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Oak Regeneration Project (BIOSTRESS)

Greenhouse experiment where oak seedlings are subjected to different types of stress
Greenhouse experiment where oak seedlings are subjected to different types of stress

The overall goal of this project (BIOSTRESS) is to better understand the multiple phases involved in the oak regeneration process in Mediterranean environments and to provide scientific guidelines for the conservation and management of oak-dominated systems. One of the main objectives of this project is to analyse how different sources of stress (biotic and abiotic) may alter the performance of oak seedlings as well as the sign and strength of biotic interactions within the oak regeneration cycle (e.g. seed dispersal, herbivory and and plant facilitation). Through field and greenhouse experiments in Stanford facilities we are studying the regeneration process of different California oak species, mostly coast live oak (Quercus agrifolia) and valley oak (Quercus lobata). These are some of the specific aims:

  1.  We study acorn predation and dispersal using video-cameras and tracking tagged acorns. Our aim is to know what animal species are involved in the removal of acorns and the fate of these acorns. We establish transition probabilities from acorn removal to seedling emergence for different animal species
  2. We study the natural distribution of seedlings and saplings in both oak savannas and woodlands to know the actual density and distribution of oak recruitment
  3. Through experimental manipulation in the field (transplanting seedlings under different conditions) we analyse the survival, growth and limiting factors for the germination of acorns and establishment of seedlings
  4. In the greenhouse we subject seedlings of different Quercus species to stress gradients to see how they respond in terms of survival, growth and ecophysiological variables.
  5. We study deer preferences for shrubs and the effect of palatable and non-palatable shrubs on the facilitation of oak seedlings

Keywords: Acorn dispersal, herbivory, deer browsing, plant facilitation, forest management, seedling establishment, scatter-hoarding, animal behavior, ecophysiology, water stress.

Financial support from the MARIE CURIE Actions (European Commission).

Contact person: Dr. Ramon Perea

Visiting Scholar

Spring 2014-2017

Jay dispersion captured by a trap camera
Video recording with a western scrub jay dispersing acorns

 

Students helping on the day of seedling plantation in Jasper Ridge (Stanford University)
Students helping on the day of transplanting seedlings in Jasper Ridge (Stanford University)

 

Video-cameras used to identify the animal species removing acorns as well as their frequency (quantity of removal)
Video-cameras used to identify the animal species removing acorns as well as their frequency (quantity of removal)

 

Paired design with protected and non-protected seedlings under different microsites
Paired design with protected and non-protected seedlings under different microsites