Habitat type determines the effects of disturbance on the breeding productivity of the Dartford Warbler Sylvia undata

Numerous studies have examined the causes and impacts of human disturbance on birds, but little is known about how these impacts vary among habitats. This is of applied importance both for predicting bird responses to changes in disturbance and in planning how to reduce disturbance impacts. The Dartford Warbler Sylvia undata , a key heathland breeding species, occupies territories in a range of heathland types. Three territory habitat groups were identified: heather-dominated territories, heather territories with significant areas of European Gorse Ulex europaeus and territories containing Western Gorse U. gallii . Productivity was significantly affected by the timing of breeding in all habitats, but disturbance only appeared to have a significant impact on the productivity of birds in heather territories. Disturbance events in heather territories delayed breeding pairs for up to 6 weeks. This significantly decreased both the number of successful broods raised and the average number of chicks fledged per pair. Nests situated close to territory boundaries in heather territories, with high numbers of disturbance events, were more likely to fail outright. It was determined that an average of between 13 and 16 people passing through a heather territory each hour would delay breeding pairs sufficiently to prevent multiple broods.     

Habitat-dependent population recovery in the Dartford Warbler Sylvia undata following a severe winter episode

Capsule?After a population crash following a long period of winter freezing and snow blanketing the ground, Dartford Warblers underwent a population recovery, positive in heathlands but non-existent in nearby early-growth forest.

Aims?To estimate the impact of a severe winter episode on the population size of Dartford Warblers in two habitats, heathland and early-growth forest.

Methods?We analysed data collected on 124 point counts in three successive years, 1 year before and 2 years after the cold spell. We first estimated trends in detected numbers in the two habitats. Second, we used distance sampling and capture–recapture approaches to estimate global population sizes corrected for detection probability, verifying that the observed trends were not biased by detection probability.

Results?Warbler populations crashed after the severe winter in 2008–9, while numbers increased in spring 2010 only on heathlands, not in early-growth forests. Variation in detection probability alone could not explain this difference.

Conclusion After the severe winter episode, Dartford Warblers showed a short-term population recovery only in heathland.     

Crocus ilvensis sp. nov. (sect. Crocus,Iridaceae), endemic to Elba Island (Tuscan Archipelago,Italy)

A new species of Crocus sect. Crocus is described as an endemic of Elba Island (Tuscan Archipelago, Italy): C. ilvensis Peruzzi & Carta sp. nov. (2n=8). The new species was wrongly referred to C. corsicus Vanucchi (2n=18), C. etruscus Parl. (2n=8) or C. vernus Hill. subsp. vernus (2n=8, 16) by previous authors. Its karyotype structure, asymmetry and chromosome dimensions show affinity with C. etruscus, and no clear relations with other related taxa. From a morphological point of view, C. ilvensis appears intermediate between C. etruscus and C. vernus subsp. vernus, showing however a peculiar combination of character‐states. The new species is completely allopatric with other Crocus sect. Crocus taxa and its possible role in the origin of tetraploid races of C. vernus is discussed.     

Foods of the Dartford warbler Sylvia undata on southern English heathland (Aves: Sylviidae)

This paper describes the invertebrates of Callunetum and gorse on lowland heaths in Dorset and relates how these were exploited by the Dartford warbler Sylvia undata , a scarce bird of interest to nature conservation and one of the small number of wholly insectivorous resident passerines in Britain. Gorse had a denser invertebrate fauna than Callunetum and was used for feeding at a frequency out of proportion to its abundance. Diets of adult birds closely reflected the taxonomic composition of the gorse and Callunetum faunas exploited in the observed proportions, though some noxious taxa were avoided and below a certain limit, creatures of above average size were selected. Major foods were beetles, spiders, lepidopteran larvae and bugs. Nestling birds received a diet differing in taxonomic composition and size from that of the adults, and variations between habitats were found which accorded with observations on the habitat preferences of the Dartford warbler. An experimental investigation showed the importance of gorse as a source of food for young and the adults flew considerable distances ignoring extensive deep stands of heather nearer to the nest. The possible influence of competing insectivorous vertebrates on Dartford warblers is discussed. Various mammals and reptiles appeared to be the major vertebrate predators in Callunetum, but little competition was anticipated in gorse. Scarcity of gorse on the heaths and low densities of invertebrates in heather explained the low densities at which Dartford warblers occur.     

