Una reevaluación de la taxonomía de Mappia (Icacinaceae) utilizando datos ambientales

Towards a more reproducible ecology

Narrow-winged damselflies (Odonata: Coenagrionidae) can be observed in a variety of habitats, by both professional collectors and amateur odonatologists. Their abundance and ease of recognition has resulted in a large amount of occurrence data, which can be used to establish species distribution maps through environmental niche modeling. Distributional models often aim to maximize the quantity of occurrence points and environmental variables to relate to the distribution, neglecting both the quality and overlap of these two datasets when generating the models. In order to examine the effects of temporal data and environmental variables influencing change in species distributions, we used occurrence data for twelve species of Coenagrionidae damselflies to generate niche models separated by time periods of specimen collection. Our study examines environmental niche models generated for four time periods for each of these coenagrionid species: Amphiagrion abbreivatum (Selys,1876), Enallagma civile (Hagen,1861), Chromagrion conditum (Hagen in Selys, 1876), Nehalennia gracilis Morse, 1895, Enallagma hageni (Walsh, 1863), Hesperagrion heterodoxum (Selys, 1868), Nehalennia irene (Hagen, 1861), Argia moesta (Hagen, 1861), Ischnura ramburii (Selys, 1850), Argia tibialis (Rambur, 1842), Argia translata Hagen in Selys, 1865, and Argia vivida Hagen in Selys, 1865. The best supported models in each analysis were generated with occurrences of specimens collected from the 1970s to 2000s, and we used occurrence data outside of this range, from the 1800s to 2017, to compare the consistency of model predictions based on specimens of different time periods. In this approach, combining traditional environmental niche modeling and analysis of the specimen records themselves, we have found that ranges for narrow-winged damselflies expand over time, with increase in distributional coverage and decrease in model strength without temporal overlap between occurrences and environmental variables.

The mechanisms generating narrow endemism have long been of interest to biologists, with a variety of underlying causes proposed. This study investigates the origins of narrow endemism of two imperiled Florida endemics, Helianthus carnosus and Phoebanthus tenuifolius, in relation to a widespread sympatric close relative, Helianthus radula, as well as other members of the genus Helianthus. Using a combination of population genetics and environmental niche modeling, this study compares evidence in support of potential mechanisms underlying the origin of narrow endemism, including environmental specialization versus inbreeding, loss of diversity, or other predominantly genetic factors. The two narrow endemics were found to be comparable in genetic diversity to H. radula as well as other widespread Helianthus species, with little to no evidence of inbreeding. Environmental niche modeling indicates that distributions of both narrow endemics are strongly related to temperature and precipitation patterns, and that both endemics are threatened with severe reductions in habitat suitability under projected climate change. Evidence indicates that genetic factors likely are not the cause of narrow endemism in these species, suggesting that these species are likely ecological specialists and thus historical narrow endemics. This makes both species vulnerable to climate change, and of immediate conservation concern.

Environmental niche modelling and associated species distribution models often ignore intraspecific ecological differentiation linked with ploidal differentiation, i.e. the occurrence of several cytotypes of the same species. Here we tested the hypotheses that (i) the tetraploid (4x) cytotype is characterized by a broader ecological niche than the diploid (2x), and (ii) niche differentiation at the regional scale can serve as a proxy measure for differentiation at a smaller landscape scale in Urtica dioica, a perennial herbaceous plant with two prevailing cytotypes (2x and 4x). We focused on southern Moravia (Czech Republic), an area with a high diversity of vegetation types and the occurrence of both diploid and tetraploid cytotypes of U. dioica. To explore the geographical distribution, ecological preferences and habitat affinities of the diploid and tetraploid plants, we collected individuals at two different spatial scales: regional (~1200 km2) and landscape (9.1 km2). We used flow cytometry to determine the ploidy level of all the plants collected and determined the distribution of the different cytotypes both in geographical and ecological space. We also compared the habitat affinities of the diploid and tetraploid plants. Analyses of ploidy revealed 93 diploids and 325 tetraploids (regional scale: 42 diploids, 85 tetraploids; landscape scale: 51 diploids and 240 tetraploids). Diploid plants occurred only in the wetter parts of the landscape and this pattern was very similar at both scales. In contrast, tetraploids occurred along the whole moisture gradient at both scales. Diploids and tetraploids differed also in their habitat affinities. While diploids occurred relatively more frequently in alluvial and wet forests, managed broadleaved forests, alluvial and wet meadows, and wetlands and riverbanks, tetraploids preferred oak and oak-hornbeam forests, ravine forests, actively managed meadows, human settlements and vineyards. Our data clearly show an ecological niche differentiation between diploid and tetraploid cytotypes of Urtica dioica. While tetraploids have a broad ecological tolerance and consequently a wide geographical distribution, diploids occur only in a narrow range of ecological conditions and their distribution is restricted to areas with a shallow water table in the bottoms of valleys. Thus, ploidal differentiation, confirmed for many plant species, should be included in environmental niche modelling and species distribution models.

