There are three research areas that I have been most interested in:

Agroecology and Forest management; this research aims to develop a numerical/quantitative tool for decision makers in Conservation Biology. We will be using as a framework the results from a long-term research program focusing on the study of tropical plant recruitment and their associated seed disperses and predators in the rain forests. The study will be conducted in eastern Nicaragua where the largest rain forests are located in Mesoamerica. We are actively searching for research funds to initiate this important research component.

Ecological consequences of seed dispersal and top-down biological interactions; the focus of this research is to present field evidence about the relative contributions of bat seed dispersal and terrestrial vertebrate seed dispersal on the recruitment dynamics of tropical tree species. In collaboration with Dr. Douglas H. Boucher from Union of Concerned Scientist, I have been able to gather a high-resolution database, our current results show a high degree of clustering in the process plant dispersion (Ruiz et al. 2009a), mainly driven by primary seed dispersal by tropical bats (Ruiz & Boucher 2008) and secondary seed dispersal by terrestrial vertebrates (Ruiz et al. 2010). I am currently expanding my research to account for the quantification of recruitment ecology in space. This research objective focuses on arriving to general underlying mathematical and statistical rules that might govern the process of plant dispersion in tropical rain forests.

My research team and I have recently presented evidence showing a beneficial effect of spider presence on seedling recruitment (Ruiz et al. 2009b). I think that our findings open new and exiting research lines about how spider predation upon herbivorous insects may increases seedling survival and growth in tropical rainforests. The next stage of this research will be to involve experimentation in order to determine the predatory coefficient of spiders upon herbivorous insects and their positive indirect effect on plant recruitment demography. I am currently writing research proposals focusing on field experimentation and space explicit quantification of the top-down control of spider presence on seedling demography. This research will be conducted at the biological station of Bluefields Indian and Caribbean University.

Disturbance and recruitment dynamics of tropical tree species; this is a long-term study that involves two components. First, is the evaluation of seedling recruitment dynamic. Here, I aim to understand whether or not recruitment different from the Janzen-Connell pattern of forest assemblage (Ruiz et al 2009a). Second, is the process of tree growth into the thinning canopy of the regenerating rainforest of eastern Nicaragua. The hypothesis is to determine whether tree species mortality is at random at this thinning canopy. For instance, if tree mortality occurs randomly, then this would provide evidence in favor of the recruitment limitation hypothesis (Hubbell 2001). Our most recent findings suggest that tree recruitment in the thinning canopy is a random walk. These results are soonly to be published in the international journal, Revista de Biología Tropical. Both research lines have been conducted in collaboration with my colleagues from the University of Michigan, Union of Concerned Scientist, Cornell University and the Bluefield Indian and Caribbean University.

I have been focusing on understanding the effect of natural disturbances on tropical tree species diversity and forest regeneration. In particular, the effect of hurricane Joan on the regeneration of the tropical rainforests of Nicaragua. This research gave the opportunity to become involved in an extensive collaboration with Dr. John Vandermeer, Dr. Ivette Perfecto and Dr. Iñigo Granzow de la Cerda from the University of Michigan and Dr. Douglas Boucher from Union of Concerned Scientist. Our contributions to the understanding about how tropical rainforest regenerate after a massive hurricane involves multiples publications in specialized scientific journals.

Our principal findings have been recently summarized in the following research components:

1) The “direct regeneration” from primary forest to primary forest after the hurricane (Yih et al. 1991).
2) tree growth and mortality in the thinning canopy (Ruiz et al. 2010).
3) The effect of forest fires on tree growth and mortality (Granzow-de-la-Cerda et al. in preparation; Ruiz et al. 2001).