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Biblioteca Digital do IPB (53.442 recursos)

A Biblioteca Digital do IPB, tem por objectivo divulgar e permitir o livre acesso à produção científica produzida pela comunidade académica, promovendo a integração, partilha e a visibilidade da informação científica e garantindo a preservação da memória intelectual do Instituto Politécnico de Bragança.

ARN - Artigos em Revistas Indexadas ao ISI

Mostrando recursos 1 - 20 de 73

  1. Standard methods for molecular research in Apis mellifera

    Evans, J.D.; Schwarz, R.; Chen, Y.P.; Budge, G.; Cornman, R. S.; De la Rúa, Pilar; Miranda, J.R.; Foret, S.; Foster, L.; Gauthier, L.; Genersch, E.; Gisder, S.; Jarosch, A.; Kucharski, R.; Lopez, D.; Lun, C.M.; Moritz, R.F.A.; Maleszka, R.; Muñoz, Irene; Pinto, M. Alice
    From studies of behaviour, chemical communication, genomics and developmental biology, among many others, honey bees have long been a key organism for fundamental breakthroughs in biology. With a genome sequence in hand, and much improved genetic tools, honey bees are now an even more appealing target for answering the major questions of evolutionary biology, population structure, and social organization. At the same time, agricultural incentives to understand how honey bees fall prey to disease, or evade and survive their many pests and pathogens, have pushed for a genetic understanding of individual and social immunity in this species. Below we describe...

  2. Standard methods for characterising subspecies and ecotypes of Apis mellifera

    Meixner, Marina D.; Pinto, M. Alice; Bouga, Maria; Kryger, Per; Ivanova, Evgeniya Neshova; Fuchs, Stefan
    The natural diversity of honey bees in Europe is eroding fast. A multitude of reasons lead to a loss of both genetic diversity and specific adaptations to local conditions. To preserve locally adapted bees through breeding efforts and to maintain regional strains in conservation areas, these valuable populations need to be identified. In this paper, we give an overview of methods that are currently available and used for recognition of honey bee subspecies and ecotypes, or that can be utilised to verify the genetic origin of colonies for breeding purposes. Beyond summarising details of morphometric, allozyme and DNA methods currently in...

  3. Maternal diversity patterns of Ibero-Atlantic populations reveal further complexity of Iberian honeybees

    Pinto, M. Alice; Henriques, Dora; Neto, Margarida; Guedes, Helena; Muñoz, Irene; Azevedo, João; De la Rúa, Pilar
    Dissecting complex diversity patterns typically exhibited by organisms of hybrid zones is among the greatest challenges in evolutionary biology. This has been a long-standing goal of numerous Iberian honeybee studies. Herein, we further contribute to this goal by a fine-scale maternal survey of the Portuguese honeybee populations. In addition to confirm a predicted African ancestry of Portuguese populations and negligible levels of C-lineage introgression, our fine-scale survey revealed unparalleled levels of African maternal diversity and a remarkable north–south cline formed by African haplotypes of distinct ancestry. This survey further highlights the distinctiveness of Apis mellifera iberiensis by showing the existence of highly contrasting diversity patterns between the...

  4. The Atlantic side of the Iberian Peninsula: a hot-spot of novel African honey bee maternal diversity

    Pinto, M. Alice; Muñoz, Irene; Chavez-Galarza, Julio; De la Rúa, Pilar
    The Iberian honey bee has been one of the most surveyed subspecies for genetic diversity. Yet, previous studies have missed an important component of Iberian honey bee variation harbored by populations inhabiting the Atlantic side of the Iberian Peninsula. Herein, we provide a fuller picture of the Iberian honey bee maternal diversity by revealing 16 novel haplotypes detected in honey bees from Portugal. Of the 16 haplotypes, all of African ancestry, 15 belong to the Atlantic sub-lineage AIII while only one fits the most common sub-lineage AI. This level of new variation is remarkable as it represents a 59% increase in the widerange African lineage and...