Aim We examine the range expansion/contraction dynamics during the last glacial cycle of the late‐successional tropical rain forest conifer Podocarpus elatus using a combination of modelling and molecular marker analyses. Specifically, we test whether distributional changes predicted by environmental niche modelling are in agreement with (1) the glacial maximum contractions inferred from the southern fossil record, and (2) population genetic‐based estimates of range disjunctions and demographic dynamics. In addition, we test whether northern and southern ranges are likely to have experienced similar expansion/contraction dynamics.Location Eastern Australian tropical and subtropical rain forests.Methods Environmental niche modelling was completed for three time periods during the last glacial cycle and was interpreted in light of the known palynology. We collected 109 samples from 32 populations across the entire range of P. elatus. Six microsatellite loci and Bayesian coalescence analysis were used to infer population expansion/contraction dynamics, and five sequenced loci (one plastid and four nuclear) were used to quantify genetic structure/diversity.Results Environmental niche modelling suggested that the northern and southern ranges of P. elatus experienced different expansion/contraction dynamics. In the northern range, the habitat suitable for P. elatus persisted in a small refugial area during the Last Glacial Maximum (LGM, 21 ka) and then expanded during the post‐glacial period. Conversely, in the south suitable habitat was widespread during the LGM but subsequently contracted. These differential dynamics were supported by Bayesian analyses of the population genetic data (northern dispersal) and are consistent with the greater genetic diversity in the south compared with the north. A contact zone between the two genetically divergent groups (corresponding to the Macleay Overlap Zone) was supported by environmental niche modelling and molecular analyses.Main conclusions The climatic fluctuations of the Quaternary have differentially impacted the northern and southern ranges of a broadly distributed rain forest tree in Australia. Recurrent contraction/expansion cycles contributed to the genetic distinction between northern and southern distributions of P. elatus. By combining molecular and environmental niche modelling evidence, this unique study undermines the general assumption that broadly distributed species respond in a uniform way to climate change.

BackgroundUsutu virus (USUV) is a mosquito-borne flavivirus, reported in many countries of Africa and Europe, with an increasing spatial distribution and host range. Recent outbreaks leading to regional declines of European common blackbird (Turdus merula) populations and a rising number of human cases emphasize the need for increased awareness and spatial risk assessment.MethodsModelling approaches in ecology and epidemiology differ substantially in their algorithms, potentially resulting in diverging model outputs. Therefore, we implemented a parallel approach incorporating two commonly applied modelling techniques: (1) Maxent, a correlation-based environmental niche model and (2) a mechanistic epidemiological susceptible-exposed-infected-removed (SEIR) model. Across Europe, surveillance data of USUV-positive birds from 2003 to 2016 was acquired to train the environmental niche model and to serve as test cases for the SEIR model. The SEIR model is mainly driven by daily mean temperature and calculates the basic reproduction number R0. The environmental niche model was run with long-term bio-climatic variables derived from the same source in order to estimate climatic suitability.ResultsLarge areas across Europe are currently suitable for USUV transmission. Both models show patterns of high risk for USUV in parts of France, in the Pannonian Basin as well as northern Italy. The environmental niche model depicts the current situation better, but with USUV still being in an invasive stage there is a chance for under-estimation of risk. Areas where transmission occurred are mostly predicted correctly by the SEIR model, but it mostly fails to resolve the temporal dynamics of USUV events. High R0 values predicted by the SEIR model in areas without evidence for real-life transmission suggest that it may tend towards over-estimation of risk.ConclusionsThe results from our parallel-model approach highlight that relying on a single model for assessing vector-borne disease risk may lead to incomplete conclusions. Utilizing different modelling approaches is thus crucial for risk-assessment of under-studied emerging pathogens like USUV.

