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1.
Sci Total Environ ; 857(Pt 3): 159603, 2023 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-36272474

RESUMO

As climate change alters the global environment, it is critical to understand the relationship between shifting climate suitability and species distributions. Key questions include whether observed changes in population abundance are aligned with the velocity and direction of shifts predicted by climate suitability models and if the responses are consistent among species with similar ecological traits. We examined the direction and velocity of the observed abundance-based distribution centroids compared with the model-predicted bioclimatic distribution centroids of 250 bird species across the United States from 1969 to 2011. We hypothesized that there is a significant positive correlation in both direction and velocity between the observed and the modeled shifts. We then tested five additional hypotheses that predicted differential shifting velocity based on ecological adaptability and climate change exposure. Contrary to our hypotheses, we found large differences between the observed and modeled shifts among all studied bird species and within specific ecological guilds. However, temperate migrants and habitat generalist species tended to have higher velocity of observed shifts than other species. Neotropical migratory and wetland birds also had significantly different observed velocities than their counterparts, which may be due to their climate change exposure. The velocity based on modeled bioclimatic suitability did not exhibit significant differences among most guilds. Boreal forest birds were the only guild with significantly faster modeled-shifts than the other groups, suggesting an elevated conservation risk for high latitude and altitude species. The highly idiosyncratic species responses to climate and the mismatch between shifts in modeled and observed distribution centroids highlight the challenge of predicting species distribution change based solely on climate suitability and the importance of non-climatic factors traits in shaping species distributions.


Assuntos
Aves , Mudança Climática , Animais , Distribuição Animal , Aves/fisiologia , Ecossistema , América do Norte
2.
Sci Rep ; 12(1): 21810, 2022 12 17.
Artigo em Inglês | MEDLINE | ID: mdl-36528749

RESUMO

Climate change alters ecological communities by affecting individual species and interactions between species. However, the impacts of climate change may be buffered by community diversity: diverse communities may be more resistant to climate-driven perturbations than simple communities. Here, we assess how diversity influences long-term thermal niche variation in communities under climate change. We use 50-year continental-scale data on bird communities during breeding and non-breeding seasons to quantify the communities' thermal variability. Thermal variability is measured as the temporal change in the community's average thermal niche and it indicates community's response to climate change. Then, we study how the thermal variability varies as a function of taxonomic, functional, and evolutionary diversity using linear models. We find that communities with low thermal niche variation have higher functional diversity, with this pattern being measurable in the non-breeding but not in the breeding season. Given the expected increase in seasonal variation in the future climate, the differences in bird communities' thermal variability between breeding and non-breeding seasons may grow wider. Importantly, our results suggest that functionally diverse wildlife communities can mitigate effects of climate change by hindering changes in thermal niche variability, which underscores the importance of addressing the climate and biodiversity crises together.


Assuntos
Aves , Mudança Climática , Animais , Aves/fisiologia , Biodiversidade , Estações do Ano , Evolução Biológica , Ecossistema
3.
Ecol Appl ; 32(7): e2679, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35588285

RESUMO

For many avian species, spatial migration patterns remain largely undescribed, especially across hemispheric extents. Recent advancements in tracking technologies and high-resolution species distribution models (i.e., eBird Status and Trends products) provide new insights into migratory bird movements and offer a promising opportunity for integrating independent data sources to describe avian migration. Here, we present a three-stage modeling framework for estimating spatial patterns of avian migration. First, we integrate tracking and band re-encounter data to quantify migratory connectivity, defined as the relative proportions of individuals migrating between breeding and nonbreeding regions. Next, we use estimated connectivity proportions along with eBird occurrence probabilities to produce probabilistic least-cost path (LCP) indices. In a final step, we use generalized additive mixed models (GAMMs) both to evaluate the ability of LCP indices to accurately predict (i.e., as a covariate) observed locations derived from tracking and band re-encounter data sets versus pseudo-absence locations during migratory periods and to create a fully integrated (i.e., eBird occurrence, LCP, and tracking/band re-encounter data) spatial prediction index for mapping species-specific seasonal migrations. To illustrate this approach, we apply this framework to describe seasonal migrations of 12 bird species across the Western Hemisphere during pre- and postbreeding migratory periods (i.e., spring and fall, respectively). We found that including LCP indices with eBird occurrence in GAMMs generally improved the ability to accurately predict observed migratory locations compared to models with eBird occurrence alone. Using three performance metrics, the eBird + LCP model demonstrated equivalent or superior fit relative to the eBird-only model for 22 of 24 species-season GAMMs. In particular, the integrated index filled in spatial gaps for species with over-water movements and those that migrated over land where there were few eBird sightings and, thus, low predictive ability of eBird occurrence probabilities (e.g., Amazonian rainforest in South America). This methodology of combining individual-based seasonal movement data with temporally dynamic species distribution models provides a comprehensive approach to integrating multiple data types to describe broad-scale spatial patterns of animal movement. Further development and customization of this approach will continue to advance knowledge about the full annual cycle and conservation of migratory birds.


