Are lignins optically active?

The accepted derivation of lignins from non(enzymatically)-controlled radical coupling reactions has been recently challenged, and it is relevant to ascertain unequivocally whether lignins are or are not (as normally assumed) optically active. Two approaches were used. First, DFRC (derivatization followed by reductive cleavage) dimers derived from beta-5- and beta-beta-units in pine lignins, which certainly retain unaltered chiral centers (as well as beta-1- and beta-O-4-units where the intactness may be debated), were shown to be optically inactive by circular dichroism (CD) and chiral high-performance liquid chromatography. CD of beta-5-derived dimers following enantiomeric separation readily demonstrated the sensitivity of the method. Second, no optical activity could be detected (above 250 nm to avoid carbohydrate contributions) by CD of lignin isolates from pine, kenaf, maize, or a CAD-deficient pine mutant. Representative lignins are therefore not, within limits of detection by these methods, optically active.     

Are There Arid Land Soilscapes in Southwestern Europe?

No studies have proven the existence of soil assemblages typical of arid lands in Europe. This study was carried out in a representative territory of the southeastern part of the Iberian Peninsula, Almería province, which is the driest part of Europe, to determine if soils characteristic of arid lands are present. In order to analyse the spatial distribution of soils, the authors made use of mathematical tools previously developed in biodiversity and pedodiversity analysis, such as richness, entropy indices, abundance distribution models, diversity‐area relationships and nested subset analysis. The study demonstrates that the soil types or pedotaxa are typical of mountainous arid lands. Shallow and weakly developed soils (e.g. Leptosols, Regosols and Arenosols), Calcisols, Gypsisols and Solonchaks, cover most of the study area, and pedodiversity analysis demonstrates that the pedotaxa spatial patterns follow the same regularities as in other areas, environments and scales. In view of the fact that the class of landscapes identified in this study is unique in Europe, the Tarbernas desert and other arid lands sites of the study area merit preservation as part of the European geological, geomorphological and pedological heritage. Copyright © 2015 John Wiley & Sons, Ltd.     

Are there real endogeic species in temperate forest mites?

The determinants of mite diversity in soil and the reasons why so many species co-exist are poorly understood. There is evidence that niche differentiation (i.e. microhabitat complexity) in the litter layers of forest floors is important, however, little is known for deeper horizons since mite density and diversity in deeper soil layers have been rarely studied. In order to address this dearth of information, we collected microarthropods from both the forest floor and the mineral soil to a depth of 1 m in two deciduous forest locations. The density exceeded 8×10⁵ microarthropods m⁻² in one location, and a number of individuals were collected from deep in the soil. No species was exclusively living in mineral horizons. Measurements of porosity spectrum, pH, water content, total C and total N were made at each depth and related to mite diversity and species richness. Meso- and microporosity were strongly correlated with species distribution while macroporosity and pH were correlated to density and species richness.     

Amphibian conservation: Are we on the right track?

Amphibian declines and extinctions are a worldwide concern. Conservation priorities for amphibians should target threatened taxa (taxonomic targets) and regions with high levels of species endemism (geographical targets). Does published research on amphibian conservation reflect the global taxonomic and geographic priorities? I surveyed six years (2000-2005) of 10 conservation and herpetological journals (Amphibia-Reptilia, Animal Conservation, Applied Herpetology, Biodiversity and Conservation, Biological Conservation, Conservation Biology, Copeia, Herpetologica, Journal of Herpetology and Oryx), and analyzed all articles on amphibians. Attention indexes were calculated for orders, threatened species and biogeographic realms. I also examined how well research from tropical developing nations (with high levels of richness and endemism) are represented in the international literature. Attention indexes results show that the most studied amphibian order is Caudata, whereas Gymnophiona is the least studied one. The same trend is observed for threatened species, with threatened Caudata species receiving proportionally more attention than threatened Anura and Gymnophiona. The biogeographic realms that receive most attention by amphibian conservationists are: Oceania, Nearctic and Palearctic. However, the Neotropical, Afrotropical and Indomalayan are the regions with higher species diversity. Forty-one countries contributed articles, but the majority of amphibian conservation research is conducted by North American and western European researchers. There is urgent need for capacity building in tropical developing nations. Amphibians are more threatened and are declining more rapidly than either birds or mammals. However, amphibian conservation is still misplacing its focus in lower-biodiversity regions and non-threatened species. If such trends are not changed, the consequences for the persistence of amphibians worldwide may be dire.     