  5. Temporal changes in mitochondrial diversity highlights contrasting population events in Macaronesian honey bees

    Muñoz, Irene; Pinto, M. Alice; De la Rúa, Pilar
    Temporal studies of the genetic diversity are important as they enable detection of genetic changes that can constitute threats to the honey bee populations. In this study, we analyzed the present mitochondrial diversity in honey bee populations inhabiting the Macaronesian archipelagos (Azores, Madeira and Canary), and compared with previous data over a 10-year period. Present populations showed mainly haplotypes characteristic of the evolutionary African sub-lineage (AIII), but foreign mitochondrial haplotypes (M7, C1 and C2) were also observed suggesting honey bee queens introductions with different origins. Differential patterns of change in mitochondrial diversity and introgression were detected: whereas a low decrease was detected on Madeira and São Miguel,...

  6. Microbial biomass and N mineralization in mixed plantations of broadleaves and nitrogen-fixing species

    Pereira, Ermelinda; Santos, Sónia A.P.; Arrobas, Margarida; Patrício, Maria do Sameiro
    Mixed stands with nitrogen fixing secondary species can improve the vigour and the stand environment of the targeted species. The aim of this study was to better understand the effect of the consociation of a N-fixing species (black locust) with a broadleaf quality timber production (wild cherry). The study was conducted in 11 year old plantations located in the Northeast of Portugal. The treatments considered were: pure black locust, pure wild cherry and mixture of wild cherry and black locust. Each plot had six lines with 12 trees and a buffer strip line. The samplings were collected on the plantation line within a radius of...

  7. Ecological status of a Margaritifera margaritifera (Linnaeus, 1758) population at the southern edge of its distribution (River Paiva, Portugal)

    Amorim, Ângela; Sobral, Carina; Froufe, Elsa; Varandas, Simone; Teixeira, Amílcar; Lopes-Lima, Manuel
    An important population of the critically endangered pearl mussel Margaritifera margaritifera (Linnaeus, 1758) was surveyed at the edge of its southern distribution (River Paiva, Portugal). Although an earlier study suggested that this population had a very low number of individuals (<500), a narrow distribution, and was mainly comprised by old specimens our data contradict these findings. Our assessment estimated a population with probably more than 5,000 individuals distributed across 80 km of the river length. From the 32 sites surveyed, 19 contained M. Margaritifera with higher abundances verified in the middle and upper parts of the river (a maximum of 78...

  8. Reproductive cycle and strategy of Anodonta anatina (L., 1758): Notes on hermaphroditism

    Hinzmann, Mariana; Lopes-Lima, Manuel; Teixeira, Amílcar; Varandas, Simone; Sousa, Ronaldo; Lopes, Anabela; Froufe, Elsa; Machado, Jorge
    Freshwater mussels have decreased dramatically in Iberia over the last decades. These animals are responsible for important ecosystem services such as recycling nutrients and improving water clarity. Under this view a better knowledge on the biological features of these animals is extremely important for future conservation and management actions. In this study the reproductive and gametogenic cycle of Anodonta anatina were studied during 2 years in one population as well as the sex ratio and hermaphroditism in six distinct populations, using standard histology. Gametogenesis was continuous in both sexes and germinal epithelium in early stages of development. Gametes were present...

  9. Development and multiplexing of microsatellite loci for the near threatened freshwater mussel Potomida littoralis (Cuvier, 1798) using 454 sequencing

    Froufe, Elsa; Sobral, Carina; Teixeira, Amílcar; Lopes, Anabela; Sousa, Ronaldo; Varandas, Simone; Lopes-Lima, Manuel
    1. The Unionidae are among the most endangered fauna in the world and globally in decline. They are particularly vulnerable to habitat loss and fragmentation, susceptible to flow, pollution and climatic disturbances and introduction of invasive species. Despite their well-recognized ecological and conservation importance, there is a surprising lack of genomic resources currently available for European species. 2. The aim of this study was to develop and characterize microsatellites for the near threatened freshwater mussel, Potomida littoralis using 454 sequencing. 3. In order to improve genotyping throughput as well as cost-effectiveness, two multiplex-PCR reactions were designed to amplify 16 new loci. All...

  10. Feeding ecology of the Ruivaco Achondrostoma oligolepis, a portuguese endemic cyprinid fish

    Santos, José M.; Encina, Lourdes; Oliveira, João; Teixeira, Amílcar
    This study assessed the feeding ecology of the ruivaco Achondrostoma oligolepis, a Portuguese endemic resident cyprinid fish whose dietary habits are virtually unknown. Samples were taken seasonally in three medium-sized rivers representing a gradient of temporality. The stomach contents of 97 individuals (42-126 mm total length, TL) were analysed. Although there was no significant overall variation in diet composition between rivers, differences were found among seasons. A broad range of food categories was identified, although a smaller subset of primarily detritus (77.6 %) and plant material (18.4 %) constituted the base diet. Of the animal prey, Coleoptera and Diptera were...

