Abstract: Aim Marginal populations are frequently neglected in static views of vegetation types, particularly when defining conservation reserves. The biogeographical and evolutionary importance of a marginal and endangered population of Pinus canariensis is addressed in this study to ascertain the need for conservation action. Diversity loss between adults and offspring and patterns of seed dispersal and recruitment were examined to provide evidence of recent degradation of marginal P. canariensis pinewoods. The scientific basis for the provision of sound
conservation policies was investigted by elucidating the factors responsible for significant population structure.
Location An isolated low-density pinewood community confined to the Arguineguin ravine, in south Gran Canaria, Canary Islands.
Methods Two cohorts, of centenary trees (those older than 100 years) and young recruits, respectively, were found in a detailed inventory of the pine population in the Arguienguin ravine. Chloroplast and nuclear microsatellites were compared to assess the levels of genetic diversity between adults and recruits. Spatial genetic structure and parentage analysis based on highly polymorphic nuclear and chloroplast microsatellites were examined to test limitations in seed dispersal. The underlying environmental factors that led to a clustering effect in the population were tested using point pattern methodologies.
Results Centenary trees retain high levels of genetic diversity and effective population size, suggesting a wider extension of the pinewood forests in the past. A significant loss of genetic diversity was detected between adults and recruits. Pinus canariensis dispersal distances were among the longest ever reported for anemochorous species, suggesting that environmental factors account for recruit clustering. Cluster models showed that recruits tend to aggregate in dry streambeds, where soil and water accumulation favours establishment.
Main conclusions Boundary populations of P. canariensis are subjected to fragmentation and reduction in effective population size as a result of human impact. Marginal populations were denser in the past and currently require specific conservation efforts. A severe reduction in genetic diversity compromises the future of present populations. Streambeds appear to play a major role in recruit establishment, but data suggest the absence of limitations to seed dispersal.
Abstract: The evolution of Spanish landscapes through history is mainly a story of deforestation. Through time,
exploitation of natural resources increased to cope with the requirements of more and more complex
civilizations. In this work, a review of how the Spanish forests were influenced by human activities and their
changes is provided. Forests were cleared for mining, charcoal, shipbuilding and caulking. The most fertile
lands were converted into cultivation and more productive cultivars were introduced. Mobile livestock, in
particular sheep, became widespread, and with it the burning of wooded land to produce pastures. Woods
were privatized through a series of disentailments. All these factors have occurred during the history of
Spain, linked to profound changes in the landscape and vegetation. Not until the beginning of the 20th
century were real efforts devoted to invert the trend to deforestation inherited from the negative woodland
management of previous centuries.
Abstract: A major goal of avian ecological research is to determine how distribution and abundance of preferred resources available influence population dynamics and contribute to understand life-history characteristics. Food is widely considered the ultimate factor influencing these traits. We studied, with seed traps, the spatiotemporal variability of Pinus canariensis seed rain during 2007â2008, as a means to explain why a post-dispersal seed predator of conservation concern, the endemic blue chaffinch Fringilla teydea, can adjust its annual life cycle with this variation in an insular environment. Generalized linear mixed models and geostatistical tools were used. Results highlight that temperature and relative humidity are important predictors of seed release rates. Additionally, a high temporal variation was detected in seed abundance (i.e., peaks of massive seed release during the summer months, intermediate values in the autumn, and minimum release rates in winter and spring). Finally, withinstand
spatial variation in seed flux was surprisingly large with the most productive microsites receiving three to four
times more seeds than the least productive ones. Pine seeds showed a high protein value and a low germination rate.Based on these findings, we suggest that the fortunes of the blue chaffinch should be intimately related to spatiotemporal annual P. canariensis seed crops, temperature acting as a proximate cue, and food availability as the ultimate factor. For the endangered blue chaffinch population on Gran Canaria, we recommend, until more data are available, improving the seed supply during the winter season, either artificially (feeders) or naturally (planting Myrica faya shrubs).
