Canary Islands Research Articles

Reproductive features of the invasive crab Cronius ruber (Brachyura, Portunidae) on the Canary Islands (central eastern Atlantic), Spain

The main features of the life cycle and ecology of the invasive species Cronius ruber in both its native range and invaded areas are unknown. Therefore, the reproductive traits of this invasive allochthonous species were studied in the Canary Islands, including sex structure, maturity, fecundity, and egg development. Females were more abundant than males, mainly in the size range between 25 and 80 mm CW. Only males were observed in size classes above 80 mm CW. Reproduction of C. ruber is continuous throughout the year, with a new oviposition immediately after the end of the egg incubation period. This process can be repeated in females up to six times, without re-mating, due to the sperm stored by females in the spermathecae. Sexual maturity was estimated at a similar size in both sexes, corresponding to 57–59 % of their maximum observed size. Egg development appeared to be completely synchronous, with a development period lasting slightly less than 1 month. The mean fecundity was 657,282 eggs, with a maximum observed fecundity of 988,509 eggs. This species shows a high reproductive potential, characteristic of invasive species.

Explosive eruption style modulates volcanic electrification signals

Volcanic lightning detection has proven useful to volcano monitoring by providing information on eruption onset, source parameters, and ash cloud directions. However, little is known about the influence of changing eruptive styles on the generation of charge and electrical discharges inside the eruption column. The 2021 Tajogaite eruption (La Palma, Canary Islands) provided the rare opportunity to monitor variations in electrical activity continuously over several weeks using an electrostatic lightning detector. Here we show that throughout the eruption, silicate particle charging is the main electrification mechanism. Moreover, we find that the type of electrical activity is closely linked to the explosive eruption style. Fluctuations in the electrical discharge rates are likely controlled by variations in the mass eruption rate and/or changes in the eruption style. These findings hold promise for obtaining near real-time information on the dynamic evolution of explosive volcanic activity through electrostatic monitoring in the future.

Syllidae Grube, 1850 (Annelida) from Conception, Amanay and Banquete Banks off Canary Islands, with the description of two new species

Syllidae Grube, 1850 (Annelida) from Conception, Amanay and Banquete Banks off Canary Islands, with the description of two new species

Danish Ships in the Canary Islands during the Second World War

This article delves into the theme of Spanish neutrality during the Second World War from the standpoint of a series of circumstances surrounding a group of Danish ships that took refuge in the Canary Islands. The Third Reich attempted to prevent the departure of these vessels whereas the Allies sought to facilitate it. This study stems from consulting primary sources in archives in Spain, Germany, the United Kingdom, and the United States. Noteworthy among the main conclusions is that the Danish policy of co-operation with the German occupation retained the Danish ships in the archipelago’s ports until 1943 and that they only set sail after the Danish government resigned in 1943. The intention of the foreign policy of the Spanish government was to defend its own interests against pressures from the belligerents. Moreover, its neutralist shift initiated in August 1942 was reinforced by the change in the course of the war in favour of the Allies.

Cory's Shearwater (Calonectris borealis): Exploring Normal Head Anatomy through Cross-Sectional Anatomy, Computed Tomography and Magnetic Resonance Imaging.

Cory's shearwater, or Calonectris borealis, stands out as a symbolic figure in the world of seabirds, playing a crucial role in marine ecosystems globally. Belonging to the Procellariidae family, it is singularized by its imposing wingspan and intricate migration patterns connecting it to various regions from the North Atlantic to the Pacific. Its role in the marine food chain, specialized diet and adaptation for nesting in the Canary Archipelago underscore its ecological importance. However, Cory's shearwater also faces important threats, such as the invasion of foreign species, highlighting the need for its conservation. Among the conservation issues, studies on its biology, the main threats it faces and its normal anatomy are essential to preserve marine biodiversity. Additionally, a variety of imaging techniques, such as computed tomography and magnetic resonance, facilitates the understanding of the bird's neuroanatomy and opens future research possibilities in comparative neuroscience. Moreover, this approach proves particularly relevant given the increasing attention these seabirds receive in environments such as zoos, rehabilitation centers and their natural habitat, where veterinarians play a crucial role in their care and well-being.

