5 resultados para Deciduous forest

em Portal de Revistas Científicas Complutenses - Espanha


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Studies on the flora and fauna of the Canary Islands show that this Archipelago is one of the planet’s diversity hot spots. However, an analysis of the differences in the phytogeographic characteristics of each of the islands that make up this Archipelago is lacking. This article focuses on the phytogeographic characterization of the island of Gran Canaria. This island exhibits geological and climatic characteristics resulting in a rich vascular flora, including endemic species and genera that are significantly different from the other islands of the Archipelago. These differences are verified through statistical analysis of the existing similarity between the floras of the members of the Canary Islands. This study also analyses the subdivision of Gran Canaria Island, indicating that there are three well-differentiated areas on the island itself. Finally, this study argues that these areas, themselves, should be considered biogeographic sectors.

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In this study, we investigated the relationship between vegetation and modern-pollen rain along the elevational gradient of Mount Paggeo. We apply multivariate data analysis to assess the relationship between vegetation and modern-pollen rain and quantify the representativeness of forest zones. This study represents the first statistical analysis of pollen-vegetation relationship along an elevational gradient in Greece. Hence, this paper improves confidence in interpretation of palynological records from north-eastern Greece and may refine past climate reconstructions for a more accurate comparison of data and modelling. Numerical classification and ordination were performed on pollen data to assess differences among plant communities that beech (Fagus sylvatica) dominates or co-dominates. The results show a strong relationship between altitude, arboreal cover, human impact and variations in pollen and nonpollen palynomorph taxa percentages.

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A phytosociological study of the forests from Sierra Maestra is conducted, following the methodology of the Zurich- Montpelier School. They are transformed into a forest typology using the standards of the Institute of Agro-Forestry Research. In general, 35 types and/or subtypes are presented. From this group, the most abundant ones belong to semi-deciduous microphyll forest, followed by those from mangroves and mountain rainforest, respectively. Silvicultural treatments are needed; among them, the protection forests are those found above 800 m asl and mangroves. 

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The authors propose a new phyiosociologic interpretation of Juniperas comniunis subsp. hemisphaerica and Juniperus sabina shrublands in the Djurdjura. They make up two new associations: the Cynosuro balansae-Juniperetun, hemisphaericae and the Daphno oleoidis-Juniperetum sabinae, belonging to the new alliance Lonicero kabylicae-Juniperion hemisphaericae included in the order Querco Cedretalia atlanticae. The ecologic and biogeograpbic value of these communities is analized in a Westem-mediterrancan context as well as their dynamic importance. On this mountain, they correspond to ihe preforested level of cedar forests. For this reason, an attempt to inlerprel Kabylian cedar forests as a whole was made they belong to the new association Senecio perralderlani-Cedretum atlanticae. A diachronic evaluation of changes in native plant communities over a 30 year period is made, in particular as related to the creation of several local structures to protect natural resources.

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Xanthoria parietina, common foliose lichen, growing in its natural habitat, was analysed for the concentration of five heavy metals (Fe, Cr, Zn, Pb and Cu) from different forest sites of North East of Morocco (Kenitra, Sidi Boughaba, Mkhinza, Ceinture Verte near Temara city, Skhirate, Bouznika and Mohammedia). The quantification was carried out by inductively coupled plasma - atomic emission spectrometry (ICP-AES). Results were highly significant p<0,001. The concentration of metals is correlated with the vehicular activity and urbanization. The total metal concentration is highest at the Kenitra area, followed by Ceinture Verte site near Temara city, which experience heavy traffic throughout the year. Scanning electron microscopy (SEM) of particulate matter on lichen of Xanthoria parietina was assessed as a complementary technique to wet chemical analysis for source apportionment of airborne contaminant. Analysis revealed high level of Cu, Cr, Zn and Pb in samples near roads.