Humoral response of Borrelia burgdorferi outer surface protein A (OspA) vaccination in equids

The objective of this study was to assess the safety and humoral response of outer surface protein A (OspA) Borrelia burgdorferi vaccine in equids via the transdermal or subcutaneous route over 355 days. Prior to vaccination, serological testing confirmed the vaccination and exposure status to B. burgdorferi. Vaccine was administered on Days 0, 22 and 226. Equids were examined for vaccine reactions at 24 h post‐vaccination. Antibodies to outer surface proteins were quantified over 355 days. A total of 42 healthy adult equids of various ages and breeds were used. These equids were selected based on unlikely exposure to B. burgdorferi. The equids were grouped according to full size, miniature, age and sex to create two relatively heterogeneous mirrored groups of 20 equids. Group TD (20 equids) was administered 1 mL (1/2 mL/site) vaccine transdermally over the pectoral region. Group SQ (19 equids) was administered 2 mL in a single injection subcutaneously at the left cervical region. Group C (3 equids) was unvaccinated. Vaccine was administered on Days 0, 22 and 226. Antibodies to outer surface proteins were quantified over 355 days. Both vaccinated groups responded with a significant increase in OspA antibodies as compared with the control group (P<0.0001) and to themselves prevaccination. The mean response was greater in vaccinated equids (Group SQ, P<0.0080; Group TD, P<0.0016) as compared prevaccine and control. Equids responded to the OspA vaccine via either route. This data may aid in strategic vaccination protocols and the development of a USDA approved vaccine for equids in the prevention of Lyme disease using the OspA vaccine.     

Evaluation of 10-year temporal and spatial variability in structure and growth across contrasting commercial thinning treatments in spruce-fir forests of northern Maine,USA

Key message

Detailed measures of growth pattern and structural heterogeneity applied in this study helped to quantify the immediate effects of various thinning regimes on forest structure and the resulting alterations in tree size as well as observed longer term stand dynamics.

Context

Forest management, stand structure, and tree growth are highly inter-correlated. Prior analyses, however, have resulted in mixed outcomes with limited success in revealing ecological mechanisms.

Aims

The study aimed at evaluating the relationship between forest structure and stand dynamics by applying several sophisticated measures of growth pattern and structural heterogeneity.

Methods

Data from a controlled and fully stem-mapped commercial thinning experiment with seven contrasting treatments including a non-thinned control at six locations across the Acadian Forest of Maine, USA, was used. Stand-level attributes examined included tree size and growth heterogeneity, spatial tree distribution, and growth dominance.

Results

Thinning generally reduced stand structural heterogeneity compared to the non-thinned control. In addition, the spatial arrangement of trees changed from fully random (non-thinned control) to a more clustered (removal of dominant and co-dominant individuals) or regular distribution (removal of intermediate and suppressed individuals). Overall, stand growth exhibited increasing (non-thinned control, removal of intermediate and suppressed individuals) or decreasing growth dominance of large trees (removal of co-dominant competitors). Forwarder trails increased basal area growth of individual trees up to a distance from the trail of approximately 5 m.

Conclusion

Findings of this study validate an earlier insight according to which interactions between management practices, forest structure, and tree growth form a permanent feedback loop.

     

Untersuchungen zum notwendigen Maß bei der Anwendung von Pflanzenschutzmitteln in Winterweizen in den Jahren 2004 bis 2016

In order to provide recommendations for future cropping systems with regard to the necessary minimum of pesticide use, a long-term field trial at the field site in Dahnsdorf of the Julius Kühn-Institute was conducted in the years 2004 to 2016 to investigate possible reduction of pesticides, taking into account the general principles of integrated pest management (Strategies to reduce the use of plant protection products). Two winter wheats (WW1 and WW2) were part of the crop rotation with six components and different quality classes (A wheat (WW1) and E wheat (WW2)) and resistance levels to important wheat pathogens. In all years, herbicides and fungicides were needed to control weeds and fungal pathogens due to the excess of the control threshold. Insecticides were only necessary in two years. When considering the treatment frequency index (TFI), the mean overall TFI varied with 2.6 in WW1 and 3.5 in WW2, but was significantly lower compared to practice. There were also differences in the mean fungicide TFI of the two crop rotation elements with 1.1 in WW1 and 1.6 in WW2 due to their different resistance level to important fungal pathogens. The same is true with regard to the herbicide TFI with of 1.1 in WW1 and 1.3 in WW2. The treatments in the strategies 2, 3 and 4 mostly resulted in significantly higher yields compared to the non-chemical strategy 1, which can be attributed to the strong weed and fungal infestations in strategy 1 and the good efficacy of the used plant protection products. The tended differences between strategy 2 with a situation-related application rate and the 25 and 50% reduced application rates in strategies 3 and 4, respectively, were not significant. A reduced application rate showed no negative long-term effects on weed emergence even after 13 years, but increased emergence numbers in strategies with reduced herbicide use. The results show that plant protection products savings are possible without significantly reducing yields. However, this requires a high level of human resources for monitoring and scoring the consistent observance of the principles of integrated pest management, such as the consideration of good crop rotation, the cultivation of resistant cultivars and the optimally coordinated treatments after the control threshold has been exceeded.     