Habitat of Paramecium biaurelia in Italy, the Island of Elba.

The new habitat of Paramecium biaurelia was found on the Island Elba.     

Core and satellite butterfly species on Elba island (Tuscan Archipelago, Italy). A study on persistence based on 120 years of collection data

Records for butterflies on Elba island in the last 120 years have been summarized and examined. I assessed species occurrence for six periods of twenty years by bibliographic, museum and field data. For five periods data appear complete and species assemblage highly concordant. Nonetheless, a certain evolution of Elba butterflies seems to be occurring. Moreover, I assessed the regression between frequency at sources and frequency on islands among species living on Italian islets and used the residuals as a tendency to be less or more common on islands compared to mainland. By a successive regression, I verified that these residuals are actually related to the number of periods each species has been recorded on Elba. Interestingly, the number of record periods is not correlated with species appearance. I concluded that there is a large core of persistent species and a few species that are occasionally reported on Elba. Such satellite species represent butterflies that are less likely to occupy island biotas and may represent endangered populations.     

Temporal Genetic Variation in a Population of Aphanius fasciatus (Cyprinodontidae) from a Brackish-water Habitat at Elba Island (Italy)

Allozyme electrophoresis was used to assess temporal genetic variation in three successive generations of the Mediterranean killifish, Aphanius fasciatus. Samplings were carried out in 1995, 1996 and 1997 in a brackish-water habitat at Elba Island, Italy and a total of 212 specimens were collected. The five loci for which polymorphism has been detected in a previous study were assayed. Mean expected heterozygosity values [H=0.397 (SE 0.077), H=0.336 (SE 0.092) and H=0.313 (SE 0.092) in 1995, 1996 and 1997, respectively] were not significantly different by ANOVA test. Deviations from Hardy–Weinberg equilibrium were minimal, with only one out of the 15 probability tests showing a significant departure from the equilibrium; whereas genotypic linkage disequilibrium was not detected. Values of Nei's genetic distance were lower than 0.04. Temporal genetic variation in the A. fasciatus population at Elba Island was observed, with F-statistics indicating significant genetic divergence among samples (=0.035, SE 0.027, p<0.001). Genetic drift acting on two loci (GPD-1 ^* and LDH-3 ^*) is presumably the main force determining the temporal genetic heterogeneity observed; however, the occurrence of selection on individual loci and/or sampling error cannot be excluded. The observed allelic variation among generations in a single population of A. fasciatus is much less than levels observed among geographically discrete samples in previous studies.     

Morphological observations on some fleshy crustose algae of the Island of Gorgona (Tuscan Archipelago)

Abstract

Morphological and ecological observations on four fleshy crustose algae collected in the eulittoral and upper sublittoral zone of the Island of Gorgona: Myrionema liechtenstenii Hauck, Hildenbrandia canariensis B?rgesen, Peyssonnelia armorica (P. et H. Crouan) Weber-van Bosse in B?rgesen and Cruoria cruoriaeformis (P. et H. Crouan) Denizot are reported. For each species, information on some aspects of their ecology, geographical distribution and notes on their vegetative and reproductive morphology are given.     

Variability at different spatial scales of a coralligenous assemblage at Giannutri Island (Tuscan Archipelago,northwest Mediterranean)

This study was carried out on the rocky cliffs of Giannutri Island (Tyrrhenian Sea, Italy) to test the hypothesis that coralligenous assemblages are consistent within the bathymetric range considered (25–35 m depth) over three different spatial scales (1000 m, 100 m and 10 m). A multi-factorial sampling design was used to assess patterns of vertical distribution in the studied area. Data on the percent cover of algae and invertebrates were collected at three depths (25, 30 and 35 m) using a photographic method, and percentage cover was obtained using a visual method. Analysis of the results using ANOVA indicated that the distribution and abundance of algae and some invertebrates of the sublittoral assemblages are clearly heterogeneous. Algae, sponges and bryozoans showed significant variability in distribution and abundance at different depths, but this variability was not consistent amongst transects. Ascidians did not show any variability, while the abundance of anthozoans differed significantly amongst transects. We concluded that heterogeneity in the distribution and abundance of the taxa analysed is related to the smallest spatial scale investigated (10's of m). Some of the possible causes of the observed variability are discussed.     