Assuntos
Migração Animal , Aves , Animais , Estações do Ano , América do Sul
4.
Glob Chang Biol ; 28(7): 2221-2235, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35060249

RESUMO

One of the most pressing questions in ecology and conservation centers on disentangling the relative impacts of concurrent global change drivers, climate and land-use/land-cover (LULC), on biodiversity. Yet studies that evaluate the effects of both drivers on species' winter distributions remain scarce, hampering our ability to develop full-annual-cycle conservation strategies. Additionally, understanding how groups of species differentially respond to climate versus LULC change is vital for efforts to enhance bird community resilience to future environmental change. We analyzed long-term changes in winter occurrence of 89 species across nine bird groups over a 90-year period within the eastern United States using Audubon Christmas Bird Count (CBC) data. We estimated variation in occurrence probability of each group as a function of spatial and temporal variation in winter climate (minimum temperature, cumulative precipitation) and LULC (proportion of group-specific and anthropogenic habitats within CBC circle). We reveal that spatial variation in bird occurrence probability was consistently explained by climate across all nine species groups. Conversely, LULC change explained more than twice the temporal variation (i.e., decadal changes) in bird occurrence probability than climate change on average across groups. This pattern was largely driven by habitat-constrained species (e.g., grassland birds, waterbirds), whereas decadal changes in occurrence probabilities of habitat-unconstrained species (e.g., forest passerines, mixed habitat birds) were equally explained by both climate and LULC changes over the last century. We conclude that climate has generally governed the winter occurrence of avifauna in space and time, while LULC change has played a pivotal role in driving distributional dynamics of species with limited and declining habitat availability. Effective land management will be critical for improving species' resilience to climate change, especially during a season of relative resource scarcity and critical energetic trade-offs.


Assuntos
Mudança Climática , Ecossistema , Biodiversidade , Dinâmica Populacional , Estações do Ano , Estados Unidos
5.
J Anim Ecol ; 90(5): 1165-1176, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33754380

RESUMO

Together climate and land-use change play a crucial role in determining species distribution and abundance, but measuring the simultaneous impacts of these processes on current and future population trajectories is challenging due to time lags, interactive effects and data limitations. Most approaches that relate multiple global change drivers to population changes have been based on occurrence or count data alone. We leveraged three long-term (1995-2019) datasets to develop a coupled integrated population model-Bayesian population viability analysis (IPM-BPVA) to project future survival and reproductive success for common loons Gavia immer in northern Wisconsin, USA, by explicitly linking vital rates to changes in climate and land use. The winter North Atlantic Oscillation (NAO), a broad-scale climate index, immediately preceding the breeding season and annual changes in developed land cover within breeding areas both had strongly negative influences on adult survival. Local summer rainfall was negatively related to fecundity, though this relationship was mediated by a lagged interaction with the winter NAO, suggesting a compensatory population-level response to climate variability. We compared population viability under 12 future scenarios of annual land-use change, precipitation and NAO conditions. Under all scenarios, the loon population was expected to decline, yet the steepest declines were projected under positive NAO trends, as anticipated with ongoing climate change. Thus, loons breeding in the northern United States are likely to remain affected by climatic processes occurring thousands of miles away in the North Atlantic during the non-breeding period of the annual cycle. Our results reveal that climate and land-use changes are differentially contributing to loon population declines along the southern edge of their breeding range and will continue to do so despite natural compensatory responses. We also demonstrate that concurrent analysis of multiple data types facilitates deeper understanding of the ecological implications of anthropogenic-induced change occurring at multiple spatial scales. Our modelling approach can be used to project demographic responses of populations to varying environmental conditions while accounting for multiple sources of uncertainty, an increasingly pressing need in the face of unprecedented global change.


