Anatomopathological aspects of avian aspergillosis     

E. Cacciuttolo  G. Rossi  S. Nardoni  R. Legrottaglie  P. Mani 《Veterinary research communications》2009,33(6):521-527

Aspergillosis is a fungal disease caused by fungi of the genus Aspergillus, in particular A. fumigatus and A. flavus. This paper focuses on anatomopathological aspects resulting from a chronic infection from Aspergillus spp in the chicken (Gallus domesticus), in the herring gull (Larus cachinnans micaelli) and in the red-legged partridge (Alectoris rufa rufa). Microscopically, we observed some histological lesions that are related to the two typical forms of Aspergillosis: a deep nodular form, typical of organs with a non-aerated parenchyma, and a non-encapsulated superficial diffuse form typical of the serosae and the lung. The observed forms of aspergillosis have been found in animals raised in poor hygienic environmental conditions or malnourished animals (chicken); in wild birds from wildlife recovery centres (herring gull), which underwent some forms of stress, such as traumas, detention, starvation, extended antibiotic treatments; in game birds (red-legged partridge) used for restocking natural areas that had been negatively affected by such stressors as captivity in aviaries, containment and transport in cages, release in unsuitable environments and malnutrition. The observed anatomopathological and istopathological aspects can therefore be regarded as the outcome of a number of factors that have reduced the typical resistance of the species and impaired the efficiency of their immune systems.  相似文献   

Patterns of species change in anthropogenically disturbed forests of Madagascar     

Mitchell T. Irwin  Patricia C. Wright  Paul Loiselle  Daniel Rakotondravony  Jonah Ratsimbazafy 《Biological conservation》2010,143(10):2351-2362

Five main conclusions arise from this review of the responses of species to anthropogenic disturbance in Madagascar: First, species’ reactions to anthropogenic disturbance are generally negative, but remain poorly known. Our knowledge is patchy among and within higher taxonomic groups; we are still largely gathering case studies. Second, taxonomic groups vary considerably in which proximate factors are most important. Third, several groups show differing responses within different ecoregions. Whether these differences are consistent across groups requires further testing. Fourth, related species often have divergent reactions to disturbance, even within lower taxonomic groupings (families or genera). Thus, we cannot rely on phylogenetic relatedness or even ecological similarity to infer similarity in responses. Finally, disturbance typically reduces species diversity (especially of native and/or endemic species), but also causes species turnover, typically with forest specialists replaced by grassland generalists, and endemics replaced by non-endemics (including invasives). Given these knowledge gaps, we stress the urgency of applied studies that assess species’ ecology, behaviour and health across disturbance gradients, including purely anthropogenic landscapes. Remaining natural vegetation and protected areas will be unable to preserve Madagascar’s biodiversity under the impact of climatic change; we must understand responses of plants and animals to disturbance in order to create buffer zones and corridors combining secondary, degraded and natural habitats.  相似文献   

谈拖拉机交通事故逃逸案件的侦破     

王云鹿 《中国农机化》2003,(3):50-52

本文分析了拖拉机交通事故肇事逃逸案件的特点、事故现场处理和分析方法，为拖拉机交通肇事逃逸案件的侦破提供了经验和依据。  相似文献   

小松PC200-7挖掘机液压泵的故障诊断、分析及排除方法     

刘维萍 《农业装备与车辆工程》2007,(6):59-61

挖掘机液压泵的优劣直接影响到其动力性、经济性、可靠性、振动、噪声与排放特性的好坏,小松PC200-7挖掘机液压泵的故障诊断方法可分为“四觉”诊断法和仪器诊断法,详细地介绍了它的故障分析与排除方法。  相似文献   

Diversity and structure of the bird community overwintering in the Himalayan subalpine zone: is conservation compatible with tourism?     

Paola Laiolo 《Biological conservation》2004,115(2):251-262

In this paper data on the bird community overwintering in the subalpine zone of Sagarmatha National Park (Khumbu Himal area, Nepal) are presented, with particular emphasis on habitat structure and bird-habitat relationships. The impact of land use and management on the conservation of diversity is analysed and discussed. Four habitat types were considered: mixed forest, pure juniper forest, dwarf rhododendron shrubbery and cultivations. Mixed forest supports the richest avifauna, but forest birds are sensitive to over-exploitation of their habitat: bird density, species richness and diversity are significantly lower in heavily utilised forest. Here, the lower density of rhododendrons, firs and birches, together with their younger age, seem to be unattractive to insectivorous gleaners and granivores, which prefer tree- and understorey-rich spots of unutilised forest. Terraced cultivations also are a rich habitat for wintering birds, and traditional cultivations with hedgerows and scattered bushes have a great potential for bird conservation. Juniper woods are important habitats mainly for frugivores, whereas dwarf rhododendron shrubberies support the poorest avifauna. This study emphasises that forest birds and habitats are severely threatened. As deforestation is the consequence of the tourist pressure for fuelwood along the trekking route to Mt. Everest Base Camp, a strict regulation of tourist-related developments is essential to preserve biodiversity and manage land uses within sustainability.  相似文献   

Surrogate taxa for biodiversity in agricultural landscapes of eastern Austria   总被引：2，自引：0，他引：2  

Norbert Sauberer  Klaus Peter Zulka  Hans-Martin Berg  Norbert Milasowszky  Christoph Plutzar  Christiane Storch  Harald Zechmeister 《Biological conservation》2004,117(2):181-190