The impact of seasonal variability in wildlife populations on the predicted spread of foot and mouth disease

Modeling potential disease spread in wildlife populations is important for predicting, responding to and recovering from a foreign animal disease incursion such as foot and mouth disease (FMD). We conducted a series of simulation experiments to determine how seasonal estimates of the spatial distribution of white-tailed deer impact the predicted magnitude and distribution of potential FMD outbreaks. Outbreaks were simulated in a study area comprising two distinct ecoregions in South Texas, USA, using a susceptible-latent-infectious-resistant geographic automata model (Sirca). Seasonal deer distributions were estimated by spatial autoregressive lag models and the normalized difference vegetation index. Significant (P < 0.0001) differences in both the median predicted number of deer infected and number of herds infected were found both between seasons and between ecoregions. Larger outbreaks occurred in winter within the higher deer-density ecoregion, whereas larger outbreaks occurred in summer and fall within the lower deer-density ecoregion. Results of this simulation study suggest that the outcome of an FMD incursion in a population of wildlife would depend on the density of the population infected and when during the year the incursion occurs. It is likely that such effects would be seen for FMD incursions in other regions and countries, and for other diseases, in cases in which a potential wildlife reservoir exists. Study findings indicate that the design of a mitigation strategy needs to take into account population and seasonal characteristics.     

KNOWLEDGE MANAGEMENT FOR LAND DEGRADATION MONITORING AND ASSESSMENT: AN ANALYSIS OF CONTEMPORARY THINKING

It is increasingly recognised that land degradation monitoring and assessment can benefit from incorporating multiple sources of knowledge, using a variety of methods at different scales, including the perspectives of researchers, land managers and other stakeholders. However, the knowledge and methods required to achieve this are often dispersed across individuals and organisations at different levels and locations. Appropriate knowledge management mechanisms are therefore required to more efficiently harness these different sources of knowledge and facilitate their broader dissemination and application. This paper examines what knowledge is, how it is generated and explores how it may be stored, transferred and exchanged between knowledge producers and users before it is applied to monitor and assess land degradation at the local scale. It suggests that knowledge management can also benefit from the development of mechanisms that promote changes in understanding and efficient means of accessing and/or brokering knowledge. Broadly, these processes for knowledge management can (i) help identify and share good practices and build capacity for land degradation monitoring at different scales and in different contexts and (ii) create knowledge networks to share lessons learned and monitoring data among and between different stakeholders, scales and locations. Copyright © 2011 John Wiley & Sons, Ltd.     

Temporal segregation in spawning between native Yellowstone cutthroat trout and introduced rainbow trout

Hybridisation with introduced taxa poses a threat to native fish populations. Mechanisms of reproductive isolation can limit or prevent hybridisation between closely related species. Understanding how these mechanisms interact between the same species across geographically distinct occurrences of secondary contact, and how regional factors influence them, can inform our understanding of hybridisation as a threat and management actions to mitigate this threat. We used data collected on adult fish migration timing and approximate emergence timing of subsequent juvenile fish paired with genomic data to assess whether temporal isolation in the timing of spawning exists between Yellowstone cutthroat trout, rainbow trout and hybrids in the North Fork Shoshone River drainage in northwest Wyoming. We found evidence that Yellowstone cutthroat trout spawn, on average, two to four weeks later than rainbow trout and hybrids and two environmental covariates related to water temperature and discharge were associated with differences in spawning migration timing. Despite statistical support for Yellowstone cutthroat trout spawning later, disproportionately high numbers of rainbow trout and hybrids, paired with extended spawning seasons, lead to substantial overlap between all genotypes. Our results provide further evidence of temporal segregation in the timing of spawning as a mechanism of reproductive isolation between closely related species, but substantial spawning overlap suggests temporal segregation alone will not be enough to curtail hybridisation in conservation populations.     

Assessment of changes in the ichthyofauna in a tropical reservoir in south-eastern Brazil: Consequences of global warming?

Increases in temperatures over the last century, more intensively after the eighties, were recorded in several databases for the south-eastern Brazil. These increases are likely to change fish communities in aquatic systems by decreasing abundances, biomass and sizes of some species more sensitive to climate change. Reservoirs may be particularly susceptible to the effects of climate change, as they isolate previously connected areas limiting fish dispersal and migration, as well as increasing water temperature and thermal stratification. We assessed temporal changes in the abundance and biomass of the ichthyofauna in an isolate reservoir (inflowing waters from small tributaries in a highland region) aiming to associate changes with climate effects over three decades (1990, 2000, 2010). Two abundant native species, a loricariid Loricariichthys castaneus (Castelnau, 1855) and a cichlid Geophagus brasiliensis (Quoy & Gaimard, 1824), were selected to assess eventual response to climate changes in their geographical distribution in the Southeast Atlantic Hydrographic Region, considering different carbon emission scenarios using ecological niche models. A decrease in the densities and biomass of the ichthyofauna and of the two selected species were observed in both summer and winter over the three decades, coinciding with increases in temperatures. These decreases were correlated with increases in positive anomalies of temperature, which may be an indicator of climatic changes, although with low explanation of the data variation. The mean size of L. castaneus decreased between the nineties and 2010, whereas no significant trend was found for the size of G. brasiliensis. Our predictions of new area for future adequacy indicated a loss in the distribution area for both species (mainly for G. brasiliensis), considering the most pessimistic scenario for 2050 and 2070, possibly due to climatic changes. Both hydroelectric dams and global warming pose threats to freshwater fish diversity, and both will interact. Changes observed in the fish assemblage over the last decades were essential for an assessment of the consequences of global warming in this type of reservoir combining larger scale studies with future projections.