Holocene fossil woods from the Caldera de Taburiente National Park (Canary Islands, Spain)

The study of 39 Pinus canariensis Holocene fossil woods from the Caldera de Taburiente is presente

The Quaternary plant fossil record from the volcanic Azores Archipelago (Portugal, North Atlantic Ocean): a review

Plant fossils are known from the Azores Islands, yet poorly studied. We present a comprehensive bibliographical review for the archipelago. A first pre-scientific reference dates from late fifteenth century, while the first scientific description was reported in 1821, accounting for trunks in pyroclastic units and silicified plants within hydrothermal deposits. Throughout the second-half of the nineteenth century and the first-half of the twentieth century, prospection by naturalists and geological mapping work, led to the discovery and description of plant fossils in most islands. From the 1970s onwards, the taxonomic interest ceased, and plant fossils were used mainly for 14C dating. Recently, sediment cores from lakes and peatlands were used for palaeoecological reconstructions and to measure anthropogenic impacts. Generally, plant fossils are younger than 50 ka, although older fossils may exist. Azorean plant fossils include somatofossils of leaves, stems, logs and seeds preserved as impressions, compressions, adpressions, permineralizations, lava tree casts and mummifications. The taphonomy of macrofloral elements is usually related to explosive volcanic activity, while palynological record is associated with lake sediments and peat bogs. The persistence in palaeobotanical and palaeopalynological studies will decisively contribute to disentangle the paleodiversity, palaeoecology, and add crucial information on insular plant phylogeny and biogeography.info:eu-repo/semantics/publishedVersio

Morphometric brain changes during aging: Results from a Brazilian necropsy sample.

The present study aimed to establish the morphometric brain changes during aging in a necropsy series from Brazil and determine whether sexual dimorphisms interfere in these changes. Methods:A cross-sectional study was conducted at the São Paulo Autopsy Service in Brazil where, after informed consent, data was gathered from next of kin interview with reference to clinical status prior to death. Brain weight, volume and density measurements were taken and then adjusted for head circumference. Descriptive statistics and tests of hypothesis and correlations were applied, considering a p-value of 0.05. Results:414 subjects, mostly men (60.4%), with a mean age of 67.1 years, were included. The mean brain weight of the sample was 1219.2g±140.9and mean volume was 1217mL±152.3. The mean brain density of the sample was 1.0g/mL±0.09. Values differed between males and females in terms of weight and volume. Brain weight decreased during aging by about 45g per decade (r= -0.300; p<0.01) and volume by about 43mL (r= -0.278; p<0.00). Mean density of the sample was 1.0 g/mL in both genders. Conclusions:Brain weight and volume (with or without corrections) decreased during aging, and these reductions were more pronounced in women. Density remained unchanged for both genders. Further studies are needed to investigate factors associated to these reductions

Past vegetation dynamics to infer holocene climate changes in Tenerife and La Gomera, Canary Islands

Oceanic islands in the low latitudes, as the Canary Islands, are generally considered to have been well buffered from the climate change of the Quaternary period. However, questions remain about whether past climatic changes on Atlantic islands are synchronic with those occurring in Africa and the Mediterranean coast or if the climate remained stable during the Holocene. Here we used fossil pollen and charcoal time series on Tenerife and La Gomera in order to: 1) provide the first inter-island picture of vegetation dynamics through the last 9600 years of this important biodiverse region of Europe; 2) detect the vegetation sensitivity, mainly tree communities, to past climatic changes; and, 3) provide evidences for human-induced changes at this potentially highly informative point. Preliminary analyses suggest very little climate change for the period 4000 years to present, but this requires confirmation by reference to additional coring sites. In La Gomera, we found strong evidences of a shift towards drier conditions at around 5500 years ago. The general vegetation pattern observed was a decrease in hygrophilous trees (Canarian palm and willow) and an expansion of Morella-Erica woody heath. Our results provide the first evidence to suggest that the general Northern Africa and Mediterranean shift towards drier conditions may be traced in the Canary Islands

14,000 years of climatic and anthropogenic change in the Afromontane forest of São Tomé Island, Gulf of Guinea