Assuntos
Aves , Mudança Climática , Animais , Teorema de Bayes , Dinâmica Populacional , Reprodução , Estações do Ano
6.
J Anim Ecol ; 90(5): 1085-1095, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33496011

RESUMO

Global climate change is driving species' distributions towards the poles and mountain tops during both non-breeding and breeding seasons, leading to changes in the composition of natural communities. However, the degree of season differences in climate-driven community shifts has not been thoroughly investigated at large spatial scales. We compared the rates of change in the community composition during both winter (non-breeding season) and summer (breeding) and their relation to temperature changes. Based on continental-scale data from Europe and North America, we examined changes in bird community composition using the community temperature index (CTI) approach and compared the changes with observed regional temperature changes during 1980-2016. CTI increased faster in winter than in summer. This seasonal discrepancy is probably because individuals are less site-faithful in winter, and can more readily shift their wintering sites in response to weather in comparison to the breeding season. Regional long-term changes in community composition were positively associated with regional temperature changes during both seasons, but the pattern was only significant during summer due to high annual variability in winter communities. Annual changes in community composition were positively associated with the annual temperature changes during both seasons. Our results were broadly consistent across continents, suggesting some climate-driven restructuring in both European and North American avian communities. Because community composition has changed much faster during the winter than during the breeding season, it is important to increase our knowledge about climate-driven impacts during the less-studied non-breeding season.


Assuntos
Aves , Mudança Climática , Animais , Europa (Continente) , América do Norte , Dinâmica Populacional , Estações do Ano
7.
Conserv Biol ; 35(5): 1484-1495, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-33486838

RESUMO

Evaluation of protected area effectiveness is critical for conservation of biodiversity. Protected areas that prioritize biodiversity conservation are, optimally, located and managed in ways that support relatively large and stable or increasing wildlife populations. Yet evaluating conservation efficacy remains a challenging endeavor. We used an extensive community science data set, eBird, to evaluate the efficacy of protected areas for birds across the Gulf of Mexico and Atlantic coasts of the United States. We modeled trends (2007-2018) for 12 vulnerable waterbirds that use coastal areas during breeding or wintering. We compared two types of protected areas-sites where conservation organizations implemented active stewardship or management or both to reduce human disturbance (hereafter stewardship sites) and local, state, federal, and private protected areas managed to maintain natural land cover (hereafter protected areas)-as well as unprotected areas. We evaluated differences in trends between stewardship, protected, and unprotected areas across the Gulf and Atlantic coasts as a whole. Similar to a background sample, stewardship was known to occur at stewardship sites, but unknown at protected and unprotected areas. Four of 12 target species-Black Skimmer (Rynchops niger), Brown Pelican (Pelecanus occidentalis), Least Tern (Sternula antillarum), and Piping Plover (Charadrius melodus)-had more positive trends (two to 34 times greater) at stewardship sites than protected areas. Furthermore, five target species showed more positive trends at sites with stewardship programs than unprotected sites during at least one season, whereas seven species showed more positive trends at protected than unprotected areas. No species had more negative trends at stewardship sites than unprotected areas, and two species had more negative trends at protected than unprotected areas. Anthropogenic disturbance is a serious threat to coastal birds, and our findings demonstrate that stewardship to reduce its negative impacts helps ensure conservation of vulnerable waterbirds.


La evaluación de la efectividad de las áreas protegidas es de suma importancia para la conservación de la biodiversidad. Las áreas protegidas que priorizan la conservación de la biodiversidad están, de manera óptima, ubicadas y manejadas de maneras que permiten el mantenimiento de poblaciones silvestres relativamente grandes y estables o en incremento. Aun así, la evaluación de la eficacia de la conservación todavía es un esfuerzo desafiante. Usamos un conjunto extensivo de datos de ciencia comunitaria, eBird, para evaluar la eficacia de las áreas protegidas a lo largo de las costas del Golfo de México y del Atlántico en los Estados Unidos. Modelamos las tendencias poblacionales (2007-2018) para doce aves acuáticas vulnerables que usan las áreas costeras durante la temporada de reproducción o de hibernación. Comparamos dos tipos de áreas protegidas - sitios en donde las organizaciones de conservación implementaron una gestión o manejo activo o ambos para reducir la perturbación humana (de ahora en adelante sitios de gestión) y las áreas protegidas locales, estatales, federales y privadas manejadas para mantener la cobertura natural del suelo (de ahora en adelante áreas protegidas) - así como las áreas desprotegidas. Evaluamos las diferencias en las tendencias entre las áreas de gestión, las protegidas y las desprotegidas a lo largo de las cosas del Golfo y del Atlántico como un todo. Similar a una muestra de fondo, se supo que la gestión ocurría en los sitios de gestión, pero no se sabía si ocurría en las áreas protegidas y desprotegidas. Cuatro de las doce especies analizadas - Rhynchops niger, Pelecanus occidentalis, Sternula antillarum y Charadrius melodus - tuvieron tendencias más positivas (2-34 veces mayor) en los sitios de gestión que en las áreas protegidas. Además, cinco especies mostraron más tendencias positivas en los sitios con programas de gestión que en los sitios desprotegidos al menos durante una temporada, mientras que siete especies mostraron más tendencias positivas en sitios protegidos que en las áreas desprotegidas. protegidas que en las desprotegidas. Ninguna especie tuvo más tendencias negativas en los sitios de gestión que en las áreas desprotegidas y dos especies tuvieron más tendencias negativas en las áreas protegidas que en las desprotegidas. La perturbación antropogénica es una amenaza seria para las aves costeras y nuestros hallazgos demuestran que la gestión para reducir sus impactos negativos ayuda a asegurar la conservación de aves acuáticas vulnerables.


