Showing papers by "A. Townsend Peterson published in 2013"

Ecological niche structure and rangewide abundance patterns of species.

Abstract: Spatial abundance patterns across species' ranges have attracted intense attention in macroecology and biogeography. One key hypothesis has been that abundance declines with geographical distance from the range centre, but tests of this idea have shown that the effect may occur indeed only in a minority of cases. We explore an alternative hypothesis: that species' abundances decline with distance from the centroid of the species' habitable conditions in environmental space (the ecological niche). We demonstrate consistent negative abundance–ecological distance relationships across all 11 species analysed (turtles to wolves), and that relationships in environmental space are consistently stronger than relationships in geographical space.

Evolutionary Processes of Diversification in a Model Island Archipelago

Abstract: Long celebrated for its spectacular landscapes and strikingly high levels of endemic biodiversity, the Philippines has been studied intensively by biogeographers for two centuries. Concentration of so many endemic land vertebrates into a small area and shared patterns of distribution in many unrelated forms has inspired a search for common mechanisms of production, partitioning, and maintenance of life in the archipelago. In this review, we (a) characterize an ongoing renaissance of species discovery, (b) discuss the changing way biogeographers conceive of the archipelago, (c) review the role molecular phylogenetic studies play in understanding the evolutionary history of Philippine vertebrates, and (d) describe how a 25-year Pleistocene island connectivity paradigm continues to provide some explanatory power, but has been augmented by increased understanding of the archipelago's geological history and ecological gradients. Finally, we (e) review new insights provided by studies of adaptive versus nonadap...

Plumbing the depths: extending ecological niche modelling and species distribution modelling in three dimensions

Abstract: Aim Ecological niche modelling (ENM) and species distribution modelling (SDM) have been used extensively to study biogeographic and macroecological patterns of terrestrial fauna and flora. Few studies to date have applied ENM and SDM to marine ecosystems, and those that have treated the marine environment as a two-dimensional space owing to limitations of the implementations of current ENM/SDM tools. For many marine organisms, ENM/SDM should be performed in three-dimensional space, taking into account latitude, longitude and depth. We present a case study demonstrating a strategy for three-dimensional ENM/SDM. Location Open ocean; global. Methods We decompose the three-dimensional structure of marine environmental and species occurrence data into a series of two-dimensional spaces using an easy-to-implement transformation, after which existing ENM/SDM tools can be used to analyse the data. We demonstrate our approach by modelling the potential distribution of a deep-sea-dwelling jellyfish with two commonly used algorithms. Potential effects of missing data and spatial sampling biases were assessed using resampling approaches. Results We demonstrate that it is feasible to derive predictive models of three-dimensional distributions of marine species using existing software tools developed with two-dimensional terrestrial situations in mind. The strategy presented here allowed us to model the distribution of a jellyfish species that inhabits the deep sea. We assessed the effects of missing occurrence data and spatial bias of occurrence data, and found that interpolation among occurrence data-points and extrapolation into unsampled conditions present distinct challenges that may require different modelling algorithms and interpretations. Main conclusions Our modified ENM/SDM approach is straightforward, and can be used to model situations that have heretofore been beyond the reach of ENM/SDM applications. In particular, geographic distributions and ecological niches of organisms inhabiting three-dimensional habitats such as water columns in marine and freshwater environments can be modelled using the framework presented here.

Global climate change adaptation priorities for biodiversity and food security.

Abstract: International policy is placing increasing emphasis on adaptation to climate change, including the allocation of new funds to assist adaptation efforts. Climate change adaptation funding may be most effective where it meets integrated goals, but global geographic priorities based on multiple development and ecological criteria are not well characterized. Here we show that human and natural adaptation needs related to maintaining agricultural productivity and ecosystem integrity intersect in ten major areas globally, providing a coherent set of international priorities for adaptation funding. An additional seven regional areas are identified as worthy of additional study. The priority areas are locations where changes in crop suitability affecting impoverished farmers intersect with changes in ranges of restricted-range species. Agreement among multiple climate models and emissions scenarios suggests that these priorities are robust. Adaptation funding directed to these areas could simultaneously address multiple international policy goals, including poverty reduction, protecting agricultural production and safeguarding ecosystem services.

Global priority conservation areas in the face of 21st century climate change.

