Chestnut cultivar diversification process in the Iberian Peninsula, Canary Islands, and Azores

This is a large-scale molecular study based on simple sequence repeat (SSR) loci of the diversification process in chestnut cultivars from Portugal and Spain, from the northern Iberian Peninsula to the Canary Islands and the Azores. A total of 593 grafted chestnut trees (Castanea sativa Mill.) were analysed with 10 SSRs: 292 from Portugal and 301 from Spain. Some of the trees studied were more than 300 years old. Accessions were analysed using a model-based Bayesian procedure to assess the geographical structure and to assign individuals to reconstructed populations based on the SSR genotypes. We found 356 different genotypes with a mean value of clonality of 33% owing to grafting. Mutations accounted for 6%, with hybridization being the main diversification process that can explain the great diversity found. Ten main cultivar groups were detected: four in northern Spain, five in the centre of the Iberian Peninsula, and one in southern Spain related to the centre of the Iberian Peninsula. This work demonstrated that cultivar origin and the diversification process was a combination of clonal propagation of selected seedlings, hybridization, and mutations, which allowed high levels of diversity to be maintained with respect to selected clones for fruit production. Furthermore, seedlings and graft sticks facilitated the transport to new destinations in the colonization process, transporting sometimes more than 3000 km if we consider the Azores and the Canary Islands.     

Evolution and diversification of the forest and hypogean ground-beetle genus Trechus in the Canary Islands

The beetle genus Trechus (Carabidae) is represented in the Macaronesian Islands by 43 endemic species. The Canary Islands have 16 endemic species, with two adapted to hypogean life. Phylogenetic relationships among 177 individuals of 38 Canarian, Madeiran, Azorean and continental Trechus species were examined using mitochondrial DNA and nuclear internal transcribed spacer 2 (ITS2) sequence data. Results show two main lineages in the Canaries: one comprising two sister groups with species from the laurel forest of La Gomera and Tenerife, and the other containing the single species from Gran Canaria and a species complex in the four western islands including two troglobites. Calibrations were applied to a linearized tree using a relaxed molecular clock method to estimate the major evolutionary divergence times of the Canarian Trechus species. Although the species assemblage in this archipelago is relatively ancient (7-8 million years), much of the species diversity is recent. Transition to the hypogean environment is more consistent with the "adaptive shift" rather than with the competing "climatic relict" hypothesis.     

Colonisation and diversification of the blue tits (Parus caeruleus teneriffae-group) in the Canary Islands

The blue tit (Parus caeruleus teneriffae group) is proposed to have colonised the Canary Islands from North Africa according to an east-to-west stepping stone model, and today, the species group is divided into four subspecies, differing in morphological, acoustic, and ecological characters. This colonisation hypothesis was tested and the population structure between and within the islands studied using mitochondrial DNA sequences of the non-coding and relatively fast evolving control region. Our results suggest that one of the central islands, Tenerife, was colonised first and the other islands from there. Three of the presently recognised four subspecies are monophyletic, exception being the subspecies teneriffae, which consists of two monophyletic groups, the one including birds of Tenerife and La Gomera and the other birds of Gran Canaria. The Gran Canarian birds are well differentiated from birds of the other islands and should be given a subspecies status. In addition, the teneriffae subspecies group is clearly distinct from the European caeruleus group, and therefore the blue tit assemblage should be divided into two species.     

Protein engineering towards natural product synthesis and diversification

A dazzling array of enzymes is used by nature in making structurally complex natural products. These enzymes constitute a molecular toolbox that may be used in the construction and fine-tuning of pharmaceutically active molecules. Aided by technological advancements in protein engineering, it is now possible to tailor the activities and specificities of these enzymes as biocatalysts in the production of both natural products and their unnatural derivatives. These efforts are crucial in drug discovery and development, where there is a continuous quest for more potent agents. Both rational and random evolution techniques have been utilized in engineering these enzymes. This review will highlight some examples from several large families of natural products.     

Fire as a threatening factor for endemic plants of the Canary Islands

The endemic flora of the Canary Islands is remarkable but highly vulnerable to environmental changes. Several factors, such as fire, could be threatening. The purpose of this study was to analyze various treatments in endemic threatened species which could have been growing in the understory of the Canary pine forest. We attempted to improve germination through dormancy breaking, and analyze the influence of fire on these plants. Seven physical and chemical treatments were tested: control, mechanical scarification, boiling water, dry heat (50 and 120?°C), smoke and smoked water. Mechanical scarification showed a positive response in germination percentage in two species characterized by hard seed coat, but out of all of the species tested, only one demonstrated a positive response to any of the treatments related to fire. At the temperatures registered on wildfires, neither the seeds situated on the aerial structure nor seeds in seed bank seem to be able to survive and germinate. The increasing incidence of fires through anthropogenic causes could contribute to the current threat status of these species and poorness of the Canary pine forest understory.     