Assuntos
Aves , Conservação dos Recursos Naturais , Animais , Biodiversidade , Cruzamento , Humanos
8.
Ecology ; 101(12): e03176, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-32870500

RESUMO

The spatial habitat heterogeneity hypothesis posits that habitat complexity increases the abundance and diversity of species. In tropical forests, lianas add substantial habitat heterogeneity and complexity throughout the vertical forest profile, which may maintain animal abundance and diversity. The effects of lianas on tropical animal communities, however, remain poorly understood. We propose that lianas have a positive effect on animals by enhancing habitat complexity. Lianas may have a particularly strong influence on the forest bird community, providing nesting substrate, protection from predators, and nutrition (food). Understory insectivorous birds, which forage for insects that specialize on lianas, may particularly benefit. Alternatively, it is possible that lianas have a negative effect on forest birds by increasing predator abundances and providing arboreal predators with travel routes with easy access to bird nests. We tested the spatial habitat heterogeneity hypothesis on bird abundance and diversity by removing lianas, thus reducing forest complexity, using a large-scale experimental approach in a lowland tropical forest in the Republic of Panama. We found that removing lianas decreased total bird abundance by 78.4% and diversity by 77.4% after 8 months, and by 40.0% and 51.7%, respectively, after 20 months. Insectivorous bird abundance and diversity 8 months after liana removal were 91.8% and 89.5% lower, respectively, indicating that lianas positively influence insectivorous birds. The effects of liana removal persisted longer for insectivorous birds than other birds, with 77.3% lower abundance and 76.2% lower diversity after 20 months. Liana removal also altered bird community composition, creating two distinct communities in the control and removal plots, with disproportionate effects on insectivores. Our findings demonstrate that lianas have a strong positive influence on the bird community, particularly for insectivorous birds in the forest understory. Lianas may maintain bird abundance and diversity by increasing habitat complexity, habitat heterogeneity, and resource availability.


Assuntos
Florestas , Clima Tropical , Animais , Aves , Ecossistema , Panamá , Árvores
9.
Ecol Appl ; 30(6): e02128, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32223029

RESUMO

Climate change poses an intensifying threat to many bird species and projections of future climate suitability provide insight into how species may shift their distributions in response. Climate suitability is characterized using ecological niche models (ENMs), which correlate species occurrence data with current environmental covariates and project future distributions using the modeled relationships together with climate predictions. Despite their widespread adoption, ENMs rely on several assumptions that are rarely validated in situ and can be highly sensitive to modeling decisions, precluding their reliability in conservation decision-making. Using data from a novel, large-scale community science program, we developed dynamic occupancy models to validate near-term climate suitability projections for bluebirds and nuthatches in summer and winter. We estimated occupancy, colonization, and extinction dynamics across species' ranges in the United States in relation to projected climate suitability in the 2020s, and used a Gibbs variable selection approach to quantify evidence of species-climate relationships. We also included a Bird Conservation Region strata-level random effect to examine among-strata variation in occupancy that may be attributable to land-use and ecoregional differences. Across species and seasons, we found strong evidence that initial occupancy and colonization were positively related to 2020 climate suitability, illustrating an independent validation of projections from ENMs across a large geographic area. Random strata effects revealed that occupancy probabilities were generally higher than average in core areas and lower than average in peripheral areas of species' ranges, and served as a first step in identifying spatial patterns of occupancy from these community science data. Our findings lend much-needed support to the use of ENM projections for addressing questions about potential climate-induced changes in species' occupancy dynamics. More broadly, our work highlights the value of community scientist observations for ground-truthing projections from statistical models and for refining our understanding of the processes shaping species' distributions under a changing climate.