Are chlorophylls good indicators of nitrogen and phosphorus levels? 1

Aubergine plants (Solanum melongena cv. Bonica) were grown under controlled greenhouse conditions on a soil substrate supplied with organic fertilizers (15 kg/m²) mixed with calcium sulfate (CaSO₄ at 500 g/m²), with different doses of nitrogen (N as N₁ = 15, N₂ = 22.5, N₃ = 30 g/m²) in the form of ammonium nitrate (NH₄NO₃), and phosphorus (P as P₁ = 24, P₂ = 36 g/m²) as phosphorus acid H₃PO₄). Plants were sampled every 15 days, and the pigments chlorophyll a, chlorophyll b, total (a+b) and ratio (a/b), carotene, licopene, and anthocyanins were determined in the leaves. The results showed that increases in rhizosphere N led to increases in foliar concentrations of chlorophyll a and b, both individually and as total chlorophyll, independently of the dose of P applied. Total chlorophyll concentrations were directly correlated with the level of P fertilization. Carotene and licopenes reflected the influence of increasing doses of N, whereas P did not affect these pigments. Anthocyanin levels were affected by both N and P.     

Are hovercraft a major cause of disturbance to intertidal invertebrates?

The densities of intertidal invertebrates in areas within and outside the hovercraft flightpath were compared by analysis of variance and least significant range tests. No evidence was found to suggest that the hovercraft had significantly reduced the density of invertebrates in the flightpath area. Only five species groups (Nereis diversicolor, Spionid spp., Bathyporeia spp., Macoma balthica and Arenicola marina) had significantly different densities between areas, and in each case there was a density gradient alongshore. In three species groups (Spionid spp., Bathyporeia spp. and Macoma balthica) density was related to the percentage of fine sand (4–5 φ) at each site.     

How Stable Are Soils for the Determination of Available N?

When potassium chloride (KCl) is used to extract “available” mineral nitrogen (N) species from field-moist soils, samples are usually transferred to the laboratory in a cool box prior to extraction and stored in a fridge until being prepared for extraction. This study shows that significant changes, especially in nitrate concentration, occur under refrigerated conditions for 16 h, especially in grassland subsoils, and these are reflected in total mineral N levels. Surprisingly, storage at room temperature for the same time caused no significant additional net nitrate production. Extractable ammonium concentrations often fell significantly during storage, especially in woodland soil samples, probably via microbial immobilization as well as nitrification. In the present study, 12 pairs of students were used to perform all extractions within 30 min of sampling in the field, which would not be generally practical. It is suggested that volumetric subsampling in the field and immediate addition to a known volume of KCl solution may be more reliable than methodology currently employed by many soil scientists.     

Are hotspots of evolutionary potential adequately protected in southern California?

Reserves are often designed to protect rare habitats, or “typical” exemplars of ecoregions and geomorphic provinces. This approach focuses on current patterns of organismal and ecosystem-level biodiversity, but typically ignores the evolutionary processes that control the gain and loss of biodiversity at these and other levels (e.g., genetic, ecological). In order to include evolutionary processes in conservation planning efforts, their spatial components must first be identified and mapped. We describe a GIS-based approach for explicitly mapping patterns of genetic divergence and diversity for multiple species (a “multi-species genetic landscape”). Using this approach, we analyzed mitochondrial DNA datasets from 21 vertebrate and invertebrate species in southern California to identify areas with common phylogeographic breaks and high intrapopulation diversity. The result is an evolutionary framework for southern California within which patterns of genetic diversity can be analyzed in the context of historical processes, future evolutionary potential and current reserve design. Our multi-species genetic landscapes pinpoint six hotspots where interpopulation genetic divergence is consistently high, five evolutionary hotspots within which genetic connectivity is high, and three hotspots where intrapopulation genetic diversity is high. These 14 hotspots can be grouped into eight geographic areas, of which five largely are unprotected at this time. The multi-species genetic landscape approach may provide an avenue to readily incorporate measures of evolutionary process into GIS-based systematic conservation assessment and land-use planning.     