Genetic characterization of Cryptosporidium spp. in the North African hedgehog (Atelerix algirus) in the Canary Islands, Spain.

The North African hedgehog (Atelerix algirus) is an introduced species from Northwest Africa and is currently distributed in the Canary Islands. This species of hedgehog has been studied as a reservoir of enteropathogens, including Cryptosporidium spp. However, there are no data at species level. Therefore, the aim of the present study was to identify the Cryptosporidium species present in a population of hedgehogs (n = 36) in the Canary Islands. Molecular screening was performed using conventional polymerase chain reaction (PCR) targeting the small subunit ribosomal RNA (18S rRNA) gene of Cryptosporidium spp. Seven of the 36 fecal samples (19.45%) were positive and confirmed by nested PCR targeting the 18S rRNA gene and Sanger sequencing. Cryptosporidium parvum and Cryptosporidium muris were identified in 11.1% (4/36) and 5.6% (2/36) of the samples, respectively, while one sample could only be identified at the genus level. The zoonotic subtypes IIdA15G1 (n = 1), IIdA16G1b (n = 1), and IIdA22G1 (n = 1) of C. parvum were identified by nested PCR followed by analysis of the 60kDa glycoprotein (gp60) gene sequence. This study is the first genetic characterization of Cryptosporidium spp. in A. algirus, identifying zoonotic species and subtypes of the parasite.

Epidemiology of Q fever in humans in four selected regions, Spain, 2016 to 2022.

BackgroundQ fever is a bacterial zoonosis caused by Coxiella burnetii. Spain has the highest number of notified human cases in Europe. Small ruminants are a key reservoir for the pathogen, transmission from animals to humans is usually airborne.AimWe aimed at exploring temporal and spatial epidemiological patterns of sporadic and outbreak cases of Q fever in four Spanish regions with the highest number of notified cases.MethodsWe extracted data on Q fever cases in the Canary Islands, Basque Country, La Rioja and Navarre between 2016 and 2022 from the Spanish National Epidemiological Surveillance Network. We calculated standardised incidence ratios (SIR), spatial relative risks (sRR) and posterior probabilities (PP) utilising Besag-York-Mollié models.ResultsThere were 1,059 notifications, with a predominance of males aged 30-60 years. In Basque Country, La Rioja and Navarre area, 11 outbreaks were reported, while no in the Canary Islands. A seasonal increase in incidence rates was observed between March and June. In the Canary Islands, elevated sRR was seen in La Palma, Gran Canaria, Lanzarote and Fuerteventura. In Basque Country, La Rioja and Navarre area, the highest sRR was identified in the south of Biscay province.ConclusionGoats were the main source for humans in outbreaks reported in the literature. Seasonal increase may be related to the parturition season of small ruminants and specific environmental conditions. Local variations in sRR within these regions likely result from diverse environmental factors. Future One Health-oriented studies are essential to deepen our understanding of Q fever epidemiology.

Phylogenetic and phylogeographic evidence for the colonization success of the diplochorous Astydamia latifolia across the Canary Islands.

