Activities in Spain

The Canaries: an important biogeographical meeting place

Aim Oceanic islands represent a special challenge to historical biogeographers because dispersal is typically the dominant process while most existing methods are based on vicariance. Here, we describe a new Bayesian approach to island biogeography that estimates island carrying capacities and dispersal rates based on simple Markov models of biogeographical processes. This is done in the context of simultaneous analysis of phylogenetic and distributional data across groups, accommodating phylogenetic uncertainty and making parameter estimates more robust. We test our models on an empirical data set of published phylogenies of Canary Island organisms to examine overall dispersal rates and correlation of rates with explanatory factors such as geographic proximity and area size.Location Oceanic archipelagos with special reference to the Atlantic Canary Islands.Methods The Canary Islands were divided into three island‐groups, corresponding to the main magmatism periods in the formation of the archipelago, while non‐Canarian distributions were grouped into a fourth ‘mainland‐island’. Dispersal between island groups, which were assumed constant through time, was modelled as a homogeneous, time‐reversible Markov process, analogous to the standard models of DNA evolution. The stationary state frequencies in these models reflect the relative carrying capacity of the islands, while the exchangeability (rate) parameters reflect the relative dispersal rates between islands. We examined models of increasing complexity: Jukes–Cantor (JC), Equal‐in, and General Time Reversible (GTR), with or without the assumption of stepping‐stone dispersal. The data consisted of 13 Canarian phylogenies: 954 individuals representing 393 taxonomic (morphological) entities. Each group was allowed to evolve under its own DNA model, with the island‐model shared across groups. Posterior distributions on island model parameters were estimated using Markov Chain Monte Carlo (MCMC) sampling, as implemented in MrBayes 4.0, and Bayes Factors were used to compare models.Results The Equal‐in step, the GTR, and the GTR step dispersal models showed the best fit to the data. In the Equal‐in and GTR models, the largest carrying capacity was estimated for the mainland, followed by the central islands and the western islands, with the eastern islands having the smallest carrying capacity. The relative dispersal rate was highest between the central and eastern islands, and between the central and western islands. The exchange with the mainland was rare in comparison.Main conclusions Our results confirm those of earlier studies suggesting that inter‐island dispersal within the Canary Island archipelago has been more important in explaining diversification within lineages than dispersal between the continent and the islands, despite the close proximity to North Africa. The low carrying capacity of the eastern islands, uncorrelated with their size or age, fits well with the idea of a historically depauperate biota in these islands but more sophisticated models are needed to address the possible influence of major recent extinction events. The island models explored here can easily be extended to address other problems in historical biogeography, such as dispersal among areas in continental settings or reticulate area relationships.

Increasing water irrigation demand combined with water scarcity and deterioration of the water quality in the Lower Jordan Valley (hereafter referred to as LJV) - Palestine, has led to a serious challenge in managing current and future water demands. This problem is not restricted to Palestine but to the region in general. Providing feasible solution strategies for water management has demonstrated to be a complex task. Mismanagement of water resources aggravates the problem. Therefore, integrated water resources management promises applicable and creative solutions for the future in terms of water strategies. The main goals of this study are to develop these strategies end based on regional agricultural strategies development. The Case Study Area (Hereafter referred to as CSA), Auja area, is located in the LJV., CSA has suffered from water scarcity and water quality deterioration, This was manifested in decreasing irrigated lands from 10,000 donums in 2010 to only about 4,000 donums in 2013and change in crop patterns in the area. Moreover high chloride concentration in shallow aquifer - with 2000μs/cm² in some wells - has caused increased deterioration in water quality. Therefore, the study investigated creative alternatives based on integrated available water resources management and the exploration of non-conventional resources in the area. The study assumed many strategies of agricultural and water resources development, which jointly constitute strategies of firstly, agriculture development and secondly, water strategies. Both strategies should act as the core of the problem as well as its solution. Accordingly, integrated water resources management (hereafter referred to as IWRM) focused on managing aquifer recharge (MAR) and using brackish water in irrigation. This idea is the base for the assumption of this research. MAR and brackish water eventually are top priority scenarios for meeting water requirements in the future. Decision-makers are urged to take these scenarios into consideration to achieve sustainable development plans in the Palestinian territories. Irrigated lands in the CSA cover 3,800 donums vis-à-vis 30,000 irrigable donums. Main water resources come from Auja Springs and shallow aquifer wells. Available irrigation water does not exceed 3.5 Mm3/a. CSA is served by field survey including soil, water, land, and agriculture cover use. CSA is composed of three Agricultural land zones: zone 1, zone 2 and zone 3. These zones reflect the current cultivated area as well as lands expansion scenarios for an additional 8,500 donums of new irrigated lands with plantations of date palm trees, intensive green house agriculture and grapes. The scenario is based on soil profile analysis of root zone and soil hydrochemistry analysis. Water Management Strategies towards Sustainable Agricultural Development XVI These three land zones represent three agricultural development strategies based on water budget analysis and are jointly linked with the three assumed water strategies. The three water strategies (WSs) are: 1- WS I which is the Do-Nothing approach which reflects large water quantities deficit; 2-The WS II is based on MAR scenario, the Mathematical model of transient GMS-Modflow It is considered as a tool for water management in the CSA. It supplies 2 million cubic meters of surplus water by direct injection into the shallow aquifer wells, in addition to infiltrated flood surface run-off from Wadi Auja. 3-The WS III, is based on 100% of IWRM using all non-conventional water resources, varying from brackish water desalination and treated effluent to importing water from outside the CSA and the use of Current Untapped Water Resources (CUWR). This strategy will change the current crop pattern taking into consideration the water budget. It could offer additional 12 million cubic meters (Mm3) for the extra irrigated expanded land scenario. Evaluating the best management scenarios regarding performance and impact assets based on Driving-Pressure-State-Impact-Response (DPSIR) frame work, would give several decision variables (DVs) as a prelude to form decision criteria analysis and analytical hierarchy procedure (AHP) used for scaling and weighing different decision variables (DVs) This would produce the best management scenario by mixing brackish and fresh water and completely change the crop pattern in the CSA. The change would accrue through planting date palms. In this context, MAR scenario comes as intermediate priority by evaluation results, although it would need further investigation in the future.