Are we approaching ‘peak timber’ in the tropics?

Over the past few decades, tropical timber production in many Asia–Pacific countries has been akin to the symmetric logistic distribution curve, or ‘Hubbert Curve’, observed in the exploitation of many non-renewable resources—a rapid increase in production followed by a peak and then decline. There are three principal reasons why logging of native tropical forests resembles the mining of a non-renewable resource: the standard cutting cycle of 30–40 years is too brief to allow the wood volume to regenerate; tropical logging catalyses considerable deforestation; and the bulk of logging is undertaken by multinational corporations with little interest in long-term local sustainability. Unless something fundamental changes, we believe tropical forests will continue to be overharvested and cleared apace, leading to an inevitable global decline in tropical timbers of non-plantation origin. It has become common these days to speak of ‘peak oil’. In the tropics, we suggest that we should also begin to discuss the implications of ‘peak timber’.     

Are mineral nutrients a critical factor for lime intolerance of lupins?

Poor growth of lupins on calcareous soils may be attributed to a number of soil physical and chemical factors. Nutrient imbalances, such as deficiency of phosphorus (P) and micronutrients or calcium (Ca) excess have been reported to be responsible for the calcifuge behavior of the plants. In the present study we investigated the importance of nutrient imbalances for the growth reduction of lupins on a lime‐containing soil. Three lupin species (Lupinus luteus, Lupinus angustifolius, and Lupinus albus) were compared with lime‐tolerant Pisum sativum. Plants were cultivated in a sandy soil containing 0.2% or 10% magnesium (Mg) limestone and were fertilized with a complete nutrient solution except for iron (Fe). In each lime treatment, three of six pots per species were supplied with iron as FeEDDHA. Strong liming greatly decreased shoot growth, rate of leaf appearance, and shoot dry matter accumulation in all Lupinus species, but only marginally in P. sativum. All Lupinus species displayed chlorosis on the strongly limed soil, whereas on the slightly limed soil, only L. luteus did so. Shoot concentrations of P, potassium (K), Ca, Mg, manganese (Mn), zinc (Zn), and copper (Cu) were generally in the adequate range. Decreased shoot growth was not associated with increased Ca concentrations. FeEDDHA fertilization alleviated chlorosis in most cases, but was not able to restore shoot growth. Therefore it is concluded, that, at least in the juvenile stage, nutrient imbalances do not play a major role in growth limitation of lupins on calcareous soils.     

Is alternate wetting and drying irrigation technique enough to reduce methane emission from a tropical rice paddy?

Combination of a pre-season wet soil condition and rice straw incorporation just before transplanting, which is typical for a tropical rice double cropping, can induce a flash of methane (CH₄) emission shortly after the transplanting. The conventional practice of alternate wetting and drying (AWD) irrigation technique that typically starts at 21 days after transplanting (DAT) can hardly reduce this emission because the soil become methanogenic before the onset of AWD treatment. Field experiments were conducted in Central Luzon, Philippines, during the 2014–2017 dry rice seasons to examine the effects of the timing of rice straw/stubble incorporation on the efficacy of AWD in reducing the CH₄ emission. Two treatments of the timing of stubble incorporation were stubbles incorporated during the start of wet land preparation (S1) and stubbles incorporated during the dry fallow tillage (S2). For the water management, we compared two treatments: continuous flooding (CF) and AWD with – 15 cm threshold for irrigation. The AWD under S2 was implemented earlier at 10 DAT. We observed a significant interaction (p < 0.01) between effects of AWD and straw management on CH₄ emissions; the seasonal total CH₄ emission was reduced by AWD compared with CF by 73% under S2, while the reduction was <20% under S1. The AWD significantly (p < 0.05) increased the nitrous oxide (N₂O) emissions by 47 and 48% relative to CF under S1 and S2, respectively. The global warming potential (GWP, CH₄ + N₂O) and yield-scaled GWP were still substantially lower by 62 and 59%, respectively, in AWD than in CF under S2, but the reduction was not realized under S1 due to the relatively smaller CH₄ reduction and increased N₂O emission. The results confirm that pre-season aerobic stubble decomposition and earlier implementation of AWD enhanced AWD’s mitigation potential in reducing substantially the CH₄ emission from the tropical rice double-cropping system.     