  11. Ecology of southern European pearl mussels (Margaritifera margaritifera): first record of two new populations on the rivers Terva and Beça (Portugal)

    Varandas, Simone; Lopes-Lima, Manuel; Teixeira, Amílcar; Hinzmann, Mariana; Reis, Joaquim; Cortes, R.; Machado, Jorge; Sousa, Ronaldo
    Southern European populations of Margaritifera margaritifera (L., 1758) are under-studied. From 1986 to 2001 this species was considered extinct in Portugal but between 2001 and 2002 six northern populations were found, five of which were previously unknown. 2. This study comprises a comparative study of the ecology and habitat requirements of two new populations in the rivers Beça and Terva (tributaries of the River Tâmega, northern Portugal) with non-Iberian populations. 3. Surveys were conducted in 2010/2011 to characterize ecological status and propose possible conservation measures. Both rivers were in good environmental condition, but the River Beça had higher biological, physicochemical and hydromorphological quality. 4....

  12. Biotic homogenization as a threat to native affiliate species: fish introductions dilute freshwater mussel’s host resources

    Douda, Karel; Lopes-Lima, Manuel; Hinzmann, Mariana; Machado, Jorge; Varandas, Simone; Teixeira, Amílcar; Ronaldo, Sousa
    Aim: The indirect consequences of biotic homogenization, the process of a gradual increase in the similarity of regional biotas driven by the combined effects of species invasions and extinctions, are still poorly understood. In this study, we aimed to assess the ability of a native affiliate species to maintain its host resources under the condition of biotic homogenization of host communities. Location: Central (Vltava River Basin, Czech Republic) and western (Douro River Basin, Portugal) Europe. Methods: We tested the ability of non-native species to serve as an alternative partner in local host–affiliate relationships. We used a European freshwater mussel, Anodonta anatina, which...

  13. Modelling stream-fish functional traits in reference conditions: regional and local environmental correlates

    Oliveira, João; Segurado, Pedro; Santos, José M.; Teixeira, Amílcar; Ferreira, Maria Teresa; Cortes, R.
    Identifying the environmental gradients that control the functional structure of biological assemblages in reference conditions is fundamental to help river management and predict the consequences of anthropogenic stressors. Fish metrics (density of ecological guilds, and species richness) from 117 least disturbed stream reaches in several western Iberia river basins were modelled with generalized linear models in order to investigate the importance of regional- and local-scale abiotic gradients to variation in functional structure of fish assemblages. Functional patterns were primarily associated with regional features, such as catchment elevation and slope, rainfall, and drainage area. Spatial variations of fish guilds were thus associated with broad geographic gradients, showing...

  14. The role of holm oak edges in the control of disturbance and conservation of plant diversity in fire-prone landscapes

    Azevedo, João; Possacos, Anabela; Aguiar, Carlos; Amado, Anabela; Miguel, Luis; Dias, Rui; Loureiro, Carlos; Fernandes, Paulo M.
    Holm oak (Quercus rotundifolia) woodlands have been able to persist in fire-prone landscapes in northern Portugal where they seem to play a relevant role in community and landscape level patterns and processes, namely in the control of disturbance events and in the maintenance of biodiversity. In this research we tested the following hypotheses: (i) holm oak woodlands affect fire behavior, mainly by disrupting and delaying fire spread; (ii) disruption and delaying of fire spread is due to fire extinction at the edge of woodlands; and (iii) plant diversity is favored by frequent low-intensity fires as a result of the control of fire...

  15. Litterfall and litter decomposition in chestnut high forest stands in northern Portugal

    Patrício, Maria do Sameiro; Nunes, Luís; Pereira, Ermelinda
    This research aimed to: estimate the inputs of litterfall; model the decomposition process and assess the rates of litter decay and turnover; study the litter decomposition process and dynamics of nutrients in old chestnut high forests. This study aimed to fill a gap in the knowledge of chestnut decomposition process as this type of ecosystems have never been modeled and studied from this point of view in Portugal. The study sites are located in the mountains of Marão, Padrela and Bornes in a west-to-east transect, across northern Portugal, from a more-Atlantic-to-lessmaritime influence. This research was developed on old chestnut high forests for quality timber production...

