Temporal evolution of 3He/4He isotopic ratio at Dos Aguas cold mineral spring, La Palma, Canary Islands

<p>Recent volcanic activity of La Palma island, the fifth in extension (706 km<sup>2</sup>) and the second in elevation (2,423 m a.s.l.) of the Canarian archipelago, has taken place exclusively in the last 123 ka at the southern part of the island, where Cumbre Vieja volcano, the most active basaltic volcano in the Canaries, has been constructed. A total of seven volcanic eruptions have been reported along the main north-south rift zone of Cumbre Vieja in the last 500 years. On October 7<sup>th</sup> and 13rd, 2017, two remarkable seismic swarms interrupted a seismic silence of 46 years in Cumbre Vieja volcano with earthquakes located beneath Cumbre Vieja volcano at depths ranging between 14 and 28 km with a maximum magnitude of 2.7. Five more seismic swarms were registered in 2020.</p><p><sup>3</sup>He/<sup>4</sup>He ratio has been monitored at Dos Aguas cold mineral spring in La Palma Island since 1991 to date as an important volcano monitoring tool able to provide early warning signal of future volcanic unrest episodes. Magmatic helium emission studies have demonstrated to be sensitive and excellent precursors of magmatic processes occurring at depth. The highest <sup>3</sup>He/<sup>4</sup>He ratio reported to date from the Canarian archipelago has been measured at Dos Aguas: 10.24 R<sub>A</sub> (being R<sub>A </sub>the ratio in atmospheric helium) (Padrón et al., 2015). This value is higher than any value found either in the lavas or terrestrial fluid in the Canary Islands, and indicates an important mantle contribution.<sup>  </sup>According to the temporal evolution of the magmatic component of helium at Dos Aguas, we suggest the occurrence of aseismic magma rising episodes beneath La Palma within the upper mantle towards an ephemeral magma reservoir in the period 2007-2017. However, in the period 2017-2020, magma rising have produced seismic swarms that were accompanied also by the highest <sup>3</sup>He/<sup>4</sup>He ratio measured at Dos Aguas (10.42 R<sub>A</sub>); both geochemical and geophysical signals confirm an upward magma migration towards a subcrustal magma reservoir beneath La Palma island.</p><p> </p><p>Padrón et al., (2015). Bull Volcanol 77:28. DOI 10.1007/s00445-015-0914-2</p>

The demography of the Canary Islands from a genetic perspective

The establishment of European colonies across the world had important demographic consequences because it brought together diverse and distant civilizations for the first time. One clear example of this phenomenon is observed in the Canary Islands. The modern Canarian population is mainly the result of the admixture of natives of North African origin and European colonizers. However, additional migratory flows reached the islands due to the importation of enslaved Africans to cultivate sugarcane and the intense commercial contact with the American continent. In this review, we evaluate how the genetic analysis of indigenous, historical, and current populations has provided a glimpse into the Canary Islands’ complex genetic composition. We show that each island subpopulation’s characterization is needed to fully disentangle the demographic history of the Canarian archipelago. Finally, we discuss what research avenues remain to be explored to improve our knowledge of the impact that the European colonization had on its native population.

New records of the land and freshwater molluscs of Gran Canaria (Canary Islands, Spain)

“Land and freshwater molluscs of Gran Canaria (Spain)” is an occurrence dataset containing 389 observations of 59 different taxa of land and freshwater molluscs encountered on Gran Canaria, an island central in the Canarian archipelago (Spain). Of these 59 different (sub)species, 27 are with certainty currently endemic to the island of Gran Canaria. Various sites were inspected in a period between 1988 and 2020. The dataset is published as a standardized Darwin Core Archive and includes for each observation a stable occurrence ID, scientific name, date, and location of the observation, as well as information on life stage and organism quantity. It also contains supplementary remarks on the determination and the observation itself and links to associated media. We have released this dataset to the public domain under a CC0 1.0 Universal (CC0 1.0) Public Domain Dedication. The aim is to contribute to the knowledge on the ecology and distribution of these species on the island, such that it may aid conservation and research of these organisms in the future. Issues with the dataset can be reported at https://github.com/BelgianBiodiversityPlatform/landsnails-occurrences

Endemics Versus Newcomers: The Ladybird Beetle (Coleoptera: Coccinellidae) Fauna of Gran Canaria

