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A Townsend Peterson

Publications and source records attributed to A Townsend Peterson.

At least 19 recordsLinked to original sources
PubMed2006

A multilocus phylogeny of New World jay genera.

We studied phylogenetic relationships of the New World Jays (NWJs) based on DNA sequences from three mitochondrial and two nuclear loci. Sampling included at least two individuals from each of the seven NWJ genera and four outgroups of closely related corvids, as well as six of the 16 Cyanocorax species (including two representatives of the previously recognized "Cissilopha"). Phylogenetic analyses were conducted using maximum parsimony, maximum likelihood, and Bayesian analyses for individual genes and a combined dataset. The combined phylogenetic analysis supports the basal position of Cyanolyca to all other NWJs, a (Cyanocorax (Calocitta, Psilorhinus)) clade, and a ((Cyanocitta, Aphelocoma) Gymnorhinus) clade that agrees with a novel morphological synapomorphy uniting Cyanocitta and Aphelocoma. Within Cyanocorax, C. yncas (former "Xanthoura") is basal to a split among former "Cyssilopha" species and the rest of the Cyanocorax species. To explore implications for the historical biogeography of the NJWs, we used Dispersal-Vicariance Analysis, which indicated that NWJs originated either in Mesoamerica or North America+Mesoamerica, with South American NWJs dispersing three times independently from Mesoamerica.

Adenylate Kinase↗
PubMed2006

Evolutionary history of woodpeckers and allies (Aves: Picidae): placing key taxa on the phylogenetic tree.

We analyzed 2995 base pairs of nucleotide sequence data (nuclear beta-fibrinogen intron 7 and mitochondrial cytochrome b and ND2 genes), using parsimony and model-based approaches to infer phylogenetic relationships of the woodpeckers and allies, yielding novel hypotheses for several critical gaps in the knowledge of picid phylogeny. We tested the monophyly of sub-families within the Picidae, and sampled from widely distributed and diverse genera (Celeus, Colaptes, Dryocopus, Melanerpes, Picoides, Picumnus, Sasia, Piculus, and Picus). Relationships of three poorly known Southeast Asian genera (Dinopium, Reinwardtipicus, and Blythipicus) were also examined, revealing unexpected sister relationships. All phylogenetic approaches recovered largely congruent topologies, supporting a monophyletic Picinae and paraphyletic Picumninae, with the monotypic piculet, Nesoctites micromegas, as sister to the Picinae. We report paraphyly for Celeus and Piculus, whereas the broadly distributed genera Picumnus and Dryocopus were supported as monophyletic. Our phylogenetic results indicate a complex geographic history for the Picidae, with multiple disjunct sister lineages distributed between the New World and Asia. The relationships and geographic distribution of basal picid lineages indicates an Old World origin of the Picidae; however, the geographic origin of the Picinae remains equivocal, as the sister relationship between the Caribbean N. micromegas and the true woodpeckers presents the possibility of a New World origin for the Picinae.

Animals↗
PubMed2006

Niche differentiation and fine-scale projections for Argentine ants based on remotely sensed data.

Modeling ecological niches of species is a promising approach for predicting the geographic potential of invasive species in new environments. Argentine ants (Linepithema humile) rank among the most successful invasive species: native to South America, they have invaded broad areas worldwide. Despite their widespread success, little is known about what makes an area susceptible--or not--to invasion. Here, we use a genetic algorithm approach to ecological niche modeling based on high-resolution remote-sensing data to examine the roles of niche similarity and difference in predicting invasions by this species. Our comparisons support a picture of general conservatism of the species' ecological characteristics, in spite of distinct geographic and community contexts.

Algorithms↗
PubMed2006

Geographic potential for outbreaks of Marburg hemorrhagic fever.

Marburg virus represents one of the least well-known of the hemorrhagic fever-causing viruses worldwide; in particular, its geographic potential in Africa remains quite mysterious. Ecologic niche modeling was used to explore the geographic and ecologic potential of Marburg virus in Africa. Model results permitted a reinterpretation of the geographic point of infection in the initiation of the 1975 cases in Zimbabwe, and also anticipated the potential for cases in Angola, where a large outbreak recently (2004-2005) occurred. The geographic potential for additional outbreaks is outlined, including in several countries in which the virus is not known. Overall, results demonstrate that ecologic niche modeling can be a powerful tool in understanding geographic distributions of species and other biologic phenomena such as zoonotic disease transmission from natural reservoir populations.