Abstract: In an era when global biodiversity is increasingly impacted by rapidly changing climate, efforts to conserve global biodiversity may be compromised if we do not consider the uneven distribution of climate-induced threats. Here, via a novel application of an aggregate Regional Climate Change Index (RCCI) that combines changes in mean annual temperature and precipitation with changes in their interannual variability, we assess multi-dimensional climate changes across the “Global 200” ecoregions – a set of priority ecoregions designed to “achieve the goal of saving a broad diversity of the Earth’s ecosystems” – over the 21st century. Using an ensemble of 62 climate scenarios, our analyses show that, between 1991–2010 and 2081–2100, 96% of the ecoregions considered will be likely (more than 66% probability) to face moderate-to-pronounced climate changes, when compared to the magnitudes of change during the past five decades. Ecoregions at high northern latitudes are projected to experience most pronounced climate change, followed by those in the Mediterranean Basin, Amazon Basin, East Africa, and South Asia. Relatively modest RCCI signals are expected over ecoregions in Northwest South America, West Africa, and Southeast Asia, yet with considerable uncertainties. Although not indicative of climate-change impacts per se, the RCCI-based assessment can help policy-makers gain a quantitative and comprehensive overview of the unevenly distributed climate risks across the G200 ecoregions. Whether due to significant climate change signals or large uncertainties, the ecoregions highlighted in the assessment deserve special attention in more detailed impact assessments to inform effective conservation strategies under future climate change.

Ecology and Geography of Transmission of Two Bat-Borne Rabies Lineages in Chile

Abstract: Universidad Andres Bello supported the PhD scholarship and provided an international internship grant at the University of Kansas for LEE.

Potential geographic distribution of hantavirus reservoirs in Brazil.

Abstract: Hantavirus cardiopulmonary syndrome is an emerging zoonosis in Brazil. Human infections occur via inhalation of aerosolized viral particles from excreta of infected wild rodents. Necromys lasiurus and Oligoryzomys nigripes appear to be the main reservoirs of hantavirus in the Atlantic Forest and Cerrado biomes. We estimated and compared ecological niches of the two rodent species, and analyzed environmental factors influencing their occurrence, to understand the geography of hantavirus transmission. N. lasiurus showed a wide potential distribution in Brazil, in the Cerrado, Caatinga, and Atlantic Forest biomes. Highest climate suitability for O. nigripes was observed along the Brazilian Atlantic coast. Maximum temperature in the warmest months and annual precipitation were the variables that most influence the distributions of N. lasiurus and O. nigripes, respectively. Models based on occurrences of infected rodents estimated a broader area of risk for hantavirus transmission in southeastern and southern Brazil, coinciding with the distribution of human cases of hantavirus cardiopulmonary syndrome. We found no demonstrable environmental differences among occurrence sites for the rodents and for human cases of hantavirus. However, areas of northern and northeastern Brazil are also apparently suitable for the two species, without broad coincidence with human cases. Modeling of niches and distributions of rodent reservoirs indicates potential for transmission of hantavirus across virtually all of Brazil outside the Amazon Basin.

Global patterns of connectivity and isolation of populations of forest bird species in the late Pleistocene

Abstract: Aim Species’ distributional responses to cool periods in the Pleistocene appear to have been diverse, but patterns of response are poorly known globally, and the nature of distributional responses to interglacial conditions remains largely unknown. The aim of this contribution is to assess distributional responses of forest bird species to Last Interglacial (LIG) and Last Glacial Maximum (LGM) conditions within nine forest regions world-wide, to test whether different regions experienced consistently different types of distributional responses. Location Global. Methods We use ecological niche modelling approaches under an assumption of ecological niche conservatism to assess degrees of fragmentation of species distributions through the LIG–LGM–present transitions. Models trained under present-day conditions were transferred to Pleistocene conditions, and fragmentation of potential distributional areas was assessed using FragStats. Results Our results showed four regions to have greater fragmentation at LGM than at LIG or at present; three showed greater connectivity at LGM; and two were equivocal. Main conclusions Our results suggest that the world is a patchwork of regions in which forest species experienced either consistently greater or consistently lesser population subdivision during the alternating cool and warm periods that characterized the Pleistocene. Speciation timing and dynamics should differ dramatically among major regions and biomes if these periods of connection and disjunction translate into speciation opportunity.

Mapping monkeypox transmission risk through time and space in the Congo Basin.

Abstract: Monkeypox is a major public health concern in the Congo Basin area, with changing patterns of human case occurrences reported in recent years. Whether this trend results from better surveillance and detection methods, reduced proportions of vaccinated vs. non-vaccinated human populations, or changing environmental conditions remains unclear. Our objective is to examine potential correlations between environment and transmission of monkeypox events in the Congo Basin. We created ecological niche models based on human cases reported in the Congo Basin by the World Health Organization at the end of the smallpox eradication campaign, in relation to remotely-sensed Normalized Difference Vegetation Index datasets from the same time period. These models predicted independent spatial subsets of monkeypox occurrences with high confidence; models were then projected onto parallel environmental datasets for the 2000s to create present-day monkeypox suitability maps. Recent trends in human monkeypox infection are associated with broad environmental changes across the Congo Basin. Our results demonstrate that ecological niche models provide useful tools for identification of areas suitable for transmission, even for poorly-known diseases like monkeypox.

