Building wood debris piles benefits avian seed dispersers in burned and logged Mediterranean pine forests

Salvage logging is a common practice carried out in burned forests worldwide, and intended to mitigate the economic losses caused by wildfires. Logging implies an additional disturbance occurring shortly after fire, although its ecological effects can be somewhat mitigated by leaving wood debris on site. The composition of the bird community and its capacity to provide ecosystem services such as seed dispersal of fleshy-fruited plants have been shown to be affected by postfire logging. We assessed the effects of the habitat structure resulting from different postfire management practices on the bird community, in three burned pine forests in Catalonia (western Mediterranean). For this purpose, we focused on the group of species that is responsible for seed dispersal, a process which takes place primarily during the winter in the Mediterranean basin. In addition, we assessed microhabitat selection by seed disperser birds in such environments in relation to management practices. Our results showed a significant, positive relationship between the density of wood debris piles and the abundance of seed disperser birds. Furthermore, such piles were the preferred microhabitat of these species. This reveals an important effect of forest management on seed disperser birds, which is likely to affect the dynamics of bird-dependent seed dispersal. Thus, building wood debris piles can be a useful practice for the conservation of both the species and their ecosystem services, while also being compatible with timber harvesting.     

Prominent role of invasive species in avian biodiversity loss

The rise of extinction rates associated with human activities has led to a growing interest in identifying extinction-prone taxa and extinction-promoting drivers. Previous work has identified habitat alterations and invasive species as the major drivers of recent bird extinctions. Here, we extend this work to ask how these human-driven impacts differentially affect extinction-prone taxa, and if any specific driver promotes taxonomic homogenization of avifauna. Like most previous studies, our analysis is based on global information of extinction drivers affecting threatened and extinct bird species from the IUCN Red List. Unlike previous studies, we employ a multivariate statistical framework that allows us to identify the main gradients of variation in extinction drivers. By using these gradients, we show that bird families with the highest extinction risk are primarily associated with threats posed by invasive species, once species richness and phylogeny are taken into account. As expected, the negative impact of invasive species was higher on island species, but our results also showed that it was particularly high in those species with small distribution ranges. On the other hand, mainland species and island species with large ranges tended to be affected by habitat destruction. Thus the impacts of invasive species promote the process of taxonomic homogenization among islands and between islands and continents. Consequently, introduced species may increase biotic homogenization not only directly, as generally believed, but also indirectly through their disproportional impact on endemic species imperilment.     

Environmental factors on virulence of <Emphasis Type="Italic">Aeromonas hydrophila</Emphasis>

Aeromonas hydrophila are known for being opportunistic pathogens, harboring various virulence factors and triggering lesions and death in fish. The disease caused by bacteria can make fish inappropriate for human consumption, besides representing a risk to public health. The pathogenesis can be influenced by environmental variables, affecting fish productivity and mortality. The present study aimed to determine whether A. hydrophila harbor the virulence genes aerolysin, hydrolipase, elastase, lipase, cytotonic enterotoxin (ast), lateral flagellum (laf), and polar flagellum (fla) and to evaluate the influence of environmental variables on in vitro growth, in vivo virulence and expression of some of these genes. Polymerase chain reaction (PCR)-based screening for the presence of these virulence genes was performed on 35 isolates. Six isolates containing different profiles of virulence genes were tested for in vitro growth under different conditions of pH, temperature, and ammonia and for in vivo virulence under these same environmental conditions. RT-qPCR was used to quantify the expression of aerolysin, lipase, and fla genes. All the tested environmental factors influenced the growth of A. hydrophila, while pH and ammonia concentrations influenced the bacterial virulence. The expression of the fla gene increased when bacteria were grown in higher ammonia concentration. The mortality established by Aeromonas is influenced by several environmental factors pinpointing the importance of its control in fish farming to avoid higher economic loses associated to bacterial disease outbreaks.     

Epidemiological relationship of human and swine Streptococcus suis isolates

Two cases of meningitis due to Streptococcus suis in humans are reported here. A butcher and an abattoir worker were referred to a health centre in Castellón (Spain) with fever and symptoms of meningitis. After adequate treatment, a slight hipoacusia persisted as sequelae in both cases. Colonies of S. suis group R, serotype 2 and phenotype MRP+EF+ were isolated from cerebroespinal fluid. Epidemiological studies showed that both workers had in common the handling of pork meat of slaughtered healthy pigs from three closed farms. A study of the tonsils from apparently healthy, slaughtered pigs was carried out. A total of 234 tonsillar samples were obtained and 81 strains of S. suis were isolated from them. Serotype 2 appeared to be the most frequent (50.6%), and the analysis for phenotype showed a high percentage of tonsillar strains with the phenotype MRP+EF+ (35.9%). The humans and 28 tonsillar swine strains showed a similar profile (S. suis group R, serotype 2 and phenotype MRP+EF+). A total of 26 of the swine isolates were analysed by ribotyping using EcoRI. The human strains showed the same six-band hybridization pattern that shared five bands with the pattern most frequently shown by most of the tonsillar N. suis group R, serotype 2 and phenotype MRP+EF+ strains, differing only in the lightest, faintest band which was slightly less anodical in human (> or = 1.8 kb) than in swine (approximately 1.8 kb). From these results, both groups of strains, humans and porcine, showed differences; how can these differences in the pattern of ribotyping be explained if they should have the same origin? Is it possible that they have undergone an adaptation to the new host or perhaps the modification is due to other unknown causes? Further studies in this area are required in order to answer these questions.     

