For all researches, please visit our "Peer-reviewed publications" page.
Kennedy M, Lang P, Grimaldo J, Martins S, Bruce A, Moore I et al. (2017)
Niche-breadth of freshwater macrophytes occurring in tropical southern African rivers predicts species global latitudinal range
Aquatic Botany 136 21-30.
The study tested the hypothesis that measurement, using multivariate Principal Components Analysis (PCA), of the niche-breadth of river macrophyte species in southern tropical Africa, may predict their larger-scale biogeographical range. Two measures of niche-breadth were calculated for 44 riverine macrophyte species, from 20 families commonly occurring in Zambia, using an approach based on PCA ordination with 16 bio-physico-chemical input variables. These included altitude, stream order, stream flow, pH, conductivity and soluble reactive phosphate concentration (SRP). In the absence of additional chemical water quality data for Zambian rivers, invertebrate-based measures of general water quality were also used. These were benthic macroinvertebrate Average Score per Taxon (ASPT), and individual abundance of nine macroinvertebrate families with differing water quality tolerance, indicated by their Sensitivity Weightings within the Zambian Invertebrate Scoring System (ZISS). Macrophyte large-scale latitudinal range was derived from world geopositional records held by online databases, and additional records held by the authors. The two niche-breadth metrics divided the species into narrow-niche and intermediate/broad-niche categories, showing significant variation (from one or both of correlation and ANOVA test outcomes) in altitude, stream flow, conductivity, SRP, pH and ASPT, but not stream order. Macrophyte alpha-diversity (as a measure of number of individual niches co-existing per habitat) showed no significant relationship with individual species niche-breadth. Narrow-niche species included a higher proportion of Afrotropical endemics than did species with broader niche size. There were significant predictive relationships between macrophyte niche-breadth and latitudinal range of the target species at global and Afrotropical scales, but not for the Neotropics.
Keywords: Africa, Aquatic plants, Benthic macroinvertebrates, Freshwater ecology, Latitudinal distribution, Niche analysis, Rivers
Am M (2016)
Human alteration of the global environment has triggered the sixth major extinction event in the history of life and caused widespread changes in the global distribution of organisms. These changes in biodiversity alter ecosystem processes and change the resilience of ecosystems to environmental change. This has profound consequences for services that humans derive from ecosystems. The large ecological and societal consequences of changing biodiversity should be minimized to preserve options for future solutions to global environmental problems.
Keywords: Digitonthophagus gazella, Scarabaeinae, biological invasion, species distribution modeling
Acosta A, Giannini T, Imperatriz-Fonseca V, Saraiva A (2016)
Worldwide Alien Invasion: A Methodological Approach to Forecast the Potential Spread of a Highly Invasive Pollinator.
PloS one 11(2) e0148295.
The ecological impacts of alien species invasion are a major threat to global biodiversity. The increasing number of invasion events by alien species and the high cost and difficulty of eradicating invasive species once established require the development of new methods and tools for predicting the most susceptible areas to invasion. Invasive pollinators pose serious threats to biodiversity and human activity due to their close relationship with many plants (including crop species) and high potential competitiveness for resources with native pollinators. Although at an early stage of expansion, the bumblebee species Bombus terrestris is becoming a representative case of pollinator invasion at a global scale, particularly given its high velocity of invasive spread and the increasing number of reports of its impacts on native bees and crops in many countries. We present here a methodological framework of habitat suitability modeling that integrates new approaches for detecting habitats that are susceptible to Bombus terrestris invasion at a global scale. Our approach did not include reported invaded locations in the modeling procedure; instead, those locations were used exclusively to evaluate the accuracy of the models in predicting suitability over regions already invaded. Moreover, a new and more intuitive approach was developed to select the models and evaluate different algorithms based on their performance and predictive convergence. Finally, we present a comprehensive global map of susceptibility to Bombus terrestris invasion that highlights priority areas for monitoring.
Keywords: Digitonthophagus gazella, Scarabaeinae, biological invasion, species distribution modeling
Aguiar L, Bernard E, Ribeiro V, Machado R, Jones G (2016)
Global Ecology and Conservation 5 22-33.
Most extant species are survivors of the last climate change event 20,000 years ago. While past events took place over thousands of years, current climate change is occurring much faster, over a few decades. We modelled the potential distribution area of bat species in the Brazilian Cerrado, a Neotropical savannah, and assessed the potential impacts of climate change up to 2050 in two scenarios. First we evaluated what the impact on the distributions of bat species would be if they were unable to move to areas where climate conditions might be similar to current ones. The novelty of our paper is that, based on least-cost-path analyses, we identified potential corridors that could be managed now to mitigate potential impacts of climate change. Our results indicate that on average, in the future bat species would find similar climate conditions 281 km southeast from current regions. If bat species were not able to move to new suitable areas and were unable to adapt, then 36 species (31.6%) could lose >80% of their current distribution area, and five species will lose more than 98% of their distribution area in the Brazilian Cerrado. In contrast, if bat species are able to reach such areas, then the number of highly impacted species will be reduced to nine, with none of them likely to disappear from the Cerrado. We present measures that could be implemented immediately to mitigate future climate change impacts.