Assuntos
Mudança Climática , Ecossistema , Animais , Aves , Modelos Teóricos , Reprodutibilidade dos Testes , Estados Unidos
10.
Sci Rep ; 7(1): 15203, 2017 11 09.
Artigo em Inglês | MEDLINE | ID: mdl-29123188

RESUMO

Large-scale climatic fluctuations have caused species range shifts. Moose (Alces alces) have expanded their range southward into agricultural areas previously not considered moose habitat. We found that moose expansion into agro-ecosystems is mediated by broad-scale climatic factors and access to high-quality forage (i.e., crops). We used crop damage records to quantify moose presence across the Canadian Prairies. We regressed latitude of crop damage against North Atlantic Oscillation (NAO) and crop area to test the hypotheses that NAO-mediated wetland recharge and occurrence of more nutritious crop types would result in more frequent occurrences of crop damage by moose at southerly latitudes. We examined local-scale land use by generating a habitat selection model to test our hypothesis that moose selected for areas of high crop cover in agro-ecosystems. We found that crop damage by moose occurred farther south during dry winters and in years with greater coverage of oilseeds. The results of our analyses support our hypothesis that moose movement into cropland is mediated by high-protein crops, but not by thermoregulatory habitat at the scale examined. We conclude that broad-scale climate combined with changing land-use regimes are causal factors in species' range shifts and are important considerations when studying changing animal distributions.


Assuntos
Distribuição Animal , Clima , Produtos Agrícolas/crescimento & desenvolvimento , Cervos , Ecossistema , Comportamento Alimentar , Herbivoria , Animais , Canadá , Análise Espaço-Temporal
11.
Physiol Rep ; 5(14)2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28716820

RESUMO

Accurate and adaptive encoding of complex, dynamic visual information is critical for the survival of many animals. Studies across a range of taxa have investigated behavioral and neuronal responses to objects that represent a threat, such as a looming object approaching along a direct collision course. By investigating neural mechanisms of avoidance behaviors through recording multineuronal activity, it is possible to better understand how complex visual information is represented in circuits that ultimately drive behaviors. We used multichannel electrodes to record from the well-studied locust nervous system to explore how object motion is reflected in activity of correlated neural activity. We presented locusts (Locusta migratoria) with objects that moved along one of 11 unique trajectories and recorded from descending interneurons within the ventral nerve cord. Spike sorting resulted in 405 discriminated units across 20 locusts and we found that 75% of the units responded to some form of object motion. Dimensionality reduction through principal component (PCA) and dynamic factor (DFA) analyses revealed population vector responses within individuals and common firing trends across the pool of discriminated units, respectively. Population vector composition (PCA) varied with the stimulus and common trends (DFA) showed unique tuning related to changes in the visual size and trajectory of the object through time. These findings demonstrate that this well-described collision detection system is more complex than previously envisioned and will drive future experiments to explore fundamental principles of how visual information is processed through context-dependent dynamic ensembles of neurons to initiate and control complex behavior.


Assuntos
Potenciais Evocados Visuais , Interneurônios/fisiologia , Percepção de Movimento , Vias Visuais/fisiologia , Animais , Gafanhotos , Masculino , Vias Visuais/citologia
12.
Biol Rev Camb Philos Soc ; 91(4): 1081-1101, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26202483

RESUMO

Understanding distribution patterns and multitrophic interactions is critical for managing bat- and bird-mediated ecosystem services such as the suppression of pest and non-pest arthropods. Despite the ecological and economic importance of bats and birds in tropical forests, agroforestry systems, and agricultural systems mixed with natural forest, a systematic review of their impact is still missing. A growing number of bird and bat exclosure experiments has improved our knowledge allowing new conclusions regarding their roles in food webs and associated ecosystem services. Here, we review the distribution patterns of insectivorous birds and bats, their local and landscape drivers, and their effects on trophic cascades in tropical ecosystems. We report that for birds but not bats community composition and relative importance of functional groups changes conspicuously from forests to habitats including both agricultural areas and forests, here termed 'forest-agri' habitats, with reduced representation of insectivores in the latter. In contrast to previous theory regarding trophic cascade strength, we find that birds and bats reduce the density and biomass of arthropods in the tropics with effect sizes similar to those in temperate and boreal communities. The relative importance of birds versus bats in regulating pest abundances varies with season, geography and management. Birds and bats may even suppress tropical arthropod outbreaks, although positive effects on plant growth are not always reported. As both bats and birds are major agents of pest suppression, a better understanding of the local and landscape factors driving the variability of their impact is needed.