The habitat first rule (HFR) proposes that radiating species initially diversify into habitat specialists and later into dietary specialists within a given habitat, whereas the general vertebrate model (GVM) adds divergence of sexually selected traits as a possible third axis of specialization subsequent to habitat and dietary divergence. In this study, using 12 Miniopterus spp. from Madagascar we test predictions of the HFR and GVM from ecological and evolutionary perspectives on Grinnellian and Eltonian niche structures. We used environmental niche models (ENMs) to quantify the Grinnellian niche, both for current and last inter-glacial climates. We used null models to examine Eltonian niche patterns of sympatric species in terms of their phylogenetic relatedness and phenotypic and sensory characters associated with the trophic niche—body size, skull morphology and echolocation. As predicted by the HFR, we found evidence for labile Grinnellian niches: there was no similarity in ENMs between sister species; overlap in ENMs was significantly low in >65 % of all possible species pairs; there was no relationship between ENM niche overlap and phylogenetic distances between species; and there was no phylogenetic signal in suitable bioclimatic zones among species. Conversely, we found equivocal support for the HFR regarding Eltonian niche patterns. Closely related species tended to be distributed among ensembles rather than within ensembles, although there was no evidence for overdispersion in phylogenetic patterns in ensembles. In <50 % of the observed combinations of sympatric Miniopterus spp., we found significant signal for overdispersion of phenotypic and sensory characters. We hypothesize that selective processes associated with the adaptive radiation of Miniopterus spp. on Madagascar may have favoured bats to diversify first into broad scale habitat specialists, but argue that understanding the relative influence of bionomic processes at a local spatial scale will require more reciprocal comparisons of Eltonian niches.

The role of past connections between the two major South American forested biomes on current species distribution has been recognized a long time ago. Climatic oscillations that further separated these biomes have promoted parapatric speciation, in which many species had their continuous distribution split, giving rise to different but related species (i.e., different potential distributions and realized niche features). The distribution of many sister species of orchid bees follow this pattern. Here, using ecological niche models and niche analyses, we (1) tested the role of ecological niche differentiation on the divergence between sister orchid-bees (genera Eulaema and Eufriesea) from the Amazon and Atlantic forests, and (2) highlighted interesting areas for new surveys. Amazonian species occupied different realized niches than their Atlantic sister species. Conversely, species of sympatric but distantly related Eulaema bees occupied similar realized niches. Amazonian species had a wide potential distribution in South America, whereas Atlantic Forest species were more limited to the eastern coast of the continent. Additionally, we identified several areas in need of future surveys. Our results show that the realized niche of Atlantic-Amazonian sister species of orchid bees, which have been previously treated as allopatric populations of three species, had limited niche overlap and similarity. These findings agree with their current taxonomy, which treats each of those populations as distinct valid species.

Oaks in the genus Quercus L. are keystone species in the forest ecosystem and are considered ideal models for the study of plant evolution. In this research, we applied population genetics, ecological niche analysis and phenotypic traits to explore patterns of species differentiation and demographic history of two Chinese montane oak species (Quercus baronii Skan and Quercus dolicholepis A. Camus) from Quercus section Ilex across species distribution ranges. Analyses of population genetics with ten nuclear microsatellite loci on 33 populations of the two oak species indicated great interspecific genetic variations with distinct genetic backgrounds for the two oaks. Simulations on species demography suggested a speciation-without-migration model as the best to explain species divergence, while an approximate Bayesian computation analysis indicated that the two studied oak species probably split at about 17.80–28.48 Ma. A comparison of two core bioclimatic factors and ecological niche tests revealed strong niche differentiation between the two oak species, and association analysis also found a significantly positive correlation between interspecific genetic variations and bioclimatic distances. Additionally, analyses of the leaf morphology of 117 specimens with five quantitative characteristics showed clear species discrepancy between Q. baronii and Q. dolicholepis. Based on this evidence from genetic, ecological and phenotypic analyses, our research indicated clear species differentiation between Q. baronii and Q. dolicholepis, possibly in relation to an early species divergence and varying adaptative features of the two oaks shaped by heterogeneous environments within Qinling-Daba Mountains and surroundings. This study provides an example for future investigation of species differentiation and evolution among related oak species with integrated analyses and highlights the importance of ecological conditions on adaptive evolution and genetic conservation of endemic tree species in montane regions.

