RESUMO
The identification of avian poxvirus and avian papillomavirus associated with cutaneous lesions in griffon vultures (Gyps fulvus) by histopathology, electron microscopy and PCR analysis is reported. Sequence analysis of the fpv140 gene revealed 99% identity to two poxviruses obtained from a white-tailed sea eagle (Haliaeetus albicilla) and a common buzzard (Buteo buteo). Partial sequence of the papillomavirus L1 gene showed sequence similarity to papillomavirus LI genes from African grey parrot (Psittacus erithacus) (69% identity), duck (Anas platyrhynchos) (68% identity), and yellow-necked francolin (Francolinus leucoscepus) (66% identity). To date, this is the first identification of avian poxvirus and papillomavirus in griffon vultures and the first evidence of infection of both viruses in live wild birds.
Assuntos
Avipoxvirus/isolamento & purificação , Doenças das Aves/virologia , Papillomaviridae/isolamento & purificação , Infecções por Papillomavirus/veterinária , Infecções por Poxviridae/veterinária , Animais , Avipoxvirus/genética , Doenças das Aves/epidemiologia , Falconiformes , Variação Genética , Itália/epidemiologia , Papillomaviridae/genética , Infecções por Papillomavirus/epidemiologia , Infecções por Papillomavirus/virologia , Filogenia , Infecções por Poxviridae/epidemiologia , Infecções por Poxviridae/virologiaRESUMO
Many small terrestrial vertebrates exhibit limited spatial movement and are considerably exposed to changes in local environmental variables. Among such vertebrates, amphibians at present experience a dramatic decline due to their limited resilience to environmental change. Since the local survival and abundance of amphibians is intrinsically related to the availability of shelters, conservation plans need to take microhabitat requirements into account. In order to gain insight into the terrestrial ecology of the spectacled salamander Salamandrina perspicillata and to identify appropriate forest management strategies, we investigated the salamander's seasonal variability in habitat use of trees as shelters in relation to tree features (size, buttresses, basal holes) and environmental variables in a beech forest in Italy. We used the occupancy approach to assess tree suitability on a non-conventional spatial scale. Our approach provides fine-grained parameters of microhabitat suitability and elucidates many aspects of the salamander's terrestrial ecology. Occupancy changed with the annual life cycle and was higher in autumn than in spring, when females were found closer to the stream in the study area. Salamanders showed a seasonal pattern regarding the trees they occupied and a clear preference for trees with a larger diameter and more burrows. With respect to forest management, we suggest maintaining a suitable number of trees with a trunk diameter exceeding 30 cm. A practice of selective logging along the banks of streams could help maintain an adequate quantity of the appropriate microhabitat. Furthermore, in areas with a presence of salamanders, a good forest management plan requires leaving an adequate buffer zone around streams, which should be wider in autumn than in spring.
Assuntos
Urodelos , Animais , Feminino , Florestas , Itália , ÁrvoresRESUMO
Environmental heterogeneity affects not only the distribution of a species but also its local abundance. High heterogeneity due to habitat alteration and fragmentation can influence the realized niche of a species, lowering habitat suitability as well as reducing local abundance. We investigate whether a relationship exists between habitat suitability and abundance and whether both are affected by fragmentation. Our aim was to assess the predictive power of such a relationship to derive advice for environmental management. As a model species we used a forest specialist, the short-toed treecreeper (Family: Certhiidae; Certhia brachydactyla Brehm, 1820), and sampled it in central Italy. Species distribution was modelled as a function of forest structure, productivity and fragmentation, while abundance was directly estimated in two central Italian forest stands. Different algorithms were implemented to model species distribution, employing 170 occurrence points provided mostly by the MITO2000 database: an artificial neural network, classification tree analysis, flexible discriminant analysis, generalized boosting models, generalized linear models, multivariate additive regression splines, maximum entropy and random forests. Abundance was estimated also considering detectability, through N-mixture models. Differences between forest stands in both abundance and habitat suitability were assessed as well as the existence of a relationship. Simpler algorithms resulted in higher goodness of fit than complex ones. Fragmentation was highly influential in determining potential distribution. Local abundance and habitat suitability differed significantly between the two forest stands, which were also significantly different in the degree of fragmentation. Regression showed that suitability has a weak significant effect in explaining increasing value of abundance. In particular, local abundances varied both at low and high suitability values. The study lends support to the concept that the degree of fragmentation can contribute to alter not only the suitability of an area for a species, but also its abundance. Even if the relationship between suitability and abundance can be used as an early warning of habitat deterioration, its weak predictive power needs further research. However, we define relationships between a species and some landscape features (i.e., fragmentation, extensive rejuvenation of forests and tree plantations) which could be easily controlled by appropriate forest management planning to enhance environmental suitability, at least in an area possessing high conservation and biodiversity values.