São Tomé (Gulf of Guinea, Central Africa) is a 854 km2 tropical island that had a pivotal role in early European colonial expansion through the Atlantic between the 15th and 16th centuries. Historical sources suggest that native vegetation has been heavily impacted since human arrival (1470 CE) due to monoculture economies and the introduction of mammals and plants, some of which now have established wild populations. The Afromontane forest of São Tomé, located above 800 m.a.sl., is particularly rich in endemic plant species and has remained relatively unaffected by direct human impacts. Here, we explore how environmental change influenced this forest through the study of a sedimentary sequence from the volcanic crater of Lagoa Amélia (1340 m a.s.l.), a palustrine system located at the boundary between submontane (800–1400 m a.s.l.) and mist forest (above 1400 m a.s.l.). We used fossil pollen, non-pollen palynomorphs, sedimentology and charcoal to determine forest dynamics from the Late Pleistocene to the present. From 14,000 to 12,500 cal yr BP the forest was dominated by taxa from higher altitudes, adapted to cooler and drier climates (e.g. Afrocarpus mannii trees and Psychotria nubicola). After 12,500 cal yr BP, a potential uphill migration was identified by an increase in taxa like the trees Symphonia globulifera and Craterispermum cerinanthum. From 11,200 cal yr BP through the rest of the Holocene taxa from lower altitudes became dominant (e.g. Prunus africana, Polyscias, and Sabicea), except at c. 8500 cal yr BP when rapid cooling led to forest opening. Charcoal showed that fires were frequent during the Late Pleistocene (14,000 to 11,200 cal yr BP), becoming rare during the Holocene until anthropogenic fires started at c. 220 cal yr BP. Other recent anthropogenic impacts detected in Lagoa Amélia included the appearance of pollen of introduced plant species (e.g., Cestrum), and the increase in pollen of economically important species (Elaeis guineensis, Zea mays) and in fungal spores related to introduced herbivores. Our results reveal that climate changed the altitudinal distribution of the Afromontane forest in São Tomé during the Late Pleistocene, as observed on the African continent, and that this ecosystem was also strongly impacted by human arrival, through fire, farming, and introduced species.info:eu-repo/semantics/publishedVersio

What do we know and what do we need to know about the macaronesian paleoclimate?: answering with participatory appraisal methods

Participatory appraisal (PA) is an approach or research procedure that seeks to incorporate the knowledge and opinions of a community with the aim of improving an area of concern. PA has several advantages over scientific discussions, as it can be used to share, analyse and evaluate diverse issues, and because it enhances creativity and group participation, regardless of participants’ backgrounds. PA is based on flexible, innovative, and highly visual tools that allow the generation of large amounts of information in short time. In this case, our aim was to define the state of knowledge about palaeoclimate of Macaronesia. To do this, we tried to address the following questions: What do we know? How sure are we? Do we agree? What are the key events and their consequences? Then, we established a research agenda by asking: What should we study next? Results indicated the best known regions (Azores-Canaries) and periods (Holocene to LGM), and highlighted a certain degree of uncertainty about our knowledge of climate history in the region. Key climatic events were mainly related to four environmental variables (temperature, humidity, wind regime and sea level oscillation), which were also considered as decisive variables for future research. Researchers agreed that most of the topics requiring future research should be addressed urgently

Listado de la biota terrestre del Archipiélago Chinijo y Lobos (Islas Canarias)

