I conduct biogeographic studies at the interface between ecology and
evolution. My current research program focuses on developing GIS-based methods
of modeling species geographic ranges using occurrence records from natural
history museums and
environmental data. In addition to these techniques of general application to
biogeography and conservation, Neotropical mammals represent my taxonomic and
geographic specialty. I received a Ph.D. at the University
of Kansas under the supervision of Dr. Robert
M. Timm and subsequently conducted postdoctoral research at the American
Museum of Natural History, sponsored by Dr. Robert
S. Voss.
My lab is funded currently by a
grant from the National Science Foundation (DEB-0717357; Systematic
Biology and Biodiversity Inventories Program, Division of Environmental Biology)
entitled “Integrating systematics and GIS modeling: biogeography of spiny
pocket mice (Heteromyidae) in South America" Read
more
My integrated research program includes three
interconnected areas detailed below:
Taxonomic
and phylogenetic studies (including fieldwork)
Evolution
of insular faunas
Modeling
species distributions using geographic information systems (GIS) and museum
records
Taxonomic and phylogenetic
studies (including fieldwork):
I undertake revisionary work on poorly known genera of mammals from the northern and central Neotropics
(Mexico to Brazil). My goals here are to elucidate species boundaries (e.g., Anderson, 1999; Anderson and
Soriano, 1999; see publications), describe new species (Anderson and Handley, 2001; Anderson and
Jarrín-V., 2002; Anderson, 2003; Anderson and Timm, 2006), and elucidate phylogenetic relationships
(Gómez-Laverde et al., 2004; Anderson et al., 2006; Anderson and Jansa,
2007). My collection-based studies also provide extensive
data sets for subsequent evolutionary and biogeographic analyses, as well as
conservation assessments.
Skulls of Heteromys australis and Heteromys anomalus;
modified from Anderson, 1999
Participants,
IUCN (World Conservation Union) Global Mammal Assessment, Andean small mammals
workshop, Villa de Leyva, Boyacá, Colombia, 6–10 February 2006. I am
standing behind Belkis Rivas, who is wearing a pink shirt.
For molecular research conducted by collaborators, new collections of key species
are necessary. I have conducted modern
inventories for mammals through field work in Colombia and Guyana (Cadena et al., 1998;
Lim et al., 1999). I am fluent in Spanish and have a strong intellectual and personal commitment to Latin
America. This has facilitated successful collaborations
with scientists from Colombia, Ecuador, and Venezuela (e.g., Anderson et al.,
2002, 2003; Anderson and Jarrín-V., 2002; Anderson and Soriano, 1999; Cadena et al., 1998 Gómez-Laverde et al.,
2004).
Since 2005, I have maintained an
active field program in Venezuela in collaboration with Dr. José
Ochoa-G. and Dr. Marisol
Aguilera. We have surveyed the Cerro Santa Ana and the Serranía
de San Luis. These isolated mountain ranges support evergreen cloud forest
but are surrounded by a lowland matrix of dry thorn forests (see more pictures
at the bottom of this page). To compare with these small isolated ranges,
we are also conducting fieldwork in the larger Cordillera de la Costa. See Evolution of Insular Faunas, below, for
more information.
Burro Burro River in Guyana and . . . . . . . . Field camp at Pakatau Falls, 1997;
see Lim et al., 1999
Cerro Santa Ana on the Península de Paraguaná in
northwestern Venezuela (fieldwork undertaken in October 2005 in collaboration
with Dr. José
Ochoa-G.).
Evolution of insular faunas:
The second branch of my research concerns factors affecting morphological and genetic evolution of insular
populations. Although important differences exist, empirical research on real islands is relevant to the
study and long-term management of landscapes fragmented by human activities.
I have studied dwarfism and speciation
in three-toed sloths of the landbridge islands of Bocas del Toro, Panama, which were formed in the past 10,000 years
by rising sea levels (Anderson and Handley, 2001, 2002). I am collaborating with
Dr. Link Olson
(University of Alaska), who is sequencing mitochondrial DNA in order to elucidate molecular
patterns of diversification among populations of insular and mainland sloths for comparison with my morphological
framework and the sequence of island formation. Because excellent collections of mammals from this region exist at the
Smithsonian Institution, the islands and mainland of Bocas del
Toro represent a superb study system
for integrated tests of evolutionary and community ecology theory in an insular fauna for our future studies
with a multi-species perspective.
The field program I have in
Venezuela (see above) closely relates to the study of insular faunas, since the
montane forests of northwestern Venezuela represent "ecological
islands" or "habitat islands" (see photographs at the bottom of
this page). However, the degree of isolation varies among species.
