Extinction of the autochthonous small mammals of Mallorca (Gymnesic Islands, Western Mediterranean) and its ecological consequences

Aim To investigate the chronology, causes and consequences of the extinction of the autochthonous Pleistocene small mammals of Mallorca. Location Mallorca (Gymnesic Islands, Balearics, Western Mediterranean). Methods We have obtained the first direct ¹⁴C ages from the bone collagen of selected samples of two extinct endemic small mammals from Mallorca: the Balearic dormouse, Eliomys morpheus (Rodentia: Myoxidae) and the Balearic shrew, Asoriculus hidalgoi (Soricomorpha: Soricidae). We also present evidence for the absence of both endemics from the earliest Mallorcan archaeological sites and for the introduction of the garden dormouse, Eliomys quercinus, and the wood mouse, Apodemus sylvaticus. Combined information from direct dating of bone collagen of E. quercinus and A. sylvaticus and from cultural associations provides an adequate framework to establish the chronology of the faunal change and to compare it with the chronological information available on climatic change and the first arrival of humans on the islands. Results The chronological record includes the latest evidence available for the survival of endemic species and the earliest introduction of small mammals into Mallorca. We present ‘uncertainty periods for extinction’ (UPEs) of both endemic mammals based on the chronology of their last occurrence and on the inferred timing of their extinction (restricted UPEs). Main conclusions Possible causes for the extinction of autochthonous small mammals on Mallorca are discussed. Once we have discarded climatic causes, predation by invasive species, competition with newcomers and habitat deterioration, the introduction of diseases emerges as the most reasonable explanation for these extinctions. Based on the identification of changes in keystone species in Mallorcan ecosystems, we propose a tentative schedule of key ecological changes that have taken place over the past 5 millennia.     

Molecular dating of caprines using ancient DNA sequences of <Emphasis Type="Italic">Myotragus balearicus</Emphasis>, an extinct endemic Balearic mammal

Background  

Myotragus balearicus was an endemic bovid from the Balearic Islands (Western Mediterranean) that became extinct around 6,000-4,000 years ago. The Myotragus evolutionary lineage became isolated in the islands most probably at the end of the Messinian crisis, when the desiccation of the Mediterranean ended, in a geological date established at 5.35 Mya. Thus, the sequences of Myotragus could be very valuable for calibrating the mammalian mitochondrial DNA clock and, in particular, the tree of the Caprinae subfamily, to which Myotragus belongs.     

Indications for a dietary change in the extinct Bovid genus Myotragus (Plio-Holocene,Mallorca, Spain)

Evolution in isolated island has shaped a variety of endemic taxa with outstanding characteristics. Amongst them is the extinct bovid genus Myotragus, endemic to Mallorca and Menorca Island, for which six succeeding species have been described: M. palomboi, M. pepgonellae, M. antiquus, M. kopperi, M. batei and M. balearicus. Myotragus has developed special cranial and post-cranial adaptations to meet the specific ecological demands of its insular habitat, like progressive dwarfing and fused limb elements. During its evolution, the dentition of Myotragus underwent subsequent changes: firstly a reduction in the number of teeth, and secondly an increase in hypsodonty. The ecological conditions inducing this dental evolution, especially Myotragus’ diet, remain unknown. In this study, methods of 3D-dental topometry, enamel surface texture analysis according to ISO/FDIS 25178-2, and Scale-Sensitive Fractal Analysis (SSFA) are applied in order to infer palaeodiets of M. pepgonellae, M. kopperi, M. batei and M. balearicus, and to test the hypothesis that a dietary change may have occurred in the Myotragus lineage which relates to gradual morphological changes on upper second molars. We detect changes in the enamel/dentin ratio, enamel ridge length and enamel surface area within the lineage. Furthermore, Myotragus balearicus has enamel surface texture characteristics also present in extant browsing ungulates, while the three antecedent Myotragus species show an enamel surface texture signal similar to extant grazers. These results suggest a dietary change and are interpreted as a successive adaptation to limited resources in an isolated, insular environment. They can either be a consequence of a change in plant community structure or a successive expansion of Myotragus’ dietary range due to increased intraspecific competition.     

