For all researches, please visit our "Peer-reviewed publications" page.
Aagesen L, Biganzoli F, Bena J, Godoy-Bürki A, Reinheimer R, Zuloaga F (2016)
Macro-Climatic Distribution Limits Show Both Niche Expansion and Niche Specialization among C4 Panicoids.
PloS one 11(3) e0151075.
Grasses are ancestrally tropical understory species whose current dominance in warm open habitats is linked to the evolution of C4 photosynthesis. C4 grasses maintain high rates of photosynthesis in warm and water stressed environments, and the syndrome is considered to induce niche shifts into these habitats while adaptation to cold ones may be compromised. Global biogeographic analyses of C4 grasses have, however, concentrated on diversity patterns, while paying little attention to distributional limits. Using phylogenetic contrast analyses, we compared macro-climatic distribution limits among ~1300 grasses from the subfamily Panicoideae, which includes 4/5 of the known photosynthetic transitions in grasses. We explored whether evolution of C4 photosynthesis correlates with niche expansions, niche changes, or stasis at subfamily level and within the two tribes Paniceae and Paspaleae. We compared the climatic extremes of growing season temperatures, aridity, and mean temperatures of the coldest months. We found support for all the known biogeographic distribution patterns of C4 species, these patterns were, however, formed both by niche expansion and niche changes. The only ubiquitous response to a change in the photosynthetic pathway within Panicoideae was a niche expansion of the C4 species into regions with higher growing season temperatures, but without a withdrawal from the inherited climate niche. Other patterns varied among the tribes, as macro-climatic niche evolution in the American tribe Paspaleae differed from the pattern supported in the globally distributed tribe Paniceae and at family level.
Domínguez M, Agrain F, Flores G, Roig-Juñent S (2016)
The main goal of this study is to use multiple insect phylogenies along with geographical information to test known vicariance hypotheses for Southern South America. We analysed the phylogenies and geographical distributions of seven insect genera endemic to southern South America using Hovenkamp's (1997) protocol, which have been in part implemented in software (vicariance inference program). Using this software, we were able to hypothesize 55 traceable vicariance events; among these, we recognized four supported vicariance events (i.e. confirmed by more than a single sister group). The first supported vicariance event consisted of an East/West separation of the faunas in all analysed trees; the second supported vicariance event is a North/South separation of the fauna located East of the Andes; the third supported vicariance event was found in the southernmost fauna located East of the Andes, which separates allopatric Patagonian species in a North/South direction; and finally, the fourth supported vicariance event separates in a North/South direction clades of the Central Chilean fauna located West of the Andes. Our results suggest that these four supported vicariance events could be correlated with the uplifting of the Andes and the marine ingressions that occurred during the Cenozoic that is the estimated age at which these events occurred. Finally, we discuss that current software implementation of Hovenkamp's ideas need to be expanded, particularly regarding the automated selection of traceable vicariance events.
Pech-May A, Peraza-Herrera G, Moo-Llanes D, Escobedo-Ortegón J, Berzunza-Cruz M, Becker-Fauser I et al. (2016)
Assessing the importance of four sandfly species (Diptera: Psychodidae) as vectors of Leishmania mexicana in Campeche, Mexico.
Medical and veterinary entomology.
Localized cutaneous leishmaniasis represents a public health problem in many areas of Mexico, especially in the Yucatan Peninsula. An understanding of vector ecology and bionomics is of great importance in evaluations of the transmission dynamics of Leishmania parasites. A field study was conducted in the county of Calakmul, state of Campeche, during the period from November 2006 to March 2007. Phlebotomine sandfly vectors were sampled using Centers for Disease Control light traps, baited Disney traps and Shannon traps. A total of 3374 specimens were captured in the two villages of Once de Mayo (93.8%) and Arroyo Negro (6.1%). In Once de Mayo, the most abundant species were Psathyromyia shannoni, Lutzomyia cruciata, Bichromomyia olmeca olmeca and Psychodopygus panamensis (all: Diptera: Psychodidae). The Shannon trap was by far the most efficient method of collection. The infection rate, as determined by Leishmania mexicana-specific polymerase chain reaction, was 0.3% in Once de Mayo and infected sandflies included Psy. panamensis, B. o. olmeca and Psa. shannoni. There were significant differences in human biting rates across sandfly species and month of sampling. Ecological niche modelling analyses showed an overall overlap of 39.1% for the four species in the whole state of Campeche. In addition, the finding of nine vector-reservoir pairs indicates a potential interaction. The roles of the various sandfly vectors in Calakmul are discussed.