The Balkan Peninsula represents one of the three southern European glacial refugia where biodiversity persisted throughout the climatically unstable Quaternary. This study considered the ‘refugia within refugia’ model, which assumes the environmental heterogeneity over time and space in larger refugia. To better understand patterns shaped during the Quaternary climatic oscillations, the present and last glacial maximum (LGM) environmental conditions and current morphological variability of Edraianthus tenuifolius, an endemic plant of the western Balkans with a well-known therphical structure, were considered. Potential present and LGM distributions were studied through environmental niche modelling using 161 data of occurrences and six bioclimatic variables, hindcasting the model to LGM conditions using three different global circulation models. To test the geographical variability of the reproductive region, 41 characters of 667 inflorescences from 35 populations within the distribution range were measured. Geographical patterns, using geostatistics together with univariate and multivariate statistical approaches, were analysed. The environmental niche model suggested the current potential distribution in correspondence to its known occurrences. The hindcast to LGM conditions suggested two separate areas of environmental suitability, one in the present-day northern Adriatic coast of Croatia (Istrian Peninsula, Kvarner) and another on the present-day south-eastern Adriatic coast (southern Dalmatia, Montenegro and northern Albania). Morphological variability showed a similar pattern, where southern populations separated from northern populations according to a major split in the central part of its distribution range (central Dalmatia). On other levels, stronger barriers were predicted to separate northern populations from the eastern Istrian Peninsula and the Kvarner area. The results suggested congruent biogeographical patterns to the already known phylogeographical structure. Both environmental niche modelling and the geographical variability of morphological characters suggested spatial partitioning, indicating the potential presence of two separate refugia during the LGM.

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 464:289-306 (2012) - DOI: https://doi.org/10.3354/meps09810 Potential feeding habitat of fin whales in the western Mediterranean Sea: an environmental niche model Jean-Noël Druon1,*, Simone Panigada2, Léa David3, Alexandre Gannier4, Pascal Mayol5, Antonella Arcangeli6, Ana Cañadas7,10, Sophie Laran8, Nathalie Di Méglio3, Pauline Gauffier9 1Joint Research Centre of the European Commission, Maritime Affairs Unit, Institute for the Protection and Security of the Citizen, Via Fermi, TP 051, 21027 Ispra (VA), Italy 2Tethys Research Institute, c/o Acquario Civico, Viale G.B. Gadio 2, 20121 Milan, Italy 3écoOcéan Institut, 18 rue des Hospices, 34090 Montpellier, France 4Groupe de REcherche sur les Cétacés (GREC), BP 715, 06633 Antibes cedex, France 5Souffleurs d’Ecume, Hôtel de Ville, 83470 La Celle, France 6Istituto Superiore per la Protezione e la Ricerca Ambientale (ISPRA), Via Vitaliano Brancati, 48, 00144 Rome, Italy 7ALNITAK, C/ Nalón 16, La Berzosa, 28240 Hoyo de Manzanares, Madrid, Spain 8Centre de Recherche sur les Mammifères Marins, UMS 3462, Université de La Rochelle/CNRS, 17000 La Rochelle, France 9Circé, Cabeza de Manzaneda, 3, 11390 Pelayo, Algeciras, Spain 10Present address: ALNILAM Research and Conservation, Cándamo 116, 28240 Hoyo de Manzanares, Madrid, Spain *Email: jean-noel.druon@jrc.ec.europa.eu ABSTRACT: The development of synoptic tools is required to derive the potential habitat of fin whales Balaenoptera physalus on a large-scale basis in the Mediterranean Sea, as the species has a largely unknown distribution and is at high risk of ship strike. We propose a foraging habitat model for fin whales in the western Mediterranean Sea relying on species ecology for the choice of predictors. The selected environmental variables are direct predictors and resource predictors available at daily and basin scales. Feeding habitat was determined mainly from the simultaneous occurrence of large oceanic fronts of satellite-derived sea-surface chlorophyll content (chl a) and temperature (SST). A specific range of surface chl a content (0.11 to 0.39 mg m−3) and a minimum water depth (92 m) were also identified to be important regional criteria. Daily maps were calibrated and evaluated against independent sets of fin whale sightings (presence data only). Specific chl a fronts represented the main predictor of feeding environment; therefore, derived habitat is a potential, rather than effective, habitat, but is functionally linked to a proxy of its resource (chl a production of fronts). The model performs well, with 80% of the presence data <9.7 km from the predicted potential habitat. The computed monthly, seasonal and annual maps of potential feeding habitat from 2000 to 2010 correlate, for the most part, with current knowledge on fin whale ecology. Overall, fin whale potential habitat occurs frequently during summer in dynamic areas of the general circulation, and is substantially more spread over the basin in winter. However, the results also displayed high year-to-year variations (40 to 50%), which are essential to consider when assessing migration patterns and recommending protection and conservation measures. KEY WORDS: Balaenoptera physalus · Potential habitat · Feeding · Mediterranean Sea · Satellite data · Fronts · Chlorophyll a · Environmental niche model Full text in pdf format Supplementary material PreviousCite this article as: Druon JN, Panigada S, David L, Gannier A and others (2012) Potential feeding habitat of fin whales in the western Mediterranean Sea: an environmental niche model. Mar Ecol Prog Ser 464:289-306. https://doi.org/10.3354/meps09810 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 464. Online publication date: September 19, 2012 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2012 Inter-Research.