The endemic bovids from Sardinia and the Balearic Islands: State of the art

Bovids are not so common in endemic insular faunas and are mainly recorded in Southeast Asia, Japan and some Mediterranean islands. In the Western Mediterranean, endemic bovids have been recorded during the late Miocene in the Tusco-Sardinian palaeobioprovince (Baccinello-Cinigiano basin, South Tuscany, and Fiume Santo, north-western Sardinia). In the latest Neogene and Quaternary, bovids showing highly endemic features were restricted to the Balearic Islands and Sardinia, while Bovini only slightly reduced in size were present on Pianosa, Malta and Sicily. On Sardinia, the richest bovid sample comes from Monte Tuttavista (Orosei), where at least three species have been identified: Asoletragus genthry, Nesogoral aff. N. melonii, and Nesogoral sp. 2. On Mallorca (Balearic Islands) six chronospecies belonging to the Myotragus endemic phylogenetic lineage have been described, spreading in age from the Early Pliocene to the Holocene. For decades, a close phylogenetic relationship between Nesogoral and Myotragus has been widely accepted by scholars. Morphological and biometrical differences shown by Balearic and Sardinian bovids have generally been regarded as the result of the evolution into two different island ecological systems, characterized by different inter and intra-guild selection pressures. Indeed, the more diversified environment of Sardinia, as well as the presence of other large mammals (similar-sized competitors belonging to the same guild and a running predator), increased the interspecific competition, forcing Sardinian bovids to exploit different resources and to occupy different niches, while Myotragus exploited under a monopoly regime the supply of resources available for large herbivores on the Eastern Balearic Islands. Nonetheless, new data suggest that Nesogoral and Myotragus possibly originated from different taxa.     

First evidence of faunal succession in terrestrial vertebrates of the Plio-Pleistocene of the Balearic Islands,western Mediterranean

Terrestrial vertebrates from the karst filling in Cap d’Artrutx, situated in the extreme Southwest of Menorca (Balearic Islands, western Mediterranean) have yielded interesting information on the migration and extinction dynamics in the terrestrial island vertebrate faunas in Mallorca and Menorca between the late Pliocene and early Pleistocene. In this site, remains of the Menorcan giant tortoise (“Testudo” gymnesica Bate, 1914) and two mammals (Nesiotites sp. and Hypnomys sp.) have been found. The remains of the Menorcan giant tortoise represent the youngest record of this species and of the so-called second faunistic group of the island. The morphology and size of Nesiotites sp. are comparable to those of Nesiotites aff. ponsi Reumer, 1979 from the Plio-Pleistocene of Pedrera de S’Ònix (Mallorca) and Nesiotites meloussae Pons and Moyà, 1980 (= Nesiotites aff. ponsi sensu Pons-Monjo et al., 2012) from the lower Pleistocene of Binigaus (Menorca). Hypnomys sp. can belong to an archaic species not yet described. They represent the first evidence of the entrance of the third faunistic group, which originally evolved on the neighbouring island of Mallorca. This association is interpreted, therefore, as the first evidence of a faunal succession in the Plio-Pleistocene in the Balearic Islands.     

Influence of phenological barriers and habitat differentiation on the population genetic structure of the balearic endemic Rhamnus ludovici-salvatoris Chodat and R. alaternus L.

Rhamnus ludovici-salvatoris, endemic to the Gymnesian Islands, coexists with the related and widespread R. alaternus in Mallorca and Menorca. In both species, the population genetic structure using RAPD, and flowering during a 3-year period to check for possible phenological barriers, were analyzed. Rhamnus ludovici-salvatoris showed lower genetic diversity and stronger population structure than R. alaternus, the Cabrera population being less diverse and the most differentiated. Rhamnus ludovici-salvatoris flowered one month later, although flowering of both species coincided sporadically. These congeners seem to have diverged through isolation by time and differentiation in habitat. The population genetic structure of R. ludovici-salvatoris could mainly be due to the existence of small populations on the one hand, and a gene flow caused by rare hybridization events on the other, which may also explain the presence of morphologically intermediate individuals in Menorca. The conservation of R. ludovici-salvatoris populations may include population reinforcements and other in situ interventions.     

