Extinction risk of wood-living model species in forest landscapes as related to forest history and conservation strategy

Dead wood is a critical resource for biodiversity in boreal forests. We analysed the persistence of five model species inhabiting dead wood. By parameterising a metapopulation model (the incidence function model), the model species were all assigned characteristics that makes it likely that they have disappeared from some (20%) forest landscapes with a long history of forest management. In the metapopulation model, a forest stand (5 ha) was regarded as a habitat patch. The amount of habitat in each patch was obtained from models of dead wood dynamics of Norway spruce in central Sweden. Dead wood generated by altered management over the entire landscape was found to be less efficient in reducing extinction risks in comparison to the same amount of dead wood generated by protecting reserves. Because generation of dead wood by altered management is often less expensive than setting aside reserves, it is difficult to determine which conservation measure is most cost-efficient. In a landscape subjected to forestry for the first time, it was better to preserve a few large reserves than many small ones. However, in a managed, highly fragmented forest landscape it was better to set aside many small reserves. The reason for this was that small plots with high habitat quality could be selected, while large reserves originally contained habitats both of high and low quality, and the rate of habitat quality increase was low. A strategy for biodiversity conservation in a managed forest landscape should include information about the history of the landscape, the current amount and spatial distribution of forest habitats, and the potential for rapid restoration of forest habitats, both on managed and unmanaged forest land.     

Contemporary issues of veterinary practice valuation and sale transactions.

This article comprises discussions on practices with little or no salable value, the determination and measurement of the value of a veterinary practice, the evolution of the small animal practice marketplace, the costs of selling a portion of a practice, lack of marketability discount, and C corporation issues.     

Impacts of salvage-logging on the status of deadwood after windthrow in Swiss forests

Downed and standing deadwood (DW) is a key resource for maintaining forest biodiversity. Although extreme events such as windthrow and fires produce large quantities of DW, this substrate is often drastically reduced by logging activities. To elucidate the respecting consequences of salvage-logging, we assessed both quantity and quality of storm-derived DW (storms Vivian 1990 and Lothar 1999) in Swiss forests using a sample of 90 windthrow sites with ≥3 ha complete windthrow and at elevations ranging from 350 to 1,800 m a.s.l. The majority had been salvage-logged (SL) a few years after the windthrow. On each site, we recorded DW amount and quality on six circular sample plots 20 or 50 m² in size. DW volume on SL sites was surprisingly high, with 76.4 m³ ha^?1 on average 20 years after Vivian and 73.8 m³ ha^?1 10 years after Lothar. In comparison, DW volumes on unsalvaged sites, that is, with no post-windthrow intervention (NI), amounted to 270 m³ ha^?1. A wide variety of wood decay stages and diameter classes (10 to ≥70 cm) was found on both NI and SL sites, suggesting considerable habitat diversity for DW-associated species irrespective of the treatment. The considerable amounts of DW left after salvage-logging distinctly exceed the minimum DW volumes in forest stands proposed by Müller and Bütler (Eur J For Res 129: 981–992, 2010) in a conservation context, which demonstrates the importance of wind disturbance for biodiversity. Further studies should quantify DW of individual tree species, since habitat requirements are species-specific.     

Effect of host resistance on genetic structure of core and accessory chromosomes in Irish <Emphasis Type="Italic">Zymoseptoria tritici</Emphasis> populations

In agricultural pathosystems resistant cultivars are typically only temporarily effective, as widespread growth of said cultivars drives selection for pathogen genotypes capable of infecting them. A gene-for-gene interaction between Z. tritici and wheat has been demonstrated for one cultivar; however results of studies into the relevance of these interactions in the field remain inconsistent. Because genetic drift does not appear to occur between Z. tritici populations that are not widely geographically separated, according to neutral genetic theory if adaptation to different host cultivars is occurring, reduced genetic variation, and some differentiation between populations sourced from different cultivars should be observed. Selectively neutral microsatellite markers were used to genotype 260 isolates of Z. tritici taken from two naturally infected randomized block trials of four different cultivars, representing a spectrum of resistance to Z. tritici from susceptible to resistant. By calculating genetic parameters such as overall heterozygosity and F _ST from this genotypic data, the presented study aimed to determine if genetic drift or host selection is impacting on the genetic structure of the Irish Z. tritici population. Results indicated that diversity was distributed almost entirely within, rather than among populations, with little or no differentiation, and almost no clone isolates were present in the dataset. However this result was not reflected in the accessory chromosomes, where evidence of minor but significant genetic structure was found. This lack of structure in the core chromosomes and weak structure in the accessory chromosomes confirms that forces of genetic drift and selection are minor compared to sexual reproduction, in concurrence with multiple previous studies on other populations worldwide.     

