Loading...
18 results
Search Results
Now showing 1 - 10 of 18
- Novas ocorrências de Sphagnum auriculatum no Sul de Portugal. Significado paleobiogeográficoPublication . Neto, C.; Arsénio, Pedro; Monteiro-Henriques, T.; Sérgio, C.; Costa, José Carlos
- Sintra vegetation and landscapePublication . Mesquita, S.; Arsénio, Pedro; Lousã, M.; Monteiro-Henriques, T.; Costa, José CarlosThe field trip to Sintra region, as part of the 48th IAVS Symposium, aims to illustrate well-preserved and representative plant communities of Sintra municipality. It consists of two short field stops and a 3 km walk
- Flora e vegetação da paisagem protegida da Arriba Fóssil da Costa de CaparicaPublication . Arsénio, PedroO trabalho de síntese agora apresentado resulta do aprofundamento dos estudos produzidos no âmbito do protocolo de colaboração (estabelecido no mês de Julho de 1998 e com a duração de três anos) entre a Paisagem Protegida da Arriba Fóssil da Costa de Caparica (Instituto de Conservação da Natureza) e o Centro de Botânica Aplicada à Agricultura (Instituto Superior de Agronomia), para execução de estudos de flora e vegetação dentro da área da PPAFCC.
- The coastal vegetation of the portuguese Divisory Sector: dunes, cliffs, saltmarshes and low-scrub communitiesPublication . Costa, José Carlos; Lousã, M.; Capelo, J.; Espírito-Santo, Maria Dalila; Izco, J.; Arsénio, Pedro
- Dinâmincas geomorfológicas como metodologia básica na avaliação da sensibilidade da paisagem. Aplicação ao Ilhéu de Vila Franca do Campo, S.Miguel, AçoresPublication . Abreu, Maria Manuela; Ribeiro, L.; Arsénio, Pedro; Bulcão, L.The Islet of Vila Franca do Campo, (S. Miguel Island, Azores) with 6,2 ha, is located 500 m from the south coast. The geology, ecology, and cultural character, makes it a place with high landscape quality, very attractive for recreation, originating a highly sensitive landscape to recreation impacts. Landscape sensitivity assessment becomes therefore a crucial step in the development of a landscape and management plan, aiming to reconcile conservation with public recreation. The main objective of this work is to show the importance of geomorphology-pedology, together with other parameters (topographic features, plant communities and cultural resources) in assessing Islet landscape sensitivity. The methodology used was based in a parametric approach. Relative values were given to the different classes of geomorphology-pedology, vegetation and topography based on natural value and resistance to recreation use. The overlaying of these values enabled de assessment of the landscape sensitivity. The Islet is a volcanic cone of stratified palagonitic tuffs from the Holocene age. Besides, in the Northwest and South-Southwest summit zones pumiceous deposits with a trachyte composition occur. The exterior hillsides of the volcanic cone (mainly NW and W cliffs) are under intensive wind and marine erosion. The geomorphic dynamics evaluated by means of the morphogenesis/pedogenesis rate allowed to consider the following areas: (a) area on Morphogenesis processes (M). This area is submitted to relative intense ablation processes by creeping and rill erosion. The area correspond mainly to outcrops of palagonitic tuffs or pumice with different weathering stages and a zone with incipient soils; (b) area on Intergrade processes to Morphogenesis (IM) which is associated to steep slopes (>25%) incipient soils or Andosoils where mass movements are observed; (c) area on Intergrade processes to Pedogenesis (IP), located on the summit zone, correspond to Andosoils which can attain 200 cm depth. The Islet’s vegetation was classified according to its structure, dominant plants and natural significance, with special attention given to the communities holding endemic plants. In general, the Islet reveals an high landscape sensitivity, given by its biological, geomorphic, pedological and topographic significant features.