Kleinia neriifolia Haw. is an endemic species on the Canarian archipelago, this species is widespread in the coastal thicket of all the Canarian islands. In the present study, genetic diversity and population structure of K. neriifolia were investigated using chloroplast gene sequences and nuclear SSR (simple sequence repeat). The differentiation among island populations, the historical demography, and the underlying evolutionary scenarios of this species are further tested based on the genetic data. Chloroplast diversity reveals a strong genetic divergence between eastern islands (Gran Canaria, Fuerteventura, and Lanzarote) and western islands (EI Hierro, La Palma, La Gomera, Tenerife), this west–east genetic divergence may reflect a very beginning of speciation. The evolutionary scenario with highest posterior probabilities suggests Gran Canaria as oldest population with a westward colonization path to Tenerife, La Gomera, La Palma, and EI Hierro, and eastward dispersal path to Lanzarote through Fuerteventura. In the western islands, there is a slight decrease in the effective population size toward areas of recent colonization. However, in the eastern islands, the effective population size increase in Lanzarote relative to Gran Canaria and Fuerteventura. These results further our understanding of the evolution of widespread endemic plants within Canarian archipelago.

Nowadays, gastropod molluscs are being utilized more and more as bioindicator organisms. Similarly, harmful metals on human health such as cadmium have been widely studied. The Canarian Archipelago (specifically the eastern islands) is constantly bathed by the African coastal upwelling, provoking oceanographic and biological differences between the islands. This process could assume an increase in the Cd concentration in their coastal waters and in the biota. Thus, in order to assess this fact, we measured cadmium concentrations in the soft parts of two species of limpets (Patella rustica and Patella candei crenata) and in a topshell snail (Osilinus atrata). Metal determination was performed using atomic absorption spectrometry (AAS). We found significant differences for metal concentrations between the eastern islands and the western islands for all species. P. rustica, P. c. crenata and O. atrata presented values ranging from 7.71, 2.11 and 7.56 μg g dry wt. (eastern islands) to 1.38, 0.4 and 1.08 μg g dry wt. (western islands) respectively. Therefore, we concluded that limpets and topshell snails seem to be suitable indicators of the cadmium concentrations in the coastal waters of the Canary Islands.

BackgroundIn the Canary Islands there are no previous data about tapeworms (Cestoda) of rodents. In order to identify the hymenolepidid species present in these hosts, a survey of 1,017 murine (349 Rattus rattus, 13 Rattus norvegicus and 655 Mus musculus domesticus) was carried out in the whole Archipelago. Molecular studies based on nuclear ITS1 and mitochondrial COI loci were performed to confirm the identifications and to analyse the levels of genetic variation and differentiation.ResultsThree species of hymenolepidids were identified: Hymenolepis diminuta, Rodentolepis microstoma and Rodentolepis fraterna. Hymenolepis diminuta (in rats) and R. microstoma (in mice) showed a widespread distribution in the Archipelago, and R. fraterna was the least spread species, appearing only on five of the islands. The hymenolepidids found on Fuerteventura, Lanzarote and La Graciosa were restricted to one area. The COI network of H. diminuta showed that the haplotypes from Lanzarote and Fuerteventura are the most distant with respect to the other islands, but clearly related among them.ConclusionsFounder effects and biotic and abiotic factors could have played important role in the presence/absence of the hymenolepidid species in determined locations. The haplotypes from the eastern islands (Fuerteventura and Lanzarote) seem to have shared an ancestral haplotype very distant from the most frequent one that was found in the rest of the islands. Two colonization events or a single event with subsequent isolation and reduced gene flow between western-central and eastern islands, have taken place in the Archipelago. The three tapeworms detected are zoonotic species, and their presence among rodents from this Archipelago suggests a potential health risk to human via environmental contamination in high risk areas. However, the relatively low prevalence of infestations detected and the focal distribution of some of these species on certain islands reduce the general transmission risk to human.