Physicochemical property guidelines for modern agrochemicals

The relentless need for the discovery and development of new agrochemicals continues as a result of driving forces such as loss of existing products through the development of resistance, the necessity for products with more favorable environmental and toxicological profiles, shifting pest spectra, and the changing agricultural needs and practices of the farming community. These new challenges underscore the demand for novel, high‐quality starting points to accelerate the discovery of new agrochemicals that address market challenges. This article discusses the efforts to identify the optimum ranges of physicochemical properties of agrochemicals through analysis of modern commercial products. Specifically, we reviewed literature studies examining physicochemical property effects and analyzed the properties typical of successful fungicides, herbicides, and insecticides (chewing and sap‐feeding pests). From the analysis, a new set of physicochemical property guidelines for each discipline, as well as building block class, are proposed. These new guidelines should significantly aid in the discovery of next‐generation agrochemicals. © 2018 Society of Chemical Industry     

Synergist induced susceptibility of tobacco caterpillar, <Emphasis Type="Italic">Spodoptera litura</Emphasis> (Fabricius) from Kerala,India exposed to conventional insecticides

The present study was undertaken to assess the insecticide resistance developed in various field collected population of S. litura and to induce susceptibility by using the synergists. Third-instar larvae collected from three different locations of Kerala viz., Thiruvananthapuram (TVM), Pathanamthitta (PTA) and Alappuzha (ALP) were exposed to conventional insecticides like chlorpyriphos, quinalphos, lambda-cyhalothrin and cypermethrin by leaf dip bioassay and resistance ratios were calculated by using the baseline data generated for respective insecticides using susceptible strain. Resistance ratios recorded were 1965, 840 and 320 against chlorpyriphos, 605, 255 and 59 against quinalphos, 926, 250 and 108 against lambda-cyahlothrin and 2566, 534 and 396 against cypermethrin respectively for TVM, PTA and ALP populations. The effect of selected synergists viz., piperonyl butoxide (PBO), diethyl maleate (DEM) and triphenyl phosphate (TPP) was studied in combination with respective test insecticides against the highly resistant population of S.litura collected from TVM of Kerala. The population was tested with insecticide in combination of the above synergists at different ratios. When PBO, TPP and DEM at ratio of 1:4 were used the synergistic ratio was 8.47, 7.26 and 3.98 for chlorpyriphos, 6.09, 5.26 and 3.05 for quinalphos, 13.37, 4.53 and 7.39 for lambda cyhalothrin and 4.77, 3.36 and 3.40 for cypermethrin respectively. PBO showed highest synergistic activity against both the organophosphates tested followed by DEM and TPP. Highest synergistic activity against synthetic pyrethroids also was shown by PBO, followed by TPP and DEM. The results obtained from the present study revealed that PBO at 1:4 ratio showed higher synergism with the test insecticides against the resistant populations of S.litura and proved to be an effective molecule alternate for breaking the resistance against conventional organophosphates and synthetic pyrethroids.     

Relationships between soil spectral and chemical properties along a climatic gradient in the Judean desert

Regions of rainfall gradients at desert margins are areas where eco-geomorphic changes and degradation in response to global warming and grazing are most intensive. Assessment and understanding of the consequences of global warming and human disturbance of these vulnerable ecosystems requires detailed information regarding the spatial variation of soil and vegetation properties and their dependence on rainfall. Such detailed information is still of limited availability. This study aimed to rectify this shortcoming by analyzing data on the chemical and spectral properties of soil samples collected along the Judean Desert climatic gradient. Six clusters of typical chemical soil properties were identified. Dependencies of clusters’ chemical properties (total iron, organic and inorganic carbon) on annual rainfall amounts were found to be significant. Two spectral Landsat TM band ratios introduced to assess soil conditions showed significant correlations with these chemical properties. These ratios were found to be higher correlated than individual chemical properties with average rainfall suggesting that spectral data may represent a broader range of chemical, physical, and biological site properties. Examining the three-way relationships between soil chemical properties, their spectral reflectance characteristics and rainfall, facilitates a better understanding of the generalized trends along the climatic gradient and more specifically of modes of transition from semi-arid to arid zones.     

Pesticide exposure assessment for surface waters in the EU. Part 1: Some comments on the current procedure

In 2001, the European Commission introduced a risk assessment project known as FOCUS (FOrum for the Coordination of pesticide fate models and their USe) for the surface water risk assessment of active substances in the European Union. Even for the national authorisation of plant protection products (PPPs), the vast majority of EU member states still refer to the four runoff and six drainage scenarios selected by the FOCUS Surface Water Workgroup. However, our study, as well as the European Food Safety Authority (EFSA), has stated the need for various improvements. Current developments in pesticide exposure assessment mainly relate to two processes. Firstly, predicted environmental concentrations (PECs) of pesticides are calculated by introducing model input variables such as weather conditions, soil properties and substance fate parameters that have a probabilistic nature. Secondly, spatially distributed PECs for soil–climate scenarios are derived on the basis of an analysis of geodata. Such approaches facilitate the calculation of a spatiotemporal cumulative distribution function (CDF) of PECs for a given area of interest and are subsequently used to determine an exposure concentration endpoint as a given percentile of the CDF. For national PPP authorisation, we propose that, in the future, exposure endpoints should be determined from the overall known statistical PEC population for an area of interest, and derived for soil and climate conditions specific to the particular member state. © 2016 Society of Chemical Industry