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- Recent geospatial dynamics of Terceira (Azores, Portugal) and the theoretical implications for the biogeography of active volcanic islandsPublication . Rijsdijk, Kenneth F.; Buijs, Simon; Quartau, Rui; Aguilée, Robin; Norder, Sietze; Ávila, Sérgio P.; Medeiros, Sara Maria Teixeira; Nunes, João Carlos Carreiro; Elias, Rui B.; Melo, Carlos S.; Stocchi, Paulo; Koene, Erik F. M.; Seijmonsbergen, A. C. (Harry); De Boer, W. M. (Thijs); Borges, Paulo A. V.Ongoing work shows that species richness patterns on volcanic oceanic islands are shaped by surface area changes driven by longer time scale (>1 ka) geological processes and natural sea level fluctuations. A key question is: what are the rates and magnitudes of the forces driving spatial changes on volcanic oceanic islands which in turn affect evolutionary and biogeographic processes? We quantified the rates of surface-area changes of a whole island resulting from both volcanogenic flows and sea level change over the last glacial-interglacial (GI) cycle (120 ka) for the volcanically active island of Terceira, (Azores, Macaronesia, Portugal). Volcanogenic activity led to incidental but long-lasting surface area expansions by the formation of a new volcanic cone and lava-deltas, whereas sea level changes led to both contractions and expansions of area. The total surface area of Terceira decreased by as much as 24% per time step due to changing sea levels and increased by 37% per time step due to volcanism per time step of 10 ka. However, while sea levels nearly continuously changed the total surface area, volcanic activity only impacted total surface area during two time steps over the past 120 ka. The surface area of the coastal and lowland region (here defined as area <300 m) was affected by sea level change (average change of 11% / 10 ka for 120–0 ka) and intra-volcanic change (average change of 17% / 10 ka for 120–0 ka). We discuss the biogeographic implications of the quantified dynamics, and we argue that surface area change is mainly driven by volcanic processes in the early stages of the island’s life cycle, while during the later stages, area change becomes increasingly affected by sea level dynamics. Both environmental processes may therefore affect biota differently during the life cycle of volcanic oceanic islands.
- Avaliação do Estado Trófico e Proveniência do Fósforo nos Pauis da Praia da Vitória, ilha Terceira, AçoresPublication . Pimentel, César Miguel Meneses; Rodrigues, Francisco; Madruga, João; Elias, Rui B.O Graben das Lajes localiza-se na vertente Nordeste do vulcão dos Cinco Picos, entre a escarpa das falhas das Fontinhas, a Sudoeste, e a de Santiago a Nordeste. Do ponto de vista hidrogeológico esta zona está associada ao troço mais oriental do aquífero de base da ilha Terceira, recarregado, em grande parte, nas zonas centrais da ilha onde a precipitação é mais elevada. Para além do aquífero basal o Graben das Lajes comporta duas massas de água subterrâneas suspensas localizadas a profundidades distintas. Na zona litoral Sudoeste do Graben das Lajes existem três zonas lagunares associadas a descargas das massas de água acima referidas – os pauis da Praia da Vitória, do Belo Jardim e da Pedreira do Cabo da Praia. Estas massas de água superficiais têm particular importância ecológica, dada a sua grande biodiversidade. Na determinação do estado trófico dos três pauis foram utilizados dados da concentração de fósforo total cedidos pela Camara municipal da Praia da Vitória no âmbito do Projeto LIFE CWR, entidade responsável pela gestão destas zonas húmidas. Utilizando o fósforo como variável dependente, foi aplicado o índice do estado trófico de Lamparelli (2004). Quando aplicado o índice trófico aos três pauis, verificou-se que, entre 2016 e 2017, todos se encontravam num estado predominantemente eutrófico.
