Devonian floral assemblages and plant megafossils from the Iberian Peninsula: A review

This paper presents a review and critical analysis of the literature on Devonian floras of the Iberian Peninsula. Although the known outcrops of Devonian strata in the Iberian Peninsula are marine, in some cases, a few fragmentary remains of vascular plants are associated with faunal remains. Records include largely specimens from the Lower Devonian of Barrancos (Alentejo, Portugal) and the Upper Devonian of Sierra de Hornachos in Badajoz province, southwest Spain; the remainder consists of drifted plant fragments from scattered sites in the Iberian Peninsula ranging in age from Lochkovian to Upper Devonian-Earliest Carboniferous. The vegetation inferred for the Lower Devonian of the Iberian Peninsula is mainly based on palynological data and corresponds to herbaceous types characterised by bryophytes, rhyniophytes (Horneophyton, Cooksonia, Rhynia), trimerophytes (Psilophyton, Pertica and Hostinella), primitive lycophytes (Drepanophycus) and incertae sedis such as Nothia and Chaleuria, all flora that developed near the coast in low-lying and, at least periodically, wet areas. In the Middle Devonian, two vegetation strata can be recognised: herbaceous (Psilophyton) and semi-arboreal (Cladoxylales). Although three levels of vegetation in the Upper Devonian, have been described from outcrops worldwide, the scarce available data from the Iberian Peninsula only indicate an arborescent lycopsid vegetation and species with uncertain botanical affinity such as Sphenopteridium keilhauii Nathorst.     

Monitoring of marine benthic communities and taxonomic resolution: an approach through diverse habitats and substrates along the Southern Iberian coastline

Studies conducted along the southern Iberian coastline validate macrobenthic community analyses at taxonomic levels higher than that of species. Twelve studies on littoral benthic communities, carried out by the same research team, were selected spanning both a variety of sampling strategies (spatial, temporal, spatio-temporal) and substrate/habitat types (sediment, rock, algae). In order to establish differences between the results obtained at the taxonomic levels of species, family and order, similarities among stations were calculated using Spearman’s coefficient for ranges. A subset of three studies was selected to investigate possible differences in ‘best-explaining’ environmental variables with taxonomic level. The environmental variables selected at species level were the same as those found at levels of family and order. It is concluded that studies at the different levels of taxonomic resolution (species, family, order) lead to similar results both with regard to relative community distributions and the environmental variables associated with these. The importance of this result for monitoring similar benthic communities is discussed.     

Archaeobotanical remains of hulled and naked cereals in the Iberian Peninsula

Archaeobotanical finds in Spain show differences in the representation of the different wheats and barleys. From the beginning of agriculture (around 5000 B.C.) onwards, all wheats and barleys can be found at the sites of the eastern Peninsula. But in later periods of the early Neolithic, free-threshing wheat becomes more important in the northeast and the southeast, compared to the hulled wheats (emmer and einkorn). Nevertheless, both naked and hulled barleys can be found in similar frequencies in this period. Seed analyses in the southeast and the east of Spain show the importance of naked barley compared with hulled barley in the third millenium uncal B.C. This is not the case in the northeast, where hulled barley has a similar frequency in this period until the Iron Age, when both hulled barley and free-threshing wheat are the most important taxa. The substitution of naked barley for hulled barley in the south-east Iberian Peninsula is very significant in the period of greatest growth of the Argar culture. Free-threshing wheat can be found at a similar frequency throughout the study area, and was an important human food source together with the barleys. Hulled wheats seem to have played a secondary role as food in all periods, although they are constantly present in our samples. Nevertheless spelt wheat does not appear until the Roman period, when it is only found on the Cantabrian north coast, where it is important.     

