Isozyme studies in the genusCheirolophus (Asteraceae:Cardueae-Centaureinae) in the Iberian Peninsula, North Africa and the Canary Islands

The phylogenetic and phenetic analysis of 109 RAPD polymorphisms inS. nebrodensis, a perennial and self-incompatible endemic of four mountain ranges in Spain, andS. viscosus, a self-compatible annual widespread in Europe, as well asS. lividus, S. sylvaticus andS. vulgaris revealed a sister group relationship between the first two species. This result contrasts sharply with the earlier hypothesis based on isozyme variation thatS. viscosus originated from within a paraphyleticS. nebrodensis and that the two species represent a progenitor-derivative pair. After considering possible reasons for the sister group relationship found, including the possibility of rooting artefacts, it is concluded that neither the RAPD data nor the isozyme data allow to draw safe conclusions about the mode of speciation and therefore the relative age of the two species. As a consequence, the limited genetic variation ofS. viscosus in comparison toS. nebrodensis as revealed by both the RAPD and the isozyme data may reflect its population history, geographical distribution, reproductive ecology, or mode of dispersal just as well as its recent origin from a paraphyleticS. nebrodensis. The result of this study calls for a critical reexamination of other taxon pairs postulated to have a progenitor-derivative relationship on the basis of isozyme evidence.     

Cretaceous diversification of angiosperms in the western part of the Iberian Peninsula

The classic leaf fossil floras from the Cretaceous of the Lusitanian Basin, Portugal, which were first described more than one hundred years ago, have played an important role in the development of ideas on the early evolution of angiosperms. Insights into the nature of vegetational change in the Lusitanian Basin through the Cretaceous have also come from studies of fossil pollen and spores, but the discovery of a series of mesofossil floras containing well-preserved angiosperm reproductive structures has provided a new basis for understanding the systematic relationships and biology of angiosperms at several stratigraphic levels through the Cretaceous. In the earliest mesofossil floras from the Torres Vedras locality, which are of probable Late Barremian-Early Aptian age, angiosperms are surprisingly diverse with about 50 different taxa. In slightly later mesofossil floras, which are of probable Late Aptian-Early Albian age, the diversity of angiosperms is still more substantial with more than hundred different kinds of angiosperm reproductive structures recognized from the Famalicão locality alone. However, this early diversity is largely among angiosperm lineages that produced monoaperturate pollen (e.g., Chloranthaceae, Nymphaeales) and early diverging monocots (Alismatales). Eudicots are rare in these Early Cretaceous mesofossil floras, but already by the Late Cenomanian the vegetation of the western Iberian Peninsula is dominated by angiosperms belonging to various groups of core eudicots. The Normapolles complex is a particularly conspicuous element in both mesofossil floras and in palynological assemblages. In the Late Cretaceous mesofossil floras from Esgueira and Mira, which are of Campanian-Maastrichtian age, core eudicots are also floristically dominant and flowers show great organisational similarity to fossil flowers from other Late Cretaceous floras described from other localities in Asia, Europe and North America.     

Colonization and diversification: towards a phylogeographic synthesis for the Canary Islands

Recently, the Canary Islands have become a focus for studies of the colonization and the diversification of different organisms. Some authors have considered Canarian endemisms as relicts of Tertiary origin, but new molecular data suggest a general pattern of continental dispersion followed by in situ speciation. Recent phylogeographic studies are revealing variants of the simple stepping-stone colonization model that seems to hold for many Hawaiian groups. Many factors can generate deviations from such a pattern: the stochastic nature of colonization, competitive exclusion, phylogenetic constraints on adaptive evolution and extinction. An understanding of island colonization and diversification can best be developed from an ecosystem level synthesis as more data for the Canarian archipelago come to hand.     

The genus Dryopteris in the Canary Islands and Azores and the description of two new tetraploid species

From studies in the field, botanic garden and herbarium we concluded that the following four species of Dryopteris grow on the Canary Islands: D. aemula (n = 41) so far found only on Gomera; D. pseudomas (n = 82, apogamous) similarly recorded only for Gomera; D. oligodonta (n = 41) the most common representative of the genus in the Islands is possibly an old Canary endemic related to some African species; D. guanchica a new tetraploid species ( n = 82) hitherto confused with D. austriaca (D. dilatata). On four islands of the Azores the following were found: D. aemula (n = 41); D. azorica (n = 41); D. pseudomas (n = 82, apogamous); and D. crispifolia a new tetraploid species ( n = 82) which is very distinct when living but in the dried pressed state is difficult to differentiate from D. austriaca and D. guanchica.     