Astydamia latifolia is the only species of the genus Astydamia, which forms an early-diverging lineage of Apiaceae, subfamily Apioideae. This species is subendemic to the Canary Islands and one of the most representative species of the coastal environments of this archipelago. Astydamia displays diplochory, that is, diaspores with two long-distance dispersal (LDD) syndromes. In particular, A. latifolia has both anemochorous and thalassochorous fruit traits (corky and winged mericarps). Although we expect this species to have a high dispersal capacity, there is no genetic study addressing it. The divergence time of this species from its sister taxon is also unknown. In this study, we aimed (i) to unveil the phylogenetic relationships and divergence times of A. latifolia; (ii) to reconstruct its phylogeographic structure across the Canary Islands; and (iii) to estimate the number of inter-island colonization events. To these ends, we first sequenced the internal transcribed spacer (ITS) region for A. latifolia, reconstructed the phylogenetic relationships of Astydamia and Apiaceae relatives and estimated divergence times. Then, two plastid DNA regions (psaI-aacD and psbK-trnS) were sequenced for 158 individuals (from 36 Canarian population and one NW African population) to reconstruct a haplotype network. The recently developed method Phylogeographic Analysis of Island Colonization Events (PAICE) was used to estimate the number of inter-island colonization events. Results show that A. latifolia is a phylogenetically isolated lineage that diverged from the most closely related genus (Molopospermum) in the Eocene-Miocene. It displays a low plastid DNA diversity (only four haplotypes detected), which is accompanied by a high degree of haplotype sharing between islands and highly linear rarefaction curves of colonization obtained in PAICE. These findings suggest a high colonization ability for this species, most likely related to the availability of two LDD syndromes.

Molecular analyses of the Kalotermes dispar-complex (Blattodea: Kalotermitidae) from the Canary Islands reveal cryptic intraspecific divergence and a connection to a lone Nearctic congener.

The Canary Islands is a Macaronesian volcanic archipelago with a depauperate community of three species of Kalotermitidae, including Kalotermes dispar. A total of 54 Kalotermes colonies were collected from Gran Canaria, Tenerife, La Gomera, La Palma, and El Hierro islands. Soldiers and imagos were morphologically examined and sequenced for four mitochondrial markers. Although morphological differences could not be detected, phylogenetic analysis of both cox1/tRNA/cox2 and rrnL markers revealed two distinct clades of K. dispar, suggesting cryptic diversity. The diversification within the Canary Kalotermes lineage most likely occurred around 7.5 Mya, while the divergence within the two clades was reconstructed at about 3.6 Mya and 1.9 Mya. Kalotermes approximatus from the southeastern Nearctic constitutes a sister to the Canary Kalotermes, while the Palearctic K. flavicollis, K. italicus, and K. phoenicae form a separate clade. It is hypothesized that a faunal exchange of Kalotermes from the Nearctic to the Canary Islands occurred via transoceanic rafting during the mid-Miocene.

SWOT Analysis of the Benefits of Hydropower Energy in Four Archipelagos

Increasing energy production through renewable sources is a challenge for islands. This paper investigates the potential of hydropower as a renewable energy source for islands in the Macaronesia region, which includes the Azores, Madeira, Canary Islands, and Cape Verde. Ecological transition towards renewable energy sources is crucial for these islands due to their current dependence on imported fossil fuels and their remoteness. The methodology used in this paper combines a SWOT analysis with a review of relevant literature. The SWOT analysis evaluates the Strengths, Weaknesses, Opportunities, and Threats associated with hydropower development on each island. The results show that each island has unique characteristics that influence its hydropower potential. The Azores has existing mini-hydropower plants and opportunities for pumped storage systems due to its rainfall and volcanic features. Madeira also utilizes hydropower, including the world's first underground pumped storage plant (UPHS) in Socorridos. However, limitations exist due to the mountainous terrain and competition for water resources. The Canary Islands showcase the success story of El Hierro Island, which significantly increased renewable energy penetration through a wind farm and pumped storage hydropower system. The topography and lack of rainfall on Cape Verde make the development of hydropower a significant challenge and, as a result, the focus has shifted to wind power. The study concludes that hydropower can play a significant role in the ecological transition of these islands. However, careful planning and consideration of environmental factors are necessary to maximize the benefits and minimize the potential drawbacks. The paper emphasizes the importance of island-specific assessments and exploring opportunities for pumped storage systems. Doi: 10.28991/CEJ-2024-010-07-019 Full Text: PDF