Abstract: We investigated how richness and composition of vascular plant species in the understory of a mixed hardwood forest stand varied with respect to the abundance and composition of the overstory. The stand is in central Spain and represents the southernmost range of distribution of several tree and herbaceous species in Europe. Understory species were identified in 46 quadrats (0.25 m2) where variables litter depth and light availability were
measured. In addition, we estimated tree density, basal area, and percent basal area by tree species within 6-m radius areas around each plot. Species richness and composition were studied using path analysis and scale dependent geostatistical methods, respectively. We found that the relative abundance of certain trees species in the overstory was more important than total overstory abundance in explaining understory species richness. Richness decreased as soil litter depth increased, and soil litter increased as the relative proportion of Fagus sylvatica in the overstory increased, which accounted for a negative, indirect effect of Fagus sylvatica on richness. Regarding understory species composition, we found that some species distributed preferentially below certain tree species. For example, Melica uniflora was most frequent below Fagus sylvatica and Quercus petraea while the increasing proportion of Q. pyrenaica in the overstory favored the presence of Cruciata glabra, Arenaria montana, Prunus avium, Conopodium bourgaei, Holcus mollis, Stellariamedia and Galium aparine in the understory. Overall, these results emphasize the importance of individual tree species in controlling the assemblage and richness of understory species in mixed stands. We conclude that soil litter accumulation is one way through which overstory composition shapes the understory community.
Abstract: â Background and Aims Marginal populations of widely distributed species can be of high conservation interest
when they hold a significant or unique portion of the genetic diversity of the species. However, such genetic
information is frequently lacking. Here the relevance of genetic surveys to develop efficient conservation
strategies for such populations is illustrated using cork oak (Quercus suber) from Minorca (Balearic Islands,
Spain) as a case study. Cork oak is highly endangered on the island, where no more than 67 individuals live
in small, isolated stands in siliceous sites. As a consequence, it was recently granted protected status.
â Methods Two Bayesian clustering approaches were used to analyse the genetic structure of the Minorcan population,
on the basis of nuclear microsatellite data. The different groups within the island were also compared with
additional island and continental populations surrounding Minorca.
â Key Results Very high genetic diversity was found, with values comparable with those observed in continental
parts of the speciesâ range. Furthermore, the Minorcan oak stands were highly differentiated from one another and
were genetically related to different continental populations of France and Spain.
â Conclusions The high levels of genetic diversity and inter-stands differentiation make Minorcan cork oak
eligible for specific conservation efforts. The relationship of Minorcan stands to different continental populations
in France and Spain probably reflects multiple colonization events. However, discrepancy between chloroplast
DNA- and nuclear DNA-based groups does not support a simple scenario of recent introduction. Gene exchanges
between neighbouring cork oak stands and with holm oak have created specific and exceptional genetic combinations.
They also constitute a wide range of potential genetic resources for research on adaptation to new
environmental conditions. Conservation guidelines that take into account these findings are provided.
Abstract: Capsule Tree cover and seeds on the ground influence the occurrence of Blue Chaffinches during the
non-breeding period.
Aims To study the feeding habitat selection of the common Tenerife Blue Chaffinch race during the nonbreeding
period as a desperate measure to conserve the endangered Gran Canaria race, whose critical
area was burnt in the summer of 2007.
Methods Basic statistics were used to test for differences between occupied sites (n = 35) and available
representative sites (n = 35). Univariate classification tree models were applied to explore the relationship
between a single response variable (presenceâabsence) and multiple explanatory variables and the relative
importance of these. Pine seed availability was quantified on the trees (n = 70) and on the ground (n = 140;
1 Ã 1 m plots).
Results We found a non-random feeding habitat selection by Blue Chaffinches on Tenerife. During the
non-breeding period Blue Chaffinches selected those areas for feeding on pine seeds where the tree
cover was higher than 38% (mature areas with tall and thick trees with good crops). When the tree cover
was lower than 38%, the mean number of seeds on the ground influenced the presence of this finch
(> 0.05 seeds per m2).
