Bird assemblages in forest fragments within Mediterranean mosaics created by wild fires   总被引：1，自引：1，他引：0  

Lluís?BrotonsEmail author  Sergi?Herrando  Jean-Louis?Martin 《Landscape Ecology》2004,19(6):663-675

The role of habitat heterogeneity as a key factor in determining species pools in habitat mosaics has been acknowledged, but we still know little on the relative importance of the different ecological processes acting within such complex landscapes. We compared species richness and distribution in forest fragments imbedded in shrub-lands to those in continuous forests or in continuous shrublands. We examined the consistency of our data with the predictions of two hypotheses: 1) the Habitat fragmentation hypothesis which states that fragmentation has negative effects on the species from the original continuous habitat; 2) the Habitat supplementation /complementation hypothesis which stipulates that the presence of a matrix habitat around the fragments will mitigate negative effects on the species from the original habitat (supplementation) or allow the presence of species that depend on the presence of both the fragment and matrix habitats (complementation). We show that: 1) species richness in forest fragments did not differ from species richness in segments of continuous forests of equal area; 2) the bird community of forest fragments got impoverished in some forest species but a higher proportion of species common in continuous forests were not affected by fragmentation; 3) fragment communities had a significant proportion of common species that were scarce in, or absent from both continuous forests and shrublands. While, a few forest species supported predictions from the fragmentation hypothesis, occurrence patterns observed in several other species were consistent with either the supplementation or the complementation hypotheses. Our results suggest that there is no single hypothesis that properly captures the consequences of a shift from continuous forests to a mosaic of forest fragments and shrublands and that different ecological mechanisms act in conjunction to determine species pools in habitat mosaics. Habitat heterogeneity at a local scale appears a key factor in maintaining bird diversity in fire driven Mediterranean landscapes.  相似文献   

Morphology and ultrastructure of Sphaeromyxa noblei sp. n. (Myxozoa), parasite of Heteroclinus whiteleggii (Pisces) from Australian New South Wales coast     

Lom J 《Folia parasitologica》2004,51(1):19-26

A new species, Sphaeromyxa noblei sp. n., is described from Heteroclinus whiteleggii (Perciformes: Clinidae), a marine fish from the coast of New South Wales in Australia. This raises the number of Sphaeromyxa species to 38; their list is presented. The species is characterised by a layer of branched glycostyles, which is about 2.4 microm thick and is a feature rather unique in Myxosporea. Pansporoblasts form one or two spores. The study of ultrastructure of this species and of those described to date result in recognition of a combination of patterns characterising the genus: plasmodia have marked surface projections, the endoplasm is full of vacuoles larger than in any other myxosporean genus, and contains a special kind of cells, the lobocytes. Sections through polar capsule reveal different appearance of subsequent stretches of the polar filament unlike in other Myxosporea.  相似文献   

Advances in the knowledge of amphizoic amoebae infecting fish     

Dyková I  Lom J 《Folia parasitologica》2004,51(2-3):81-97

Free-living amoebae infecting freshwater and marine fish include those described thus far as agents of fish diseases, associated with other disease conditions and isolated from organs of asymptomatic fish. This survey is based on information from the literature as well as on our own data on strains isolated from freshwater and marine fish. Evidence is provided for diverse fish-infecting amphizoic amoebae. Recent progress in the understanding of the biology of Neoparamoeba spp., agents responsible for significant direct losses in Atlantic salmon and turbot industry, is presented. Specific requirements of diagnostic procedures detecting amoebic infections in fish and taxonomic criteria available for generic and species determination of amphizoic amoebae are analysed. The limits of morphological and non-morphological approaches in species determination are exemplified by Neoparamoeba, Vannella and Platyamoeba spp., which are the most common amoebae isolated from fish gills, Acanthamoeba and Naegleria spp. isolated from various organs of freshwater fish, and by other unique fish isolates of the genera Nuclearia, Thecamoeba and Filamoeba. Advances in molecular characterisation of SSU rRNA genes and phylogenetic analyses based on their sequences are summarised. Attention is particularly given to specific diagnostic tools for fish-infecting amphizoic amoebae and ways for their further development.  相似文献   

Comparative study of biochemical methods for the identification of Dichelobacter nodosus     

Jiménez R  Píriz S  Mateos EM  Vadillo S 《Acta veterinaria Hungarica》2004,52(3):267-273