The chronology of the human colonization of the Canary Islands

The human colonization of the Canary Islands represents the sole known expansion of Berber communities into the Atlantic Ocean and is an example of marine dispersal carried out by an African population. While this island colonization shows similarities to the populating of other islands across the world, several questions still need to be answered before this case can be included in wider debates regarding patterns of initial colonization and human settlement, human-environment interactions, and the emergence of island identities. Specifically, the chronology of the first human settlement of the Canary Islands remains disputed due to differing estimates of the timing of its first colonization. This absence of a consensus has resulted in divergent hypotheses regarding the motivations that led early settlers to migrate to the islands, e.g., ecological or demographic. Distinct motivations would imply differences in the strategies and dynamics of colonization; thus, identifying them is crucial to understanding how these populations developed in such environments. In response, the current study assembles a comprehensive dataset of the most reliable radiocarbon dates, which were used for building Bayesian models of colonization. The findings suggest that i) the Romans most likely discovered the islands around the 1st century BCE; ii) Berber groups from western North Africa first set foot on one of the islands closest to the African mainland sometime between the 1st and 3rd centuries CE; iii) Roman and Berber societies did not live simultaneously in the Canary Islands; and iv) the Berber people rapidly spread throughout the archipelago.

A novel method to calculate solar energy potential based on cadastre data: A Canary Island case study

A novel method to calculate solar energy potential based on cadastre data: A Canary Island case study

Further knowledge of the genus Nyctobrya Boursin, 1957 from the Canary Islands (Spain), with description of a new species from El Hierro (Lepidoptera: Noctuidae)

Further knowledge of the genus Nyctobrya Boursin, 1957 from the Canary Islands (Spain), with description of a new species from El Hierro (Lepidoptera: Noctuidae)

Endless forms most frustrating: disentangling species boundaries in the Ramalina decipiens group (Lecanoromycetes, Ascomycota), with the description of six new species and a key to the group.

Oceanic islands have been recognized as natural laboratories in which to study a great variety of evolutionary processes. One such process is evolutionary radiations, the diversification of a single ancestor into a number of species that inhabit different environments and differ in the traits that allow them to exploit those environments. The factors that drive evolutionary radiations have been studied for decades in charismatic organisms such as birds or lizards, but are lacking in lichen-forming fungi, despite recent reports of some lineages showing diversification patterns congruent with radiation. Here we propose the Ramalina decipiens group as a model system in which to carry out such studies. This group is currently thought to be comprised of five saxicolous species, all of them endemic to the Macaronesian region (the Azores, Madeira, Selvagens, Canary and Cape Verde islands). Three species are single-island endemics (a rare geographic distribution pattern in lichens), whereas two are widespread and show extreme morphological variation. The latter are suspected to harbor unrecognized species-level lineages. In order to use the Ramalina decipiens group as a model system it is necessary to resolve the group's phylogeny and to clarify its species boundaries. In this study we attempt to do so following an integrative taxonomy approach. We constructed a phylogenetic tree based on six molecular markers, four of which are newly developed and generated competing species hypotheses based on molecular (species discovery strategies based on both single locus and multilocus datasets) and phenotypic data (unsupervised clustering algorithms based on morphology, secondary chemistry and geographic origin). We found that taxonomic diversity in the Ramalina decipiens group has been highly underestimated in previous studies. In consequence, we describe six new species, most of them single-island endemics and provide a key to the group. Phylogenetic relationships among species have been reconstructed with almost full support which, coupled with the endemic character of the group, makes it an excellent system for the study of island radiations in lichen-forming fungi. Citation: Blázquez M, Pérez-Vargas I, Garrido-Benavent I, et al. 2024. Endless forms most frustrating: disentangling species boundaries in the Ramalina decipiens group (Lecanoromycetes, Ascomycota), with the description of six new species and a key to the group. Persoonia 52: 44-93. https://doi.org/10.3767/persoonia.2024.52.03 .

