Can we face different types of storms under the same umbrella? Efficiency and consistency of connectivity umbrellas across different patchy landscape patterns

Context

The umbrella approach applied to landscape connectivity is based on the principle that the conservation or restoration of the dispersal habitats for some species also can facilitate the movement of others. Species traits alone do not seem to be enough to identify good connectivity umbrella species, showing the need to investigate the influence of additional factors on this property.

Objectives

We test whether the potential of a species as a connectivity umbrella can be influenced by landscape composition and configuration.

Methods

We simulated movement routes for eight hypothetical species in artificial patchy landscapes with different levels of fragmentation, habitat amount and matrix permeability. We determined the effectiveness of the connectivity umbrella of the virtual species using pairwise intersections of important habitats for their movements in all landscapes.

Results

The connectivity umbrella performance of all species was affected by the interaction of fragmentation level and habitat amount. In general, species performance increased with decreasing fragmentation and increasing habitat amount. In most landscapes and considering the same dispersal threshold, species able to move more easily through the matrix showed higher umbrella performance than those for which the matrix offered greater resistance.

Conclusions

The connectivity umbrella is not a static feature that depends only on the species traits, but rather a dynamic property that also varies according to the landscape attributes. Therefore, we do not recommend spatial transferability of the connectivity umbrella species identified in a landscape to others that have divergent levels of fragmentation and habitat quantity.

     

First molecular epidemiological study of Mycobacterium avium subsp. paratuberculosis in cattle and buffalo from different regions of Brazil

Tropical Animal Health and Production - Paratuberculosis is an incurable disease in ruminants with great worldwide economic impact, caused by Mycobacterium avium subsp. paratuberculosis (MAP). The...     

Multi-scale assessment of human-induced changes to Amazonian instream habitats

Context

Land use change and forest degradation have myriad effects on tropical ecosystems. Yet their consequences for low-order streams remain very poorly understood, including in the world´s largest freshwater basin, the Amazon.

Objectives

Determine the degree to which physical and chemical characteristics of the instream habitat of low-order Amazonian streams change in response to past local- and catchment-level anthropogenic disturbances.

Methods

To do so, we collected field instream habitat (i.e., physical habitat and water quality) and landscape data from 99 stream sites in two eastern Brazilian Amazon regions. We used random forest regression trees to assess the relative importance of different predictor variables in determining changes in instream habitat response variables.

Results

Multiple drivers, operating at multiple spatial scales, were important in determining changes in the physical habitat and water quality of the sites. Although we found few similarities in modelled relationships between the two regions, we observed non-linear responses of specific instream characteristics to landscape change; for example 20 % of catchment deforestation resulted in consistently warmer streams.

Conclusions

Our results highlight the importance of local riparian and catchment-scale forest cover in shaping instream physical environments, but also underscore the importance of other land use changes and activities, such as road crossings and upstream agriculture intensification. In contrast to the property-scale focus of the Brazilian Forest code, which governs environmental regulations on private land, our results reinforce the importance of catchment-wide management strategies to protect stream ecosystem integrity.

     

Factors associated with vesicular stomatitis in animals in the western United States

OBJECTIVE: To compare published recommendations regarding biosecurity practices for various production animal species and classes. DESIGN: Literature review. POPULATION: Educational materials available on the World Wide Web that provided biosecurity recommendations for dairy cattle, beef cattle, small ruminant, swine, and poultry producers. PROCEDURES: Web sites for national producer organizations, university cooperative extension services, and state departments of agriculture were searched to identify educational materials with biosecurity recommendations. RESULTS: A single national organization was selected as representing each animal agriculture commodity group. A total of 53 university Web sites were visited, and 65 publications prepared by university cooperative extension services were identified and evaluated. Web sites for all 50 state departments of agriculture were searched, and 29 were found to have at least 1 publication related to biosecurity practices, for a total of 46 publications. Evaluation of the biosecurity recommendations revealed wide variations by source and within and among commodity groups. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that educational materials for producers contained wide variations in recommended biosecurity practices. It is possible that some producers choose not to implement biosecurity recommendations because of confusion as to the specific recommendations they should follow.     

Factors associated with endemic raccoon (Procyon lotor) rabies in terrestrial mammals in New York State, USA

This study evaluated characteristics associated with raccoon (Procyon lotor) rabies in New York State (NYS), USA, where this disease has been endemic for the last 15 years. The study included 4448 cases of raccoon rabies in terrestrial mammals reported across 1639 census tracts of NYS during 1997-2003. A Poisson-regression model with census tract-year as the unit of analysis revealed a higher number of raccoon-variant rabies cases per square kilometer in census tracts with each percent increase in the proportion of low-intensity residential areas (those with a lower concentration of housing units) (RR=7.68) and a lack of rivers/lakes (RR=1.20) and major roads (RR=1.10), while the number of cases decreased with each 1-m increase in land elevation (RR=0.998), and each percent increase in the proportion of wetlands (RR=0.01). The model was adjusted for county, ecoregion, and latitude to help control for unknown spatially dependent covariates. The model may be used in prioritizing areas for rabies control based on differential risk, including use of costly intervention methods such as oral rabies vaccine.     

Suckling behavior,performance, and Kleiber index in calves of different genetic groups under shaded and unshaded environments

Tropical Animal Health and Production - According to previous studies, lamb mortality is high in the Ethiopian highlands. The present study aims to evaluate the execution of preventive sheep herd...     

Bioactivity of formulas containing essential oils from the family Myrtaceae for the management of deltamethrin-resistant Plutella xylostella (L.) (Lepidoptera: Plutellidae)

Plutella xylostella is the major pest of Brassica and is resistant to more than 95 synthetic insecticides, including deltamethrin, which is frequently used in family farming activities in the state of Pernambuco, Brazil. A possible strategy for overcoming such resistance is the use of botanical insecticides containing essential oils. The aim of the present study was to determine the chemical composition of essential oils from Syzygium aromaticum, Melaleuca alternifolia, Melaleuca leucadendra, Eucalyptus citriodora and Eucalyptus globulus and evaluate the effects of these oils as well as selected constituents (β-pinene, α-terpinene, ρ-cymene, limonene, 1,8-cineole, γ-terpinolene, citronellal, terpinen-4-ol, eugenol, β-caryophyllene and E-nerolidol) on different stages of development of two populations of P. xylostella – one susceptible and one resistant to deltamethrin. Chemical analysis by gas chromatography-mass spectrometry revealed eugenol (S. aromaticum), 1,8-cineole (E. globulus), citronellal (E. citriodora), terpinen-4-ol (M. alternifolia) and E-nerolidol (M. leucadendra) to be the major constituents. Among the oils tested, S. aromaticum was the most promising in the different modes of action and had the same level of toxicity to the two populations of P. xylostella analyzed. Among the constituents, E-nerolidol and terpinen-4-ol exhibited promising larvicidal action, whereas limonene exhibited promising ovicidal and antifeedant action. None of the oils presented severe phytotoxicity to the host plant. All results were compared to those achieved with deltamethrin and azadirachtin, which were used as positive controls. The deltamethrin-resistant population of P. xylostella did not exhibit pre-adaptive resistance to the oil from S. aromaticum or E-nerolidol, terpinen-4-ol and limonene.