Ograniczanie wyników

Czasopisma help
Autorzy help
Lata help
Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 40

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych:  Iberian Peninsula
help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
To analyse the population structure and reproductive biology of the Iberian hare Lepus granatensis Rosenhauer, 1856, 498 hares (264 males and 234 females) were collected in monthly samples from October 1998 to September 1999. Females reached larger sizes than males, with approximately 400 g difference in body mass on reaching sexual maturity. The total sex ratio was 1:1, with a bias in favour of males in winter. Sexually active males and females appeared in every month but August, when no sexually active female was found. Births occurred in every month and were more frequent between March and July. Seasonal variation in kidney fat index (KFI) followed a similar pattern in males and females, with an increase in mid-autumn and a decline at the end of winter. Reproductive activity appeared in every month, with a maximum from February to June. Reproductively hyperactive females (simultaneously pregnant and nursing) appeared in every month except in January, with a first peak in March and a second lower peak in May-June. Litter size fluctuated between 1 and 7 leverets. The most frequent gestations involved 1 or 2 foetuses. The mean annual litter size was 2.08 and the average number of litters per productive female per year was estimated to be 3.48. The maximum productivity was recorded between March and May. The total annual production of young per adult female was estimated to be 7.21. The minimum annual survival rate of young was 27.91%. On the basis of these results we propose to maintain the limit of the hunting period between October and December. We discuss the relationship between the low young/adult ratio obtained and the hunting method used.
Placobdella costata is a leech specific to freshwater turtle Emys orbicularis. Both genera are native to North America and have co-evolved and undergone dispersion through the Palearctic. The leech is present throughout the Mediterranean area, always associated with E. orbicularis. Their only known presence in the Iberian Peninsula is in the north and center of the peninsula. Here we present the first description of the leech in southern Spain (Andalusia) in association with a small fragmented population of fresh-water turtles in which E. orbicularis and Mauremys leprosa coexist. Unusually, the leech was found attached to the carapace of a male M. leprosa.
The diet of Sorex coronatus (Millet, 1828) was studied by the analysis of digestive tracts from 178 individuals collected in Quinto Real Massif, western Pyrenees (north of the Iberian Peninsula). In total, 28 different types of food were determined. The most important prey species, as determined by numerical presence (N) and Simpson's do­minance index (D"), were Chilopoda (%N = 12.8; D" = 21.4), Diptera larvae (%N = 22.0; D"= 17.7), Oligochaeta: Opistopora (%N = 11.3; D" = 12.2), Gastropoda (%N = 7.0; D" = 8.7), adult Coleoptera (%N = 6.9; D" = 8.0) and Hemiptera (%N = 6.0; D" = 5.3). Diets of both sexes were similar. The diet of S. coronatus in the study area was similar to the diet of S. araneus described in the literature.
Adult and sub-adult otters Lutra lutra (Linnaeus, 1758) caught and consumed 3.36 prey (fish) per hour (n = 32 captures). This represents 273.8 g of wet mass/h of activity outside the rest sites (10.5-13.1% of the day) and it is enough to get their daily needs. Otters ate the prey without hiding on average (n = 93) 0.46 m from the bank (up to 3.9 m) and 0.25 m above water level (up to 2.05 m). Prey weighing less than 150-200 g were consumed entirely; for this reason prey remains are very rare (except large trout, American crayfish and gravide cyprinid females). Unpleasant tasting or toxic parts and sharp or wide parts of the bones, scales, teeth, claws, heads or leggs in large prey were not eaten.
Available information on the distribution of the European species of the Sorex arañéis group in the Iberian Peninsula suggests that the Iberian System (north-central Spain might be a sympatric area between S. coronatus Millet, 1828 and S. granarius Miller, 1910. With the aim to assess this hypothesis, multivariate analyses based on 16 skull and mandible parameters were carried out on 78 shrews from the Iberian System. A preliminary specific determination was performed on 57 specimens using a discrim­inant function established in a previous study. Two further discriminant functions based on skull and mandible variables respectively were constructed from the sample analysed and both provided an identical classification of the specimens, although slight.y different from that of the preliminary determination. In order to summarize the n.orphometric interspecific relationships a principal components analysis was performed. Results obtained confirm the presence of S. coronatus and strongly suggest that of S. granarius and of a contact zone between both species in the Iberian System. In this area both species share the same general habitats, occupying oro- and supramedi- terrarean bioclimatic levels. Taking into account the distributional pattern reported for S. araneus and S. coronatus in sympatric areas, and considering the convergence in size observed between S. granarius and S. coronatus in the Iberian System, we suggest that in this contact zone both species might have a parapatric distribution, due most probably to microhabitat segregation.