In an agricultural landscape in eastern Austria eight terrestrial organism groups were investigated as potential biodiversity indicators. We present a cross-taxon congruence assessment obtained at the landscape scale using two groups of plants (bryophytes and vascular plants), five groups of invertebrates (gastropods, spiders, orthopterans, carabid beetles and ants) and one vertebrate taxon (birds). We tested four different approaches: correlated species counts, surrogate measures of the overall species richness that was assessed, a multi-taxa (or shopping basket) approach and a simple complementarity algorithm. With few exceptions, pairwise correlations between taxa, correlations between one taxon and the species richness of the remaining groups, and correlations between a combination of the richness of two taxa and the remaining species richness were highly positive. Complementarity-derived priority sets of sampling sites using one taxon as a surrogate for the pooled species richness of all other taxa captured significantly more species than selecting areas randomly. As an essential first step in selecting useful biodiversity indicators, we demonstrate that species richness of vascular plants and birds showed the highest correlations with the overall species richness. In a multi-taxa approach and in complementarity site selection, each of the eight investigated taxa had the capability to capture a high percentage of the overall species richness.  相似文献   

Habitat-suitability modelling to assess the effects of land-use changes on Dupont’s lark Chersophilus duponti: A case study in the Layna Important Bird Area     

Javier Seoane  Jorge H. Justribó  Francisco García  Javier Retamar  Cristina Rabadán  Juan C. Atienza 《Biological conservation》2006,128(2):241-252

Habitat-suitability modelling is being increasingly used as a tool for conservation biology. Although studies at large spatial scales are more appropriate for reserve design and management, there is a scarcity of published work on local, high-resolution applications of such models. In this work we develop high-resolution habitat models (1 ha) and study habitat preferences (focal points) of Dupont’s lark Chersophilus duponti, an endangered shrub-steppe passerine, in the partially overlapping Special Protected Area for birds (SPA) and Important Bird Area (IBA) of “páramos de Layna” (NW Spain), to assess both the adequacy of the reserve’s limits and the effect of land-use changes on the species’ population size. Both analytical approaches show that the Dupont’s lark favours flat areas characterized by small shrubs with bare ground, so that, for example, a conversion of dry crops to shrubs promoted by agri-environment schemes under CAP could increase the population size up to 80%. Although the IBA and SPA are similar in size - as compelled by EU environmental policy - the latter shows rugged topography typically avoided by the species. We further discuss the possible conflict between EU environmental and agricultural policies on the conservation of this species and suggest it can be addressed with our study approach.  相似文献   

The responses of understorey birds to forest fragmentation, logging and wildfires: An Amazonian synthesis     

J. Barlow  C.A. Peres  P.C. Stouffer  J.M. Wunderle 《Biological conservation》2006,128(2):182-192

We combine mist-net data from 24 disturbance treatments taken from seven studies on the responses of understorey Amazonian birds to selective logging, single and recurrent wildfires, and habitat fragmentation. The different disturbance treatments had distinct effects on avian guild structure, and fire disturbance and the isolation of forest patches resulted in bird communities that were most divergent from those in continuous, undisturbed forest in terms of their species composition. Although low-intensity logging treatments had the least noticeable effects, the composition of understorey birds was still markedly different from the composition in undisturbed forest. This analysis demonstrates the importance of preventing habitat fragmentation and the spread of fires in humid tropical forests, and highlights the need for more research to determine the long-term suitability of large areas of degraded forest for forest birds.  相似文献   

Effects of habitat fragmentation on avian nesting success: a review of the evidence at multiple spatial scales     

Scott E Stephens  David N Koons  Jay J Rotella 《Biological conservation》2004,115(1):101-110

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Avian assemblages along a gradient of urbanization in a highly fragmented landscape   总被引：1，自引：0，他引：1  

Kevin R Crooks  Andrew V Suarez  Douglas T Bolger 《Biological conservation》2004,115(3):451-462

Our goal was to evaluate how avian assemblages varied along a gradient of urbanization in the highly fragmented landscape of coastal southern California. We measured species richness and abundance of birds within continuous blocks of habitat, within urban habitat fragments that varied in landscape and local habitat variables, and within the urban matrix at different distances from the wildland interface. These comparisons allowed us to characterize patterns of avifaunal response to a gradient of urban fragmentation. At the fragment scale, we found that fragment area was a strong, positive predictor of the total number of breeding species detected per fragment; total bird abundance per point count also increased with fragment size. Tree cover was higher in small fragments, as was the abundance of birds that typically occupy wooded habitats. Comparisons between core, fragment, and urban transects revealed differing patterns of response of individual bird species to urbanization. In unfragmented habitat, we recorded a relatively high diversity of urbanization-sensitive birds. In urban transects, these species were rare, and a relatively few species of non-native and anthropophilic birds were common. These urbanization-enhanced birds were also recorded in previous urban gradient studies in northern California and Ohio. Bird communities along the urban gradient reached their highest richness and abundance in fragments. The marked difference in vegetation structure between urban and natural landscapes in this arid shrubland system likely contributed to this pattern; the presence of native shrubs and exotic trees in fragments enabled both shrub and arboreal nesters to co-occur. As is characteristic of biotic homogenization, urban fragmentation in coastal southern California may increase local diversity but decrease overall regional avifaunal diversity.  相似文献