The Cenozoic vegetation of the Iberian Peninsula: A synthesis

The aim of this work is to provide a first approach to the evolution of Iberia's vegetation during the Cenozoic (with the exclusion of the Quaternary). The Palaeogene was floristically defined by Palaeotropical elements forming tropical/subtropical rainforests, mangrove swamps, edaphically-mediated laurophyllous forests and leguminous-sclerophyllous communities. During the Miocene, Iberian landscapes were drastically modified due to geographic and climatic changes (mainly cooling and aridification) changes. Open, steppe-like environments developed towards the interior of the peninsula and Arctotertiary elements invaded mountainous and riparian ecosystems, coexisting with or becoming part of evergreen, broadleaved forests of Palaeotropical species. From the Late Miocene onwards these forests suffered changes due to the extinction of taxa, the impact of environmental change on the survivors, and the perturbations caused by the arrival of further Arctotertiary elements. However, several Palaeotropical taxa overcame the environmental and climatic changes of the Miocene and Pliocene to form a part of the modern flora of the Iberian Peninsula.     

Cladosporium airborne spore incidence in the environmental quality of the Iberian Peninsula

Cladosporium spores are ubiquitous in the air and are included in the fungal contaminants that define environmental quality. This paper provides an updated review of their concentration in the Iberian Peninsula, based on data from 12 sampling stations collected using a common non-viable volumetric sampling method and the same subsequent data-treatment techniques. The database comprised 84 annual periods, covering the period 1993–2009. Mean annual total spore concentrations for each station, calculated as the sum of daily concentrations, ranged from 54 459 in Cartagena to 933 485 in Sevilla; other sampling stations recorded annual total spores between 93 052 (Porto) and 579 953 (Mérida). Analysis of annual spore-distribution patterns revealed either one or two peaks (spring and fall) depending on the location and prevailing climate of the area where the sampling stations have been placed. For all stations, average temperature was the meteorological parameter displaying the strongest positive correlation with airborne spore concentrations.     

Genetic signatures of a Mediterranean influence in Iberian Peninsula sheep husbandry

Highly adaptable and versatile populations of domestic sheep, the result of millennia of intense husbandry, are found in almost every corner of the world. Here we describe a genetic survey of sheep from the western fringe of its European distribution. We studied the mitochondrial DNA control region sequences from 161 individuals belonging to 7 Portuguese sheep breeds. Our study revealed a high level of genetic diversity, with an average breed haplotype diversity of 0.983, substantially above that observed in central European breeds, as well as the presence of maternal lineages until now only found in the Middle East and Asia. A broad north-south pattern describes the most important trend in the Portuguese sheep population with a southern population clearly distinct from most other breeds. A recurrent influx of new genetic diversity, probably via the Mediterranean Sea, may explain these patterns and appears to corroborate the importance of this maritime route in the history of both mankind and livestock. Zooarchaeological studies of sheep bones from southern Portugal indicate a marked size increase during the Moslem period that may reflect an improvement of this animal--perhaps part of the well known "Arab agricultural revolution" in Andalusia. This could have been a time when the gene pool of Iberian sheep was substantially enriched and may help to explain the history of modern sheep breeds in this peninsula.     

The eco-sociological value of dispersal spectra of two plant communities

Summary A new system of dispersal units has been elaborated, based on weight and morphological features functional in dispersal. Weight was divided into eight classes and the functional morphological features were selected in such a way that their effectiveness could be tested by experiments.The spectra of weight and dispersal adaptations of dispersal units sampled in Euphorbio-Pinetum nigrae and Fumano-Stipetum habitats south of Vienna are calculated with this system and then compared.The results show that both communities can be characterized with such spectra. It is also possible with these spectra to make statements about the ecological and social position of the association in a succession.Nomenclature follows Ehrendorfer (1973).     