Taxonomy and new bacterial symbioses of gutless marine Tubificidae (Annelida, Oligochaeta) from the Island of Elba (Italy)

In shallow sublittoral sediments of the north-west coast of the Island of Elba, Italy, a new gutless marine oligochaete, Olavius ilvae n. sp., was found together with a congeneric but not closely related species, O. algarvensis Giere et al., 1998. In diagnostic features of the genital organs, the new species differs from other Olavius species in having bipartite atria and very long, often folded spermathecae, but lacking penial chaetae. The Elba form of O. algarvensis has some structural differences from the original type described from the Algarve coast (Portugal). The two species from Elba share characteristics not previously reported for gutless oligochaetes: the lumen of the body cavity is unusually constricted and often filled with chloragocytes, and the symbiotic bacteria are often enclosed in vacuoles of the epidermal cells. Regarding the bacterial ultrastructure, the species share three similar morphotypes as symbionts; additionally, in O. algarvensis a rare fourth type was found. The divergence of the symbioses in O. algarvensis, and the coincidence in structural and bacteria-symbiotic features between the two taxonomically different, but syntopic host species at Elba are discussed.     

Some Field Notes on the Spectacled Warbler (Sylvia conspicillata conspicillata Temminck)

T he Spectacled Warbler is the characteristic small bird of the Salicornia areas of the Camargue, where the following notes on early breeding behaviour were made in April 1937 and 1938. Its status in this region was for some time in doubt (1), but the confusion between it and the Dartford Warbler ( Sylvia undata Bodd.) has now been without possible question cleared up by the late Rev. F. C. R. Jourdain (2), and the observations of recent visitors have thoroughly confirmed this opinion(3), (4).     

Anomalous coloration in European pine marten Martes martes in Elba Island,Central Italy

Evidence of abnormal coloration in wild animals provides useful information to better understand its adaptive function and its impact on survival. For this reason, we need to know the frequency and distribution of these abnormal phenotypes in wild populations. Here, we report two records of hypopigmentation in European pine marten Martes martes, obtained during a camera‐trapping survey on Elba Island, Central Italy. We do not know what has caused anomalous coloration of pine marten on Elba Island, but it is possible that the inbreeding may have played a role in this isolated population. Although the light coloration certainly entails an increased visibility of pine martens, it is possible that the low predator pressure and the absence of other wild carnivore populations in our study could mitigate the mortality risk due to the light phenotype. The increased use of camera traps across the world can potentially facilitate the discovery of cases of anomalous colorations in wild populations, providing an unprecedented insight into the occurrence of this phenomenon in wild mammal species.     

Molecular survey of morphological subspecies reveals new mitochondrial lineages in Podarcis muralis (Squamata: Lacertidae) from the Tuscan Archipelago (Italy)

Recent analyses of molecular markers have significantly revised the traditional taxonomy of Podarcis species (Squamata: Lacertidae), leading to critically reconsider the taxonomic value of several subspecies described only on morphological bases. In fact, lizards often exhibit high morphological plasticity both at the intra‐specific and the intra‐population level, especially on islands, where phenotypic divergences are mainly due to local adaptation, rather than to evolutionary differentiation. The Common wall lizard Podarcis muralis exhibits high morphological variability in biometry, pholidosis values and colour pattern. Molecular analyses have confirmed the key role played by the Italian Peninsula as a multi‐glacial refuge for P. muralis, pointing out the lack of congruence between mitochondrial lineages and the four peninsular subspecies currently recognized. Here, we analyse a portion of the protein‐encoding cytochrome b gene in the seven subspecies described for the Tuscan Archipelago (Italy), in order to test whether the mitochondrial haplotypes match the morphologically based taxonomy proposed for Common wall lizard. We also compare our haplotypes with all the others from the Italian Peninsula to investigate the presence of unique genetic lineages in insular populations. Our results do not agree completely with the subspecific division based on morphology. In particular, the phylogenetic analyses show that at least four subspecies are characterized by very similar haplotypes and fall into the same monophyletic clade, whereas the other three subspecies are closer to peninsular populations from central Italy. From these results, we conclude that at least some subspecies could be better regarded as simple eco‐phenotypes; in addition, we provide an explanation for the distinctiveness of exclusive lineages found in the archipelago, which constituted a refuge for this species during last glacial periods.     