Use-Wear Analysis of Obsidian and Other Volcanic Rocks: An Experimental Approach to Working Plant Resources

AbstractThis experimental study aims to contribute to functional analysis research on tools which specifically served to work wood and non-woody plants. They were made of obsidian and other volcanic rocks (basalt, trachyte, and phonolite) characterised by an amorphous matrix and phenocrysts of different number and size. In spite of prior functional analysis research resorting to these raw materials, there remain gaps in our understanding of specific activities. The work thus focused on working different types of wood from the Canary Island as well as on harvesting cereals. It is likewise centred on craftwork, especially regarding certain rarely studied contact materials such as palm leaves and rushes. The results reveal use-wear differences stemming from working woody and non-woody plants with both obsidian and other volcanic rocks. A special attention was given to the identification and description of the different features depending on the raw materials and the characteristics of their knapped surfaces. Identifying the combination of attributes has been essential to attain more accurate diagnostics. There are limits to each of the types of raw materials. The surfaces of obsidian are easier to observe and allow more specific identifications. In turn, the heterogeneous surfaces of volcanic rocks with phenocrysts that require more to time to develop diagnostic traces render use-wear amongst these types of rocks more difficult to observe. It is possible to distinguish longitudinal and transversal actions between woody and non-woody plants on every rock. Actions related to basketry, such us splitting and scraping, are more complicated to identify. The state of the worked plant (dry or fresh) and the time of use are key factors to consider in each case.

Teaching Sustainability through Traditional Sporting Games

Traditional sports games (TSGs), deeply rooted in local culture, serve as valuable resources for educating in sustainable development, aligning with guidelines set forth by international resolutions such as the Agenda 2030. This study investigated how ethnomotor variables in the educational use of TSGs with objects influenced emotional well-being and the acquisition of significant and contextualised physical and social sustainability learning involving various educational agents. The study adopted a qualitative and inductive approach centred on an ethnomotor intervention to promote sustainable learning within and beyond the educational setting. A total of 226 primary school students aged between 11 and 12 from seven primary education centres in the Canary Islands, Spain participated. Seven intervention sessions were conducted, including out-of-school activities involving family members and in-school activities with the collaboration of teaching staff and a specialised researcher. Various data collection instruments were employed (field notes, questionnaires, and interviews). A content analysis of qualitative data was conducted and subsequently transformed into quantitative data. For statistical analyses of these data, multidimensional frequency areas, crosstab (Pearson’s chi-square), associated effect size (Cramer’s V), and decision trees were utilised. This research discusses the relevance of TSGs as tools for promoting physically and socially sustainable learning. Furthermore, the role of various educational agents, including family members, teachers, and teacher-researchers, in developing these experiences is highlighted. The findings also highlight emotional well-being (psychosocial and socio-emotional affectivity) as a key aspect in the process of meaningful and contextualised sustainable learning.

Blunt Force Trauma in the Canarian Houbara Bustard (Chlamydotis undulata fuertaventurae) Produced by Collision with Overhead Lines.

The mortality of birds resulting from collisions and electrocutions with overhead lines, such as power lines and phone lines, among others, has been implicated in the decline of various avian species globally. Specifically, overhead line collisions pose a significant threat to the conservation of the Canarian houbara bustard (Chlamydotis undulata fuertaventurae), an endangered subspecies endemic to the Canary Islands. This study centers on the postmortem findings of Canarian houbara bustards that have collided with overhead lines, providing insights into the post-collision outcomes for these birds. A complete standardized necropsy of nine Canarian houbara bustards revealed that trauma was the cause of death in all cases. The most notable gross lesions associated with trauma included bone fractures, soft tissue lacerations, hemorrhages, luxations, and hemocoelom. The inguinal area, chest, and wings were the body regions more frequently affected. A histopathology, immunohistochemistry, and entomology analysis confirmed that numerous birds survived the initial trauma. We concluded that when a houbara bustard collides with an overhead line, it frequently survives the initial trauma, with a survival time ranging from minutes to hours. The histopathology, immunohistochemistry, or entomologic analysis may be helpful to approximate the timing interval between trauma and death.

