Staff Profile
Ivan Castro-Arellano

Postdoctoral Fellow

Phone: (860) 486-1772
Fax: (860) 486-1753
Email: ivan.castro@uconn.edu

Curriculum Vitae

List of projects, publications and presentations

Education

2005.  Ph.D. Texas A&M University.  Department of Wildlife and Fisheries Sciences.
2000.  M.S. Texas A&M University.  Department of Wildlife and Fisheries Sciences.
1997.  B.S. (Honors). Universidad Nacional Autonoma de Ciencias.  Biology major.

Research Interests

My core interest as an ecologist is how ecological processes interact across scales of time and space to determine diversity distribution patterns we observe in nature. I see ecology moving more and more toward integrated studies that do not rely exclusively in hypothetico-deductive studies at local scales but also integrate nonexperimental inductive approaches at larger scales.  Within this research agenda the inclusion of phylogenetic information and spatially explicit frameworks will close gaps between ecology, evolution and biogeography.  Academic endeavor is not the only purpose of integrative biodiversity studies, given that they are also an urgent need for conservation biology.  Both objectives will require extensive collaborations that gather diverse expertise, and it is within such a group that my research and contributions will fit most appropriately.

Current and Past Research

My formation and experience have been in mammal ecology and biogeography for both academic and conservation objectives.  Early on my career (1993) I joined Dr. G. Ceballos research group at the Instituto de Ecologia of the National Autonomous University of Mexico (UNAM).  My participation in diverse field projects and interactions at this laboratory greatly influenced my ideas about how sound research is conducted and about current questions in our field.  My research has focused on both community ecology of small mammals and large-scale mammalian biogeographic patterns.  For my undergraduate thesis project, I statistically quantified the latitudinal species gradient of terrestrial African mammals using polynomial regression analyses and during a summer internship at the Smithsonian NMNH, I studied biogeography of elephant shrews (Macroscelidea), an African endemic order.

My doctoral research addressed community assembly patterns of two rodent communities occurring over a sharp altitudinal gradient at El Cielo Biosphere Reserve in northeast Mexico.  Species at this reserve represent a unique mix of both neartic and neotropical origins thus enabling unique comparisons between communities.  I investigated temporal partitioning, microhabitat use, vertical habitat stratification and landscape co-occurrences using both multivariate statistics and null models using Monte Carlo simulations.  Patterns of species segregation and niche complementarity revealed them as highly structured assemblages.  My study adds further proof to the role of heterogeneity in species segregation and provides evidence of structural organization in subtropical rodent communities, such as the one present in well-studied systems like desert rodent communities.

A very important contribution of my research is about the role of temporal partitioning in community assembly.  I provide the first demonstration of non-random structure in temporal niche partitioning for a diverse rodent community.  Very few ecologists regard time as an important niche axis but recent finds in several taxa are showing otherwise.  I contend that as small mammal ecologists we have not given enough attention to this niche axis that deserves further research.  Lastly, concomitant with my doctoral study I developed other projects and established collaborative efforts to address other objectives:

• Stomach contents or rodent specimens from El Cielo were analyzed by Ludivina Rubalcava and Jesus Garcia, from the Instituto Tecnologico de Ciudad Victoria, to quantify the consumption of fungi.  Almost nothing is known about micophagy in rodent species of Mexico and this survey represents one of a few and likely the one with largest sample size.  A masters thesis was completed with this data and a manuscript is currently being prepared.
• Phylogenetic relationships of Reithrodontomys species from el Cielo are being examined using molecular data in collaboration with Dr. Elizabeth Arellano from the Centro de Educación Ambiental e Investigación Sierra de Huautla, Universidad Autónoma del Estado de Morelos.

• I used camera trap and hair trap surveys to assess landscape habitat use of medium and large mammals at El Cielo Reserve.  I am currently co-chairing a thesis committee of a Mexican student that is analyzing this data we both collected from 2000 to 2003.

In my current participation as a postdoctoral fellow at the University of Connecticut, I am addressing the response of bat communities to Reduced Impact Logging practices at Tapajos National Forest in Brazil.  Silvicultural demonstration plots of selective logging with RIL practices were established at this forest and bat communities where surveyed and compared to areas of undisturbed forest.

Additionally, I am involved with the research at the Luquillo LTER site in Puerto Rico where the assemblages of terrestrial gastropods are being studied to understand the community response to disturbance over long temporal scales.

Research Agenda: rodent diversity across scales.

My interests within ecology are highly spatial and scale oriented with rodents and other small mammals being my taxon choice to study how biotas are assembled.  Rodents suit well for these objectives since they are globally widespread, usually locally abundant, and represent a diverse group of mammals both ecologically and taxonomically.  For my future work, I want to address several questions that although framed at different scales, are ultimately linked in an evolutionary ecology continuum:

• At the local scale I want to develop in-depth ecological research of communities where temporal partitioning has evolved.  Understanding selection forces that shape diel rhythms of rodents at these assemblages will likely provide insights into the role of time as a niche axis.
• At the landscape and regional level I want to address community assembly histories by means of comparative phylogeographic studies of constituent species.  “Historical effects” are usually referred to in community assembly studies but have infrequently been quantified.
• At the global scale I want to test for non-random patterns of range overlap between congeneric rodents by using a null model approach.  Subsequent comparisons of genera with different life histories, body masses, range extents, and species richness will likely yield insight on how geographic space is allocated among species and how continental biotas are assembled.  Rigorous quantitative analyses in this area have not been attempted on a large scale before but new geographic tools and global data set compilations will make this possible.
• At this same scale I think there is also a current need to asses global patterns of diversity, endemism and endangerment for rodents and other small mammals.  These groups have not been subject to detailed global analyses such as the ones already done for bats, carnivores and primates.  Interestingly, rodents constitute almost half of all mammalian species and have experienced more extinctions than any other mammal order in the last two centuries (Ceballos and Brown, Conservation Biology 9:559-568, 1995).  Differences in our knowledge for each order are partially responsible for lack of detailed analyses in some groups.  Current global data compilations will partially alleviate this problem and even relatively simple data (eg., range size, body mass, life history) will allow tests to assess correlates of global threat.