The extent of the area occupied by populations of roe deer and the diversity of environments in which it lives, determine the existence of different local forms or ecotypes. In order to characterize the populations of the Guadarrama Mountains in the centre of the Iberian Peninsula we examined the morphology and fur colouration of 154 roe deer (Capreolus capreolus) based on their body size, age and sex. To determine the age of roe deer, we analyzed tooth cementum layers (incisor I1) to observe the growth lines. The remaining individual data (body size, sex and fur colouration) were obtained in the field, from animals hunted in the study area. In adult individuals, the average body weight in males was significantly higher than in females, being these weight ranges similar to those of the Iberian Peninsula and the rest of Europe. Body measurements were positively related to individuals age, but only significant differences in body girth were found between males and females. The analysis of fur colouration of dead specimens showed a high variability with four different ecotypes during the summer coat and not significant differences were found in the body size between individuals with different summer coats. The morphological parameters described in the roe deer of the Guadarrama Mountains do not correspond with the latitudinal gradient as it was indicated for other Spanish populations. However, the existence of Pleistocene refuges in the central mountains of the Iberian Peninsula seems to have provided a high variety of ecotypes in relation to fur colouration in the populations of Guadarrama Mountains.
The Iberian hare Lepus granatensis is a common and abundant species throughout the Iberian Peninsula; however, studies documenting its ecology are scarce. Between August 1996 and September 1997, after a long drought, we studied the effects of a widespread flood on the Iberian hare ecology in ecotone pastures of Doñana National Park. Hares were captured using vertical nets through part of 1996 and 1997. Fourteen adult hares (nine females and five males) were tagged with radiocollars and located by triangulation on a daily basis at least once a week. Habitat use was estimated using a geographical information system. The average home range size was 28 ha for males and 24 ha for females. No significant differences were observed between sexes. Significant differences were observed in the use of scrub areas and in dry pastures. During the dry and wet seasons, males and females were most often located in the pastures of the ecotone, rush stands and scrub. The dense bracken (Pteridium aquilinum) and seaside bulrush (Scirpus maritimus) communities were avoided. These results are the first on the spatial ecology of this species in its native habitat.
Crusafontia amoae sp. nov. (Dryolestida, Stem Cladotheria) is represented by two isolated upper molars (M4 or M5 and M6 or M7) from the terminal Hauterivian–basal Barremian (Early Cretaceous) of the El Castellar Formation (Galve, Spain). The molars have a deep ectoflexus, a distinct metacone, a continuous metacrista, and an antero−lingually placed paracone. They differ from the molars of the other species of the genus, Crusafontia cuencana, by their larger size, by their outsized parastyle, by the pointed lingual slope of the paracone, their more symmetrical appearance with a deep ectoflexus in occlusal view, and the well−developed metacone. Revision of three isolated teeth previously attributed to Crusafontia cuencana suggests that instead of being upper premolars belonging to Crusafontia cuencana they in fact belong to Pocamus pepelui, of the stem cladotherian superorder Zatheria, probably “peramuran”. As such, the stem Cladotheria record from the Early Cretaceous of the Iberian Peninsula is composed of two dryolestids (Crusafontia amoae and Crusafontia cuencana) and one zatherian (Pocamus pepelui).
Preservation of foraging habitats is a fundamental approach to bat conservation. Yet, knowledge on the primary foraging sites of Mediterranean bats remains scarce, particularly during the summer when the availability of prey can be limiting. This study was designed to determine in which habitats bats forage in Southern Portugal, during this potentially stressful period. During the summers of 1994 and 1995, bat foraging activity was monitored in representative habitat types using an ultra-sound detector. The number of feeding-buzzes and bat-passes were counted and species identified through the analysis of recorded echolocation calls. None of the recorded species restricted its foraging activity to a single habitat type, but water sites were preferred by most bats. Tadarida teniotis was an exception to this habitat use. Further analysis confirmed that riparian habitats when surrounded by autochthonous broad-leaved forests seem to provide optimal foraging areas for bats during summer. Opposite, water sites within habitats resulting from intensive agriculture or forestry, provide very poor foraging areas. The typical Mediterranean landscape of Iberia, dominated by oak-woodlands and with numerous, scattered and well vegetated water sites, seems to grant optimal foraging habitat for bats during summer. However, this landscape is itself at risk. Current production demands are causing substantial land-use changes and, despite some European programmes on the preservation of Mediterranean oak woodlands and their biodiversity, the furtherance of this landscape is at stake. The preservation of traditional management strategies of oak-woodlands and associated water sites should be strongly encouraged.