Keywords: Leishmania mexicana, Mexico, Phlebotomine sandflies, ecological niche
Báez S, Malizia A, Carilla J, Blundo C, Aguilar M, Aguirre N et al. (2015)
PloS one 10(5) e0126594.
General patterns of forest dynamics and productivity in the Andes Mountains are poorly characterized. Here we present the first large-scale study of Andean forest dynamics using a set of 63 permanent forest plots assembled over the past two decades. In the North-Central Andes tree turnover (mortality and recruitment) and tree growth declined with increasing elevation and decreasing temperature. In addition, basal area increased in Lower Montane Moist Forests but did not change in Higher Montane Humid Forests. However, at higher elevations the lack of net basal area change and excess of mortality over recruitment suggests negative environmental impacts. In North-Western Argentina, forest dynamics appear to be influenced by land use history in addition to environmental variation. Taken together, our results indicate that combinations of abiotic and biotic factors that vary across elevation gradients are important determinants of tree turnover and productivity in the Andes. More extensive and longer-term monitoring and analyses of forest dynamics in permanent plots will be necessary to understand how demographic processes and woody biomass are responding to changing environmental conditions along elevation gradients through this century.
Keywords: Leishmania mexicana, Mexico, Phlebotomine sandflies, ecological niche
Cuyckens G, Christie D, Domic A, Malizia L, Renison D (2015)
Climate change and the distribution and conservation of the world’s highest elevation woodlands in the South American Altiplano
Global and Planetary Change.
Climate change is becoming an increasing threat to biodiversity. Consequently, methods for delineation, establishment and management of protected areas must consider the species’ future distribution in response to future climate conditions. Biodiversity in high altitude semiarid regions may be particularly threatened by future climate change. In this study we assess the main environmental variables that best explain present day presence of the world’s highest elevation woodlands in the South American Altiplano, and model how climate change may affect the future distribution of this unique ecosystem under different climate change scenarios. These woodlands are dominated by Polylepis tarapacana (Rosaceae), a species that forms unique biological communities with important conservation value. Our results indicate that five environmental variables are responsible for 91% and 90.3% of the present and future P. tarapacana distribution models respectively, and suggest that at the end of the 21st century, a significant reduction (56%) in the potential habitat for this species due to more arid conditions. Since it is predicted that P. tarapacana’s potential distribution will be severely reduced in the future, we propose a new network of national protected areas across this species distribution range in order to insure the future conservation of this unique ecosystem. Based on an extensive literature review we identify research topics and recommendations for on-ground conservation and management of P. tarapacana woodlands.
Keywords: MaxEnt, Polylepis tarapacana, models, potential distribution
Díaz S, Kattge J, Cornelissen J, Wright I, Lavorel S, Dray S et al. (2015)
Earth is home to a remarkable diversity of plant forms and life histories, yet comparatively few essential trait combinations have proved evolutionarily viable in today’s terrestrial biosphere. By analysing worldwide variation in six major traits critical to growth, survival and reproduction within the largest sample of vascular plant species ever compiled, we found that occupancy of six-dimensional trait space is strongly concentrated, indicating coordination and trade-offs. Three-quarters of trait variation is captured in a two-dimensional global spectrum of plant form and function. One major dimension within this plane reflects the size of whole plants and their parts; the other represents the leaf economics spectrum, which balances leaf construction costs against growth potential. The global plant trait spectrum provides a backdrop for elucidating constraints on evolution, for functionally qualifying species and ecosystems, and for improving models that predict future vegetation based on continuous variation in plant form and function.