- Assessing the effects of climate change on arthropod abundance in Azorean pastures: PASTURCLIM project's baseline monitoring dataPublication . Wallon, Sophie; Melo, Catarina; Tsafack, Noelline; Elias, Rui B.; Borges, Paulo A.V.Background The data we present are part of the project PASTURCLIM (Impact of climate change on pasture’s productivity and nutritional composition in the Azores). The project aims to assess the consequences of climate change (e.g. temperature increase) on the grass production and its quality for forage, as well as to assess changes in the arthropod communities associated with the Azorean intensive pastures. An in situ experiment was set up using Open Top Chambers (OTCs), in order to simulate an increasing of temperature (average of +1.2ºC) on pastures. In this contribution, we present the data relative to the arthropod sampling. New information We provide an inventory of all arthropods recorded inside OTCs and in control plots in three intensively managed pastures dominated by grasses in Terceira Island (Azores): two of them dominated by ryegrass, Lolium multiflorum Lam. (Poaceae), located respectively at 186 m and 301 m above sea level; and one field dominated by common velvetgrass, Holcus lanatus L. (Poaceae), located at an altitude of 385 m. A total of 41351 specimens were collected. Organisms collected belong to four classes, 15 orders, 60 families and 171 species/morphospecies (including 34 taxa identified only at order, family or genus level). Therefore, for only 137 taxa, we have a scientific name associated (n = 38918). A total of 75% of the species (n = 129 species) are considered introduced (including all the species with indeterminate colonisation status that are possibly also exotic species (n = 7622)), representing 71% of the total abundance (n = 29664 specimens). A total of 19% of the species (n = 33 species) are considered native non-endemic representing 28% of the total abundance (n = 11608 specimens). Only one endemic species was sampled, the wolf spider Pardosa acorensis Simon, 1883 (1% of the species), representing 0.2% of the total abundance (n = 79 specimens). Spiders (5056 specimens) and beetles (18310 specimens) were the dominant taxa representing, respectively, 20 and 78 morphospecies. Since the main aim of this study was to have a better knowledge on arthropod communities present in Azorean pastures under a simulated temperature increase, the principal novelty of this paper is the contribution with distribution and abundance data to a baseline knowledge on the future consequences of climate changes on arthropod communities in Azorean pastures.
- Monitoring grassland’s arthropods in a in situ climate change experimentation (Terceira, Azores, Portugal)Publication . Wallon, Sophie; Borges, Paulo A. V.; Elias, Rui B.The data presented are part of the project PASTURCLIM (Impact of climate change on pasture’s productivity and nutritional composition in the Azores). The project aims to assess consequences of climate change (in this case, increasing temperature) on the grass production and quality for cattle forage. The project also aims to assess changes in the arthropod’s community associated to the grassland. An in situ experimentation was set up using Open Top Chambers (OTC’s), in order to simulate an increasing of temperature (average of +1.5⁰C) on grassland. In this paper, we present data relative to the arthropods collection. Overall, we collected 41,351 specimens belonging to four classes, 15 orders, 60 families and 171 morphospecies (including 34 taxa identified only at order, family of genus level). Therefore, for only 137 taxa we have a scientific name associated (n = 38918).
- Tree growth-climate relationship in the Azorean holly in a temperate humid forest with low thermal amplitudePublication . Pavão, Diogo Cláudio; Jevšenak, Jernej; Engblom, J.; Borges Silva, L. Borges; Elias, Rui B.; Silva, LuísDendroclimatic records in areas with high relative humidity and low thermal amplitude are manifestly scarcer and only a few studies are applied to species that are present in areas with weak seasonality. The Azores archipelago with temperate climate, with low thermal amplitude, has unique biodiversity, including the Azorean holly, Ilex azorica Gand., that is dominant in most extant natural forests. Hence, the importance of understanding its behavior and relation with climate. In this study, we try to understand tree-ring patterns of this species and examine the relationship between radial tree growth and main climatic drivers. For this purpose, we sampled four populations from São Miguel Island and two from Terceira Island. We found a diffuse-ring porous wood with a common layer of vessels associated to the ring boundary, which was critical to identify annual tree-rings. Generalized linear models were used to relate different variations of temperature and precipitation parameters, resulting into a diverse climate-growth relationships of different populations, while the composite population exhibited pronounced effect of temperature. We conclude that, I. azorica forms reliable annual tree-rings, which can be statistically related to climate, mostly temperature. However, there are differences among specific sites, thus the climate sensitivity depends on other site characteristics, such as soil and slope, but probable also to other ecological drivers, such as the competition, water drainage, among others.
- Assessing the efficiency of protected areas to represent biodiversity : a small island case studyPublication . Vergílio, Marta H. S.; Fonseca, Catarina; Calado, Helena; Borges, Paulo A. V.; Elias, Rui B.; Gabriel, Rosalina; Martins, António; Azevedo, Eduardo B.; Cardoso, PedroProtected areas (PAs) have been selected using either subjective or objective criteria applied to an extremely limited subset of biodiversity. Improved availability of species distribution data, better statistical tools to predict species distributions and algorithms to optimize spatial conservation planning allow many impediments to be overcome, particularly on small islands. This study analyses whether 219 species are adequately protected by PAs on Pico Island (theAzores, Portugal), and if they are as efficient as possible, maximizing species protection while minimizing costs. We performed distribution modelling of species’ potential distributions, proposed individual conservation targets (considering the context of each species in the archipelago and their current conservation status) to determine the efficiency of current PAs in meeting such targets and identify alternative or complementary areas relevant for conservation. Results showed that current PAs do not cover all taxa, leaving out important areas for conservation. We demonstrate that by using optimization algorithms it is possible to include most species groups in spatial conservation planning in the Azores with the current resources. With increasing availability of data and methods, this approach could be readily extended to other islands and regions with high endemism levels.