Angola↗
PubMed2005

Time-specific ecological niche modeling predicts spatial dynamics of vector insects and human dengue cases.

Numerous human diseases-malaria, dengue, yellow fever and leishmaniasis, to name a few-are transmitted by insect vectors with brief life cycles and biting activity that varies in both space and time. Although the general geographic distributions of these epidemiologically important species are known, the spatiotemporal variation in their emergence and activity remains poorly understood. We used ecological niche modeling via a genetic algorithm to produce time-specific predictive models of monthly distributions of Aedes aegypti in Mexico in 1995. Significant predictions of monthly mosquito activity and distributions indicate that predicting spatiotemporal dynamics of disease vector species is feasible; significant coincidence with human cases of dengue indicate that these dynamics probably translate directly into transmission of dengue virus to humans. This approach provides new potential for optimizing use of resources for disease prevention and remediation via automated forecasting of disease transmission risk.

Aedes↗
PubMed2005

West Nile virus survey of birds and mosquitoes in the Dominican Republic.

We report West Nile virus (WNV) activity from a new area on Hispaniola, in the vicinity of Monte Cristi National Park in northwest Dominican Republic. Specific anti-WNV antibodies were detected in 12 of 58 (21%) resident birds sampled in March 2003, representing six species in the orders Cuculiformes (cuckoos), Strigiformes (owls), and Passeriformes (song birds). This seroprevalence is the highest reported from any site in the Caribbean Basin. Virus was not detected in any mosquitoes or tissues from bird specimens. Testing of 20 sick or dead birds was negative for WNV. Undetermined flavivirus antibodies were detected in four resident birds at Monte Cristi, as well as in five resident birds at Sierra de Baoruco National Park in southwest Dominican Republic. These data suggest that an unidentified flavivirus, as well as WNV, is active in the Dominican Republic.

Animals↗
PubMed2005

Fine-scale predictions of distributions of Chagas disease vectors in the state of Guanajuato, Mexico.

One of the most daunting challenges for Chagas disease surveillance and control in Mexico is the lack of community level data on vector distributions. Although many states now have assembled representative domestic triatomine collections, only two triatomine specimens had been collected and reported previously from the state of Guanajuato. Field personnel from the state's Secretaría de Salud conducted health promotion activities in 43 of the 46 counties in the state and received donations of a total of 2,522 triatomine specimens between 1998 and 2002. All specimens were identified, and live insects examined for Trypanosoma cruzi. In an effort to develop fine-scale distributional data for Guanajuato, collection localities were georeferenced and ecological niches were modeled for each species by using evolutionary-computing approaches. Five species were collected: Triatoma mexicana (Herrich-Schaeffer), Triatoma longipennis (Usinger), Triatoma pallidipennis (Stål), Triatoma barberi (Usinger), and Triatoma dimidiata (Latreille) from 201 communities located at elevations of 870-2,200 m. Based on collection success, T. mexicana had the broadest dispersion, although niche mapping indicates that T. barberi represents the greatest risk for transmission of Chagas disease in the state. T. dimidiata was represented in collections by a single adult collected from one village outside the predicted area for all species. For humans, an estimated 3,755,380 individuals are at risk for vector transmission in the state, with an incidence of 3,500 new cases per year; overall seroprevalences of 2.6% indicate that 97,640 individuals are infected with T. cruzi at present, including 29,300 chronic cases.

Algorithms↗
PubMed2004

Geographical potential of Argentine ants (Linepithema humile Mayr) in the face of global climate change.

Determining the spread and potential geographical distribution of invasive species is integral to making invasion biology a predictive science. We assembled a dataset of over 1000 occurrences of the Argentine ant (Linepithema humile), one of the world's worst invasive alien species. Native to central South America, Argentine ants are now found in many Mediterranean and subtropical climates around the world. We used this dataset to assess the species' potential geographical and ecological distribution, and to examine changes in its distributional potential associated with global climate change, using techniques for ecological niche modelling. Models developed were highly predictive of the species' overall range, including both the native distributional area and invaded areas worldwide. Despite its already widespread occurrence, L. humile has potential for further spread, with tropical coastal Africa and southeast Asia apparently vulnerable to invasion. Projecting ecological niche models onto four general circulation model scenarios of future (2050s) climates provided scenarios of the species' potential for distributional expansion with warming climates: generally, the species was predicted to retract its range in tropical regions, but to expand at higher latitude areas.