The aim of this study was to compare four identification procedures to detect Dichelobacter nodosus and develop a rapid, simple and effective method to identify D. nodosus strains isolated from cases of ovine footrot. The four methods used were: (a) the classic guidelines set down by Holdeman et al. (1977) and Summanen et al. (1993) which are based on gas liquid chromatography (GLC) and different biochemical tests, this method was considered as landmark; (b) Baron and Citron's flowchart for the rapid identification of Gram-negative rod-shaped anaerobes (1997); (c) the API rapid 32 A system (bio Mérieux), and (d) Mast ID Anaerobe ID Ring (MID8) (Mast Diagnostics). None of the four methods used allowed us to correctly identify the D. nodosus strains (neither the strains isolated from cases of ovine footrot nor those originating from type collection). Because of the difficulties encountered in obtaining a correct identification of D. nodosus, we propose a simple, rapid and effective way to achieve this task. Our flowchart will provide the means to identify this microorganism in any laboratory of general microbiology without having to use any specialised equipment.  相似文献   

Effectiveness of different adjuvants in stimulating Dichelobacter nodosus antibody in sheep vaccinated against ovine footrot     

Martín-Palomino P  Píriz S  Jiménez R  Serrano FJ  Vadillo S 《Acta veterinaria Hungarica》2004,52(3):275-285

This research consists of an evaluation of the effectiveness of different substances administered as adjuvants in the stimulation of humoral immune response induced by the vaccine composed of strains A1, A2 and C of Dichelobacter nodosus. To do this, a total of 120 Merino sheep were vaccinated and revaccinated. These sheep were selected from a farm located in the region of Extremadura (Spain), and they were divided into 12 groups of 10 animals each. An additional group with 10 sheep was used as control. The immune response (titre of antibodies) was determined by agglutination tests and ELISA. The most pronounced immune response was obtained by the use of Freund's incomplete adjuvant and aluminium hydroxide as adjuvants.  相似文献   

Prevalence and age-related variation of Cryptosporidium species and genotypes in dairy calves   总被引：8，自引：0，他引：8  

Santín M  Trout JM  Xiao L  Zhou L  Greiner E  Fayer R 《Veterinary parasitology》2004,122(2):103-117

Fifteen dairy farms in seven states on the east coast of the US were each visited on two consecutive years to determinate the prevalence of Cryptosporidium species in pre-weaned (5 days to 2 months) and post-weaned calves (3-11 months), respectively. After each of 971 fecal specimens collected directly from each calf was sieved and subjected to density gradient centrifugation to remove debris and concentrate oocysts, specimens were examined by immunofluorescence microscopy, and polymerase chain reaction (PCR). For all PCR-positive specimens the 18S rRNA gene of Cryptosporidium was sequenced. Cryptosporidium was identified from all farms. Types of housing appeared to have no influence with regard to prevalence of infection. Of 971 calves, 345 were infected with Cryptosporidium (35.5%), but more pre-weaned calves (253 of 503; 50.3%) than post-weaned calves (92 of 468; 19.7%) were found to be infected. A total of 278 PCR-positive specimens characterized by gene sequencing revealed Cryptosporidium parvum, Cryptosporidium andersoni, and two unnamed Cryptosporidium genotypes Bovine B (AY120911) and deer-like genotype (AY120910). The prevalence of these Cryptosporidium species and genotypes appeared to be age related between pre- and post-weaned calves. C. parvum, the only zoonotic species/genotype, constituted 85% of the Cryptosporidium infections in pre-weaned calves but only 1% of the Cryptosporidium infections in post-weaned calves. These findings clearly demonstrate that earlier reports on the presence and prevalence of C. parvum in post-weaned cattle that were based solely on oocyst morphology must be reassessed using molecular methods to validate species and genotype. This finding also indicates that persons handling or otherwise exposed to calves under 2 months of age are at greater risk of zoonotic infection from Cryptosporidium than the risk of infection from exposure to older calves.  相似文献   

Comparison and standardisation of serological methods for the diagnosis of Neospora caninum infection in bovines     

von Blumröder D  Schares G  Norton R  Williams DJ  Esteban-Redondo I  Wright S  Björkman C  Frössling J  Risco-Castillo V  Fernández-García A  Ortega-Mora LM  Sager H  Hemphill A  van Maanen C  Wouda W  Conraths FJ 《Veterinary parasitology》2004,120(1-2):11-22