Conclusions This study highlights that Blue Chaffinches primarily select sheltered sites for feeding
during the non-breeding period. The selection of less sheltered sites seems to be mediated by pine seed
availability. Therefore, in this endemic forest system, perceived predation risk, food abundance and
availability, and overall availability of safe foraging options are all possibly determining the winter
feeding habitat selection. We recommend selective cuts in high-density pine stands to recreate those
conditions that allow the pine trees to set seed and management aimed at creating a structure of
dispersed small-area compartments with mature trees that provide food and shelter. The installation of
artificial feeders seems to be a post-fire priority action for the conservation of the Gran Canaria
race.
Abstract: Leaf morphological variation was examined in recruits of two hybridising oaks in a small sympatric area from Central Spain. Nuclear microsatellites were used to identify hybrids and assess the parental lineage. By Bayesian clustering analysis, 5% of hybrids were found. Principal component analysis was used to reduce 15 morphometric variables to four components associated with leaf size, lobation/pubescence and overall shape of the leaf. The percentage of variance due to genetic factors was evaluated through nested analysis of variance. As much as 70% of variance component was due to the factor ââspeciesââ for lobation/pubescence, suggesting high adaptive value for these traits, possibly related to ecological constraints of the species. The genetic component of variance or leaf size and overall shape of the leaf was below 33%. Age and height of the recruits did not correlate with sunleaf morphology. Competition indexes and diameter of the recruits showed slight, although significant, correlations with leaf size and lobation/pubescence components, pointing to some trade-offs between competition for light and leaf morphology of Q. petraea and Q. pyrenaica recruits.
Abstract: Nuclear (AFLPs and ITSs) and chloroplast DNA markers (cpDNA) were analysed in Quercus suber L., Q. ilex
L. and Q. coccifera L. in order to detect vicariant patterns in the Western Mediterranean Basin populations.
Clustering methods, i.e., parsimony, minimum spanning network, UPGMA and PCO, were used to obtain
robust phylogenies. The Mantel test was used to check the geographic structure of the populations. Nuclear
markersâ based phylogenies showed high bootstrap values at basal nodes of clusters indicative of species.
Within species, Q. suber and Q. ilex showed three and two groups respectively with strong geographic structure
for cytoplasmic and nuclear markers. In contrast, Q. coccifera had overlapping cpDNA lineages and nuclear
markers did not show any group with strong geographic structure. Taxonomic assignation of the species was
well-supported by our data. Ongoing allopatric speciation was inferred for Q. suber and Q. ilex derived from
Pliocene vicariant events. Quercus coccifera showed a more homogeneous genetic pattern in the Western
Mediterranean.
Abstract: Aim A multiple glacial refugia hypothesis for Mediterranean plant species was tested with the evergreen Quercus complex (Quercus suber L., Quercus ilex L. and Quercus coccifera L.) from the Iberian Peninsula, using molecular and palaeobotanical data.
Location The Iberian Peninsula, which is an ecologically and physiographically complex area located on the western edge of the Mediterranean Basin.
Methods We sampled 1522 individuals from 164 populations of Q. suber, Q. ilex and Q. coccifera. A review of the recent literature on fossil pollen and charcoal records and a nested clade analysis on chloroplast DNA polymerase chain reaction-restriction fragment length polymorphism was carried out to infer demographic and historical processes.
Results The analysis indicates at least one glacial refugium for Q. suber in southwestern Iberia. Extensive introgression of Q. suber with Q. ilex indicates several potential refugia in eastern Iberia. Past fragmentation was followed by a restricted range flow/range expansion, suggesting multiple refugia for Q. ilexâQ. coccifera
elsewhere in central and northern Iberia and multiple areas of secondary contact. This finding is consistent with fossil records.
Main conclusions The predicted multiple refugia during glacial periods indicates the existence of secondary post-glaciation contact areas. These areas contained complex diversity patterns resulting mainly from range expansions followed by isolation by distance. To a lesser degree, traces of restricted and longdistance
dispersal were also found.
Abstract: Aim To analyse the role of the Balearic Islands as a refuge area for evergreen Quercus (cork oak: Quercus suber L., holm oak: Q. ilex L., kermes oak: Q. coccifera .), by using molecular, historical and palaeobotanical data.
Location The Western Mediterranean Basin (Balearic Islands, eastern Iberia, Provence, Sardinia, Corsica, Sicily, Malta, Italy, Northern Africa).