Historical diversification of a terra-firme forest bird superspecies: a phylogeographic perspective on the role of different hypotheses of Amazonian diversification

Among those few hypotheses of Amazonian diversification amenable to falsification by phylogenetic and population genetics methods, three can be singled out because of their general application to vertebrates: the riverine barrier, the refuge, and the Miocene marine incursion hypotheses. I used phylogenetic and population genetics methods to reconstruct the diversification history of the upland (terra-firme) forest superspecies Xiphorhynchus spixii/elegans (Aves: Dendrocolaptidae) in Amazonia, and to evaluate predictions of the riverine barrier, refuge, and Miocene marine incursion hypotheses. Phylogeographic and population genetics analyses of the X. spixiilelegans superspecies indicated that the main prediction of the riverine barrier hypothesis (that sister lineages occur across major rivers) hold only for populations separated by "clear-water" rivers located on the Brazilian shield, in central and eastern Amazonia; in contrast, "white-water" rivers located in western Amazonia did not represent areas of primary divergence for populations of this superspecies. The main prediction derived from the refuge hypothesis (that populations of the X. spixii/elegans superspecies would show signs of past population bottlenecks and recent demographic expansions) was supported only for populations found in western Amazonia, where paleoecological data have failed to support past rainforest fragmentation and expansion of open vegetation types; conversely, populations from the eastern and central parts of Amazonia, where paleoecological data are consistent with an historical interplay between rainforest and open vegetation types, did not show population genetics attributes expected under the refuge hypothesis. Phylogeographic and population genetics data were consistent with the prediction made by the Miocene marine incursion hypothesis that populations of the X. spixii/elegans superspecies found on the Brazilian shield were older than populations from other parts of Amazonia. In contrast, the phylogeny obtained for lineages of this superspecies falsified the predicted monophyly of Brazilian shield populations, as postulated by the Miocene marine incursion hypothesis. In general, important predictions of both riverine barrier and Miocene marine incursion hypotheses were supported, indicating that they are not mutually exclusive; in fact, the data presented herein suggest that an interaction among geology, sea level changes, and hydrography created opportunities for cladogenesis in the X. spixii/elegans superspecies at different temporal and geographical scales.     

Colonization and speciation on volcanic islands: phylogeography of the flightless grasshopper genus Arminda (Orthoptera,Acrididae) on the Canary Islands

Abstract Volcanic archipelagos represent excellent areas to study colonization and speciation processes. The grasshopper genus Arminda is one of many endemic taxa of the Canary Islands. It consists of seven wingless species, most of which are single‐island endemics. We sequenced two mitochondrial (12s rRNA, ND5) and two nuclear gene fragments (28s rRNA, ITS2) to reconstruct the colonization pattern of the genus. Our results are in accordance with a stepping‐stone colonization model from east to west, corresponding to the prevailing ocean currents, but alternative hypotheses cannot be fully rejected. The populations of A. brunneri from Tenerife belong to two different lineages (east and west) consistent with the geological history of the island. It remains to be tested whether these lineages represent different species and whether further lineages exist on this island. The five clades of the four western islands (A. brunneri group) have approximately similar branch lengths. The short internodes between these lineages resulted in a poorer phylogenetic resolution. Specimens from La Palma were genetically distinct and are subsequently described as a new species, Arminda palmae sp.n. Our results suggest in situ speciation on Gran Canaria, which was accompanied by a stronger degree of morphological diversification than the inter‐island speciation processes. The aberrant species A. canariensis has formerly been assigned to a monotypic subgenus Chopardminda, which is now synonymized with Arminda syn.n. based on its phylogenetic position. Gran Canaria seems to be the only island where Arminda species occur sympatrically, although allopatric speciation seems likely due to the long history of volcanism and erosion on the island.     

Growth form diversity on the Canary Islands

An analysis is given of the growth form composition of the flora of the Canary Islands based on a checklist published by Hansen & Sunding (1985) and the authors' field studies. Results are compared with similar data available from Israel and California. Special attention is given to endemism, the Mediterranean-wides and introduced species, as well as to some special plant features such as succulence, spinescence and fleshy fruits. Long-distance dispersal is stressed as the mechanism by which the Canaries obtained their flora. The growth-form composition of the Canaries is discussed in the context of the prevailing present-day environmental conditions, not in the context of climatic conditions in geological time. Characteristic features are the low percentages of endemic and even of indigenous annuals, the high percentage of chamaephytes (many of whom are endemic), the strong development of arborescence, the richness in leaf succulents, and the paucity of spines.     