Spring aphid-parasitoid (Hom., Aphididae, Hym., Braconidae) associations and interactions in a Mediterranean arable crop ecosystem, including Bt maize

Conspecific and heterospecific associations of aphid parasitoids (Hymenoptera, Braconidae, Aphidiinae) were used to determine the interactions between crops forming the main arable crop ecosystem (wheat, alfalfa, isogenic and [Bt Bacillus thuringiensis] transgenic maize) in an irrigated area in Catalonia, Spain. Species composition and instars of parasitized aphids (mummies) were used to detect the parasitoid population movements between the crops and proved interactions (alternation) between the crops, including transgenic maize. Parasitoid interactions were species-dependent, appearing in the movements between alfalfa-wheat-maize in the individual species. Aphidius ervi Hal., A. rhopalosiphi DeSt.-Perez, A. uzbekistanicus Luzh., Lysiphlebus testaceipes (Cress.) and Praon volucre (Hal.) were classified as key-stone species in the target agroecosystems in the area. No differences were found in aphid-parasitoid associations on Bt transgenic maize and isogenic maize for aphid species composition and associated parasitoid guild.     

Rabies-vaccination coverage and profiles of the owned-dog population in Santa Cruz de la Sierra, Bolivia

The Bolivian government issued a regulation for rabies control in November 2005, owing to increasing the prevalence of dog and human rabies cases in recent years. An assessment of rabies-vaccination coverage and other factors that might influence the success of the on-going vaccination campaign was needed. The objective of this study was to investigate dog rabies vaccination coverage and risk factors associated with dogs being unvaccinated against rabies, and profiles of the owned-dog population in Santa Cruz de la Sierra, Bolivia, where dog rabies was endemic. Mainly due to logistical reasons, the WHO's expanded programme on immunization cluster-survey method was used. The 390 households were included in the study. Information about dog population and management characteristics was obtained for 542 dogs from 301 households. On average, households had 1.4 dogs and 1.8 dogs per dog-owning household (median = 1). The human-to-dog ratio was 4.6 : 1. During the last 1 year prior to the study, of the 539 dogs aged >or=1 month, 463 (85%; 95% CI 79-91; design effect 3.6) were classified as vaccinated. Amongst the study dogs, dogs aged 1-11 months were the higher risk of dogs not being vaccinated (OR = 8.2; 95% CI 4.3-15.6; P < 0.01). Almost two-thirds of the study dogs were allowed to roam freely throughout the day or in part. Community education efforts should address the importance of dog ownership and movement restriction, and the need to vaccinate young dogs.     

The biodiversity and genetic structure of Balearic sheep breeds

The Balearic sheep breeds, Mallorquina, Menorquina, Roja Mallorquina, Ibicenca and one possible new genetic group, Formentera, constitute a unique genetic resource in the Mediterranean farming landscape, displaying high genetic diversity levels and being well differentiated among themselves and with respect to the continental sheep breeds. We used a microsatellite panel of markers to study genetic diversity and relationships with other Spanish breeds. The results reported in this study have important implications for the use, conservation and breeding of Balearic sheep stocks. A mean number of 7.59 alleles was found among the Balearic sheep breeds for the microsatellites scored. The whole mean value of observed heterozygosity amounted to 0.62, whereas the expected heterozygosity value was 0.69, suggesting the presence of a great degree of genetic variability, although a significant deficit of heterozygotes was detected for some markers. Genetic distance estimates showed that Balearic sheep are differentiated from the other Spanish breeds and in particular, from the Merino type. The Ibicenca breed showed the highest distance value from other breeds. The neighbour‐net method of analysis clustered the Roja Mallorquina, Menorquina and Mallorquina breeds. The Structure results clearly demonstrated the genetic differentiation among the four Balearic sheep breeds, with the Ibicenca and Formentera races joined, with slight migration among them. Few external genetic influences from the Spanish mainland breeds were detected.     

Regeneration and genetic transformation of Spanish rice cultivars using mature embryos

To establish a plant regeneration system from embryogenic callus derived from mature rice embryos, the addition of aminoacids and the effect of two macronutrient solutions MSD and N6D to the basal callus induction medium was tested in three Spanish varieties, Senia, Tebre and Bahia. Aminoacids enhanced the production of embryogenic callus in Tebre and Senia whereas in the case of Bahia, embryogenic callus, which gave rise to a high rate of differentiated shoots, was induced without aminoacids. The macronutrient solution had also to be adjusted for each variety. Pre-regeneration treatment with ABA significantly improved the regeneration rate in all media tested, independently of the media in which the embryogenic callus were induced. In a comparison of growth regulators, BA yielded more shoots than Kin in all varieties whereas the effect of the auxins NAA or IAA was dependent on the variety. Transgenic plants from the three varieties were obtained via an Agrobacterium tumefaciens transformation system, using the optimised culture media. This revised version was published online in July 2006 with corrections to the Cover Date.