Currently, my students and I are using GIS models (see below) to estimate the
potential distribution of each species, allowing us to quantify their level of
isolation. We will then test the prediction that more-isolated species
exhibit greater morphological and genetic differentiation. This work is in
collaboration with Dr. José
Ochoa-G. and Dr. Marisol
Aguilera.
Map of the archipelago of Bocas del Toro, with an insert map showing its position within Panama;
modified from Anderson and Handley, 2001
Map of
northern Falcón,
Venezuela, showing the Istmo de los Médanos,
which connects the Península
de Paraguaná
to the "mainland." Note the Serranía
de San Luis (the east-west mountain range in the south) and the Cerro Santa Ana
(the tiny, circular mountain on the Península
de Paraguaná.
Modeling species distributions using GIS:
At the forefront of my current research
agenda is the use of species occurrence localities (especially museum records),
environmental data, and Geographic Information Systems (GIS) to model species
potential geographic distributions. The niche-based nature of these models allows for synthetic
studies of evolutionary ecology and biogeography (Anderson 2003, Anderson et al.,
2002a, b, 2003).
These techniques are also relevant to invasive
species management, the effects of global climate change, and conservation
biology. For instance, I modeled the rare species Heteromys
teleus endemic to western Ecuador, estimating the location of remaining areas of
suitable habitat for the species (Anderson and Martínez-Meyer, 2004).
My undergraduate student Mariya Shcheglovitova is repeating these analyses with
new techniques and environmental data (see People),
to guide field surveys that will be conducted by our Ecuadorian collaborator Santiago
Burneo and students.
Currently, my
students and I are working to integrate GIS distributional modeling into
systematic studies based on morphological and genetic information. This work is supported by a grant from the National
Science Foundation (DEB-0717357; Systematic
Biology and Biodiversity Inventories Program, Division of Environmental Biology)
entitled “Integrating systematics and GIS modeling: biogeography of spiny
pocket mice (Heteromyidae) in South America." For the
comparative aspects of this research, we are collaborating with Dr. Duke
S. Rogers and his students at Brigham Young University, who are sequencing
mitochondrial and nuclear DNA and conducting phylogenetic analyses.
Read
more.
Over the
past several years, I have worked in the development and use of techniques from
machine learning (Maxent; Maximum entropy methods) to model species
distributions. In this research, I have collaborated with Dr. Steven J. Phillips
at AT&T-Research and Dr.
Robert E. Schapire at Princeton, and Dr. Miroslav Dukík (then also at
Princeton; now at Carnegie Mellon). Their Maxent software is available for download,
and their websites provide documentation on Maxent. We successfully
applied it to the distributions of two species of Neotropical mammals (Bradypus
variegatus and Microryzomys minutus) in a recent project (Phillips et
al., 2006). Maxent is among the highest-performing techniques for modeling
species distributions with presence-only data (see Elith et al., 2006) and is
being used by myriad researchers worldwide.
My
students and I continue to use and develop Maxent. We are applying it to
study the evolution, biogeography, and conservation of Heteromys in South
America (see NSF grant, above), as well as using it in our studies of montane
mammals in Venezuela (see fieldwork and Evolution of insular faunas,
above). Furthermore, we are conducting methodological studies to increase
the robustness of Maxent to biases in sampling (work with Israel Gonzalez; see People)
and to propose principles for selecting the appropriate study region for
modeling species distributions (work with Ali Raza; see People).
Predictive potential distributional
model of Bradypus variegatus in the Neotropics; from Phillips et al.,
2006; locality data from Anderson and Handley, 2001.
More photos from
our field program in Venezuela:
Near
the summit of Cerro Santa Ana, at a clear moment.
Dwarf
cloud forest on Cerro Santa Ana.
Thorn
forest near the base of Cerro Santa Ana.
Outline
of Cerro Santa Ana in the distance, from northern slopes of the Serranía
de San Luis. Note the Istmo de los Médanos
on the right, connecting the Península
de Paraguaná
to the rest of Venezuela.
Extensive
stands of columnar cacti (cardonales) south of the Serranía
de San Luis.
Thorn
forest on the northern slopes of the Serranía
de San Luis.
Cloud
forest in the Serranía
de San Luis.
Robert
Anderson explains the differences between rodents and marsupials to young
citizens of Santa Ana.
Dr. José
Ochoa-G. (dark shirt, standing) shares information regarding our research and
conservation of mammals and their environments to a crowd at the Casa de la
Cultura, Santa Ana.
Lower:
Carlos Valerio, Robert P. Anderson, Ruth Peña,
Franger García;
Upper: Simón Bolívar
(bust). Santa Ana, Falcón,
Venezuela.
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R. P. Anderson
Copyright © 2002-2008.
Unless noted, all photographs by RPA
Last modified: 8 May 2008 (RPA)
