scholarly journals Study of the current vegetation of the historical lava flows of the Arafo Volcano, Tenerife, Canary Islands, Spain

2020 ◽  
Vol 41 (2) ◽  
pp. 193-212
Author(s):  
Victoria Eugenia Martín Osorio ◽  
Wolf Hermann Wildpret Martín ◽  
Rocío González Negrín ◽  
Wolfredo Wildpret De la Torre
Keyword(s):  
Canary Islands ◽  
Nutrient Deficiency ◽  
Lava Flows ◽  
Pinus Canariensis ◽  
Healthy Tree ◽  
New Associations ◽  
Colonization Dynamics ◽  
Vegetation Complex ◽  
High Degree ◽  
Two Populations

Vegetation research on the lava flows of the historic volcanic eruption of 1705 in Arafo, Tenerife, Canary Islands, is presented. The study area located in the 830000-year-old valley of Güímar was created after a massive landslide 47 km3 in volume. The research is divided into three parts, which cover an altitudinal range from around 35 to 1583 m a.s.l. from the Lower-semiarid Inframediterranean up to the Lower-dry lower-Mesomediterranean bioclimatic belts. First, a phytosociological study of the vegetation present in the area was made and concluded that richness in pioneer communities form a vegetation complex with a high degree of endemicity. Two new associations and four pioneer communities are proposed. Especially notable are the communities of Stereocauletum vesuviani and the pioneer communities of Pinus canariensis. The second part of the research was a field sampling study of 450 individuals of Pinus canariensis, which were measured at different altitudes to obtain data about the colonization dynamics of this species on this 300 years old substrate. We found that stem diameter seems to be a good indicator for healthy tree development at a range between 700 to 1300 m asl, which corresponds to the pine forest as potential vegetation and that many individuals show signs of nutrient deficiency. The third part consists of the publication of two new populations of the Canarian endemism Himantoglossum metlesicsianum, a highly endangered orchid. The monitoring of these two populations has recently begun, and further research will be conducted on all three aspects of this publication, which will be presented and expanded upon in the future.

Lava flow modelling at El Hierro (Canary Islands): the case of Montaña Aguarijo volcano

2021 ◽  
Author(s):  
Alejandro Rodriguez-Gonzalez ◽  
Claudia Prieto-Torrell ◽  
Meritxell Aulinas ◽  
Francisco José Perez-Torrado ◽  
Jose-Luis Fernandez-Turiel ◽  
...  
Keyword(s):  
Lava Flow ◽  
Canary Islands ◽  
Flow Simulation ◽  
Maximum Length ◽  
Lava Flows ◽  
Rheological Parameters ◽  
The Real ◽  
El Hierro ◽  
Typical Morphology ◽  
Spatial Propagation

<p>Lava flow simulations are valuable tools for forecasting and assessing the areas that may be potentially affected by new eruptions, but also for interpreting past volcanic events and understanding the controls on lava flow behaviour. The plugin Q-LavHA v3.0 (Mossoux et al., 2016), integrated into QGIS, allows simulating the inundation probability of an a’a lava flow from one or more eruptive vents spatially distributed in a Digital Elevation Model (DEM). Q-LavHA allows running probabilistic and deterministic methods to calculate the spatial propagation and the maximum length of lava flows, considering a number of morphometric and/or thermo-rheological parameters.</p><p>El Hierro is the smallest and westernmost island of the Canary Archipelago where basaltic lava flows infer the major volcanic hazard. However, no lava flow emplacement modelling has been carried out yet on the island. Here we present Montaña Aguarijo's lava flow simulation, a monogenetic volcano located on the NW rift of El Hierro. Detailed geological fieldwork and current topographic-bathymetric data were used to reconstruct the pre-eruption (before the eruption modifies the relief) and post-eruption (at the end of the eruption, prior to erosive processes) DEMs. The obtained morphometric parameters of the lava flow (2,268m long; 5m medium thickness; 422,560m<sup>3</sup>) were used to run probabilistic (Maximum Length) and deterministic (FLOWGO) models. The latter also considers a set of thermo-rheological properties of the lava flow such as initial viscosity, phenocryst content, or vesicle proportion.</p><p>Results obtained show a high degree of overlap between the real and simulated lava flows. Therefore, the thermo-rheological parameters considered in the deterministic approach are close to the real ones that constrained Montaña Aguarijo lava flow propagation. Moreover, this work evidence the effectiveness of Q-LavHA plugin when simulating complex lava flows such as Montaña Aguarijo’s lava which runs through a coastal platform, a typical morphology of oceanic volcanic islands.     </p><p>Financial support was provided by Project LAJIAL (ref. PGC2018-101027-B-I00, MCIU/AEI/FEDER, EU). This study was carried out in the framework of the Research Consolidated Groups GEOVOL (Canary Islands Government, ULPGC) and GEOPAM (Generalitat de Catalunya, 2017 SGR 1494).</p><p><strong>References</strong></p><p>Mossoux, S., Saey, M., Bartolini, S., Poppe, S., Canters F., Kervyn, M. (2016). Q-LAVHA: A flexible GIS plugin to simulate lava flows. <em>Computers & Geosciences</em>, 97, 98-109.</p>