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.     

Colonization patterns and genetic structure of peripheral populations of the trumpeter finch (Bucanetes githagineus) from Northwest Africa, the Canary Islands and the Iberian Peninsula

Aim This paper has three aims: (1) to reconstruct the colonization history of two peripheral populations of the trumpeter finch (Bucanetes githagineus) presumably originating from the same source, one the result of an ancient expansion process and the other recently established and still expanding; (2) to estimate the importance of key events, such as past and current gene flow and bottlenecks, in both expansion processes and their contribution to the present population structure and genetic diversity; and (3) to find out whether two peripheral populations that established at widely differing times also differ in terms of genetic diversity. Location Northwest Africa (assumed source population), Canary Islands (long‐established peripheral) and south‐eastern Iberian Peninsula (recently established peripheral). Methods Bayesian analysis of population structure, individual assignment tests, F‐statistics, maximum likelihood migration estimates, genetic diversity indices and bottleneck tests were calculated with microsatellite data from 194 trumpeter finches from five breeding and two seasonal non‐breeding sites. Results Our data support the existence of two subpopulations (Canary Island and Ibero‐African) as the most likely population structure. Seasonal sites in the Iberian Peninsula had the highest percentage of birds assigned to other, mainly Iberian, sites. Pairwise F_ST values showed that the Canary Island localities were very similar to each other, but differed from the rest. Gene flow estimates within subpopulations were only slightly higher in the Canary Island population than in the Ibero‐African one. Gene diversity indices were similar at all localities. Canary Island sites show evidence of bottlenecks, whereas the Ibero‐African sites do not. Main conclusions Our data show that, at present, birds from the Canary Islands are genetically differentiated from those in North Africa and continental Spain. We could not unequivocally confirm the African origin of Canary populations because the contrary is also plausible. The Iberian Peninsula seems to have repeatedly received individuals from North Africa, which would have led to the relatively high genetic diversity found in these recently established localities and prevented bottlenecks. Movements of individuals towards sites outside their current range during the non‐breeding season are likely to precede the establishment of new breeding sites at the periphery of the distribution range.     

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.     

Anisian floras from the NE Iberian Peninsula and Balearic Islands: A synthesis

This paper focuses on the diversity and palaeontological significance of the Anisian floral record in the Triassic of the northeastern Iberian Peninsula. A summary of published information is followed by new records from macrofloral localities at Rodanas (Aragonese Branch of the Iberian Range) and at Maya del Baztán (Basque-Cantabrian Domain, Pyrenees). Both of these new localities also yielded three Anisian microfloral assemblages. These records provide new evidence of Anisian (basal Middle Triassic) floras in Spain. They are found to be somewhat similar to the classical flora of the Grès à Voltzia Formation (Upper Buntsandstein) of the northern Vosges in north-eastern France, of whose age has been shown to be early Anisian.     

Floral rewards in someScrophularia species (Scrophulariaceae) from the Iberian Peninsula and the Balearic Islands

The genusScrophularia in the Iberian Peninsula and Balearic Islands comprises two sections,Scrophularia andCanina G. Don. Analyses were carried out on flower production, flower duration and their sexual phases, pollen and nectar production together with observations on their pollinators. Nectar production is correlated with corolla size and pollen production with anther size. The taxa of sect.Scrophularia show greater nectar and pollen production than those of sect.Canina. Also, those of the first section produce more ovules per ovary than those of the second group, production being correlated with the ovary size.Some observations on floral and reproductive biology in some species ofScrophularia from the Iberian Peninsula and the Balearic Islands. I.     