Evolutionary molecular studies of island radiations may lead to insights in the role of vicariance, founder events, population size and drift in the processes of population differentiation. We evaluate the degree of population genetic differentiation and fixation of the Canary Islands blue tit subspecies complex using microsatellite markers and aim to get insights in the population history using coalescence based methods. The Canary Island populations were strongly genetically differentiated and had reduced diversity with pronounced fixation including many private alleles. In population structure models, the relationship between the central island populations (La Gomera, Tenerife and Gran Canaria) and El Hierro was difficult to disentangle whereas the two European populations showed consistent clustering, the two eastern islands (Fuerteventura and Lanzarote) and Morocco weak clustering, and La Palma a consistent unique lineage. Coalescence based models suggested that the European mainland forms an outgroup to the Afrocanarian population, a split between the western island group (La Palma and El Hierro) and the central island group, and recent splits between the three central islands, and between the two eastern islands and Morocco, respectively. It is clear that strong genetic drift and low level of concurrent gene flow among populations have shaped complex allelic patterns of fixation and skewed frequencies over the archipelago. However, understanding the population history remains challenging; in particular, the pattern of extreme divergence with low genetic diversity and yet unique genetic material in the Canary Island system requires an explanation. A potential scenario is population contractions of a historically large and genetically variable Afrocanarian population, with vicariance and drift following in the wake. The suggestion from sequence-based analyses of a Pleistocene extinction of a substantial part of North Africa and a Pleistocene/Holocene eastward re-colonisation of western North Africa from the Canaries remains possible.

Improving second-pass permeate quality using thin film nanocomposite (TFN) membranes

Aim The aim of this paper is to identify the patterns in the morphological differentiation in Canary Island mice, based on fossil and modern samples. In order to achieve this, the mouse species present on the archipelago were first compared with a set of continental mice. The differences between the continental and Canary Island samples, and among the Canary Island samples, provide insights into the processes of colonization and the subsequent insular evolution.Location Canary archipelago.Methods An outline analysis based on Fourier transformation was used to quantify shape differences between lower molars. Together with the fossil and modern Canary Island samples, a reference set of genotyped continental populations of the commensalMus musculusand the wildMus spretuswas used for comparison.Results The morphometric analysis showed that all the mouse specimens from the Canary Islands and Cape Verde belonged toMus musculus domesticus.Lower molars of extant mice from La Gomera, El Hierro, Gran Canaria, Tenerife, and to a lesser degree from Lanzarote, were similar to those of genotypedM. m. domesticusfrom the continent, while teeth of extant mice from Fuerteventura were more divergent. Fossil mice from Fuerteventura were very similar to the extant representatives on this island, and similar to the fossil mice on the nearby islands of Lobos and La Graciosa.Main conclusions The mouse present on the Canary archipelago has been identified as the house mouseM. m. domesticus. Based on the shape of the lower molar, the Canary Island mice are divergent from the continental ones, but the degree of divergence varies with the geography of the archipelago. Overall, populations from eastern islands are more divergent from the continental mice than populations from western ones. Fossil populations indicate that this situation was established several centuries ago. Two main factors may have contributed to this pattern: the appearance of different types of environment on the islands since the successful settlement of the mouse, and/or the number of subsequent introductions of continental individuals via shipping.

Electron beam treatment of textile dyeing wastewater: operation of pilot plant and industrial plant construction

Desalination of sea and brackish water is gaining interest as a viable water source in several arid regions of the world where limited freshwater resources are under stress from increasing demands and deteriorating water quality. Although a few large desalination plants exist and are planned for future implementation, most desalinization facilities are constructed on a small scale to satisfy domestic requirements for individual cities and resort areas. As the cost of desalination continues to decline with improved technologies, integrated methodologies are needed for optimally locating and sizing desalinization facilities over regional scales. The problem is complicated by multiple, noncommensurate objectives related to economic, social, and political criteria and complex spatial analysis in locating facilities. A methodology is presented that integrates geographic information systems with multicriteria decision analysis for regionally locating and sizing desalinization facilities for domestic water supply. Application to the northwestern coast of Egypt, a region remote from freshwater sources in the Nile Valley and Delta, prioritizes cities to be served and optimally locates and sizes desalination facilities over the region.