Lecanora sabinae, a new lichen species from the Canary Islands

Lecanora sabinae sp. nov. from the Canary Islands (El Hierro and La Gomera) is characterized chiefly by its greenish thallus with abundant pruinose apothecia ranging in colour from light yellow to almost black. It contains usnic acid, zeorin, and an unknown chemical product SAB-1, is by preference lignicolous and lives in association with the conifer Juniperus phoenicea.     

Deep-water macroalgae from the Canary Islands: new records and biogeographical relationships

Due to the geographical location and paleobiogeography of the Canary Islands, the seaweed flora contains macroalgae with different distributional patterns. In this contribution, the biogeographical relations of several new records of deep-water macroalgae recently collected around the Canarian archipelago are discussed. These areBryopsidella neglecta (Berthold) Rietema,Discosporangium mesarthrocarpum (Meneghini) Hauck,Hincksia onslowensis (Amsler et Kapraun) P. C. Silva,Syringoderma floridana Henry,Peyssonnelia harveyana J. Agardh,Cryptonemia seminervis (C. Agardh) J. Agardh,Botryocladia wynnei Ballantine,Gloiocladia blomquistii (Searles) R. E. Norris,Halichrysis peltata (W. R. Taylor) P. Huvé et H. Huvé,Leptofauchea brasiliensis Joly, andSarcodiotheca divaricata W. R. Taylor. These new records, especially those in the Florideophyceae, support the strong affinity of the Canary Islands seaweed flora with the warm-temperate Mediterranean-Atlantic region. Some species are recorded for the first time from the east coast of the Atlantic Ocean, enhancing the biogeographic relations of the Canarian marine flora with that of the western Atlantic regions.     

Hybrid constructed wetlands for wastewater treatment and reuse in the Canary Islands

The performance of two substrates commonly available in the zone, gravel and lapilli, was tested for their use in hybrid constructed wetland pilot plants for the treatment and reuse of urban wastewater in Gran Canaria, Canary Islands, Spain. The first stage of the systems was a vertical subsurface-flow constructed wetland and the second stage was a horizontal subsurface-flow constructed wetland. Parallel experiments were carried out with one system containing only crushed stone basaltic gravel as substrate and the other with only lapilli, a very porous volcanic sediment. The comparative effect of substrate type, hydraulic loading rate and planting was studied.Tracer studies indicated that the experimental TRHs were significantly lower than the theoretical ones, particularly for the vertical flow with gravel. Though the vertical flow with lapilli performed better than the one with gravel, the hybrids showed quite similar removals.Planting or varying the hydraulic loading rate introduced little differences between the vertical flows or the hybrids. Average removals for the gravel-based hybrid constructed wetland were 86% for BOD, 80% for COD, 88% for ammonia-N, 96% for SS and turbidity, 24% for phosphate-P, and 99.5% for faecal coliforms and 99.7% for faecal enterococci. Thus, it can be concluded that hybrid constructed wetlands proved to be robust configurations for wastewater treatment in the Canary Islands.     

New records of bryophytes from the Canary Islands

Abstract

Two members each of the Adelanthaceae and Schistochilaceae and three of the Porellaceae are recorded from Mulanje Mountain, of which Adelanthus lindenbergianus (Lehm.) Mitt., Porella abyssinica (Nees) Trev. var. hoehnelii (Steph.) Pócs, Porella capensis (Gott.) Mitt. and P. subdentata (Mitt.) Steph. are first records for Malawi.     

Tracking colonization and diversification of insect lineages on islands: mitochondrial DNA phylogeography of Tarphius canariensis (Coleoptera: Colydiidae) on the Canary Islands.

The genus Tarphius Erichson (Coleoptera: Colydiidae) is represented by 29 species on the Canary Islands. The majority are rare, single-island endemics intimately associated with the monteverde (laurel forest and fayal-brezal). The Tarphius canariensis complex is by far the most abundant and geographically wide-spread, occurring on Gran Canaria, Tenerife and La Palma. Eighty-seven individuals from the T. canariensis complex were sequenced for 444 bp of the mitochondrial DNA cytochrome oxidase I gene (COI), 597 bp of the COII gene and the intervening tRNA(leu) gene. A neighbour-joining analysis of maximum-likelihood distances put La Palma as a single monophyletic clade of haplotypes occurring within a larger clade comprising all Tenerife haplotypes. Gran Canarian haplotypes were also monophyletic occurring on a separate lineage. Using a combination of the phylogeographic pattern for T. canariensis, geological data, biogeography of the remaining species and estimated divergence times, we proposed a Tenerifean origin in the old Teno massif and independent colonizations from here to north-eastern Tenerife (Anaga), Gran Canaria and La Palma. New methods of estimating diversification rates using branching times were applied to each island fauna. All islands exhibited a gradually decreasing rate of genetic diversification similar to that seen for Brachyderes rugatus (Coleoptera: Curculionidae) from the Canary Islands.