Floristic changes in the Iberian Peninsula and Balearic Islands (south-west Europe) during the Cenozoic

Aim  The aim of this work was to identify the main changes in the flora and vegetation of the Iberian Peninsula over the Cenozoic Era, to record the disappearance of taxa associated with these changes and to determine the influence of climate and human activity on these events.
Location  The Iberian Peninsula and Balearic Islands.
Methods  A critical review was made of the palaeobotanical literature with the aims of detecting patterns of floristic change and extracting information on the disappearance of different taxa over the Cenozoic. These data are viewed alongside the most recent data for the climate of this period. A critical analysis is made of the role of Palaeotropical and Arctotertiary taxa in the forest communities of the Iberian Peninsula throughout the Cenozoic.
Results  Although the Eocene–Oligocene transition was a time when many taxa disappeared, the most outstanding events occurred between the end of the Oligocene and throughout the Miocene. Substantial floristic changes took place over this period, including the disappearance of 177 Palaeotropical taxa. This was probably related to acute cooling and aridification; no evidence exists that the Messinian Salinity Crisis had any important effect in the Iberian Peninsula. The last great disappearance of Palaeotropical taxa (36 in total) ended in the Middle–Late Piacenzian; Arctotertiary taxa were most affected during the Pleistocene. The Lower–Middle Pleistocene transition, best represented by marine isotopic stages (MIS) 36–34 and 20–18 and characterized by a change in glacial cyclicity, was the time of the last notable disappearance of taxa.
Main conclusions  This work provides the first chronogram of extinctions for the Iberian flora, and records the disappearance of 277 taxa during the Cenozoic. A clear relationship was detected between the main climatic events and the latest appearances of the different taxa.     

Sexual reproduction in someScrophularia species (Scrophulariaceae) from the Iberian Peninsula and the Balearic Islands

The reproductive biology of someScrophularia species in the Iberian Peninsula and Balearic Islands has been studied. Levels of fruit-set in bagged and unbagged inflorescences, the production of seeds/capsule, the effectiveness of seed-set following cross-pollination in the genus and the pollen/ovule ratios have been analyzed.Some observations on floral and reproductive biology in some species ofScrophularia from the Iberian Peninsula and Balearic Islands. II. For first part seeOrtega Olivencia & Devesa 1993.     

The genus <Emphasis Type="Italic">Artemisia</Emphasis>: distribution and phytochemistry in the Iberian Peninsula and the Canary and Balearic Islands

This review summarizes the species distribution of the genus Artemisia in the Iberian Peninsula and the Canarian and Balearic Archipelagos, describing their conservation status according to the European and the Spanish Red List. Furthermore, this review covers recent studies on the phytochemical composition of species from the genus Artemisia distributed in the targeted geographical area, their biological effects if described, and points out the need of further research in the phytochemistry and activity of some Iberain species.     

Laurel forests in Tenerife, Canary Islands

The general wood structure, vessel size and distribution along the stem xylem radius and in petioles were studied in Laurus azorica trees living in a Tenerife laurel forest. The fractions of volume occupied by dry matter, water and air in percentage of wood fresh volume were also studied. The wood showed a diffuse-porous structure, with solitary vessels or vessels somewhat clustered in small radially oriented groups. Vessels had a diameter ranging from 20 to 130 µm. This diameter was minimal close to the pith, increased more than 2-fold with age, and reached its maximum width close to the cambium. Vessel density decreased from 36 vessels mm^-2 near the pith to about 13 vessels mm^-2 near the cambium. Accordingly, the lumen area was small in young xylem close to the pith (0.0015 mm²), reaching a value 5 times larger (0.007 mm²) near the cambium than in the centre of the stem. Lumen area of vessels in petioles was about 1.5% of petiole cross-sectional area and thus much lower than in stems. Mean hydraulic diameter of these vessels was about 20 µm, and mean vessel density about 136 per petiole. There were only small differences in proportions of dry matter, water and air along stem radius. The relevance of each one of these fractions in the wood is discussed as evidence of the possible existence of a number of embolized vessels dispersed in the total functional cross-sectional area of the xylem.     

Laurel forests in Tenerife, Canary Islands

The efficiency of the conductive system in about 40-year-old Laurus azorica trees growing in a laurel forest was evaluated by comparing main stems and leaves (petioles) on the basis of theoretical sap flow values (1) calculated from vessel anatomy (taking vessels as ideal capillaries), (2) derived from measured dye velocity and (3) data taken from direct sap flow measurements. It was found that actual sap flow rate per wood area increases in stems from the pith towards the cambium. The outermost part of the stem is the most important part of the tree for conducting water. Maximum actually measured transpiration (sap flow rate) for the stand was practically identical to the theoretical rate calculated based on petiole anatomy, but it was about 45 times lower than that calculated based on stem anatomy. This illustrates the safety features of stem wood, which due to its high vessel density, is capable of transporting all the water required even when only a small area of its vessels is working. In the petioles, xylem is more efficiently used, but almost all vessels must work in order to supply water to leaves and any disturbance may cause leaf loss.     

