Mostrando recursos 1 - 11 de 11

  1. Can we use niche models of indicator species to predict the distribution of endangered communities?

    Chefaoui, Rosa M.; Chozas, Sergio; Correia, Otilia; Santos, Ana M. C.; Hortal, Joaquín
    European-wide conservation policies are based on the identification of priority habitats. However, research on conservation biogeography often relies on the results and projections of species distribution models to assess species' vulnerability to global change. We assess whether the distribution and structure of threatened communities can be predicted by the suitability of the environmental conditions for their indicator species. We present some preliminary results elucidating if using species distribution models of indicator species at a regional scale is a valid approach to predict these endangered communities. Dune plant assemblages, affected by severe conditions, are excellent models for studying possible interactions among their integrating species and the environment. We use...

  2. Landscape metrics as indicators of coastal morphology and its use in ecological niche modelling of seagrass species

    Chefaoui, Rosa M.; Assis, Jorge; Duarte, Carlos M.; Serrão, Ester
    Dependence of some species on landscape structure has been proved in numerous studies. So far, however, little progress has been made in the integration of landscape metrics in the prediction of species associated with coastal features. Specific landscape metrics were tested as predictors of coastal shape using three coastal features of the Iberian Peninsula (beaches, capes and gulfs) at different scales. We used the landscape metrics in combination with environmental variables to model the niche and find suitable habitats for a seagrass species (Cymodocea nodosa) throughout its entire range of distribution. Landscape metrics able to capture variation in the coastline enhanced significantly the accuracy of the models, despite...

  3. Large-scale prediction of seagrass distribution: the case of Cymodocea nodosa (Mediterranean-Atlantic)

    Chefaoui, Rosa M.; Assis, Jorge; Duarte, C. M.; Serrão, Ester
    Understanding the factors that affect seagrass meadows encompassing their entire range of distribution is challenging yet important for their conservation. We model the environmental niche of Cymodocea nodosa using a combination of environmental variables and landscape metrics to examine factors defining its distribution and find suitable habitats for the species. The most relevant environmental variables defining the distribution of C. nodosa were sea surface temperature (SST) and salinity. We found suitable habitats at SST from 5.8 ºC to 26.4 ºC and salinity ranging from 17.5 to 39.3. Optimal values of mean winter wave height ranged between 1.2 m and 1.5 m, while waves higher than 2.5 m seemed...

  4. Using niche modelling of indicator species to predict the distribution of xerophitic shrub dune communities in South-Western Portugal

    Chefaoui, Rosa M.; Chozas, Sergio; Correia, Otilia; Santos, Ana M. C.; Hortal, Joaquín
    Inland sand dune systems are amongst the most threatened habitat types of Europe. Affected by severe conditions, these habitats present distinct community compositions, which makes them excellent for studying possible interactions among their integrating species and the environment. We focus on understanding the distribution and cooccurrence of the species from dune plant assemblages as a key step for the adequate protection of these habitats. Using data from an extensive survey we identified the shrub species that could be considered indicators of the different xerophytic scrub dune communities in South West Portugal. Then, we modelled the responses of these species to the environmental conditions using Ecological Niche Factor Analysis....

  5. Successional dynamics in inland dune shrub communities drive changes in functional diversity

    Chozas, Sergio; Correia, Otilia; Santos, Ana M. C.; Chefaoui, Rosa M.; Hortal, Joaquín
    Communities can be defined as assemblages of species coexisting under particular environments. The relationship between environment and species are regulated by both environmental requirements –which ultimately determine the species capacity to establish and survive in a particular environment– and the ecological interactions occurring during assembly processes –which also determine community composition by conditioning species coexistence. In this context, plant functional traits are attributes that represent ecological strategies and determine how plants respond to environmental factors and interact with other species. Therefore, the analysis of how traits vary through the dynamics of communities, such as along successions, can give insights about how environmental requirements and species interactions may determine the composition...

  6. Growth hormone profiles and development of somatotrophs in Atlantic Halibut Larvae

    Einarsdóttir, Ingibjörg E.; Sweeney, Glen; Power, Deborah; Kristjánsson, Birgir A.; Björnsson, Björn Thrandur
    The Atlantic halibut is the largest flatfish species, and as other flatfish, has a complicated larval development. The pelagic larvae hatch after about two weeks and feeding starts six weeks later. After three to four months, they start to undergo metamorphosis. Following major changes in body shape, including the migration of the left to the right side, the larvae settle as bottom dwelling. In Atlantic halibut aquaculture, the larval rearing is a critical rearing stage, with high incidence of mortality and abnormal development.

  7. Warfarin effects in the skeletal development of zebrafish (Danio rerio)

    Peres dos Santos, R.; Bensimon-Brito, A.; Gavaia, Paulo J.; Cancela, Leonor
    The vitamin K-dependent (VKD) gamma-glutamyl carboxylase promotes the conversion of glutamic acid residues (Glu) to gamma-carbolxyglutamic acid (Gla) in a post translational modification that is essential for the functionality of VKD proteins. This process affects homeostasis, apoptosis, signal transduction, growth control, arterial calcification and bone development.

  8. Warfarin effects in the skeletal development of zebrafish (Danio rerio)

    Peres dos Santos, R.; Bensimon-Brito, A.; Gavaia, Paulo J.; Cancela, Leonor
    Vitamin K-dependent gamma carboxylation (VKGC) is crucial for posttranslational modification of glutamate residues to form α-carboxy glutamic acid (Gla) in the presence of reduced vitamin K, molecular oxygen, and carbon dioxide (1). This modification has important implications, mainly physiological, like homeostasis, signal transduction and bone calcification. This mechanism ensures complete carboxylation of coagulation factors, and proteins like bone Gla protein (BGP) and matrix Gla protein (MGP), being essential for their biological activity. Warfarin is a known anticoagulant that inhibits the action of VKGC (2), inhibiting consequently the activity of the referred proteins.

  9. Two isoforms of vasa maternal factor in Senegalese sole: Biotechnological applications

    Pacchiarini, T.; Cabrita, E.; Cross, I.; Ortiz-Delgado, J. B.; Leite, Ricardo B.; Gavaia, Paulo J.; Herráez, M. P.; Rebordinos, L.; Sarasquete, C.
    Primordial Germ Cells (PGCs) identification and manipulation present considerable potential for hatchery practice and surrogate broodstocks. To carry out the PGCs characterization a specific molecular marker is required. The vasa gene is a good candidate to identify PGCs and others germinal cells (Nagasawa et al., 2009). The aim of this study was the cloning of the Solea senegalensis vasa cDNA and its expression pattern during early development and adulthood.

  10. Expression of Gla proteins during fish skeletal development

    Gavaia, Paulo J.
    Apear early in development: frequent in reared larva; reflect culture conditions. Leads to: decreased growth rate; increased mortality; increased prodution costs; decreased market price.

  11. Skeletal development and bone-related gene expression in fish larvae

    Gavaia, Paulo J.; Cancela, Leonor
    Skeletogenesis in fish starts early in embrionic development. First calcified structures are normaly asociated tofeding and movement.

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