Composition and bycatch of semi-floating shrimp-trap fisheries (SSTF) were compared among areas with different levels of anthropogenic alteration of marine ecosystems. The three areas selected were Madeira, the Canary Islands and Cape Verde. Mean species richness and diversity of the SSTF did not show significant differences among areas. The dominant species in catches of the SSTF for all regions studied was the main target species, Plesionika edwardsii, which accounted for 96.0% of the catch in Cape Verde, 75.8% in Madeira and 59.1% in the Canary Islands. Targeted pandalid shrimps accounted for more than 96.8% of total catches for all areas combined. Numbers of non-target species caught were 18 (Madeira), 14 (Canary Islands) and 16 (Cape Verde), of which 13 (Madeira), 8 (Canary Islands) and 11 (Cape Verde) were always discarded. Bycatch accounted for 0.5% (Madeira), 0.7% (Canary Islands) and 3.1% (Cape Verde) in numbers. Shark species accounted for 0.11% of all individuals caught. A total of 5 species in Madeira, 6 in the Canary Islands and 4 in Cape Verde, accounting for 0.2% to 0.8% of total catches, were not landed due to the small size of individuals or low numbers of individuals caught (self-consumption). The present results suggest that the selectivity of traps for the main target species, P. edwardsii, in SSTF changes due to changes in species dominance, which are probably linked to the degree of human fishing exploitation of the marine ecosystems in each area.

Trypanosomosis is a global animal issue, causing significant economic losses, particularly in Africa. In Spain, only one pathogenic species, Trypanosoma evansi, has been identified so far. It was first detected in a dromedary camel in the Canary Islands in 1997. Since then, numerous cases of the disease, known as Surra, have been diagnosed, prompting various studies and efforts in control and surveillance. Given the lack of a comprehensive database that consolidates the most relevant data in this area, the development of a national atlas, with a focus on the Canary Islands, to incorporate all available information on T. evansi in Spain became a necessity. For the development of the atlas, a repository was constructed, encompassing a range of datasets and documents spanning from 1997 to 2022. Information from each source, and in particular georeferenced locations and results of blood tests on animals, were extracted and integrated into a comprehensive database. A total of 31 sources were analysed, providing a total of 99 georeferenced locations and 12,433 animal samples. Out of these samples, 601 (mostly from dromedaries) were found to be positive for T. evansi. The Card Agglutination Test for T. evansi (CATT/T. evansi), a serological test, was the most commonly used diagnostic method, and it showed a higher prevalence for all tested animal species. Positive cases were mainly concentrated in the Canary Islands, specifically in the eastern islands, with isolated cases found in the province of Alicante (Iberian Peninsula). This atlas provides an overview of the history and occurrence of Surra in Spain, and it represents a valuable tool for future control initiatives and for research. Still, the need for more studies remains, especially for further testing of potential hosts other than camelids and for the examination of their potential transmission vectors.

U-series disequilibria in volcanic rocks from the Canary Islands: Plume versus lithospheric melting

Biogeographical relationships between the Canary Islands and north-west Africa are often explained by oceanic dispersal and geographical proximity. Sister-group relationships between Canarian and eastern African/Arabian taxa, the 'Rand Flora' pattern, are rare among plants and have been attributed to the extinction of north-western African populations. Euphorbia balsamifera is the only representative species of this pattern that is distributed in the Canary Islands and north-west Africa; it is also one of few species present in all seven islands. Previous studies placed African populations of E. balsamifera as sister to the Canarian populations, but this relationship was based on herbarium samples with highly degraded DNA. Here, we test the extinction hypothesis by sampling new continental populations; we also expand the Canarian sampling to examine the dynamics of island colonization and diversification. Using target enrichment with genome skimming, we reconstructed phylogenetic relationships within E. balsamifera and between this species and its disjunct relatives. A single nucleotide polymorphism dataset obtained from the target sequences was used to infer population genetic diversity patterns. We used convolutional neural networks to discriminate among alternative Canary Islands colonization scenarios. The results confirmed the Rand Flora sister-group relationship between western E. balsamifera and Euphorbia adenensis in the Eritreo-Arabian region and recovered an eastern-western geographical structure among E. balsamifera Canarian populations. Convolutional neural networks supported a scenario of east-to-west island colonization, followed by population extinctions in Lanzarote and Fuerteventura and recolonization from Tenerife and Gran Canaria; a signal of admixture between the eastern island and north-west African populations was recovered. Our findings support the Surfing Syngameon Hypothesis for the colonization of the Canary Islands by E. balsamifera, but also a recent back-colonization to the continent. Populations of E. balsamifera from northwest Africa are not the remnants of an ancestral continental stock, but originated from migration events from Lanzarote and Fuerteventura. This is further evidence that oceanic archipelagos are not a sink for biodiversity, but may be a source of new genetic variability.