Vue d'ensemble de la végétation des Îles Baléares

Résumé La végétation des îles Baléares est nettement méditerranéenne. Les climax forestiers appartiennent à l'alliance méditerranéenne septentrionale du Quercion ilicis (parties pluvieuses de Majorque et de Minorque) et à l'alliance méditerranéenne méridionale de l'Oleo-Ceratonion (Querco-Lentiscetum d'affinité ibérique à Ivice; groupement àCeratonia siliqua etCneorum tricoccum dans la partie sèche de Majorque, groupement àOlea europaea etPrasium majus dans la partie la plus sèche de Minorque). Des groupements riches en endémiques caractérisent le karst des hauts sommets de Majorque et les rochers littoraux des côtes venteuses de Majorque et de Minorque. L'influence tyrrhénienne, importante dans les Gymnésies (Majorque et Minorque) est bien plus faible dans le groupe des Pithyuses (Ivice et Formentera), plus rapproché de la Péninsule Ibérique.

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Summary The vegetation of the Balearic Islands is pure mediterranean. The climax forests belong to the northern mediterranean alliance of the Quercion ilicis (rainy regions in Majorca and Menorca) and to the southern mediterranean community of the Oleo-Ceratonion (Querco-Lentiscetum with Iberic affinity in Ibiza; community withCeratonia siliqua andCneorum tricoccum in the dry region in Majorca, community withOlea europaea andPrasium majus in the driest region in Menorca). Communities rich in endemic plants characterize the karst of the high summits in Majorca, and coastrocks of the windy shores in Majorca and Menorca. The tyrrhenic influence, important in the Gymnesies (Majorca and Menorca), is more feeble in the group of the Pithyuses (Ibiza and Formentera), nearer to the Iberic Peninsula.

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Zusammenfassung Die Vegetation der Balearischen Inseln ist rein mediterran. Die Klimaxwälder gehören zu dem nördlichen Mittelmeerverband des Quercion ilicis (regnerische Gegenden von Mallorca und Menorca) und dem südlichen Mittelmeerverband des Oleo-Ceratonion (Querco-Lentiscetum mit iberischer Verwandtschaft auf Ibiza; Gesellschaft mitCeratonia siliqua undCneorum tricoccum in der trockenen Gegend von Mallorca, Gesellschaft mitOlea europaea undPrasium majus in der trockensten Gegend von Menorca). Endemitenreiche Pflanzengesellschaften charakterisieren den Karst der hohen Gipfel von Mallorca, und die Küstenfelsen der windreichen Küsten Mallorcas und Menorcas. Der tyrrhenische Einfluß, bedeutend in den Gymnesien (Mallorca und Menorca), ist entschieden schwächer in der Gruppe der Pithyusen (Ibiza und Formentera), die der Iberischen Halbinsel näher liegt.

     

Population genetic study in the Balearic endemic plant species Digitalis minor (Scrophulariaceae) using RAPD markers