Various existing serological tests were compared with a standard panel of 523 sera in a multicentred study across Europe. Well characterised sera from animals that were experimentally or naturally infected with Neospora caninum as well as sera from cattle deemed uninfected with N. caninum were provided by the participants of the study and analysed in several commercial (CHEKIT Dr. Bommeli/Intervet, CIVTEST BOVIS NEOSPORA Hipra, Cypress Diagnostics C.V., Herd Check IDEXX, Mastazyme MAST Diagnostics, P38-ELISA Animal Welfare and Food Safety GmbH (AFOSA)) as well as in-house assays (five ELISAs and one IFAT). Most tests showed a high level of agreement in the interpretation of the test results (positive or negative). A further distinct increase in agreement between tests was obtained after the application of standardised cut-offs offered by a two-graph receiver operating characteristic analysis. This procedure allows a standardised interpretation of results obtained with different tests used in independent, parallel seroepidemiological studies.  相似文献   

Prevalence of Giardia duodenalis genotypes in pre-weaned dairy calves   总被引：1，自引：0，他引：1  

Trout JM  Santín M  Greiner E  Fayer R 《Veterinary parasitology》2004,124(3-4):179-186

To determine the prevalence of Giardia genotypes in pre-weaned dairy calves, fecal samples were collected from a minimum of 18, 1-7-week-old dairy calves per farm on two farms each in the states of Vermont, New York, Pennsylvania, Maryland, Virginia, North Carolina, and Florida. Samples cleaned of fecal debris and concentrated using CsCl density gradient centrifugation were stained and examined by immunofluorescence microscopy and also subjected to PCR and gene sequence analysis. Prevalence by PCR ranged from 9% on a farm in Pennsylvania to 93% on a farm in Vermont, with an average prevalence for 407 calves on 14 farms of 40%. Gene sequence analysis of the TPI, beta-giardin and 16S rRNA genes revealed 85% of the positive samples to be Assemblage E, while 15% were Assemblage A, although the percentages of these genotypes varied greatly from farm to farm. Some farms had no Assemblage A Giardia. Thus, while a majority of the calves were infected with a genotype that is not known to be infectious for humans, calves on 7 of 14 farms did harbor Assemblage A Giardia. Calves should be considered as a potential source of human infectious cysts in the environment.  相似文献   

Anaplasma infection in free-ranging Iberian red deer in the region of Castilla-La Mancha, Spain   总被引：4，自引：0，他引：4  

De La Fuente J  Vicente J  Höfle U  Ruiz-Fons F  Fernández De Mera IG  Van Den Bussche RA  Kocan KM  Gortazar C 《Veterinary microbiology》2004,100(3-4):163-173

Organisms in the genus Anaplasma are obligate intracellular pathogens that multiply in both vertebrate and invertebrate hosts. The type species, Anaplasma marginale, causes bovine anaplasmosis and infects erythrocytes of the vertebrate host and undergoes a complex developmental cycle in ticks which serve as biological vectors. Infected cattle, wild ruminants and ticks can all serve as reservoirs of A. marginale. In this study, hunter killed Iberian red deer (Cervus elaphus hispanicus) from the region of Castilla-La Mancha in southwestern Spain were tested for Anaplasma infection. We found that 10% of the deer examined were seropositive for Anaplasma. Three A. marginale strains were subsequently obtained from salivary glands of Hyalomma marginatum that were removed from these deer, and the sequence of the major surface protein (msp)4 gene was determined for each strain and used for phylogenetic studies. Maximum parsimony analyses of msp4 sequences from H. marginatum ticks in comparison with New World cattle and bison isolates reported previously, suggested different origins for these Spanish A. marginale strains. The results of this study demonstrated that Iberian red deer are naturally infected with Anaplasma, and may therefore serve as a wildlife reservoir of the pathogen. Although the link between deer infection and the strains of A. marginale identified in ticks was not established, H. marginatum and Rhipicephalus bursa were identified as potential biological vectors for A. marginale in this region and may effect transmission of A. marginale between deer and cattle populations.  相似文献   

The Bologna Treaty: a contribution to the development of quality education in Europe     

González-Soriano J  Rodríguez-Veiga E 《Journal of veterinary medical education》2004,31(3):212-215

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