Methods We sampled 108 populations and used the PCR-RFLP technique with five universal cpDNA primers to define haplotypes in the sampled populations. Diversity, differentiation parameters and spatial analysis of the populations, using a spatial version of amova, were linked to the geological history of the Western Mediterranean Basin in order to explain the present spatial pattern of the evergreen Quercus populations in the Balearics.
Results Evergreen Quercus cpDNA shows a complex structure, with remnants of ancient diversity in the Balearics. Balearic populations of holm oak are related to Iberian populations, while for cork and kermes oaks, we found both Tyrrhenian and Iberian haplotypes.
Main conclusions The complex spatial patterns of cpDNA in Balearic evergreen Quercus appears explicable in terms of a combination of physical (vicariance and long distance dispersal) and biological (introgressive hybridization) factors. The Balearics constitute a glacial refuge area and a reservoir of genetic variation with
traces of ancient diversity from MessinianâPliocene stages.
Abstract: Chloroplast DNA variation was studied in three evergreen Quercus species (Q. suber L., Q. ilex L. and Q. coccifera L.) from the Western Mediterranean Basin using PCR-RFLP. We studied five primer pair/enzyme combinations, four of them previously used in other European Quercus, obtaining a large number of haplotypes (81) grouped in three main types (suber type, ilex-coccifera I type and ilex-coccifera II type). Such level of haplotype diversity is higher than previously reported for the genus. Remarkable differences in haplotype richness between species have been found. Q. ilex and Q. coccifera usually share the same haplotypes,
while a number of Q. suber populations possesses variants of the ilex-coccifera I type. This fact is interpreted as a result of genetic introgression between Q. suber and Q. ilex. Reproductive factors that could determine this exchange are discussed, as well as the influence of different species histories on the present structure of evergreen Quercus in the Western Mediterranean Basin.
Abstract: European aspen (Populus tremula L.) has been traditionally thought to establish new stands by vegetative propagation through root suckers produced by very few individuals (often only one). Morphological traits and isozyme patterns were studied in five small stands in northern Spain. Both isozyme and morphological approaches showed variation within andbetween stands. Estimated intrapopulational variation was higher than the expected, and clusters of individuals with the same isozyme multilocus patterns within each population have
been identified. In order to check to what extent morphological markers are affected by the genotypes or clones, comparisons between leaf parameters and isozyme patterns were performed by hierarchical ANOVA and tests of hypothesis were constructed from the components of variance. Leaf shape parameters show a good correlation with the isozyme multilocus patterns. On the other hand, leaf size parameters, were more influenced
by environmental factors. These traits may be useful as tools for the definition of in situ conservation units in endangered European aspen stands.
Abstract: Leaf morphology was assessed in nine mixed oak stands (Quercus petraea and Q. robur) located in eight European countries. Exhaustive sampling was used in an area of each stand where the two species coexisted in approximately equal proportions (about 170 trees/species/ stand). Fourteen leaf characters were assessed on each of 5 to10 leaves collected from the upper part of each tree. Three multivariate statistical techniques (CDA, canonical discriminant analysis; PCA, principal component analysis; MCA, multiple correspondence analysis) were used in two different ways: first on the total set of leaves over all stands (global analysis) and second, separately within each stand (local analysis). There was a general agreement of the results among the statistical methods used and between the analyses conducted (global and local). The first synthetic variable derived by each multivariate analysis exhibited a clear and sharp bimodal distribution, with overlapping in the central part.
The two modes were interpreted as the two species, and the overlapping region was interpreted as an area where the within-species variations were superimposed. There was no discontinuity in the distribution or no visible evidence of a third mode which would have indicated the existence of a third population composed of trees with intermediate morphologies. Based on petiole length and number of intercalary veins, an âeasy
to useâ discriminant function applicable to a major part of the natural distribution of the species was constructed. Validation on an independent set of trees provided a 98% rate of correct identification. The results were interpreted in the light of earlier reports about extensive hybridization occurring in mixed oak stands. Maternal effects on morphological characters, as well as a lower frequency or fitness of hybrids in comparison
with parent species could explain the maintenance of two modes, which might be composed of either pure species or pure species and introgressed forms.