Digitalis minor (Scrophulariaceae) is a cardenolide-producing plant endemic to the eastern Balearic Islands (Mallorca, Menorca, and Cabrera) that occurs in two morphologically distinct varieties: D. minor var. minor (pubescent) and D. minor var. palaui (glabrous). Levels and patterns of genetic diversity in 162 individuals from 17 D. minor populations across the entire geographic range were assessed using random amplified polymorphic DNA (RAPD) markers. Comigrating RAPD fragments tested were found to be homologous by Southern hybridization in both var. minor and var. palaui. To avoid bias in parameter estimation, analyses of population genetic structure were restricted to those RAPD bands that fulfilled the 3/N criterion (observed frequencies were less than 1 - [3/N] in each population) either among or within each island. Analyses of molecular variance (AMOVAs) with distances among individuals corrected for the dominant nature of RAPD (genotypic analysis) showed low values (1.57-17.55%) of between-population variability, indicating a relatively restricted population differentiation as expected for an outcrossing species such as D. minor. Nested AMOVAs demonstrated, however, a not significant partitioning of genetic diversity among Mallorca, Menorca, and Cabrera islands. Estimates of the Wright, Weir, and Cockerham and the Lynch and Milligan F(ST) from null allele frequencies corroborated AMOVA partitioning and provided evidence for population differentiation in D. minor. Our RAPD data did not show significant differences between pubescent and glabrous populations of D. minor, suggesting a failure to find a correlation between the RAPD loci and this morphological trait.     

Radiocarbon evidence for a prehistoric deliberate translocation: the weasel (Mustela nivalis) of Mallorca

We present radiocarbon evidence for the presence of the weasel (Mustela nivalis) on Mallorca prior to the Roman colonization of the Balearics. Bone collagen from a single specimen recovered at Cova del Ninot, Mallorca rendered two radiocarbon ages, independently obtained at two laboratories (2σ interval: 386–206 cal BC). These dates indicate that the translocation of the weasel to Mallorca occurred in Late Prehistory. The inhabitants of Mallorca at that time were the Talaiotic people (Iron Age settlers of the Balearics). The weasel appears to have been introduced by Talaiotic mercenaries returning to the island on Carthaginian ships. This is the first documented case of the translocation of a wild carnivorous mammal to the Gymnesic Islands (i.e., Mallorca and Menorca) in prehistoric times. Some ecological consequences of this invasion are outlined.     

The reproductive biology of the Mediterranean endemic Cyclamen balearicum Willk. (Primulaceae)

Knowledge of the reproductive biology of endemic plants improves our understanding of how mating system may be related to patterns of species abundance and provides a basis for the development of rational conservation programmes. In this paper we present natural population data on the floral biology and reproductive ecology of the endemic Mediterranean species Cyclamen balearicum Willk. This is a long-lived, diploid perennial herb which occurs in southern France in five fragmented and isolated regions and on the Balearic Islands of Mallorca, Menorca, Ibiza, Cabrera and Draponera. Our observations indicate a particularly scarce pollinator activity (rare syrphid visits) and dispersal by ants over small distances. A controlled pollination experiment in a natural population showed that in southern France C. balearicum is fully self-compatible and that selfing is autonomous and probably delayed (i.e. following opportunities for outcrossing). The proximity of stigmas and anthers will favour autonomous selfing. The high pollen/ovule ratio indicates nevertheless that C. balearicum has a mixed mating system. Patterns of variation in stigma-anther separation and pollen production per flower suggest that not only has the current mating system of the species evolved from an outcrossing ancestor but that due to the fragmentation and isolation of populations greater levels of selfing have evolved in southern France (and to an intermediate degree on Ibiza and Menorca). On the island of Mallorca where larger continuous belts of C. balearicum habitat still exist the species has floral traits indicating a more outcrossed mating system. To our knowledge this is the first paper to document such trends in floral traits in the endemic component of the Mediterranean flora.     

New data on the origin of Nesiotites (Soricidae,Mammalia) in Menorca (Balearic Islands,Spain)

The presence of the shrew Nesiotites in Menorca is not yet adequately explained. Some authors consider that its ancestor arrived during the Messinian Salinity Crisis, as happened in Mallorca. Other authors consider that fossil populations in Menorca are the result of a later migration from Mallorca. In this work, several biometrical and morphological characters of abundant fossil populations from both islands have been studied. The results indicate that Early Pleistocene populations in Mallorca and Menorca are rather indistinguishable. Therefore, an early post-Messinian (Pliocene) isolation of Nesiotites in both islands is quite unlikely.     