Keywords: MaxEnt, Polylepis tarapacana, models, potential distribution
Gomez J, Cassini M (2015)
Environmental predictors of habitat suitability and biogeographical range of Franciscana dolphins (Pontoporia blainvillei)
Global Ecology and Conservation 3 90-99.
The aim of this study was to use species distribution models to estimate the effects of environmental variables on the habitat suitability of river dolphins Pontoporia blainvillei (franciscanas) along their overall biogeographical distribution. Based on the literature, we selected six environmental variables to be included in the models; four climatic factors (surface sea temperature, salinity, turbidity and productivity) and two biotic factors (prey availability and fishing effort). We determined that the biographic range is under the following limits: temperature less than 19°C, a salinity of 36 psu and a minimal probability of the occurrence of fish C. guatucupa of 0.297. In the discussion, we postulate hypotheses on the behavioural and physiological mechanisms that cause these associations between environmental predictors and Franciscanas distribution. There was a good fit between the distribution predicted by the species distribution model and the one proposed by the experts of the International Union for Conservation of Nature; however, our analysis failed to highlight the fundamental role of bycatch as the main threat to this dolphin species.
Keywords: Food preference, Marine mammal, Salinity, Species distribution model, Temperature
Hinojosa L, Gaxiola A, Pérez M, Carvajal F, Campano M, Quattrocchio M et al. (2015)
Non-congruent fossil and phylogenetic evidence on the evolution of climatic niche in the gondwana genus Nothofagus
Journal of Biogeography.
Aim We used fossil and phylogenetic evidence to reconstruct climatic niche evolution in Nothofagus, a Gondwana genus distributed in tropical and temperate latitudes. To assess whether the modern distribution of the genus can be explained by the tropical conservatism hypothesis, we tested three predictions: (1) species from all Nothofagus subgenera coexisted under mesothermal climates during the early Eocene; (2) tolerance to microthermal climates evolved during the Eocene–Oligocene cooling from an ancestor that grew under mesothermal conditions; and (3) the climatic niche in Nothofagus is phylogenetically conserved. Location Australia, New Zealand, New Caledonia, Papua-New Guinea and South America. Methods We estimated the palaeoclimate of the Early Eocene, fossil-bearing Ligorio Marquez Formation (LMF, Chile), using coexistence and leaf physiognomic analysis. We reconstructed ancestral climatic niches of Nothofagus using extant species distributions and a time-calibrated phylogeny. Finally, we used the morphological disparity index and phylogenetic generalized least squares to assess whether climatic variables follow a Brownian motion (BM) or an Ornstein–Uhlenbeck (OU) model of evolution. Results Our palaeoclimatic estimates suggest mesothermal conditions for the LMF, where macrofossils associated with subgenera Lophozonia and possibly Fuscospora, and fossil pollen of Brassospora and Fuscospora/Nothofagus were recorded. These results are not supported by our phylogenetic analysis, which instead suggests that the ancestor of Nothofagus lived under microthermal to marginally mesothermal conditions, with tolerance to mesothermal conditions evolving only in the subgenus Brassospora. Precipitation and temperature dimensions of the realized climatic niche fit with a gradual BM or constrained OU model of evolution. Main Conclusions Our results suggest that the use of phylogenetic reconstruction methods based only on present distributions of extant taxa to infer ancestral climatic niches is likely to lead to erroneous results when climatic requirements of ancestors differ from their extant descendants, or when much extinction has occurred.
Keywords: Eocene, Gondwana, Nothofagaceae, into the tropics, niche modelling, palaeoclimate, phylogenetic signal, tropical conservatism hypothesis
Lucifora, L. O., Barbini, S. A., Di Giácomo, E. E., Waessle, J. A. & Figueroa D (2015)
Estimating the geographic range of a threatened shark in a data-poor region: Cetorhinus maximus in the South Atlantic Ocean
Advancing biodiversity science 61.