Keywords: Brazil, Brazilian Cerrado, Chiroptera, Conservation, Ecological niche models
Almeida T, Salino A (2016)
Journal of Systematics and Evolution.
For ferns and lycophytes, the Neotropics is a hotspot of diversity (3000–4500 species), and second only to Southeastern Asia in richness and endemism. This paper presents the current state of knowledge on fern and lycophyte systematics in the Neotropics, and emphasizes sampling sufficiency and current taxonomic and phylogenetic knowledge. Plant systematics plays an important role in documenting diversity and geographic distribution patterns that are needed to understand relationships and evolutionary patterns, and a vital role in species conservation. Although in recent decades this field of science has undergone a revolution because of new approaches and techniques, data presented in this work shows that large gaps remain and there is still a long path towards fully understanding fern and lycophyte systematics in Neotropics. Approaches and how to choose areas that should be targeted in order to try to fulfill these knowledge gaps are discussed.
Keywords: biogeography, collections, phylogeny, pteridophytes, taxonomy
André T, Salzman S, Wendt T, Specht C (2016)
Molecular Phylogenetics and Evolution 103 55-63.
Species can arise via the divisive effects of allopatry as well as due to ecological and/or reproductive character displacement within sympatric populations. Two separate lineages of Costaceae are native to the Neotropics; an early-diverging clade endemic to South America (consisting of ca. 16 species in the genera Monocostus, Dimerocostus and Chamaecostus); and the Neotropical Costus clade (ca. 50 species), a diverse assemblage of understory herbs comprising nearly half of total familial species richness. We use a robust dated molecular phylogeny containing most of currently known species to inform macroevolutionary reconstructions, enabling us to examine the context of speciation in Neotropical lineages. Analyses of speciation rate revealed a significant variation among clades, with a rate shift at the most recent common ancestor of the Neotropical Costus clade. There is an overall predominance of allopatric speciation in the South American clade, as most species display little range overlap. In contrast, sympatry is much higher within the Neotropical Costus clade, independent of node age. Our results show that speciation dynamics during the history of Costaceae is strongly heterogeneous, and we suggest that the Costus radiation in the Neotropics arose at varied geographic contexts.
Keywords: Diversification, Macroevolution, Phylogenetics, Zingiberales
Ballesteros-Mejia L, Kitching I, Jetz W, Beck J (2016)
Putting insects on the map: Near-global variation in sphingid moth richness along spatial and environmental gradients
Despite their vast diversity and vital ecological role, insects are notoriously underrepresented in biogeography and conservation, and key broad-scale ecological hypotheses about them remain untested – largely due to generally incomplete and very coarse spatial distribution knowledge. Integrating records from publications, field work and natural history collections, we used a mixture of species distribution models and expert estimates to provide geographic distributions and emergent richness patterns for all ca. 1,000 sphingid moth species found outside the Americas in high spatial detail. Total sphingid moth richness, the first for a higher insect group to be documented at this scale, shows distinct maxima in the wet tropics of Africa and the Oriental with notable decay toward Australasia. Using multivariate models controlling for spatial autocorrelation, we found that primary productivity is the dominant environmental variable associated with moth richness, while temperature, contrary to our predictions, is an unexpectedly weak predictor. This is in stark contrast to the importance we identify for temperature as a niche variable of individual species. Despite divergent life histories, both main sub-groups of moths exhibit these relationships. Tribal-level deconstruction of richness and climatic niche patterns indicate idiosyncratic effects of biogeographic history for some of the less species-rich tribes, which in some cases exhibit distinct richness peaks away from the tropics. The study confirms, for a diverse insect group, overall richness associations of remarkable similarity to those documented for vertebrates and highlights the significant within-taxon structure that underpins emergent macroecological patterns. Results do not, however, meet predictions from vertebrate-derived hypotheses on how thermoregulation affects the strength of temperature-richness effects. Our study thus broadens the taxonomic focus in this data-deficient discourse. Our procedures of processing incomplete, scattered distribution data are a template for application to other taxa and regions.
Keywords: Distribution modelling, Lepidoptera, Productivity, Spatial scale, Sphingidae, Tropics
Barbosa F (2016)
Ecological Informatics 36 114-117.