Foundations for conservation of intraspecific genetic diversity revealed by analysis of phylogeographical structure in the endangered endemic lizard Podarcis lilfordi

Aim  To describe and analyse phylogeographical patterns in the endangered endemic lizard Podarcis lilfordi from across its remaining range and thereby establish baseline information on genetic diversity that will help determine conservation priorities and assist future reintroduction programs.
Location  Balearic Islands, Spain.
Methods  We analysed mitochondrial DNA (2382 bp sequence from eight genes) from 118 individuals and characterized the relationships among haplotypes using parsimony networks, as well as phylogenetic inference. Analyses of historical gene flow and population growth were used to provide further insights into population histories.
Results  Four unconnected parsimony networks were obtained that mirrored the main clades in the phylogenetic tree: (I) all Menorcan populations, (II) Dragonera, Malgrats and Toro islands (Western Mallorca) (III and IV) and the remaining populations from Cabrera and Mallorca. Two major haplotype groups were detected in Menorca (I) and these provided signatures of a demographic expansion and asymmetrical historical gene flow, respectively, concordant with the expected direction of colonization from south to north of the island. Populations from western Mallorca (II) showed evidence of historical allopatric fragmentation events following isolation around the start of the Pleistocene. In networks III and IV, Cabreran populations appear to have become isolated from north and south Mallorca quite recently, with asymmetric gene flow indicating a northwards dispersal direction.
Main conclusions  P. lilfordi is a genetically diverse species that shows substantial mtDNA structuring both between regions and, at a finer scale, between some islet populations within regions. The precarious state of some islet populations shown here to be quite divergent (e.g. Toro island in western Mallorca) means that conservation of this intraspecific biodiversity requires urgent action.     

Historical influence of predation pressure on escape by Podarcis lizards in the Balearic Islands

Island tameness (reduced escape behaviour on islands where prey have experienced prolonged relaxation of predation pressure) is known in several taxa, although the relationships between recent predation pressure and escape on islands are poorly known. We investigated escape by numerous populations exposed to differing predation pressure of two sister species of Podarcis lizards in the Balearic Islands. Our main findings are that flight initiation distance was greater in Podarcis pityusensis than Podarcis lilfordi and increased as predation pressure increased in P. pityusensis. Island tameness led to extinction of P. lilfordi on Menorca and Mallorca following anthropogenic introduction of predators; this species is extant only on nearby islets. The lack of relationship between recent predation pressure and flight initiation distance in P. lilfordi indicates that the historically acquired deficit in the ability to adjust escape behaviour to predation pressure still exists. Podarcis pityusensis, which was exposed to greater natural predation pressure before human introduction of predators, survives on Ibiza and Formentera, as well as on islets. Retention of the ability to respond to predation pressure is consistent with our finding that flight initiation distance increases as predation pressure increases among current populations. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, ?? , ??–??.     

Paleogenomics in a Temperate Environment: Shotgun Sequencing from an Extinct Mediterranean Caprine

Background

Numerous endemic mammals, including dwarf elephants, goats, hippos and deers, evolved in isolation in the Mediterranean islands during the Pliocene and Pleistocene. Most of them subsequently became extinct during the Holocene. Recently developed high-throughput sequencing technologies could provide a unique tool for retrieving genomic data from these extinct species, making it possible to study their evolutionary history and the genetic bases underlying their particular, sometimes unique, adaptations.

Methodology/Principals Findings

A DNA extraction of a ∼6,000 year-old bone sample from an extinct caprine (Myotragus balearicus) from the Balearic Islands in the Western Mediterranean, has been subjected to shotgun sequencing with the GS FLX 454 platform. Only 0.27% of the resulting sequences, identified from alignments with the cow genome and comprising 15,832 nucleotides, with an average length of 60 nucleotides, proved to be endogenous.

Conclusions

A phylogenetic tree generated with Myotragus sequences and those from other artiodactyls displays an identical topology to that generated from mitochondrial DNA data. Despite being in an unfavourable thermal environment, which explains the low yield of endogenous sequences, our study demonstrates that it is possible to obtain genomic data from extinct species from temperate regions.     