Se presenta un nuevo listado de la biota terrestre de las isletas más orientales del archipiélago canario (Roque del Este, Roque del Oeste, Montaña Clara, Alegranza, La Graciosa y Lobos) resultado de una exhaustiva recopilación bibliográfica y de bases de datos. El listado incluye briófitos, plantas vasculares, hongos, cordados, artrópodos y moluscos. Un breve análisis estadístico de la flora y fauna de los islotes revela que existen algo más de 700 especies en el conjunto de los mismos, la gran mayoría de ellas nativas, con más de un 25% de endemismos y menos de un 10% de especies exóticas, lo que avala la alta calidad de estos espacios protegidos. Con diferencia los taxa que más contribuyen a la biodiversidad inventariada son los artrópodos y las plantas vasculares, como ocurre en el resto del archipiélago. Hasta siete taxones diferentes, cuatro especies de araña, un ave –ya extinta–, un molusco y una planta vascular, son endémicos de estas isletas. La disponibilidad de esta lista contribuirá a la realización de análisis biogeográficos más rigurosos, pues hasta ahora la biota de las isletas no se encontraba desagregada de las islas mayores, Lanzarote y Fuerteventura, a las que pertenecen políticamente.A new checklist of the terrestrial biota from the easternmost islets from Canary Islands (Roque del Este, Roque del Oeste, Montaña Clara, Alegranza, La Graciosa and Lobos) isprovided as a result of a wide bibliographic and database compilation. The checklist includes bryophytes, vascular plants, fungi, chordates, arthropods and mollusks. Additionally, a short analysis of the fauna and flora species richness reveals that there are slightly more than 700 terrestrial species in the islets, the big majority of them being native, with > 25% endemics and < 10% exotics, what argues in favour of the high conservation quality of this protected area. By far, the more important taxa contributing to this biodiversity are arthropods and vascular plants, as happen in the rest of the archipelago. Up to seven different taxa, four spiders, one bird –already extinct–, one snail and one vascular plant, have been found to be endemic to the islets. Finally, the availability of this new checklist will contribute significantly towards more accurate biogeographic analyses of the Canarian biota, because until now the islets’ biota distribution was not disaggregated of the main islands, Lanzarote and Fuerteventura, to which politically belong

Post-Mortem diagnosis of dementia by informant interview.

The diagnosis of normal cognition or dementia in the Brazilian Brain Bank of the Aging Brain Study Group (BBBABSG) has relied on postmortem interview with an informant. Objectives:To ascertain the sensitivity and specificity of postmortem diagnosis based on informant interview compared against the diagnosis established at a memory clinic. Methods:A prospective study was conducted at the BBBABSG and at the Reference Center for Cognitive Disorders (RCCD), a specialized memory clinic of the Hospital das Clínicas, University of São Paulo Medical School. Control subjects and cognitively impaired subjects were referred from the Hospital das Clínicas to the RCCD where subjects and their informants were assessed. The same informant was then interviewed at the BBBABSG. Specialists' panel consensus, in each group, determined the final diagnosis of the case, blind to other center's diagnosis. Data was compared for frequency of diagnostic equivalence. For this study, the diagnosis established at the RCCD was accepted as the gold standard. Sensitivity and specificity were computed. Results:Ninety individuals were included, 45 with dementia and 45 without dementia (26 cognitively normal and 19 cognitively impaired but non-demented). The informant interview at the BBBABSG had a sensitivity of 86.6% and specificity of 84.4% for the diagnosis of dementia, and a sensitivity of 65.3% and specificity of 93.7% for the diagnosis of normal cognition. Conclusions:The informant interview used at the BBBABSG has a high specificity and sensitivity for the diagnosis of dementia as well as a high specificity for the diagnosis of normal cognition

Honeybees and pollen as indicators of alien plant species in two native forest ecosystems of an oceanic island (La Palma, Canary Islands)

Apis mellifera L. is a generalist pollinator present in most of the Canary Islands. When foraging, honeybees transfer pollen grains to honey, and presence and abundance of pollen from different species can be interpreted as a sign of local flora, and a cue to spread of aliens. The relative use of alien vs native species by honeybees could influence island pollination mutualisms and/or favour alien species. Analyzing pollen content data from honey samples an approach can be made to the relative foraging intensity on different plant communities and identify the importance of alien plant species in nearby areas. Based on published information on pollen contents of honeys from beehives in La Palma, we made an indirect evaluation of the use of endemic, native and alien species by honeybees in two native forests of the island (evergreen laurel forest and Canarian pine forest). Some of the most pervasive alien plants in the Canary Islands were represented in these pollen samples. The most frequent species in pollen counts was Castanea sativa. Proportion of alien species’ pollen was significantly higher in the laurel forest, while the most visited group in the pine forest was that of endemics (p < 0.05). Specific composition of pollen samples analysed with Detrended Correspondence Analysis revealed (61.3 % variance explained) a pattern related to species distribution in each forest type. Pollen content has revealed the presence of alien species in forests of La Palma, some of them considered invasive. The laurel forest is the most threatened of both ecosystems, mainly affected by the proximity to urban areas and the presence of intersperse arboreal plantations. The overall prevalence of aliens in the evaluated pollen data suggests that honeybees are prone to exploit exotics, and that the selection of plant species by honeybees in this oceanic island is not random. This may have serious consequences for island pollination systems and favour the spread of some exotic species