecological communities more vulnerable to other threats, for example habitat
   destruction or fragmentation. We developed a spatially-explicit meta-community
   model to explore the effects of habitat destruction and phenological changes on
   the mutualistic networks.

   Habitat destruction causes the gradual erosion of local diversity, leading to
   global meta-community collapses. Restoration of meta-communities, by recovering
   destroyed sites back to habitable, can be difficult due to [8]hysteresis.

              [FIG: Diversity vs phenological shift and site destruction]

   Shifts in phenologies (e.g. 10, 20, 30 days earlier, on average) can weaken
   mutualistic interactions, enabling meta-community collapses by lower amounts of
   habitat destruction. We found that the combined effects of phenological shifts
   and habitat destruction can re-inforce each other synergistically, i.e. their
   joint detrimental effects are larger than the sum of their effects.

  Effects of population structure on mutualisms

   In many systems mutualism occur only during very specific life-stages, such as
   the adult phase of an insect. We developed a plant-pollinator model where the
   pollinator is divided into adults and larva. By consuming nectar, the adults give
   pollination services to the plants. Changes in the life-cycle of the insect,
   caused by climate change or pesticides for example, will alter the balance
   between servicing adults and useless larvae, affecting the quality of the service
   for the plants.

   This model predicts that large plant abundances are positively related with large
   adult to larva ratios, and that for plants that strongly depend on pollination
   services, decreases in adult:larva ratios could lead to a sudden drop in plant
   abundances.

                      [FIG: Plant abundance vs adult:larva ratio]

   If other life-stages are actually harmful, such as herbivorous larvae, changes in
   population structure can even change the net sign of the interaction. To
   demonstrate this, we considered a model where the larvae consume the tissues of
   the same plant pollinated by the adults. This model can develop oscillations like
   many predator-prey models. An important detail of these oscillations is that the
   plant population can cycle above and below its carrying capacity (in some cases
   entirely above) thanks to the positive effects of pollination. Essentially, the
   dynamics can display a periodic alternances between antagonism (larvae in
   control) and mutualism (adults in control).

                         [FIG: Plant-pollinator oscillations]

  Functional and numerical responses in mutualistic interactions

   The exchange of resources such as nectar or nutrients, or services such as
   pollination, requires the existence of structures or organs, such as fruits and
   flowers. These are usually short lived compared with dynamics of interacting
   populations. We considered these structures in an interaction model.

                        [FIG: Flower dynamics and pollination]

   Since flowers or fruits are ephemeral, we consider that their numbers attain a
   steady state very rapidly. This allows a mechanistic derivation of functional and
   numerical responses in plants and pollinators. For the plants for example, the
   "handling time" of a plant turns out to be proportional to the amount of time
   required to produce a new flower.

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  Mutualism, competition and adaptation

   Predators can promote prey coexistence by preying more on abundant preys and less
   on rare preys. In contrast, if pollinators tend to pollinate the most common
   plants, this can make common plants more common and rare plants more rare. I am
   investigating this kind of mutualistic driven apparent competition using simple
   community modules, e.g. 2 plants + 2 pollinators.

                           [FIG: Plant -- Pollinator module]

   Using optimal foraging theory, we can understand better how adaptation in
   pollinators and seed dispersers can affect plant diversity.

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Past research

   I investigated topics such as resource competition between juvenile and adult
   stages and the coexistence and stability conditions under intra-guild predation.
   During my doctorate I worked on the dynamics of multispecies resource
   competition. I also did research that concerns human health, like the
   characterization of the mortality of disease vectors, or the hypothetical use of
   viruses against other viruses.

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Collaborators/Colleagues

     * [9]Jesus Alberto León
     * [10]Diego Rodríguez
     * [11]Maria-Josefina Hernández
     * [12]Harold Perez de Vladar

     * [13]Luis Fernando Chaves
     * [14]Franz Weissing
     * [15]Francisco Encinas-Viso
     * [16]Rampal Etienne

     * [17]Gisela García-Ramos
     * [18]Ciska Veen
     * [19]Michel Loreau
     * [20]Vlastimil Krivan
     ____________________________________________________________________________

             [21]Home [22]Contact [23]Research [24]Publications [25]Links


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References

   1. http://tomrevilla.sdf.org/index.html
   2. http://tomrevilla.sdf.org/contact.html
   3. http://tomrevilla.sdf.org/research.html
   4. http://tomrevilla.sdf.org/pubs.html
   5. http://tomrevilla.sdf.org/links.html
   6. http://www.thefreedictionary.com/phenology
   7. http://www.thefreedictionary.com/mutualism
   8. http://en.wikipedia.org/wiki/Hysteresis
   9. https://www.meer.com/en/63965-jesus-alberto-leon
  10. https://www.researchgate.net/scientific-contributions/Diego-J-Rodriguez-2032851793
  11. https://www.researchgate.net/profile/Mj-Hernandez
  12. https://hpvladar.wordpress.com/
  13. https://orcid.org/0000-0002-5301-2764
  14. http://www.rug.nl/staff/f.j.weissing/
  15. https://people.csiro.au/E/F/Francisco-Encinas-Viso
  16. http://www.rug.nl/staff/r.s.etienne/
  17. https://www.researchgate.net/scientific-contributions/Gisela-Garcia-Ramos-37933070
  18. http://www.linkedin.com/pub/ciska-veen/25/49b/852
  19. https://sete-moulis-cnrs.fr/fr/recherches/ctmb/equipe/item/179-loreau-michel
  20. http://mathbio.prf.jcu.cz/en/krivan/
  21. http://tomrevilla.sdf.org/index.html
  22. http://tomrevilla.sdf.org/contact.html
  23. http://tomrevilla.sdf.org/research.html
  24. http://tomrevilla.sdf.org/pubs.html
  25. http://tomrevilla.sdf.org/links.html