Niche Conservatism and Disjunct Populations: A Case Study with Painted Buntings (Passerina ciris)

Abstract: . Painted Buntings (Passerina ciris) breed in a variety of habitat s across the southern United States; however, a 500-km gap divides the species into eastern and western populations with dramatically different molting schedules. By contrast, the closely related Indigo Bunting (P. cyanea) is syntopic with Painted Buntings, but its range includes the 500-km gap. To date, no well-supported hypothesis explains the gap in the range of Painted Buntings. We used MaxEnt to describe ecological niches of both species and performed comparative analyses of model results to evaluate niche similarity between the two Painted Bunting breeding populations and the range gap. All present-day niche models for both species predicted a single contiguous breeding range, which suggests that the gap in the Painted Bunting range is not bioclimatic in origin. Comparative analyses of the three different environments suggest little bioclimatic divergence. Distribution models during the Last Glacial Maximum suggest that Paint...

A New Species of Scytalopus Tapaculo (Aves: Passeriformes: Rhinocryptidae) from the Andes of Central Peru

Abstract: We describe a new species of Scytalopus tapaculo (Aves: Passeriformes: Rhinocryptidae) from the temperate humid montane forests (2,400–3,200 m) of Junin Department, Peru. This species has a unique song that differs strikingly from that of any known Scytalopus species, consisting of a rapidly repeated series of ascending phrases. Phenotypically, the new species is uniformly blackish in color and small-to-medium in size, most similar to members of the allopatric S. latrans complex. At least six species of Scytalopus occur along an elevational gradient on the eastern slopes of the Andes in Junin; in the vicinity of the type locality, the new species replaces S. femoralis at 2,400–2,500 m, and is replaced by S. acutirostris at 2,900–3,200 m. Throughout its elevational range, the new species is broadly syntopic with the larger S. macropus. This species is currently known from a single river drainage; although it probably occurs more broadly, it is likely a range-restricted species endemic to central Peru.

Spatial epidemiology of bat-borne rabies in Colombia

Abstract: To the Editor: In their article, “Geographic distribution of wild rabies risk and evaluation of the factors associated with its incidence in Colombia, 1982–2010,” Brito and colleagues (1) analyzed the spatial distribution of batborne rabies in Colombia and showed an association of occurrence of rabies outbreaks with climatic tendencies. The authors also identified risk clusters for rabies based on modeled potential distributions. While we appreciate this work, which fills knowledge gaps regarding the epidemiology of vampire-borne rabies in Latin America, we are also concerned because some of the data presented merits re-evaluation and correction. The distribution of rabies in Colombia was modeled using an ecological niche modeling approach. The authors analyzed its distribution with respect to 15 climatic variables, using all available occurrences in model calibration. Model evaluation, a critical issue if modeling results are to be incorporated in public health decision making, was thus limited in scope and strength. Our goal herein is to evaluate the quality, quantity, and distribution of rabies occurrences data and effectiveness of the environmental data used by Brito and colleagues. We based our analyses on the data used in and provided by the article. First, Brito and colleagues used all available occurrence points in model calibration. Generally, however, clusters of occurrences can lead to overfitting models to specific environments in specific areas (2). To avoid biases in model calibration, we therefore used single occurrences per cell—indeed, in some cases, multiple occurrences grouped within single cells in the environmental layers used by the authors. This step left 2 008 of the original 2 330 occurrences. This minor correction reduces overfitting, and increased area identified as suitable by > 4%. Another major concern centers on use of climatic variables as environmental information in analyses across such restricted extents. Using principal components analysis, we found the climatic layers to be highly intercorrelated: indeed, just three principal components summarized > 99% of variance among the 15 climatic layers analyzed by Brito and colleagues. We compared models calibrated with respect to that same climatic information against those based on remotely sensed data (monthly Normalized Difference Vegetation Index [NDVI] data sets for October 1992 – September 1993 0.01° resolution), which provide finer spatial resolution and less need for interpolation. Indeed climate data showed environmental homogeneity across broad areas, with spatial lags of > 350 km, whereas remotely-sensed data offered a richer and more detailed environmental characterization: 11 principal components were required to summarize > 99% of overall variance, and spatial lags were only < 250 km (Figure 1). The contrast in detail available from these two data sources is evident in Figure 2. Brito and colleagues subdivided available data at random for calibration versus evaluation of their model, and used approaches that weight presence and absence data equally (2). We evaluated model predictions more rigorously, with spatial subdivision of occurrences into calibration and evaluation areas, and using evaluation tools that emphasize presence information (2, 3). Models calibrated based on presence

Spatial Scaling of Prevalence and Population Variation in Three Grassland Sparrows

Abstract: . Henslow's Sparrows (Ammodramus henslowii) are distributed in tallgrass prairies in central North America; however, this species is restricted further to specific habitats within these prairies—large expanses with relatively little woody vegetation but an accumulation of standing grasses and forbs, conditions that result from infrequent disturbances by fire, mowing, or grazing. Henslow's Sparrows have been documented to be unpredictable at breeding sites from year to year, but studies to date have considered only local spatial scales. We compared resettlement behavior (prevalence of occurrence and variation in abundance) of Henslow's Sparrows to that of two other grassland sparrows, Grasshopper Sparrows (A. savannarum) and Savannah Sparrows (Passerculus sandwichensis), across multiple spatial resolutions. In Henslow's Sparrows, prevalence was lower and variation in abundance was greater than in the other two species. Indeed, Henslow's Sparrows do not occur consistently at extents of less than 120...