Seed rain into upland plant communities in Hong Kong, China

Hong Kong is an extreme example of tropical landscape degradation, with no substantial remnants of the original forest cover and a highly impoverished disperser fauna. Seed availability is a potential limiting factor in vegetation recovery in such landscapes. To assess the quantity and quality of the seed rain of woody taxa, seed traps were placed in the major upland vegetation types: fire-maintained grassland, shrubland, and secondary forest. Within the grassland site, traps were placed under isolated trees, isolated male and female shrubs of Eurya chinensis, and in the open. Seeds were collected every 2 weeks for 2 years. The seed rain was highest under female shrubs in grassland (6455 seeds m⁻² year⁻¹), where it was almost entirely confined to their fruiting period. Next highest were isolated trees (890 seeds), followed by male isolated shrubs (611 seeds), shrubland (558 seeds), forest (129 seeds) and open grassland (47 seeds). The number of seed taxa was highest in shrubland (59), followed by isolated trees (42), forest (42), female isolated shrubs (28), male isolated shrubs (15), and open grassland (9). The seed rain differed in species composition between the forest, shrubland, and grassland sites, while the differences within the grassland site were largely in terms of quantity. Birds (particularly bulbuls, Pycnonotus spp.) are known or inferred to be the major dispersal agents for 85% of the seed taxa trapped, 99% of the total number of seeds trapped, and 99.8% of the seeds trapped in the grassland site. Few taxa and of the total seeds were dispersed by wind and no seed taxa were definitely dispersed by fruit bats. The results suggest that even in the most degraded landscape the seed rain is adequate for the development of woody vegetation cover, but that human intervention will be needed for the restoration of plant diversity.     

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.     

Differences in the vegetation of the North Iberian Peninsula during the last 16,000 years

The dynamics of vegetation in the North Iberian Peninsula have been historically established from peaty and lacustrine records obtained in strongly continental mountainous areas. Pollen records located in areas with a more oceanic climate, have allowed a more precise evaluation of the changes and differences in the vegetation development of the various biogeographical areas in the North Iberian Peninsula, during the Late-glacial and Holocene. It was found that: (1) The vegetation of the Cantabrian–Atlantic province in northern Iberian Peninsula responded to climatic changes during the last 16000 years. (2) Tree vegetation declined during the Oldest Dryas, with steppe vegetation in the interior and cryophilous vegetation along the coast. (3) During the time of the Lateglacial Interestadial, lowlands, arboreal vegetation was dominant in the landscape (Pinus, Betula, Quercus, Corylus). (4) During the Younger Dryas the differences between coast and interior are less obvious. (5) During the Holocene oceanic decidious forests of Quercus robur, Corylus avellana, Tilia sp. and Fagus sylvatica were present along the coast. At low altitudes, in the interior, forests of Quercus robur / pyrenaica, enclaves of pine woods and Mediterranean types of forest (Quercus ilex, Olea europea) were present. At higher altitudes Pinus (P. sylvestris and P. uncinata) or mixed forests of Pinus and Betula were dominant.     

Quantity,quality and the effectiveness of seed dispersal by animals

Disperser effectiveness is the contribution a disperser makes to the future reproduction of a plant. Although it is a key notion in studies of seed dispersal by animals, we know little about what determines the effectiveness of a disperser. The role of the present paper is to review the available information and construct a hierarchical framework for viewing the components of disperser effectiveness.Effectiveness has both quantitative and qualitative components. The quantity of seed dispersal depends on (A) the number of visits made to the plant by a disperser and (B) the number of seeds dispersed per visit. The quality of seed dispersal depends on (A) the quality of treatment given a seed in the mouth and in the gut and (B) the quality of seed deposition as determined by the probability that a deposited seed will survive and become an adult. In this paper I review the ways disperser behavior, morphology and physiology can influence these major components of disperser effectiveness, and when data permit present preliminary analyses of relationships among components.     

Steppes, savannahs, forests and phytodiversity reservoirs during the Pleistocene in the Iberian Peninsula

A palaeobotanical analysis of the Pleistocene floras and vegetation in the Iberian Peninsula shows the existence of patched landscapes with Pinus woodlands, deciduous and mixed forests, parklands (savannah-like), shrublands, steppes and grasslands. Extinctions of Arctotertiary woody taxa are recorded during the Early and Middle Pleistocene, but glacial refugia facilitated the survival of a number of temperate, Mediterranean and Ibero-North African woody angiosperms. The responses of Iberian vegetation to climatic changes during the Pleistocene have been spatially and temporarily complex, including rapid changes of vegetation in parallel to orbital and suborbital variability, and situations of multi-centennial resilience or accommodation to climatic changes. Regional characteristics emerged as soon as for the Middle Pleistocene, if not earlier: Ericaceae in the Atlantic coast indicating wetter climate, thermo-mediterranean elements in the south as currently, and broad-leaf trees in the northeastern. Overall, steppe landscapes and open Pinus woodlands prevailed over many continental regions during the cold spells of the Late Pleistocene. The maintenance of a high phytodiversity during the glacials was linked to several refuge zones in the coastal shelves of the Mediterranean and intramountainous valleys. Northern Iberia, especially on coastal areas, was also patched with populations of tree species, and this is not only documented by palaeobotanical data (pollen and charcoal) but also postulated by phylogeographical models.     