Dietary divergence in space and time – Lessons from the dwarf-goat Myotragus balearicus (Pleisto-Holocene,Mallorca, Spain)

Newly colonised, isolated habitats, like islands, provide diverse niches to be filled and are prone to facilitate ecological separation which might lead to an adaptive radiation. Examples of such radiations can be found in the Mediterranean for the genera Candiacervus (Crete), Nesogoral (Sardinia) and Hoplitomeryx (Gargano). A different strategy to cope with limited resources on islands is generalism. We test whether populations of the endemic bovid Myotragus balearicus from two sites and Pleistocene as well as Holocene levels on Mallorca island displays ecological separation indicated by diet, or whether the species shifted its dietary trait towards generalism. We expect to find either: (1) dietary divergence in space and time (between sites and stratigraphic levels), which would indicate niche partitioning and/or a shift in dietary traits due to environmental influences; or (2) dietary congruence in a less specialised, generalistic dietary strategy in space and time which would indicate a flexible trait to cope with instable resource availability. We compare individuals from a fossil assemblage at a northern site and one assemblage from the eastern coast in terms of their dietary traits. Traits are reconstructed using dental dietary proxies, complementary in time scale and resolution. (1) 3D-dental topometry and (2) enamel surface texture analysis. Data suggest that individuals from both assemblages of M. balearicus behaved as variable browse dominated intermediate feeders. We thus conclude that the observed variability relates to a shift towards generalism as a subsistence strategy. We consider hypsodonty the pre-adaptation for this life style that enabled M. balearicus to exploit almost any food source in its energetically restricted island habitat.     

Genetic structure of Balearic honeybee populations based on microsatellite polymorphism

The genetic variation of honeybee colonies collected in 22 localities on the Balearic Islands (Spain) was analysed using eight polymorphic microsatellite loci. Previous studies have demonstrated that these colonies belong either to the African or west European evolutionary lineages. These populations display low variability estimated from both the number of alleles and heterozygosity values, as expected for the honeybee island populations. Although genetic differentiation within the islands is low, significant heterozygote deficiency is present, indicating a subpopulation genetic structure. According to the genetic differentiation test, the honeybee populations of the Balearic Islands cluster into two groups: Gimnesias (Mallorca and Menorca) and Pitiusas (Ibiza and Formentera), which agrees with the biogeography postulated for this archipelago. The phylogenetic analysis suggests an Iberian origin of the Balearic honeybees, thus confirming the postulated evolutionary scenario for Apis mellifera in the Mediterranean basin. The microsatellite data from Formentera, Ibiza and Menorca show that ancestral populations are threatened by queen importations, indicating that adequate conservation measures should be developed for protecting Balearic bees.     

The role of seed dispersal,pollination and historical effects on genetic patterns of an insular plant that has lost its only seed disperser

Aim The genetic structure of many plant species is heavily dependent on their pollinators and seed dispersers, and can thus be altered if either of the associated mutualistic interactions is disrupted. In this study we assess the genetic diversity and structure and infer the seed/pollen gene‐flow patterns among insular populations of Daphne rodriguezii, a shrub pollinated and dispersed by animals that has lost its only disperser (the lizard Podarcis lilfordi) in most of its populations. Location The island of Menorca and the islet of Colom (Balearic Islands, Western Mediterranean). Methods To assess the contribution of gene flow via pollen and seeds to the genetic structure of D. rodriguezii we used amplified fragment length polymorphisms (AFLPs; seeds and pollen) and plastid DNA sequences (cpDNA; seeds). We sampled individuals from all population nuclei of the species (12–19 adults per population): one population in Colom, where the plant–lizard interaction persists, and four in Menorca, where the seed dispersal mutualism disappeared with the extinction of the lizard. Results The highest heterozygosity values were found in Colom and in its closest population (Favàritx), whereas values were lower in the smallest Menorcan populations, which also had higher relatedness among individuals. We found distinct genetic signals between AFLP and cpDNA analyses. While AFLP markers showed low differentiation between populations, cpDNA showed a clear differentiation between them. Main conclusions Our results point to negative impacts of the disperser loss on genetic diversity and relatedness in the smaller and more isolated populations. They also suggest an old isolation by seeds, probably occurring well before the extinction of the lizard (c. 2000 years ago). Gene flow was maintained via pollination; however, the seed disperser loss may ultimately hinder pollinator‐mediated gene flow, as a result of reduced probabilities of effective pollination among increasingly distant and scarce individuals.     