Animals↗
PubMed2004

Evolution of seasonal ecological niches in the Passerina buntings (Aves: Cardinalidae).

The evolution of migration has long been considered complex and recent work has demonstrated additional complexity: some species follow the same ecological conditions throughout the year, whereas others 'switch niches' between breeding and wintering ranges. Hypotheses regarding the evolution of migration would generally predict niche-following as primitive, and niche-switching as derived. However, no test has, to our knowledge, yet determined the directionality of evolution of these states within a lineage. We present an analysis of phylogenetic dimensions of seasonal niches in the Passerina buntings that indicates greater evolutionary change in the niches of breeding populations than among those of wintering populations. These results are consistent with hypotheses of (i) niche conservatism (in winter, at least) across a recently speciated lineage; and (ii) the derived state of the breeding (rather than winter) ecological niches of each species.

Animal Migration↗
PubMed2004

Biodiversity informatics: managing and applying primary biodiversity data.

Recently, advances in information technology and an increased willingness to share primary biodiversity data are enabling unprecedented access to it. By combining presences of species data with electronic cartography via a number of algorithms, estimating niches of species and their areas of distribution becomes feasible at resolutions one to three orders of magnitude higher than it was possible a few years ago. Some examples of the power of that technique are presented. For the method to work, limitations such as lack of high-quality taxonomic determination, precise georeferencing of the data and availability of high-quality and updated taxonomic treatments of the groups must be overcome. These are discussed, together with comments on the potential of these biodiversity informatics techniques not only for fundamental studies but also as a way for developing countries to apply state of the art bioinformatic methods and large quantities of data, in practical ways, to tackle issues of biodiversity management.

Biodiversity↗
PubMed2004

Using epidemiological survey data to infer geographic distributions of leishmaniasis vector species.

An important aspect of tropical medicine is analysis of geographic aspects of risk of disease transmission, which for lack of detailed public health data must often be reduced to an understanding of the distributions of critical species such as vectors and reservoirs. We examine the applicability of a new technique, ecological niche modeling, to the challenge of understanding distributions of such species based on municipalities in the state of São Paulo in which a group of 5 Lutzomyia sandfly species have been recorded. The technique, when tested based on independent occurrence data, yielded highly significant predictions of species' distributions; minimum sample sizes for effective predictions were around 40 municipalities.

Algorithms↗
PubMed2004

Extinction risk from climate change.

Climate change over the past approximately 30 years has produced numerous shifts in the distributions and abundances of species and has been implicated in one species-level extinction. Using projections of species' distributions for future climate scenarios, we assess extinction risks for sample regions that cover some 20% of the Earth's terrestrial surface. Exploring three approaches in which the estimated probability of extinction shows a power-law relationship with geographical range size, we predict, on the basis of mid-range climate-warming scenarios for 2050, that 15-37% of species in our sample of regions and taxa will be 'committed to extinction'. When the average of the three methods and two dispersal scenarios is taken, minimal climate-warming scenarios produce lower projections of species committed to extinction ( approximately 18%) than mid-range ( approximately 24%) and maximum-change ( approximately 35%) scenarios. These estimates show the importance of rapid implementation of technologies to decrease greenhouse gas emissions and strategies for carbon sequestration.

Animals↗
PubMed2004

New developments in museum-based informatics and applications in biodiversity analysis.

Information from natural history collections (NHCs) about the diversity, taxonomy and historical distributions of species worldwide is becoming increasingly available over the Internet. In light of this relatively new and rapidly increasing resource, we critically review its utility and limitations for addressing a diverse array of applications. When integrated with spatial environmental data, NHC data can be used to study a broad range of topics, from aspects of ecological and evolutionary theory, to applications in conservation, agriculture and human health. There are challenges inherent to using NHC data, such as taxonomic inaccuracies and biases in the spatial coverage of data, which require consideration. Promising research frontiers include the integration of NHC data with information from comparative genomics and phylogenetics, and stronger connections between the environmental analysis of NHC data and experimental and field-based tests of hypotheses.

Journal Article↗
PubMed2004

Genetic variation coincides with geographic structure in the common bush-tanager (Chlorospingus ophthalmicus) complex from Mexico.