Climate change will promote substantial effects on the distribution of invasive species. Here, I used an ensemble of bioclimatic envelope models (Gower Distance, Chebyshev Distance, and Mahalanobis Distance) to forecast climatically suitable areas of South America for 13 invasive African grass species under future climate conditions (year 2050). Under current climatic conditions, the areas with the potential for the highest invasive species richness are located mostly in the tropical climates of South America, except for the Amazon region. In the year 2050, the overall pattern of invasive species richness will not change considerably, and increases in northeastern Amazon and portions of the temperate regions of South America are predicted.
Keywords: Bioclimatic envelope models, Biological invasions, Ensemble forecast
Batalha-Filho H, Miyaki C (2016)
Late Pleistocene divergence and postglacial expansion in the Brazilian Atlantic Forest: multilocus phylogeography of Rhopias gularis (Aves: Passeriformes)
Journal of Zoological Systematics and Evolutionary Research.
In the last decade, phylogeographic studies have revealed a complex evolutionary history of the Brazilian Atlantic Forest (AF) biota. Here, we investigated the evolutionary history of Rhopias gularis, an endemic bird of the AF, based on sequences of two mitochondrial genes and three nuclear introns from 64 specimens from 15 localities. We addressed three main questions: (1) Does the genetic diversity of R. gularis exhibit a distribution pattern congruent with the refuge hypothesis postulated for the AF? (2) Is the population genetic structure of R. gularis congruent with those observed in other AF species? (3) What were the possible historical events responsible for the population structure of this species? Our mtDNA data revealed two phylogroups: (1) phylogroup central-south, with samples from the central and southern parts of the range; (2) and phylogroup north, which included individuals from southern Bahia. Nevertheless, nuclear loci did not reveal any evidence of population structure. Bottleneck tests indicated that the central-south lineage experienced demographic expansion, starting around 20 kya, which coincides with the end of the last glacial maximum. However, there was no evidence of population growth in phylogroup north. Isolation with migration analysis indicated that these phylogroups split c.a. 304 kya, with limited gene flow among them. Palaeodistribution models indicated that R. gularis had a reduced distribution in the south and central AF during the last glacial maximum. Our results support a diversification scenario that is in accordance with proposed Pleistocene refugia. The phylogeographic results from our study exhibited spatial and temporal concordances and discordances with previous studies of organisms from the AF. Differences in habitat requirements of these species could be behind this complex scenario. Future studies correlating variables of the niche of these species with the observed phylogeographic patterns may help understand why there are congruent and incongruent results.
Keywords: Last glacial maximum, Thamnophilidae, coalescence, refuge hypothesis
Bubadué J, Cáceres N, Carvalho R, Sponchiado J, Passaro F, Saggese F et al. (2016)
Hystrix, the Italian Journal of Mammalogy 27(2).
In South America, the crab-eating fox Cerdocyon thous occurs in sympatry to the ecologically similar, and phylogenetically close Lycalopex vetulus to the North, and Lycalopex gymnocercus to the South of its range. We studied character displacement in Cerdocyon under the effect of Bergmann's rule and the presence (or absence either) of Lycalopex within the crab-eating fox range. We performed skull shape analysis on 191 C. thous specimens and divided them in three distinct groups, depending on whether Cerdocyon occurs in sympatry or in allopatry to Lycalopex species. We tested for differences in size and shape between Cerdocyon groups and regressed both skull size and sexual size dimorphism against latitude and temperature, while controlling for spatial autocorrelation in the phenotypes. Southern Cerdocyon specimens present enlarged temporalis muscle and slender carnassial, both suggestive of a shift towards increased carnivory. Such a niche shift is interpreted as a mean to reduce competition to the larger Lycalopex species, which is still smaller than Cerdocyon . Consistently with the above, the degree of sexual shape and size dimorphism in Cerdocyon increases southward. We found a complex but coherent pattern of size and shape differentiation in Cerdocyon groups, which is consistent with the effects of both competition and Bergmann's rule. Cerdocyon reduces competition to Lycalopex by growing larger in the North. To the South, Cerdocyon is still larger, in keeping with Bergmann's rule, but strongly differs in skull shape from both its Lycalopex competitor and from any other Cerdocyon . Since the Southern Lycalopex species is much more similar in size to Cerdocyon than its Northern congeneric, this suggests that shape differences serve the goal of reducing competition between Cerdocyon and Lycalopex to the South, as size differences do to the North. The absence of the hypercarnivorous canid Speothos venaticus from the southern range of Cerdocyon may have allowed such a pattern to take place.
Keywords: Bergmann’s rule, Canidae, South America, character displacement, crab-eating fox, geometric morphometrics, sexual size dimorphism, shape disparity