We studied diet and prey selection in Mehelyi's horseshoe bats Rhinolophus mehelyi in the south-western Iberian Peninsula, during the breeding seasons of 2003, 2006, and 2007. Faecal pellets were collected individually and arthropod fragments identified to family level, where possible. Arthropod availability was assessed using Malaise traps. Selection analyses were performed using Compositional Analysis and a Chi-square goodness-of-fit test. The bulk of the diet of R. mehelyi consisted of Lepidoptera, representing more than the 80% of the consumed volume on average (excluding juveniles), and more than 90% of the average percentage occurrence. This pattern was consistent across localities. Neuroptera and Tipulidae were locally abundant. Other important prey categories were Chrysomelidae, Brachycera, and Chironomidae. ANOVA tests showed that there were no significant differences between males and females in consumed prey categories, whereas juveniles consumed significantly less Lepidoptera than adults. Lepidoptera was the first prey category in the preference rank, followed by Myrmeleontidae, Chrysopidae and Tipulidae, and all of these were consumed more than expected by chance. This work shows that R. mehelyi is a moth specialist and suggests that juveniles may acquire this strategy while gaining hunting experience. Given the similarities in echolocation call characteristics and diet in the sibling R. mehelyi and R. euryale, they may compete for trophic resources in sympatry. Nevertheless, subtle differences in wing morphology between both species are probably large enough to permit spatial resource partitioning.
Thirty-four helminth species were obtained from the helminthological analysis of 399 foxes in the Iberian Peninsula. The species found were classified into three groups. Uncinada stenocephala, Eucoleus aerophilus and Pearsonema plica were classified as core species. The secondary species included Mesocestoides spp., Taenia polyacantha, Toxascaris leonina, Toxocara canis, Angiostrongylus vasorum, Crenosoma vulpis, Pterygodermatites affinis and Physaloptera sibirica. The remainder, including Alaria alata, Brachylaima sp., Metorchis bilis, Opistliorchis felineus, Taenia crassiceps, T. hydatigena, T. taeniaeformis, T. pisiformis, Echinococcus granulosus, Joyeuxiella pasqualei, J. echinorhynchoides, Diplopylidium noelleri, Aonchotheca putorii, Trichuris vulpis, Dirofilaria immitis, Toxocara cati, Ancylostoma caninum, Vigisospirura potekhinae, Molineus patens, M. legerae, Spirocerca lupi, Mastophorus maris and Macracanthorhynchus catulinus were considered as satellite species. A significantly high prevalence of trematodes was found in certain peninsular areas. The most prevalent and abundant cestodes were Mesocestoides spp. Nematodes were the most numerous set of species encompassing several of the most prevalent species. The findings of A. putorii and V. potekhinae constitute new host records for Vulpes vulpes, in the Iberian Peninsula (in the case of the capillariid) and in its entire geographical range (in the case of the spirurid). D. noelleri is also reported for the first time as parasitizing foxes in Europe. The majority of the species found are host generalists and have indirect life cycles. The richness of the helminth community seems to be strongly influenced by the broadness of the alimentary spectrum in different peninsular areas.
The present study analyses the helminth communities found in one hundred and two specimens of Martes martes from the Iberian Peninsula and the Balearic Archipelago. The component community is constituted by seventeen helminth species, which frequency and mean abundance show a bimodal pattern. The set of core species is constituted by the trichurids Pearsonema plica, Eucoleus aerophilus and Aonchotheca putorii (72.2% of total helminth individuals found), while the remaining can be considered satellite species. Significant co-occurrences were found among E. aerophilus/A. putorii and E. aerophilus/P. plica. These results demonstrate the great importance of earthworms within the diet of pine marten and contribute to the knowledge of the pine marten’s food ethology, since this kind of prey normally goes undetected in diet studies. Several helminth species, as Sobolevingylus petrowi, Centrorhynchus aluconis, Uncinaria criniformis, Mastophorus muris and Spirura rytipleurites seurati seem to show geographical distributions limited to insular ecosystems. Moreover, helminth communities of M. martes among four Spanish territories, including mainland and insular areas, are characterized and compared.
Two year-old needles of Pinus sylvestris were collected from 32 individuals in the Sierra de Baza (Spain). The needles were analysed in respect to 15 morphological and anatomical characters. Data obtained were subject of multivariate statistical analyses. The most stable characters appear to be needle thickness/ width ratio, thickness and width of epidermal cells. The most variable characters include the distance between vascular bundles and Marcet's coefficient. Intrapopulational variation is low.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.