Cloud forests are distributed in the Neotropics, from northern Mexico to Argentina, under very specific ecological conditions, namely slopes with high humidity input from clouds and mist. Its distribution in Mesoamerica is highly fragmented, similar to an archipelago, and taxa are thus frequently represented as sets of isolated populations, each restricted to particular mountain ranges and often showing a high degree of divergence, both morphologically and genetically. The common bush-tanager (Chlorospingus ophthalmicus, Aves: Thraupidae) inhabits cloud forests from eastern and southern Mexico south to northwestern Argentina. Here we use 676bp of mtDNA (around the ATPase 8 gene) to explore the genetic variation and phylogeographic structure of the Mexican populations of C. ophthalmicus. Phylogenetic analyses of mtDNA sequences indicate deep genetic structure. Five major clades, which segregate according to geographic breaks, are identified (starting from the deepest one in the phylogeny): (1) Southern Chiapas and Northern Central America, (2) Tuxtlas massif, (3) Sierra Madre del Sur, (4) Eastern Oaxaca and Northern Chiapas, and (5) Sierra Madre Oriental. The long history of isolation undergone by each clade, as suggested by the phylogeny, implies that the species status of each of them should be revised.

Animals↗
PubMed2004

Distribution of members of Anopheles quadrimaculatus say s.l. (Diptera: Culicidae) and implications for their roles in malaria transmission in the United States.

The Anopheles quadrimaculatus s.l. (Say) complex consists of at least five species distinguished by distribution, genetic incompatibility, and allele frequencies. However, the distributions of the members have only been described by collection locations. Building on this information and environmental data, preliminary predictions of their distribution were produced using a genetic algorithm and point occurrence data. Based on resulting predicted border areas and undersampled regions, we obtained and analyzed additional geo-referenced specimens and compared their distribution with our preliminary predictions. We found good agreement between the preliminary predictions and the subsequent collections, regardless of the fact that additional specimens were deliberately sought from areas most likely to reveal inconsistencies. Final predicted distributions describe widespread distribution of A.quadrimaculatus throughout the eastern United States. A. maverlius and A. smaragdinus have similar predicted ranges limited to the southeastern United States. The predicted ranges of the sister taxa A. diluvialis and A. inundatus were similar to one another along the southeastern coast even though they seem to be allopatric. The historical role of A. quadrimaculatus s.l. in transmission of malaria was also examined. We conclude that A. quadrimaculatus s.s. was the only species of the complex capable of vectoring malaria in the United States throughout the area in which malaria occurred. However, any or all the members of the complex may have been regionally important, particularly in areas of most intense transmission.

Algorithms↗
PubMed2004

Ecologic and geographic distribution of filovirus disease.

We used ecologic niche modeling of outbreaks and sporadic cases of filovirus-associated hemorrhagic fever (HF) to provide a large-scale perspective on the geographic and ecologic distributions of Ebola and Marburg viruses. We predicted that filovirus would occur across the Afrotropics: Ebola HF in the humid rain forests of central and western Africa, and Marburg HF in the drier and more open areas of central and eastern Africa. Most of the predicted geographic extent of Ebola HF appear to have been observed; Marburg HF has the potential to occur farther south and east. Ecologic conditions appropriate for Ebola HF are also present in Southeast Asia and the Philippines, where Ebola Reston is hypothesized to be distributed. This first large-scale ecologic analysis provides a framework for a more informed search for taxa that could constitute the natural reservoir for this virus family.

Africa↗
PubMed2004

Potential mammalian filovirus reservoirs.

Ebola and Marburg viruses are maintained in unknown reservoir species; spillover into human populations results in occasional human cases or epidemics. We attempted to narrow the list of possibilities regarding the identity of those reservoir species. We made a series of explicit assumptions about the reservoir: it is a mammal; it supports persistent, largely asymptomatic filovirus infections; its range subsumes that of its associated filovirus; it has coevolved with the virus; it is of small body size; and it is not a species that is commensal with humans. Under these assumptions, we developed priority lists of mammal clades that coincide distributionally with filovirus outbreak distributions and compared these lists with those mammal taxa that have been tested for filovirus infection in previous epidemiologic studies. Studying the remainder of these taxa may be a fruitful avenue for pursuing the identity of natural reservoirs of filoviruses.

Africa↗