DIFFERENT LEVELS OF VARIABILITY IN THE FEMALE SONG OF WILD SILVERY GIBBONS (HYLOBATES MOLOCH)

Behaviour ◽  
2001 ◽  
Vol 138 (5) ◽  
pp. 629-648 ◽  
Author(s):  
Robert Dallmann ◽  
Thomas Geissmann
Keyword(s):  
Sample Size ◽  
Individual Recognition ◽  
Individual Variability ◽  
Introductory Note ◽  
Hylobates Moloch ◽  
Broad Variety ◽  
High Degree ◽  
Two Populations ◽  
Different Levels ◽  
Great Call

AbstractGibbon songs are known to include species- and sex-specific characteristics. It has been suggested frequently that these songs also exhibit a high degree of individuality, but quantifying individuality has rarely been attempted. Because the statistical methods used in earlier studies were highly dependent on sample size (Kruskal-Wallis one-way analysis of variance by ranks), it was not possible to compare results among studies directly. We introduce a mean pairwise difference (MPD) of scaled variables in order to quantify great-call variability and individuality. Because of its construction as simple normalised difference, the MPD is largely independent of sample size. This makes it possible to compare results directly with those of other studies on other populations or species. Even various levels of variability (intra- vs. inter-individual, intra- vs. inter-population variability) can be determined and compared with this method. In addition, the MPD can be calculated independently for any acoustic variable. This opens up a broad variety of research options in the area of comparative analysis of acoustic communication. For instance, variability in various parts of a phrase, in various parts of a song bout, in various contexts or in various seasons can be compared, and this is possible even if the variables under comparison are not the same. As an example we analysed female great-call phrases of wild silvery gibbons in Java (Indonesia). We found that inter-individual variability is significantly higher than intra-individual variability. This implies that females can be distinguished by their great-calls, although this was not examined during the present study. Additionally, variability of female songs was found to be significantly lower within one population than among any two populations. The various sections of the great-call differ in their variability. The first half of the great-call (excluding the introductory note) shows the highest potential for individual recognition.

Interpretability of Quaternary palaeo dune fields (Eastern Canary Islands)

2020 ◽  
Author(s):  
Christopher-B. Roettig ◽  
Thomas Kolb ◽  
Christoph Schmidt ◽  
Ludwig Zöller ◽  
Dominik Faust
Keyword(s):  
Canary Islands ◽  
Driving Force ◽  
Lava Flows ◽  
Sand Transport ◽  
Western Coast ◽  
Carbonate Sand ◽  
Sedimentation Pattern ◽  
Shallow Marine ◽  
Stratigraphic Position ◽  
Carbonate Crust