In defense of ‘niche modeling’

Species distribution modelling comprises a range of widely used tools for predicting potential changes in insect pest species distributions with climate change. We review the current literature to see the effectiveness of different approaches, particularly in comparing predictions based on current distribution data (correlative or 'environmental niche models') and those based on life-history traits and determination of thermal limits (mechanistic models). We review new developments in implementing processes such as dispersal and biotic interactions within species distribution models and how these could be used to develop management strategies incorporating natural enemies into climate change predictions. We propose that species distribution models should be linked with key trait data where possible to inform better of response to climate change.

Species‐level environmental niche modeling has been crucial in efforts to understand how species respond to climate variation and change. However, species often exhibit local adaptation and intraspecific niche differences that may be important to consider in predicting responses to climate. Here, we explore whether phylogeographic lineages of the bank vole originating from different glacial refugia (Carpathian, Western, Eastern, and Southern) show niche differentiation, which would suggest a role for local adaptation in biogeography of this widespread Eurasian small mammal. We first model the environmental requirements for the bank vole using species‐wide occurrences (210 filtered records) and then model each lineage separately to examine niche overlap and test for niche differentiation in geographic and environmental space. We then use the models to estimate past [Last Glacial Maximum (LGM) and mid‐Holocene] habitat suitability to compare with previously hypothesized glacial refugia for this species. Environmental niches are statistically significantly different from each other for all pairs of lineages in geographic and environmental space, and these differences cannot be explained by habitat availability within their respective ranges. Together with the inability of most of the lineages to correctly predict the distributions of other lineages, these results support intraspecific ecological differentiation in the bank vole. Model projections of habitat suitability during the LGM support glacial survival of the bank vole in the Mediterranean region and in central and western Europe. Niche differences between lineages and the resulting spatial segregation of habitat suitability suggest ecological differentiation has played a role in determining the present phylogeographic patterns in the bank vole. Our study illustrates that models pooling lineages within a species may obscure the potential for different responses to climate change among populations.

The western spadefoot (Spea hammondii) is a Species of Special Concern in California and is now under review by the U.S. Fish and Wildlife Service for listing under the Endangered Species Act. We delineated potential conservation units within S. hammondii by analyzing spatial genetic structure across the species’ range using five nuclear and one mitochondrial loci. For both nuclear and mitochondrial markers we found that S. hammondii consists of two genetically distinct, allopatric clusters divided by the Transverse Ranges. To corroborate the northern and southern genetic clusters as conservation units from an ecological perspective, we applied a niche identity test to environmental niche models of the two groups. We found that the niche models of the northern and southern clusters were significantly different, suggesting they may be ecologically non-exchangeable. Given our demonstration of significant genetic and ecological differentiation between allopatric clusters of S. hammondii, we recommend that ongoing conservation efforts consider each as a separate unit with potentially unique management needs.