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.     

Seed dispersal in Erythronium grandiflorum (Liliaceae)

Primary and secondary seed dispersal was investigated for the glacier lily Erythronium grandiflorum in the Colorado Rocky Mountains. These heavy seeds have no obvious adaptations for biotic or abiotic dispersal, but can be thrown short distances when the dehiscent fruits are shaken by wind. We used sticky traps to measure primary transport of seeds up to 1 m away from individual plants. A seed cafeteria experiment examined the role of ants and rodents in secondary seed transport. Primary dispersal by wind was positively skewed and median transport distances were influenced by variation in plant height. Secondary dispersal was negligible compared to Viola nuttallii, an elaiosome-bearing species. Thus, seed dispersal was highly restricted in E. grandiflorum, and a 1 m radius encompassed the modal section of the seed dispersal curve. The seed dispersal component of gene flow was quantified and combined with previous measurements of pollen flow to yield a more complete estimate of Wright's neighborhood size, N _e, for E. grandiflorum. The lack of a special seed dispersal mechanism in E. grandiflorum is discussed in terms of a source-sink model for seedling establishment with respect to distance from the parental plants.     

Seed dispersal in Erythronium dens-canis L. (Liliaceae): variation among habitats in a myrmecochorous plant

Erythronium dens-canis is a geophyte which produces a single flower each season. The fruits produce small seeds with relatively large elaiosomes. We performed experiments to investigate primary and secondary seed dispersal mechanisms of this species in different habitats in the western part of the Cantabrian Range in northwest Spain. Sticky traps were used to measure primary dispersal of seeds up to 0.5 m from mother plants. Seed cafeteria experiments were performed in different habitats to examine the role of ants and rodents in secondary seed transport and seed predation. Our results indicate that: (a) primary seed dispersal is positively skewed (99% of seeds fall within 20 cm of the mother plant) and seed dispersal distances vary significantly among plants; (b) secondary dispersal is exclusively by myrmecochory, although the proportion of seeds removed by ants differs significantly among habitats; (c) ant species composition and abundances vary among habitats; and (d) freshly dropped seeds are more likely to be removed than seeds that have begun to dry out. We conclude that secondary dispersal of seeds is greatly influenced by habitat but not by small-scale microhabitat. This revised version was published online in June 2006 with corrections to the Cover Date.     

Geographic variation among Iberian communities of the exotic halophyte Cotula coronopifolia

The exotic annual forb Cotula coronopifolia has locally invaded salt marsh communities naturally dominated by Spergularia marina along large parts of the Iberian coastline. While the floristic composition of C. coronopifolia dominated communities on the Atlantic coast of northern Portugal has already been described, this information was missing for the southern part of the country. We carried out a phytosociological study at 21 sites along the south-western and southern coast of mainland Portugal to determine the ecology and syntaxonomical status of these communities, and to compare them to the Atlantic ones. Plant communities co-dominated by C. coronopifolia and S. marina were generally found in the sub-halophilous inner part of salt marshes. They occupied gaps within taller perennial vegetation (Juncus maritimus formations), such as small pools temporarily inundated with brackish waters. Southern communities differed from the northern ones by the high abundance of Triglochin barrelieri and the absence of salt-intolerant species that are present in the Atlantic communities. This difference may result from the drier summer climate in southern regions, leading to intense water evaporation and thus, more saline conditions. We propose to classify the Mediterranean communities in a new association, the Cotulo coronopifoliae–Triglochinetum barrelieri. High abundance of Limonium diffusum further allowed the distinction of a new subassociation limonietosum diffusi for the southernmost part of Portugal. Results show that invasive exotic plants can form new phytosociological associations with a characteristic species composition, but that these community types, despite being dominated by the same invader, still show ecological and geographical differentiation.     