A new species of rail (Aves: Rallidae) from the Upper Pleistocene and Holocene of Eivissa (Pityusic Islands, western Mediterranean)

A new species of rail is described from a Pleistocene and Holocene cave deposit on the island of Eivissa, Pityusic Islands (western Mediterranean Sea). Rallus eivissensis sp. nov. was an insular relative of the European Water Rail Rallus aquaticus . Compared with the extant Water Rail, the new species was smaller and stouter, had shorter and more robust hind limbs and shorter wings, with probably reduced flight ability. The Pityusics were the only Mediterranean islands with a vertebrate Quaternary fauna lacking terrestrial mammals, and this absence is no doubt related to the Eivissan rail evolution. The chronology of the Rallus eivissensis sp. nov. extinction overlaps broadly with a period of uncertainty for the arrival of humans at Eivissa, suggesting a relationship between the two events.     

Laut?u?erungen der Sommergoldh?hnchen von den Inseln Madeira und Mallorca (Regulus ignicapillus madeirensis, R. i. balearicus)

Zusammenfassung Von den Inselpopulationen des Sommergoldhähnchens auf den Balearen (Mallorca),Regulus ignicapillus balearicus, und auf Madeira,R. i. madeirensis, wird die Struktur des Reviergesanges und der Rufe dargestellt. Ssp.madeirensis weicht in beiden markant von denen der Nominatform ab, ssp.balearicus nur im Strophenaufbau geringfügig. Die intra-und interindividuelle Variabilität der Strophentypen ist bei ssp.balearicus höher als auf dem Festland. Am Strophenende treten häufig Elementgruppen auf, die in Mitteleuropa fehlen. Seltene Elementtypen der Nominatform (ssp.ignicapillus) finden sich bei ssp.balearicus gehäuft, ähnlich wie bei ssp.laeneni (Nordafrika). Drift-Effekte gelten als Ursachen für die Unterschiede zwischen Balearen/N-Afrika und Mitteleuropa. Jedes von ssp.madeirensis benutzt nur einen Strophentyp; er variiert interindividuell stark. Die Strophe ist dreiphrasig und wird von modifizierten Kampf- und Erregungsrufen dominiert. Die Erregungsrufe sind stark frequenzmoduliert und weisen Obertöne auf, die in der Gesangsstrophe fehlen können. Wahrscheinlich sind die Erregungsrufe dem Weia-Element aus dem Subsong von ssp.ignicapillus homolog. Der hohe Anteil angeborener Rufe immadeirensis-Reviergesang wird mit Lernentzug der Erstsiedler begründet. Attrappenversuche belegen die markanten akustischen Differenzen zwischen Sommergoldhähnchen von Madeira und Mitteleuropa. Reviergesang und Erregungsrufe vonR. i. madeirensis werden von der Nominatform ssp.ignicapillus in Mitteleuropa nicht als artspezifisch erkannt. Die Madeira-Goldhähnchen reagieren hingegen auf mittel- und südosteuropäische Strophentypen (ssp.ignicapillus undcaucasicus) stark territorial.