- A methodological approach to potential vegetation modeling using GIS techniques and phytosociological expert-knowledge: application to mainland PortugalPublication . Capelo, J.; Mesquita, S.; Costa, José Carlos; Arsénio, Pedro; Neto, C.; Monteiro-Henriques, T.; Aguiar, C.; Honrado, J.; Espírito-Santo, Maria Dalila; Lousã, M.An attempt to obtain a consistent spatial model of natural potential vegetation (NPV) for the mainland Portuguese territory is reported. Spatial modeling procedures performed in a Geographic Information System (GIS) environment, aimed to operationalize phytosociological expert-knowledge about the putative distribution of potential zona1 forest communities dominam in the Portuguese continental territories. The paradigm for NPV assumed was that of RIVAS-MARTINE(1Z9 76) and RIVAS-MARTINEeZt al. (1999), which presupposes, for a given territory, a univocal correspondence between a uniform combination of bioclimatic stage and lithology' gi ven a biogeographical context, and a unique successional sequence leading to a single climax community (i. e. a vegetation series (VS)). Information issued from both literature and a team of phytosociologists possessing detailed knowledge about Portuguese vegetation, namely about forests and its seria1 vegetation, was acknowledged as a starting point for the construction of such a habitat-vegetation correspondence model. First, a bioclimatic map concerning the "Worldwide Bioclimatic Classification System" (WBCS) of RIVAS-MARTINE(1Z9 81 -2004), obtained by multivariate grostatistical interpolation issuing from the work of MESQUITA(2 005), was set. Severa1 partia1 matrices, one for each biogeographical Province, combined such habitat statements to VS. Initial incoherence due to vagueness of statements led to an important amount of both superimposition of VS and habitat gaps in the matrices. Further rearrangement of the table according to known field distribution of VS by experts allowed setting an approximate univocal correspondence VS-habitat. Finally, an intersection of bioclimatic, lithology and biogeographic maps yielded over a thousand habitat combinations to be associated each to a single VS through implementation of the matrices as a set of rules. Again, inconsistencies were solved likewise, but this time by direct observation of the map by experts. Keeping of phytosociological consistency and fidelity to information on actual vegetation field distribution was always mandatory during the process
- Geographic variation among iberian communities of the exotic halophyte Cotula coronopifoliaPublication . Costa, José Carlos; Neto, C.; Arsénio, Pedro; Capelo, J.The exotic annual forb Cotula coronopifolia has locally invaded salt marsh communities naturally dominated by Spergularia marina along large parts of the Iberian coastline. While the floristic composition of C. coronopifolia dominated communities on the Atlantic coast of northern Portugal has already been described, this information was missing for the southern part of the country. We carried out a phytosociological study at 21 sites along the south-western and southern coast of mainland Portugal to determine the ecology and syntaxonomical status of these communities, and to compare them to the Atlantic ones. Plant communities co-dominated by C. coronopifolia and S. marina were generally found in the sub-halophilous inner part of salt marshes. They occupied gaps within taller perennial vegetation (Juncus maritimus formations), such as small pools temporarily inundated with brackish waters. Southern communities differed from the northern ones by the high abundance of Triglochin barrelieri and the absence of salt-intolerant species that are present in the Atlantic communities. This difference may result from the drier summer climate in southern regions, leading to intense water evaporation and thus, more saline conditions. We propose to classify the Mediterranean communities in a new association, the Cotulo coronopifoliae– Triglochinetum barrelieri. High abundance of Limonium diffusum further allowed the distinction of a new subassociation limonietosum diffusi for the southernmost part of Portugal. Results show that invasive exotic plants can form new phytosociological associations with a characteristic species composition, but that these community types, despite being dominated by the same invader, still show ecological and geographical differentiation.
- Uma ericácea nova para a flora portuguesaPublication . Capelo, J.; Bingre, P.; Arsénio, Pedro; Espírito-Santo, Maria Dalila
- Aproximação às metodologias de cartografia de vegetação - aplicação à vegetação de MombejaPublication . Arsénio, PedroO presente trabalho constitui uma aproximação às técnicas de cartografia temática de vegetação, recorrendo às modernas tecnologias de aquisição de informação geográfica tais como o Global Positioning System (GPS) e aos sistemas informáticos genericamente conhecidos por Sistemas de Informação Geográfica (SIG). Foi executado o estudo da vegetação espontânea de uma região inserida nos concelhos de Beja e Ferreira do Alentejo que corresponde sensivelmente à área compreendida entre as vilas de Beringel, Peroguarda e Mombeja. A área estudada consta da Proposta Preliminar da Lista Nacional de Sítios de Interesse Comunitário (Continente) (1996), sob o número 88, constituindo uma das áreas propostas para integrar a Rede NATURA 2000. O estudo incidiu sobre as orientações contidas na Directiva 92/43/CEE - «Directiva Habitats», nomeadamente no que diz respeito aos valores florísticos e da vegetação natural com interesse para conservação. Foram aplicadas as metodologias da designada Fitossociologia Paisagista, bem como o método de classificação TWINSPAN para a caracterização das formações vegetais encontradas, procedendo-se em seguida à sua cartografia, em formato vectorial.
- The landscape and plant communities of Serra da ArrábidaPublication . Costa, José Carlos; Capelo, J.; Arsénio, Pedro; Monteiro-Henriques, T.The field trip takes place in the biogeographic territories of the Sadensean-Dividing Portuguese Subprovince (Coastal Lusitan- Andalusian Province, Mediterranean Region), throughout the upper thermomediterranean thermotype and subhumid ombrotype.