Revealed strategies in wineries’ grape supply: the case of the Canary Islands

PurposeThis paper aims to deal with the grape sourcing strategies of wineries in the Canary Islands.Design/methodology/approachSourcing decisions are analysed from official registers of transactions between wineries and their external suppliers. The main sources of information are harvest reports submitted by wineries containing data about observable dimensions of their purchasing decisions. The general behaviour in the wine-grape zones that make up the grape market in the Canary Islands is described, and different strategies of individual wineries are revealed. Grape purchasing decisions are interpreted in terms of the potential explanatory factors involved in the undeclared objectives of wineries’ sourcing strategies. Two research questions are considered in this study: the spatial dimension, which refers to plot location, and the social dimension, which refers to the relationships between wineries and winegrowers.FindingsThe location of grape producers is a key factor in achieving the desired wine quality for wineries. The sourcing strategy of wineries is also influenced by size, but the impact of size varies depending on the short and long-term objectives of wineries.Originality/valueTypically the literature on grape sourcing strategies relies on interviews with winemakers. However, this paper analyses wineries’ sourcing decisions based on records and reports that reveal their decisions in the specific context of the Canary Islands.

Exploring the effects of fire on bryophyte functional groups along an elevational gradient on an oceanic island

Fire modifies the composition and distribution of biodiversity, but the availability of broad elevational gradients for evaluating its effects is limited. Studies conducted along elevational gradients provide valuable insights into the impacts of large-scale disturbances. Due to their sensitivity to environmental changes and low palatability to invasive herbivores, bryophytes serve as effective bioindicators for analyzing disturbance levels in oceanic island ecosystems where herbivores have been introduced. Our research focused on examining how α and β diversity and bryophyte species composition change along an elevational gradient from 200 to 2000 m a.s.l. in areas affected by fire 20 years ago compared to control areas that have been fire-free for at least 50 years. This study was carried out using different functional bryophyte groups in the pine forest of La Palma Island (Canary Islands), where this ecosystem is well represented. The findings revealed the sensitivity of the Canarian pine forest ecosystem to fire. Pine forest areas burnt 20 years ago were significantly poorer in bryophyte species than those in areas free from fire for at least 50 years. α-diversity is proposed as the most indicative parameter for analyzing the impacts of fire on the studied functional groups along the entire gradient analyses. However, β-diversity is more dependent on environmental conditions, increasing in the wettest pine forests. The results suggest that the fire impacts vary depending on the specific functional group of bryophytes and the type of pine forest.

Morphological Characterization of Opuntia Accessions from Tenerife (Canary Islands, Spain) Using UPOV Descriptors

Twenty Opuntia accessions from Tenerife (Canary Islands, Spain) were classified according to 52 quantitative and qualitative descriptors, including the traits of the cladodes, flowers, fruits, and spines, as described by the International Union for the Protection of New Varieties of Plants (UPOV) guidelines. A database composed of 20 accessions and 52 traits was used to perform a cluster analysis based on the Euclidian distance and Ward’s method and a canonical discriminant analysis. In terms of the analyzed characteristics, cactus pears with orange flesh showed less variability than cactus pears with white or purple flesh. Good classifications according to fruit flesh color were obtained using discriminant analysis. As a result of the cluster analysis, Opuntia plant accessions with white, orange, or purple-fleshed fruits were classified into four homogeneous groups according to the cubic clustering criteria. This study proves that it was possible to make a preliminary classification of Opuntia varieties from the Canary Islands based on a few main morphological characteristics. To improve the classification, a molecular analysis of the different Opuntia plants is necessary.