Essential‐Oil Composition of Helichrysum italicum (Roth) G.Don ssp. italicum from Elba Island (Tuscany,Italy)

The composition of 21 essential‐oil samples isolated from Helichrysum italicum collected in seven locations of Elba Island (Tuscany, Italy), characterized by different soil types, during three different periods (January, May, and October 2010) was determined by GC‐FID and GC/EI‐MS analyses. In total, 115 components were identified, representing 96.8–99.8% of the oil composition. The oils were characterized by a high content of oxygenated monoterpenes (38.6–62.7%), while monoterpene and sesquiterpene hydrocarbons accounted for 2.3–41.9 and 5.1–20.1% of the identified constituents, respectively. The main oxygenated derivatives were nerol (2.8–12.8%) and its ester derivative neryl acetate (5.6–45.9%). To compare the chemical variability of the species within Elba Island and between the island and other localities within the Mediterranean area, studied previously, multivariate statistical analysis was performed. The results obtained showed a difference in the composition of the essential oils of H. italicum from Elba Island, mainly due to the environment where the plant grows, and, in particular, to the soil type. These hypotheses were further confirmed by the comparison of these oils with essential oils obtained from H. italicum collected on other islands of the Tuscan archipelago.     

Priority invasive alien plants in the Tuscan Archipelago (Italy): comparing the EPPO prioritization scheme with the Australian WRA

For the first time, we tested the European and Mediterranean Plant Protection Organization (EPPO) prioritization process (EPP) on 212 alien plant species thriving in the Tuscan Archipelago, Central Italy. We compared the results of the EPPO procedure with those of the Australian Weed Risk Assessment (A-WRA) system. The two methods were also tested against the categorization performed at the national and local level by a panel of experts. Our results suggest that both methods accurately predict the invasiveness of species already present in the Tuscan Archipelago. However, the total numbers of species included in the highest risk categories by the two methods differed greatly, with the EPPO prioritization process including fewer species in the highest risk class. The two methods differed in the ability to correctly detect the invasive species, with the A-WRA method being more conservative, but at cost of more species in the highest risk class. Using Generalized Linear Models, we showed that both methods suffer from some degree of dependence from one or more of the tested explanatory variables (life span, year of first record). The results suggest that the choice of a risk assessment method should be driven by the main aim of the assessment, i.e., distinguishing between a more predictive tool (A-WRA) and a prioritization tool (EPP) for already introduced species.     

The scorpion of Montecristo, Euscorpius oglasae Di Caporiacco, 1950, stat. nov. (Scorpiones, Euscorpiidae): a paleo-endemism of the Tuscan Archipelago (northern Tyrrhenian, Italy)

The scorpion of Montecristo Island (Tuscan Archipelago, Italy): Euscorpius carpathicus oglasae Di Caporiacco, 1950, is a poorly known taxon. We redescribe and illustrate the insular endemism of E. c. oglasae for the first time, and elevate this subspecies to the rank of species following a thorough study of the comparative morphology of 372 specimens (including 7 related taxa). Euscorpius oglasae stat. nov. is an oligotrichous form that differs from the related species by the inner proximal surface of pedipalp movable finger, with a reduced lobe and a slightly swollen telson vesicle in males. Attention was given to the analysis of the hemispermatophore and peg sensilla of pectens. The hemispermatophore is small, with the basal lobe bearing a very short spine. We also discuss aspects of the ecology, conservation and biogeography of this species.     

Benthic marine flora in the Tuscan Archipelago. A first contribution: Isles of Capraia,Elba, Formiche di Grosseto,Giglio, Scoglio d'Africa,Montecristo and Giannutri

Abstract

Benthic marine flora of Tuscan Archipelago has been studied. Several samples were collected along five islands and some rocks. This paper is a compendium of new and already published data, in which 267 species, varieties, forms and stadia of algae and seagrasses are listed: 5 Bangiophyceae, 182 Florideophyceae, 45 Phaeophyceae, 6 Chlorophyceae, 28 Bryopsidophyceae, 1 Angiospermae.