- Climate–Growth Relationships in Laurus azorica—A Dominant Tree in the Azorean Laurel ForestPublication . Pavão, Diogo Cláudio; Jevšenak, Jernej; Silva, Lurdes da Conceição Borges; Elias, Rui B.; Silva, LuísForests on oceanic islands, such as the Azores archipelago, enable interesting dendroclimatic research, given their pronounced climatic gradients over short geographical distances, despite the less pronounced seasonality. The Lauraceae play an essential ecological role in Macaronesian natural forests. An example is Laurus azorica (Seub.) Franco, a relevant species given its high frequency and physiognomic dominance in Azorean laurel forests. This study aims to quantify climate–growth relationships in L. azorica using a dendroecological approach. We sampled four stands at São Miguel and two stands at Terceira islands, for a total of 206 trees. Following standard dendrochronological methods and rigorous sample selection procedures, we obtained relatively low rbar values and high temporal autocorrelation. Using a stepwise Random Forest analysis followed by Generalized Linear Models calculation, we found prominent effects of present and previous year temperature, but a low precipitation signal on growth rings, with some model variation between stands. Our results agreed with previous observations for broad-leaved species with diffuse porous wood, contributing to increase the baseline dendroecological knowledge about Azorean forests. Due to the high levels of within- and between-stand variation, and to refine the climatic signal analysis, complementary approaches should be explored in the future.
- Influence of Climate Variability and Soil Fertility on the Forage Quality and Productivity in Azorean PasturesPublication . Melo, Catarina D.; Dias, Cristiana S. A. M. Maduro; Wallon, Sophie; Borba, Alfredo Emílio Silveira de; Madruga, João; Borges, Paulo A. V.; Ferreira, Maria Teresa; Elias, Rui B.This work aimed to determine and compare the effect of elevation and season on the productivity and the nutritive value of pastures in the Azores (Terceira Island). Forage was collected and analysed for dry matter (DM), crude protein (CP), neutral detergent fibre (NDF), acid detergent fibre (ADF), acid detergent lignin (ADL), ether extract (EE), mineral ash (Ash), dry matter digestibility (DMD) and organic matter digestibility (OMD). The net productivity (NP) was higher in the low elevation pasture A (1.80 g m⁻²), lower in pasture B (0.98 g m⁻²) and peaked in the winter in both pastures A (3.57 g m⁻²) and B (2.33 g m⁻²) and during the summer in the high elevation pasture C (2.15 g m⁻²). The soil chemical proprieties varied significantly among the three pastures. The highest soil pH, available P, K, Ca and Mg were recorded in pasture A. Positive correlations were observed between all soil parameters analysed and NP, except for the OM content. The DM, PB and EE changed significantly with elevation, while all nutritive parameters (except CP, EE and Ash) increased significantly along the growth season. Environmental factors influenced the nutritive parameters and productivity, suggesting that climate change might have significant impacts on forage production and quality.
- Is there solid evidence of widespread landscape disturbance in the Azores before the arrival of the Portuguese?Publication . Elias, Rui B.; Connor, Simon; Góis-Marques, Carlos A.; Schaefer, Hanno; Silva, Luís; Sequeira, Miguel M.; Moura, Mónica; Borges, Paulo A. V.; Gabriel, RosalinaRaposeiro et al. conclude that human occupation of the Azores islands began between 700 and 850 CE, causing widespread landscape disturbance and raising doubts about the islands’ presumed pristine nature when the Portuguese arrived. However, previous paleoecological studies from Flores, Pico, and Sao Miguel Islands (Table 1) show that permanent changes in the vegetation occurred only after the early 15th century. The authors’ work also shows the permanent decline, to the lowest levels, in arboreal pollen on Corvo and Flores occurring during Portuguese occupation, not before. […].
- New records of the critically endangered fern Grammitis azorica (Polypodiaceae)Publication . Elias, Rui B.; Pereira, FernandoGrammitis azorica (H. Schaef.) H. Schaef. is a critically endangered epiphytic fern, endemic to the Azores Islands. Until 2013, its presence was only confirmed on Flores Island. Our new records expand the distribution of this species from one to three islands and the altitudinal range to 640 – 1130 m a.s.l. Nevertheless, the fact that only four additional individuals were found confirms the rarity of this fern. Our new data also highlight the importance of montane forests and woodlands as hotspots of biodiversity in the Azores and the need to increase the protection status of all areas with remnant natural forest patches.
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