Assuntos
Aves/fisiologia , Quirópteros/fisiologia , Ecossistema , Florestas , Comportamento Predatório/fisiologia , Agricultura , Animais , Clima Tropical
13.
Integr Zool ; 10(5): 436-52, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26201263

RESUMO

In its 40-year history, the science of conservation has faced unprecedented challenges in terms of environmental damage and rapid global change, and environmental problems are only increasing as greater demands are placed on limited natural resources. Conservation science has been adapting to keep pace with these changes. Here, we highlight contemporary and emerging trends and innovations in conservation science that we believe represent the most effective responses to biodiversity threats. We focus on specific areas where conservation science has had to adjust its approach to address emerging threats to biodiversity, including habitat destruction and degradation, climate change, declining populations and invasive species. We also document changes in attitudes, norms and practices among conservation scientists. A key component to success is engaging and maintaining public support for conservation, which can be facilitated through the use of technology. These recent trends in conservation and management are innovative and will assist in optimizing conservation strategies, increasing our leverage with the general public and tackling our current environmental challenges.


Assuntos
Biodiversidade , Conservação dos Recursos Naturais/tendências , Ecossistema , Atitude , Mudança Climática , Conservação dos Recursos Naturais/métodos , Espécies Introduzidas , Opinião Pública
14.
Environ Toxicol Chem ; 34(11): 2513-22, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26033510

RESUMO

Ecotoxicology research on polychlorinated biphenyl (PCB) mixtures has focused principally on short-term effects on reproduction, growth, and other physiological endpoints. Latent cognitive effects from early life exposure to low-level PCBs were examined in an avian model, the European starling (Sturnus vulgaris). Thirty-six birds, divided equally among 4 treatment groups (control = 0 µg, low = 0.35 µg, intermediate = 0.70 µg, and high = 1.05 µg Aroclor 1254/g body weight), were dosed 1 d through 18 d posthatch, then tested 8 mo to 9 mo later in captivity in an analog to an open radial arm maze. Birds were subject to 4 sequential experiments: habituation, learning, cue selection, and memory. One-half of the birds did not habituate to the test cage; however, this was not linked to a treatment group. Although 11 of the remaining 18 birds successfully learned, only 1 was from the high-dosed group. Control and low-dosed birds were among the only treatment groups to improve trial times throughout the learning experiment. High-dosed birds were slower and more error-prone than controls. Cue selection (spatial or color cues) and memory retention were not affected by prior PCB exposure. The results indicate that a reduction in spatial learning ability persists among birds exposed to Aroclor 1254 during development. This may have implications for migration ability, resource acquisition, and other behaviors relevant for fitness.


Assuntos
Cognição/efeitos dos fármacos , Bifenilos Policlorados/toxicidade , Animais , Comportamento Animal/efeitos dos fármacos , Encéfalo/efeitos dos fármacos , Encéfalo/fisiologia , Feminino , Aprendizagem/efeitos dos fármacos , Masculino , Estorninhos/crescimento & desenvolvimento , Estorninhos/fisiologia
15.
Environ Sci Technol ; 49(14): 8367-76, 2015 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-26098364

RESUMO

Neonicotinoids are commonly used seed treatments on Canada's major prairie crops. Transported via surface and subsurface runoff into wetlands, their ultimate aquatic fate remains largely unknown. Biotic and abiotic wetland characteristics likely affect neonicotinoid presence and environmental persistence, but concentrations vary widely between wetlands that appear ecologically (e.g., plant composition) and physically (e.g., depth) similar for reasons that remain unclear. We conducted intensive surveys of 238 wetlands, and documented 59 wetland (e.g., dominant plant species) and landscape (e.g., surrounding crop) characteristics as part of a novel rapid wetland assessment system. We used boosted regression tree (BRT) analysis to predict both probability of neonicotinoid analytical detection and concentration. BRT models effectively predicted the deviance in neonicotinoid detection (62.4%) and concentration (74.7%) from 21 and 23 variables, respectively. Detection was best explained by shallow marsh plant species identity (34.8%) and surrounding crop (13.9%). Neonicotinoid concentration was best explained by shallow marsh plant species identity (14.9%) and wetland depth (14.2%). Our research revealed that plant composition is a key indicator and/or driver of neonicotinoid presence and concentration in Prairie wetlands. We recommend wetland buffers consisting of diverse native vegetation be retained or restored to minimize neonicotinoid transport and retention in wetlands, thereby limiting their potential effects on wetland-dependent organisms.