The distribution of the pla nktivorous basking shark, Cetorhinus maximus , is influenced by zooplankton abundance at small scales and temperature at medium scales in the North Atlantic. Here, we estimate the distribution of basking sharks on South Atlantic continental shelves, and the relative importance of chlorophyll concentration, as a proxy for zooplankton abundance, and temperature in det ermining habitat suitability for basking sharks at large scales. We us ed maximum entropy (MaxEnt) and maximum likelihood (MaxLike) speci es distribution modelling to test three hypotheses: the distribution of basking sharks is determined by (1) temperature, (2) chlor ophyll concentration, or (3) both chlorophyll and temperature, while c onsidering other factors, such as oxygen and salinity. Off South America, basking shark habitat included subtropical, temperate and cool-temperate waters between approximately 20 o S and 55 o S. Off Africa, basking shark habitat was limited to cool-temperate waters off Namibia an d southern South Africa. MaxLik e models had a better fit than MaxEnt models. The best model included minimum chlorophyll concentration, dissolved oxygen concentration, and sea surface temperature range, supporting hypothesis 3. However, of all variables included in th e best model, minimum chlorophyll concentration had the highes t influence on basking shark distribution. Unlike the Nort h Atlantic distribution, the South Atlan tic distribution of basking sharks includ es subtropical and cool-temperate waters. This difference is explained by high minimum chlorophyll concentration off southern Brazil as compar ed to North Atlantic subtropical areas. Observati ons in other regions of the world support this conclusion. The highest habitat suita bility for basking sharks is located close to nearshore areas that experience high anthropogenic impact
Keywords: Basking shark, Chondrichthyes, Geographic, MaxEnt, MaxLike, Southern Hemisphere, range
Molineri C, Salles F, Peters J (2015)
Phylogeny and biogeography of Asthenopodinae with a revision of Asthenopus, reinstatement of Asthenopodes, and the description of the new genera Hubbardipes and Priasthenopus (Ephemeroptera, Polymitarcyidae).
The Neotropical species of Asthenopodinae are revised in a formal phylogenetic context. The five known species of Asthenopus Eaton, 1871, together with other five new species were included in a cladistic analysis using morphological characters (continuous and discretes). Representatives of the Afro-Oriental group of the subfamily (Povilla Navás, 1912 and Languidipes Hubbard, 1984) were also included to test the monophyletic hypothesis traditionally accepted for the group. Additional taxa representing the other subfamilies of Polymitarcyidae were incorparated: Ephoron Williamson, 1802 (Polymitarcyinae) and Campsurus Eaton, 1868, Tortopus Needham & Murphy, 1924 and Tortopsis Molineri, 2010 (Campsurinae). A matrix of 17 taxa and 72 characters was analyzed under parsimony resulting in a single tree supporting the monophyly of the subfamily Asthenopodinae. Other results include the monophyly of the Afro-Oriental taxa (Povilla and Languidipes), the paraphyletic nature of Neotropical Asthenopodinae, and the recognition of four South American genera: Asthenopus (including Asthenopuscurtus (Hagen), 1861, Asthenopusangelae de Souza & Molineri, 2012, Asthenopusmagnus sp. n., Asthenopushubbardi sp. n., Asthenopusguarani sp. n.), Asthenopodes Ulmer, 1924, stat. n. (including Asthenopuspicteti Hubbard, 1975, stat. n., Asthenopodestraverae sp. n., Asthenopodeschumuco sp. n.), Priasthenopus gen. n. (including Priasthenopusgilliesi (Domínguez), 1988, comb. n.), and Hubbardipes gen. n. (including Hubbardipescrenulatus (Molineri et al.), 2011, comb. n.). Descriptions, diagnoses, illustrations and keys are presented for all Neotropical taxa of Asthenopodinae (adults of both sexes, eggs and nymphs). Additionally a key to the subfamilies and genera of Polymitarcyidae is included. A quantitative biogeographic analysis of vicariance is presented and discussed through the study of the "taxon history" of the group. Abstract available from the publisher.
Keywords: Campsurinae, Campsurus, Ephemeroidea, Ephemeroptera, Fossoriae, Languidipes, Neotropics, Povilla, Tortopsis, Tortopus, evolution, vicariance