Miocene to Pliocene vegetation reconstruction and climate estimates in the Iberian Peninsula from pollen data

Pollen analysis of Miocene and Pliocene sediments from the Iberian Peninsula shows a progressive reduction in plant diversity through time caused by the disappearance of thermophilous and high-water requirement plants. In addition, an increase in warm-temperate (mesothermic), seasonal-adapted “Mediterranean” taxa, high-elevation conifers and herbs (mainly Artemisia) occurred during the Middle and Late Miocene and Pliocene. This has mainly been interpreted as a response of the vegetation to global and regional processes, including climate cooling related to the development of the East Antarctic Ice Sheet and then the onset of the Arctic Ice Sheet, uplift of regional mountains related to the Alpine uplift and the progressive movement of Eurasia towards northern latitudes as a result of the northwards subduction of Africa. The development of steppe-like vegetation in southern Iberia is ancient and probably started during the Oligocene. The onset of a contrasted seasonality in temperature during the Mid-Pliocene superimposed on the pre-existing seasonality in precipitation, the annual length of which increased southward. The Mediterranean climatic rhythm (summer drought) began about 3.4 Ma and caused the individualization of modern Mediterranean ecosystems. Quaternary-type Mediterranean climatic fluctuations started at 2.6 Ma (Gelasian) resulting in repeated steppe vs. forest alternations. A latitudinal climatic gradient between the southern and the northern parts of the Iberian Peninsula existed since the Middle Miocene.     

The effect of air temperature on the starting dates of theUlmus, Platanus andOlea pollen seasons in the SE Iberian Peninsula

A study is made of the effect of air temperature on the start of the pollen seasons of three tree species—Ulmus, Platanus andOlea—in the southeastern Iberian Peninsula. These initial results are based on an aerobiological analysis performed over a 4-year period in the city of Granada, Spain. Sampling was carried out with a Burkard spore trap. The main aim of the present study was to use regression analysis to identify the preseasonal date when these species start to accumulate heat in their floral buds, enabling models to be created that indicate the onset of the pollen season for these taxa. ForUlmus there was no significant correlation between the onset of pollination and the mean temperature during the preceding period, whereasPlatanus presented a significant correlation with mean temperature during the month of January, andOlea with mean temperature during the second fortnight in February and the month of March. ForUlmus, the start of the pollen season ranged between 30 January and 8 February; forPlatanus, between 13 and 17 March; and forOlea, between 20 April and 13 May. The accumulated temperature needed to induce the onset of flowering ranged between 121 and 256°C forUlmus, with values of 428–607°C and 656–881°C forPlatanus andOlea, respectively.     

Amphibians and reptiles from the Early Miocene of the Bardenas Reales of Navarre (Ebro Basin, Iberian Peninsula)

The Lower Miocene deposits of the Bardenas Reales of Navarre (NW Ebro Basin, northern Iberian Peninsula) have yielded a diverse vertebrate fauna, including remains of amphibians and reptiles. These remains occur in several localities in the Tudela Formation. The fossiliferous levels belong to the Biozones MN2b-3 (Biozones Z-A of the Ramblian, i.e., Late Aquitanian to Early Burdigalian in age). The amphibians and reptiles represent at least 13 out of 37 vertebrate species. Amphibians consist of a salamandrid urodele and two or three anurans. All the turtles are cryptodirans and consist of the chelydrid Chelydropsis apellanizi, the testudinids Ptychogaster (Temnoclemmys) bardenensis and Ptychogaster ronheimensis, and a Trionychinae indet. Squamates are represented by the anguid lizard Ophisaurus sp., a non-anguid lacertilian, an amphisbaenian, the erycine boid? Eryx sp., and indeterminate colubrids. Crocodilian remains are assigned to the basal alligatoroid Diplocynodon sp. The fossil associations of the Bardenas Reales of Navarre suggest that the vertebrates lived in the centre of an endoreic basin with stretches of water under intertropical to subtropical climatic conditions.