Research on the fauna of beetles (Coleoptera) of the Canary Islands has a long tradition, which enables tracking changes in their species composition and arrival of new species. In this paper, we provide new faunistic data on the ladybird beetles (Coccinellidae) recorded on Gran Canaria, one of the central islands of the archipelago, and then analyze available information on the Gran Canarian ladybird fauna from geographical and historical points of view. The field survey resulted in recording 1402 ladybird individuals belonging to 30 species. Ten of these species were new to Gran Canaria and three of them, Chilocorus bipustulatus (Linnaeus), Nephus bisignatus (Boheman), and Nephus ulbrichi Fürsch, had not previously been reported to be on any of the islands of the Canarian archipelago. Tetrabrachys tinerfensis (Hodgson) is synonymized with T. deserticola (Wollaston). Our survey and literature reports allowed us to recognize 42 species of Coccinellidae so far recorded on Gran Canaria. Seventeen of them (40%) belonged to the Canarian endemic and subendemic species, and 21 (50%) were newcomers and presumed newcomers. Colonization of Gran Canaria and other islands of the archipelago by ladybird species of various origins seems to be a frequent phenomenon that may pose a threat to the unique communities of the native Canarian species.

A paradise for parasites? Seven new haemogregarine species infecting lizards from the Canary Islands

Oceanic islands are hotspots of biodiversity due to their high levels of endemism, with the Canary Islands being a notable example. A previous molecular study on the biogeography and host associations of haemogregarines (Apicomplexa: Adeleorina) infecting lizards from this archipelago detected seven parasite haplogroups. These haplogroups exhibited high host-specificity and geographical structure, suggesting that they might correspond to distinct biological identities. In this study, along with sequencing a longer fragment of the 18S rRNA, we further explore the distinctiveness of these parasites by analysing their morphology, effects on host erythrocytes and parasitaemia levels. These lines of evidence together with their genetics, host associations, frequency of occurrence and geographical distribution support them as different biological entities. As such, we describe seven new species: Karyolysus canariensis sp. nov., Karyolysus galloti sp. nov., Karyolysus stehlini sp. nov., Karyolysus gomerensis sp. nov., Karyolysus atlanticus sp. nov., Karyolysus tinerfensis sp. nov. and Karyolysus makariogeckonis sp. nov. These new taxa are further examples of endemic diversity in the Canarian archipelago. They also contribute to clarify the taxonomy within the Apicomplexa, a phylum estimated to have one of the lowest percentages of described species.

Urban form in the tourist cities of the coast of the Canary Islands. The morphologies of leisure

The tourist city has been a space with few and weak reflections from the urban discipline. The developed planning, at best, has been uncritically exported from the residential city. However, in these cities, almost 12% of Spanish GDP is generated. The vast majority of Spanish coasts, especially on the Mediterranean coast and in the archipelagos, are occupied by large areas of holiday cities. Many of them were born in the first boom of Spanish tourism in the 60's. The mass tourism model, predominant in our coast, also generates a mass city. The morphology of this city does not follow the common and more consolidated patterns of the residential city. Today many of these tourist destinations begin to show of obsolescence. For this reason, the analysis of its urban form is a valuable tool in the face of its renovation project. In this work, we propose the analysis of the tourist micro-destinations of the Canarian archipelago. In order to this we will identify the main morphological patterns and characterize them from the analysis of a set of descriptive indicators related to public and private space. References Gaja, F. (ed.) (2012) DeCoastruction (Universidad Politécnica de Valencia, Valencia). Pié, R. and Rosa, C. (eds.) (2013) Turismo líquido (Instituto Hábitat Turismo Territorio, UPC and UM, Barcelona). Simancas Cruz, M. R. and Hernández Martín R. (Eds.) (2015) Reinventando alojamientos turísticos. Casos de éxito y soluciones innovadoras (Cátedra de Turismo de Cajacanarias - ASAHOTEL - Universidad de La Laguna, Tenerife Simancas Cruz, M. R. and García Cruz, J. I. (2015): ‘La modelización territorial de un espacio urbano-turístico de litoral: una propuesta para el plan de rehabilitación de las infraestructuras turísticas de Puerto de la Cruz (España)’, in GeoFocus, nº 15, p 105-132. Temes R. and Tuset, J., R. (eds.) (2015) Orilla marítima. Territorio litoral (General de ediciones de Arquitectura, Valencia).

The 2011-2012 El Hierro submarine eruption: a challenge of geochemical and thermal imaging for volcano monitoring

A shallow submarine eruption occurred between October 12, 2011 and March 5, 2012 about 2 km off the southern coast of El Hierro, the youngest and smallest of the seven major islands of the Canarian archipelago. This submarine eruption rose from a depth of 363 meters and finally reached 89 meters bsl and provided us a unique chance to study a variety of precursory signals before the eruption as well as to evaluate for the very first time magma emission rates from a shallow submarine eruption using airborne thermal imaging.