<p>Generally, the Quaternary palaeo dune fields on the Eastern Canary Islands are built up by different dune generations which are seperated by reddish silty layers. The biogenic carbonate sands originate from the shallow marine shelf around the islands and reach the dune fields from northern direction.</p><p>On northern Fuerteventura different lava flows were formed during the Late Pleistocene, and gradually interrupted the sand pathways of the dune fields close to the western coast. The sedimentation pattern in these dune fields indicates that this cut off was completed not later than 50 ka. A huge calcium carbonate crust in the outcrops marks the stratigraphic position of that final cut off. This crust was a subject of intensive debates, and was formerly linked to unstable environmental conditions. However, within the dune fields on the neigbouring island Lanzarote we did not find a comparable carbonate crust at the similar stratigraphic position. Instead, the El Jable dune field on northwestern Lanzarote shows a well-resolved dune sequence with intercalated silty layers during that period.</p><p>Consequently, the dune fields on the Eastern Canary Islands point to the importance of carbonate sand transport as the main driving force within the sediment system. Finally we can conclude that unimpaired sand pathways are a mandatory prerequisite for the buildup of palaeoclimatic signals in the Quaternary dune archives.</p>

Genetic variation between and within two populations of Rhabdocline pseudotsugae in Germany

2016 ◽  
Vol 46 (5) ◽  
pp. 716-724 ◽  
Author(s):  
Kristin Morgenstern ◽  
Jens-Ulrich Polster ◽  
Doris Krabel
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Spatial Distribution ◽  
Pseudotsuga Menziesii ◽  
Early Stage ◽  
Start Codon ◽  
Fruiting Bodies ◽  
Clear Differentiation ◽  
High Degree ◽  
Two Populations

Knowledge of the ecology and biology of Rhabdocline pseudotsugae Sydow is still at a very early stage. Recent results indicate the existence of an endophytic stage of the fungus in the form of symptomless infections in various Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) tissue types. This study represents the first description of genetic variation between and within two populations of R. pseudotsugae. Needles featuring fruiting bodies of R. pseudotsugae were collected from sample areas in Saxony and North Rhine-Westphalia (in Germany), with different fungal genotypes distinguished using the start codon targeted polymorphism (SCoT) and branch point signal sequences (BPS) techniques. Five of the 20 primers tested could be selected for further investigation. A total of 349 fragments were amplified at an average of 69.8 fragments per primer. Results showed the two sample areas to exhibit a high degree of both genetic variability and genetic diversity. A clear differentiation between the sample areas was not observed. There was nevertheless a clear connection between the genetic distance and spatial distribution of the fruiting bodies of R. pseudotsugae within the sample areas themselves.

Artificial Neural Networks in Wood Identification: The Case of two Juniperus Species from the Canary Islands

IAWA Journal ◽  
2009 ◽  
Vol 30 (1) ◽  
pp. 87-94 ◽  
Author(s):  
Luis García Esteban ◽  
Francisco García Fernández ◽  
Paloma de Palacios de Palacios ◽  
Ruth Moreno Romero ◽  
Nieves Navarro Cano
Keyword(s):  
Neural Network ◽  
Neural Networks ◽  
Canary Islands ◽  
Training Group ◽  
Similar Species ◽  
Traditional Methods ◽  
Mathematical Structures ◽  
Sample Testing ◽  
Artificial Neural ◽  
High Degree

Neural networks are complex mathematical structures inspired on biological neural networks, capable of learning from examples (training group) and extrapolating knowledge to an unknown sample (testing group). The similarity of wood structure in many species, particularly in the case of conifers, means that they cannot be differentiated using traditional methods. The use of neural networks can be an effective tool for identifying similar species with a high percentage of accuracy. This predictive method was used to differentiate Juniperus cedrus and J. phoenicea var. canariensis, both from the Canary Islands. The anatomical features of their wood are so similar that it is not possible to differentiate them using traditional methods. An artificial neural network was used to determine if this method could differentiate the two species with a high degree of probability through the biometry of their anatomy. To achieve the differentiation, a feedforward multilayer percepton network was designed, which attained 98.6% success in the training group and 92.0% success in the testing or unknown group. The proposed neural network is satisfactory for the desired purpose and enables J. cedrus and J. phoenicea var. canariensis to be differentiated with a 92% probability.