Laurel forests in Tenerife,Canary Islands

 Stand structure and leaf area distribution of a laurel forest in the Agua García mountains of Tenerife are described. The site is situated at 820 m a.s.l., faces NNE, and has a humid mediterranean climate. Summer droughts are mitigated by relatively high air humidity and clouds. The natural mixed hardwood forest is composed of six major tree species: Laurus azorica (Seub.) Franco, Persea indica (L.) Spreng, Myrica faya Ait., Erica arborea L. and two species of Ilex (I. platyphylla Webb & Berth. and I. canariensis Poivet.). The experimental stand had a density of 1693 trees ha^– 1, a basal area of 33.7 m²ha^– 1, and a cumulated volume of above-ground parts of trees of 231 m³ ha^– 1 with a corresponding dry mass of 204 ton ha^– 1. Diameters at breast height ranged from 6 to 46 cm. Mean concentration of plant dry mass per volume was 1.17 kg m^– 3. The vertical pattern of leaf area distribution in individual trees for all tree species was characterized by a Gaussian-like curve. Stand leaf area index was 7.8. These evergreen, broad-leaved (laurisilva or lucidophyllous) forests represent a relic forest that was widespread in the Mediterranean region some 20 million years ago. Our data illustrate some of the structural characteristics of this historically widespread forest type. Received: 2 December 1994 / Accepted: 6 November 1995     

Spatial and environmental determinants of vascular plant species richness distribution in the Iberian Peninsula and Balearic Islands

Using an exhaustive data compilation, Iberian vascular plant species richness in 50 times 50 UTM grid cells was regressed against 24 explanatory variables (spatial, geographical, topographical, geological, climatic, land use and environmental diversity variables) using Generalized Linear Models and partial regression analysis in order to ascertain the relative contribution of primary, heterogeneous and spatially structured variables. The species richness variation accounted for by these variables is reasonably high (65% of total deviance). Little less than half of this variation is accounted for spatially structured variables. A purely spatial component of variation is hardly significant. The most significant variables are those related to altitude, and particularly maximum altitude, whose cubic response reflects the occurrence of the maximum number of species at the highest altitudes. This result highlighted the importance of Iberian mountains as hotspots of diversity and the relevance of large and small scale historical factors in contemporary plant distribution patterns. Climatic or energy-related variables contributed little, whereas geological (calcareous and acid rocks) and, to a lesser extent, environmental heterogeneity variables (land use diversity and altitude range) seem to be more important.     

Cranial variation in the Iberian Peninsula and the Balearic Islands: Inferences about the history of the population

A multivariate analysis of four prehistoric and nine historic populations from the Iberian Peninsula and Balearic Islands with large sample sizes (n > 30 individuals for the neurocranium and n > 15 for the facial skeleton) is presented, considering 874 male and 557 female skulls and using 20 craniometric measurements. Cluster analyses have been undertaken using the squared Euclidean distance as a measure of proximity and the average linkage between groups (UPGMA), and neighbor-joining algorithms as a branching method, and a bootstrap analysis was used to assess the robustness of the clustering topology. The study was complemented with a principal coordinate analysis and with the application of the Mantel test to measure the degree of correspondence between the information furnished by the female and the male samples. The analyses show that the main source of morphometric variability in the Iberian Peninsula is the Basque population. The second source of variation is provided by two populations (Muslims and Jews), different from the rest from an archaeological and cultural point of view, and can probably be attributed to influences from sub-Saharan Africa. The massive deportations of the Jews in 1492 and of the Moors between the 15th and 17th centuries may have erased this source of variability from the present population of the Iberian Peninsula. The remaining studied populations, including samples from Castile, Cantabria, Andalusia, Catalonia and Balearic Islands, are grouped together, showing a notable morphological homogeneity, despite their temporal and geographic heterogeneity. These results are in general agreement with those obtained in synthetic maps, by analyzing multiple genetic markers. In such studies, the Basque population is described as the main source of genetic variability, not only in the Iberian Peninsula, but also in Western Europe. © 1996 Wiley-Liss, Inc.