A new species of Brush-Finch (Arremon; Emberizidae) from western Mexico

Abstract: A new highland species of chestnut-capped Arremon brush-finch is described from the Sierra Madre del Sur of central Guerrero. This form, although indistinguishable in external phenotype from adjacent populations to the east in Oaxaca, is dramatically differentiated in mitochondrial DNA sequence characters, and quite unexpectedly is the sister lineage to the very distinct (phenotype and genotype), central-Mexican-endemic A. virenticeps. Nuclear sequence differentiation in the new lineage is more subtle than in mitochondrial DNA, but is on par with that in the well-marked A. virenticeps. The new species is thus distinct from its sister lineage in genotype and phenotype, and clearly distinct from all other forms in genotype; however, it has retained an ancestral external phenotype similar to other members of the broader A. brunneinucha complex.

Sylvatic species of Echinococcus from rodent intermediate hosts in Asia and South America.

Abstract: During a global survey of the diversity of vertebrates and their parasites including the Gobi and desert/steppe biomes ranging from south central to western Mongolia, we found metacestodes (larvae) of Echinococcus multilocularis (Leuckart 1863) in the liver of an individual vole (Microtus limnophilus Buchner 1889) collected in grassland habitat at Har Us Lake, southeast of Hovd, Mongolia. Positive identification of E. multilocularis from near Hovd was made via comparative cyst morphology, study of hooks from the rostellum derived from protoscolexes, and DNA sequencing of the COX1 mitochondrial gene extracted from tissue of the cysts frozen in the field. This report represents the first record of this species from an arvicolid intermediate host in Mongolia. This report also includes a second record from Bolivia of E. vogeli Rausch and Bernstein 1972 (confirmed by measurements of the hooks and cyst morphology) from the common intermediate host, Cuniculus paca Linnaeus 1758, collected in the Pilon Lajas Biosphere Reserve, Beni Department.

Forecasting ecological impacts of sea-level rise on coastal conservation areas in India

Abstract: In addition to the mounting empirical data on direct implications of climate change for natural and human systems, evidence is increasing for indirect climate change phenomena such as sea-level rise. Rising sea levels and associated marine intrusion into terrestria.htm"l environments are predicted to be among the most serious eventual consequences of climate change. The many complex and interacting factors affecting sea levels create considerable uncertainty in sea-level rise projections: conservative estimates are on the order of 0.5-1.0 m globally, while other estimates are much higher, approaching 6m. Marine intrusion associated with 1-6 m sea-level rise will impact species and habitats in coastal ecosystems severely. Examining areas most vulnerable to such impacts may allow design of appropriate adaptation and mitigation strategies. We present an overview of potential effects of 1m and 6m sea level rise for coastal conservation areas in the Indian Subcontinent. In particular, we examine the projected magnitude of areal losses in relevant biogeographic zones, ecoregions, protected areas (PAs) and important bird areas (IBAs). In addition, we provide a more detailed and quantitative analysis of likely effects of marine intrusion on 22 coastal PAs and IBAs that provide critical habitat for birds in the form of breeding areas, migratory stopover sites and overwintering habitats. Several coastal PAs and IBAs are predicted to experience higher than 50% areal losses to marine intrusion. We explore consequences of such inundation levels for species and habitats in these areas.

Case 3623 Grallaria fenwickorum Barrera et al., 2010 (Aves, formicariidae): proposed replacement of an indeterminate holotype by a neotype

Abstract: . The purpose of this application, under Article 75.5 of the Code, is to replace the incomplete and improperly described holotype of the antpitta Grallaria fenwickorum Barrera et al., 2010 with a neotype that constitutes a full, diagnosable, name-bearing type. Because the holotype of G. fenwickorum was described poorly, was not deposited appropriately in a scientific collection and does not possess the characters that diagnose the taxon, and because the taxonomy of Grallaria ranks among the most fluid of all avian genera, it is crucial that a full, information-rich, recognizable type be available to the scientific community to represent this new taxon. I consider G. fenwickorum to be a nomen dubium and urge declaration of a neotype as a basis for a more stable foundation in the complex taxonomy of this genus.