Assuntos
Pradaria , Inseticidas/análise , Modelos Teóricos , Poluentes Químicos da Água/análise , Áreas Alagadas , Anabasina/análise , Produtos Agrícolas , Ecossistema , Plantas , Análise de Regressão , Saskatchewan
16.
Environ Sci Technol ; 49(10): 6274-83, 2015 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-25893686

RESUMO

Birds exposed to endocrine disrupting chemicals during development could be susceptible to neurological and other physiological changes affecting migratory behaviors. We investigated the effects of ecologically relevant levels of Aroclor 1254, a polychlorinated biphenyl (PCB) mixture, on moult, fattening, migratory activity, and orientation in juvenile European starlings (Sturnus vulgaris). Birds were orally administered 0 (control), 0.35 (low), 0.70 (intermediate), or 1.05 (high) µg Aroclor 1254/g-body weight by gavage from 1 through 18 days posthatch and later exposed in captivity to a photoperiod shift simulating an autumn migration. Migratory activity and orientation were examined using Emlen funnel trials. Across treatments, we found significant increases in mass, fat, and moulting and decreasing plasma thyroid hormones over time. We observed a significant increase in activity as photoperiod was shifted from 13L:11D (light:dark) to 12L:12D, demonstrating that migratory condition was induced in captivity. At 12L:12D, control birds oriented to 155.95° (South-Southeast), while high-dosed birds did not. High-dosed birds showed a delayed orientation to 197.48° (South-Southwest) under 10L:14D, concomitant with apparent delays in moult. These findings demonstrate how subtle contaminant-induced alterations during development could lead to longer-scale effects, including changes in migratory activity and orientation, which could potentially result in deleterious effects on fitness and survival.


Assuntos
Migração Animal/efeitos dos fármacos , Exposição Ambiental/análise , Muda/efeitos dos fármacos , Estorninhos/crescimento & desenvolvimento , Administração Oral , Animais , Feminino , Masculino , Testes de Toxicidade
17.
PLoS One ; 9(3): e92821, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24671127

RESUMO

Neonicotinoids currently dominate the insecticide market as seed treatments on Canada's major Prairie crops (e.g., canola). The potential impact to ecologically significant wetlands in this dominantly agro-environment has largely been overlooked while the distribution of use, incidence and level of contamination remains unreported. We modelled the spatial distribution of neonicotinoid use across the three Prairie Provinces in combination with temporal assessments of water and sediment concentrations in wetlands to measure four active ingredients (clothianidin, thiamethoxam, imidacloprid and acetamiprid). From 2009 to 2012, neonicotinoid use was increasing; by 2012, applications covered an estimated ∼11 million hectares (44% of Prairie cropland) with >216,000 kg of active ingredients. Thiamethoxam, followed by clothianidin, were the dominant seed treatments by mass and area. Areas of high neonicotinoid use were identified as high density canola or soybean production. Water sampled four times from 136 wetlands (spring, summer, fall 2012 and spring 2013) across four rural municipalities in Saskatchewan similarly revealed clothianidin and thiamethoxam in the majority of samples. In spring 2012 prior to seeding, 36% of wetlands contained at least one neonicotinoid. Detections increased to 62% in summer 2012, declined to 16% in fall, and increased to 91% the following spring 2013 after ice-off. Peak concentrations were recorded during summer 2012 for both thiamethoxam (range:

Assuntos
Anabasina/análise , Monitoramento Ambiental , Pradaria , Inseticidas/análise , Poluentes Químicos da Água/análise , Áreas Alagadas , Canadá , Geografia , Sedimentos Geológicos/química , Modelos Lineares , Estações do Ano
18.
Eur J Med Genet ; 57(5): 185-94, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24503147