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Vocalisations of Firecrests from the islands of Madeira and Mallorca (Regulus ignicapillus madeirensis, R. i. balearicus)

Summary The vocal repertoire of two island populations of the Firecrest (R. ignicapillus) was studied. The song structure ofR. i. balearicus from Mallorca does not differ from that of nominateignicapillus, although intra- and interindividual variation of song types in Mallorca is higher than within continental populations, i.e. individual males use higher numbers of song types than nominateignicapillus in Central Europe. Several song types are terminated by distinct element groups strongly resembling song structures of North AfricanR. i. laeneni. The fixation of relatively rare element types and song patterns compared to Central EuropeanR. i. ignicapillus is explained by drift effects. The song repertoire of the individualR. i. madeirensis male is reduced to only one song type. This is divided into three phrases, two of them consisting of modified display and rage calls. While those song elements resemble innate calls, the reduction of learning opportunities which went along with the colonisation of Madeira is thought to be the main cause for the evolution of the Madeiran song type. Display calls are used in territorial contexts and differ greatly from those of other Firecrest subspecies in covering a larger frequency range and in including additional harmonics. Display calls are suspected to be a homologon of the excitement calls of nominateignicapillus, the weija note, which is also produced in subsong. Field experiments corroborate the evidence of a wide gap betweenR. i. madeirensis and nominateignicapillus song. Song and calls ofR. i. madeirensis do not evoke a notable territorial reaction in Central EuropeanR. i. ignicapillus, while the Madeiran Firecrests show strong reaction to the playback of Central and South-East European song types (ssp.ignicapillus andcaucasicus). Consequently,R. i. madeirensis is the only population of the Firecrest studied so far which differs considerably with respect to vocalisations from all four subspecies ofR. ignicapillus.

     

The vegetational history of the northern Apennines, Italy: information from three new sequences and a review of Regional vegetational change

Abstract. The results of pollen analysis and radiocarbon dating are presented from three northern Apennine sequences; Lago Padule in northern Tuscany and Lago Pratignano and Ospitale in the Emilia-Romagnan Apennines. This is the first detailed pollen stratigraphic information from sites in Emilia-Romagna and north Tuscany and extends eastwards the area from which information on vegetational history is available. The sequence from Lago Padule is one of the most complete Holocene records known from the northern Apennine region. Lago Pratignano has the deepest sequence of organic sediments (1544 cm) and the fastest rates of sediment accumulation (up to 28 cm per 100 years) providing the highest resolution record for the mid to late Holocene periods in the region. High rates of sedimentation have also occurred at Ospitale where organic sediments are 780 cm deep and began to form at approximately 5500 bp. The record from Lago Padule is compared with Holocene records from two nearby sites and a series of Regional Pollen Assemblage Zones is defined for the eastern area of the northern Apennines. The main features of vegetational change identified are: (i) a‘pioneer’phase of rapid forest development during the early Holocene followed by the establishment of an upper forest belt dominated by Abies, and a belt of mixed deciduous forest at lower altitudes; (ii) the appearance and rapid expansion of Fagus between approximately 5200 bp and 2900 bp forming a mixed Abies-Fagus association in the upper forest belt; and (iii) the overall reduction of forest cover, and dominance of Fagus in the arboreal vegetation from around 2900 bp. The scheme of Regional PAZs for the eastern area is used as a framework for the review of pollen stratigraphic information and radiocarbon dates from other sites in the northern Apennine region. Characteristics of pollen records which can be identified in sequences from across the region are identified and the chronology of similar changes in pollen stratigraphy is examined. The scheme of four regional PAZs for the Holocene period is shown to be valid for the entire northern Apennine region. The examination of a series of pollen records shows that Fagus appeared earlier in the western than the eastern part of the region during the mid Holocene and became dominant in the northern Apennine forests post 3000 bp. The impact of anthropogenic activity and climatic change on the spread and development of Fagus are discussed. The palynological evidence which is now available from the northern Apennines is compared with information for the region shown in the‘European pollen maps’of Huntley & Birks (1983). This study provides an updated review of the representation of different tree taxa in Holocene pollen records from the northern Apennines and illustrates the role of the northern Apennines as a refugium for trees during the Wurmian Lateglacial.