Accumulating pollutants in conifer needles on an Atlantic island – A case study with Pinus canariensis on Tenerife, Canary Islands

2005 ◽  
Vol 136 (3) ◽  
pp. 397-407 ◽  
Author(s):  
Michael Tausz ◽  
Walter Trummer ◽  
Walter Goessler ◽  
Astrid Wonisch ◽  
Dieter Grill ◽  
...  
Keyword(s):  
Canary Islands ◽  
Pinus Canariensis ◽  
Conifer Needles ◽  
Atlantic Island

scholarly journals Horizontally transmitted symbiont populations in deep-sea mussels are genetically isolated

2019 ◽  
Author(s):  
Devani Romero Picazo ◽  
Tal Dagan ◽  
Rebecca Ansorge ◽  
Jillian M. Petersen ◽  
Nicole Dubilier ◽  
...  
Keyword(s):  
Bacterial Colonization ◽  
Gill Tissue ◽  
Genetic Isolation ◽  
Isolated Populations ◽  
Genome Wide ◽  
Colonization Dynamics ◽  
Symbiont Transmission ◽  
Environmental Bacteria ◽  
Host Life ◽  
High Degree

AbstractEukaryotes are habitats for bacterial organisms where the host colonization and dispersal among individual hosts have consequences for the bacterial ecology and evolution. Vertical symbiont transmission leads to geographic isolation of the microbial population and consequently to genetic isolation of microbiotas from individual hosts. In contrast, the extent of geographic and genetic isolation of horizontally transmitted microbiota is poorly characterized. Here we show that chemosynthetic symbionts of individual Bathymodiolus brooksi mussels constitute genetically isolated populations. The reconstruction of core genome-wide strain sequences from high-resolution metagenomes revealed distinct phylogenetic clades. Nucleotide diversity and strain composition vary along the mussel lifespan and individual hosts show a high degree of genetic isolation. Our results suggest that the uptake of environmental bacteria is a restricted process in B. brooksi, where self-infection of the gill tissue results in serial founder effects during symbiont evolution. We conclude that bacterial colonization dynamics over the host life-cycle is thus an important determinant of population structure and genome evolution of horizontally transmitted symbionts.

Breeding, Population Dynamics and Habitat Relationships of Sminthopsis dolichura (Marsupialia : Dasyuridae) in Semi-arid Shrublands of Western Australia

1997 ◽  
Vol 24 (3) ◽  
pp. 245 ◽  
Author(s):  
G. R. Friend ◽  
B. W. Johnson ◽  
D. S. Mitchell ◽  
G. T. Smith
Keyword(s):  
Seasonal Pattern ◽  
Rapid Development ◽  
Demographic Data ◽  
High Mobility ◽  
Breeding Population ◽  
Eastern Australia ◽  
History Of ◽  
High Degree ◽  
Two Populations ◽  
Semi Arid

Demographic data were gathered from two populations of the little long-tailed dunnart, Sminthopsis dolichura, inhabiting semi-arid nature reserves in the Western Australian wheatbelt in order to place the ecology of this species (formerly part of the Sminthopsis murina complex) in perspective. In all respects, S. dolichura is similar to S. murina from south-eastern Australia, and, indeed, to most other species of the Sminthopsis group. High mobility and transiency rates, an extended seasonal pattern of reproduction, relatively rapid development of the young and the probable existence of polyoestry characterise the life history of S. dolichura and most other species within the group that have been studied. These attributes enable a high degree of reproductive flexibility and permit these species to opportunistically invade new habitats and ephemeral post-fire seral stages. The observed sympatry with highly seasonal monoestrous dasyurids of the genus Antechinus is postulated to occur through spatial and temporal selection of different microhabitats, but also suggests that phylogenetic factors may be at least as important as the predictability of climate and food resources in explaining the evolution of different reproductive strategies.

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