RESUMO

The duplication of the short arm (p) of chromosome 12 is a rare chromosomal abnormality, and most reported cases result from malsegregation of a balanced parental translocation associated with other chromosomal imbalances. Of the reported cases, only 15 involve a pure and complete 12p duplication and only 10 involve a pure and partial duplication overlapping the 12p12.3p13.1 region, including a single instance of an inherited duplication in two related individuals. Here, we report three new patients with a pure 12p duplication, detected by conventional cytogenetic studies and characterized by array-comparative genomic hybridization (array-CGH) and fluorescence in situ hybridization (FISH). The first patient was a child carrying a de novo inverted duplication of the short arm of chromosome 12. His phenotype was similar to that of the "trisomy 12p syndrome", characterized by developmental delays and craniofacial abnormalities including a high forehead, a short nose with anteverted nostrils and an everted lower lip. The second and third patients were a mother and son with a direct 12p12.3p13.1 duplication, exhibiting a milder phenotype characterized by moderate developmental delays, dysmorphic facial features, behavioral problems and obesity. The present data, including the rarity of the familial cases, should contribute to our knowledge of the genotype/phenotype correlation in trisomy 12p patients.


Assuntos
Anormalidades Múltiplas/diagnóstico , Receptores de N-Metil-D-Aspartato/genética , Trissomia/diagnóstico , Anormalidades Múltiplas/genética , Adolescente , Adulto , Cromossomos Humanos Par 12/genética , Hibridização Genômica Comparativa , Feminino , Humanos , Cariotipagem , Masculino , Trissomia/genética
19.
Anal Cell Pathol ; 25(3): 115-22, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-12775915

RESUMO

In order to identify genomic changes associated with a resistant phenotype acquisition, we used comparative genomic hybridization (CGH) to compare a human ovarian cell line, Igrov1, and four derived subcell lines, resistant to vincristine and presenting a reversion of malignant properties. Multicolor FISH (Multiplex-FISH and Spectral Karyotype) and conventional FISH are also used to elucidate the karyotype of parental cell line. The drug-resistant subcell lines displayed many chromosomal abnormalities suggesting the implication of different pathways leading to a multidrug resistance phenotype. However, these cell lines shared two common rearrangements: an unbalanced translocation der(8)t(8;13)(p22;q?) and a deletion of the 11p. These chromosomal imbalances could reflected the acquisition of the chemoresistance (der(8)) or the loss of tumorigenicity properties (del(11p)).


Assuntos
Adenocarcinoma/tratamento farmacológico , Adenocarcinoma/genética , Resistencia a Medicamentos Antineoplásicos/genética , Neoplasias Ovarianas/tratamento farmacológico , Neoplasias Ovarianas/genética , Adenocarcinoma/patologia , Antineoplásicos Fitogênicos/farmacologia , Linhagem Celular Tumoral , Aberrações Cromossômicas , Citogenética , Feminino , Humanos , Hibridização in Situ Fluorescente , Cariotipagem , Neoplasias Ovarianas/patologia , Fenótipo , Poliploidia , Vincristina/farmacologia
20.
Cancer Genet Cytogenet ; 132(1): 51-4, 2002 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-11801309

RESUMO

In order to identify genomic changes associated with drug-resistance acquisition, we performed R-banding karyotyping, fluorescence in situ hybridization, and comparative genomic hybridization to compare a human T-cell lymphoblastic leukemia cell line, CEM-wild type, and a subline with resistance to vinblastine (CEM-VLB) and overexpressing P-glycoprotein. Comparative genomic hybridization analysis showed that the CEM-VLB cell line carried chemoresistance-associated chromosomal abnormalities (amplification of 7q11 approximately q22, losses of chromosomes 2, 3, 5, 9, 10, and 16, and deletion of 4q13 approximately qter). Fluorescence in situ hybridization identified an amplified 7q21 region translocated on the short arm of a chromosome 2. This region contained the MDR1 gene locus and probably neighboring genes, such as SRI or MDR3/ABCB4. According to previous reports, this chromosomal rearrangement occurred during drug selection and attested a resistance acquisition.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Leucemia de Células T/genética , Células Tumorais Cultivadas/efeitos dos fármacos , Vimblastina/farmacologia , Aberrações Cromossômicas , Mapeamento Cromossômico/métodos , Cromossomos Humanos Par 7/genética , Resistencia a Medicamentos Antineoplásicos , Humanos , Hibridização in Situ Fluorescente/métodos , Cariotipagem/métodos , Proteínas de Neoplasias/genética , Hibridização de Ácido Nucleico/métodos , Células Tumorais Cultivadas/metabolismo , Células Tumorais Cultivadas/ultraestrutura
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