  16. Modeling dominant height growth of maritime pine in Portugal using GADA methodology with parameters depending on soil and climate variables

    Nunes, Luís; Patrício, Maria do Sameiro; Tomé, José; Tomé, Margarida
    Background Maritime pine (Pinus pinaster Ait.) is a common conifer species in Portugal that contributes significantly to the national economy. Accurate classification of forest productivity based on site index and height growth dynamics is the main basis for sustainable forest management of this species. Objectives The main objective of this study was to develop a new dynamic site-dependent height–age model for the maritime pine in Portugal, using the generalized algebraic difference approach (GADA) methodology, and to explore possible improvements of the model´s performance by expanding its parameters as sub-functions of soil and climate variables. Methods We tested for this purpose several dynamic equations,...

  17. Prediction of annual tree growth and survival for thinned and unthinned even-aged maritime pine stands in Portugal from data with different time measurement intervals

    Nunes, Luís; Tomé, José; Tomé, Margarida
    An annual individual tree survival and growth model was developed for pure even-aged stands of maritime pine in Portugal, using a large data set containing irregularly time-spaced measurements and considering thinning effects. The model is distance-independent and is based on a function for diameter growth, a function for height growth and a survival function. Two approaches are compared for modeling annual tree growth. The first approach directly estimates a future diameter or height using well-known growth functions formulated in difference form. The second approach estimates diameter or height using a function in differential form estimating the increment over a year period. In both approaches, the function parameters...

  18. Growth, soil properties and foliage chemical analysis comparison between pure and mixed stands of Castanea sativa Mill. and Pseudotsuga menziesii (Mirb.) Franco, in Northern Portugal

    Nunes, Leónia; Coutinho, João; Nunes, Luís; Rego, Francisco; Lopes, Domingos
    Ecosystems with mixed species compared to the ones with pure compositions provide a broader range of options in the fields of biodiversity, conservation, protection and restoration. Industrial plantations in Portugal are mostly monocultures with the predominance of coniferous forests, so the introduction of broadleaves could be important for the biodiversity and sustainability of Portuguese forests. This study aims to present and discuss field data from pure and mixed-species plantations of European chestnut (Castanea sativa Mill.) and douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] with different intercropping densities in a total of 5 treatments with two replicate blocks. In respect to growth, the results showed significant difference (P <...

  19. Effect of gamma and electron beam irradiation on the physico-chemical and nutritional properties of mushrooms: a review

    Fernandes, Ângela; Antonio, Amilcar L.; Oliveira, M.B.P.P.; Martins, Anabela; Ferreira, Isabel C.F.R.
    The short shelf-life of mushrooms is an obstacle to the distribution and marketing of the fresh product. Thus, prolonging postharvest storage, while preserving their quality, would benefit the mushroom industry as well as consumers. There has been extensive research on finding the most appropriate technology for mushrooms preservation. Gamma, electron-beam and UV irradiation have been shown to be potential tools in extending the postharvest shelf-life of fresh mushrooms. Studies evaluating the effects of ionizing radiation are available mainly in cultivated species such as Agaricus bisporus, Lentinus edodes and Pleurotus ostreatus. This review comprises a comprehensive study of the effects of irradiation on physico-chemical parameters (weight, colour,...

  20. Carbon storage in the Mediterranean upland shrub communities of Montesinho Natural Park, northeast of Portugal

    Fonseca, Felícia; Figueiredo, Tomás de; Ramos, Maria Alice Bompastor
    Carbon storage is one of the several important functions of shrub communities in terrestrial ecosystems and could represent an effective way to mitigate climate change. Accordingly, biomass carbon (above and belowground), litter carbon and soil organic carbon (SOC) were studied in three shrub species – Cistus ladanifer (C. ladanifer), Cytisus multiflorus (C. multiflorus) and Erica australis spp. Aragonensis (E. australis) – representing dominant shrub communities found in Montesinho Natural Park (PNM), NE Portugal. The experimental design envisaged testing the effects of species and topography on variables mentioned and procedures carried out included assessments in areas covered by the three communities...

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