Are spiders reacting to local or landscape scale effects in Hungarian pastures?

Declines of West-European farmland biodiversity have been associated with intensive agricultural practices, Central and Eastern European grasslands still harbour a diverse and unique arthropod community. However, our understanding of the effects of farmland management both at local and landscape levels is rather limited there. A paired field approach was used to compare extensively (0.5 cows/ha) and intensively (>1 cows/ha) grazed pastures in 42 fields in three distinct biogeographic regions within Hungary. Spiders belonging to the hunting and web-building communities were sampled using funnel traps. We found no management effect either on richness and abundance or on species composition, which shows that both forms of grazing management at the intensity levels studied support valuable spider fauna. At the local scale plant and litter cover were the two most important variables that significantly affected the communities overall, meaning both the hunting and to some degree the web-building communities. No significant landscape effects were found in the analyses on spider richness and abundance, but community structure was affected by two landscape level factors (grassland patch density and grassland percentage). We suggest that to protect the valuable spider and other fauna of these regions, the recently launched national agri-environmental program should be further supported and enlarged to maintain and reintroduce the traditional grazing management on these semi-natural grasslands.     

Are molecular weights of proteins determined by superose 12 column chromatography correct?

Our research on several proteins indicates that accurate molecular weights cannot be determined by Superose 12 column chromatography. In support of this statement, we present data on molecular weights of purified red kidney bean alpha-amylase inhibitor (RKB alphaAI) and white kidney bean alpha-amylase inhibitor (WKB alphaAI) to document this problem. The molecular weight of purified RKB alphaAI determined by Sephadex G-100 gel filtration, polyacrylamide gel electrophoresis, Superose 12 gel filtration and cDNA were 49.0, 51.0, 22.9, and 49.805 kDa (not glycosylated), respectively. The molecular weights of WKB alphaAI by several methods were as follows: Sephadex G-100 gel filtration, 51.0 kDa; Superose 12 gel filtration in 0.2 M NaCl buffer, 23.1 kDa; polyacrylamide gel electrophoresis (PAGE), 51.0 kDa; sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), 45.0 kDa; multiangle laser light scattering (MALLS), 49.940 kDa; laser-assisted time-of-flight mass spectrometry (LATOFMS), 56.714 kDa; and cDNA sequence (with 12.2% carbohydrate), 55.9 kDa. The data indicate there is ionic interaction between proteins and the matrix of Superose 12 in low ionic strength buffers and hydrophobic interaction at higher ionic strength buffers. Researchers should be cautious when using Superose 12 columns for molecular weight determinations.     

Canadian Power Stations and the National Pollutant Release Inventory (NPRI): A Success Story for Pollution Intensity?

This paper presents a comprehensive analysis of the pollutant emissions and intensity from Canada’s power stations. An analysis of National Pollutant Release Inventory (NPRI) and site generation data shows significant variability with the dominant emissions pathway being point-source air emissions. In general, power stations are a very small fraction of Canada’s direct facility and estimated diffuse emissions, as well as showing significant variability of pollutant intensities per megawatt or megawatt hour of capacity or generation. The evidence also suggests that increased scale does not lead to a lower pollutant intensity, and that transfers and disposal pollutant loads are substantial, often representing most of the total reported pollutants. Overall, this study provides a valuable insight into the current status of pollutant intensities from Canada’s power stations, possible improvements to the NPRI and a valuable benchmark for future studies and international comparisons.     

Are conservation strategies effective in avoiding the deforestation of the Colombian Guyana Shield?

There is general agreement regarding the importance of analysing the territories’ roles under different biodiversity management figures in order to support better decision making in the management of natural resources in tropical countries. In this study we analyse the deforestation process to address the question of whether existing strategies such as national protected areas (PAs) and indigenous reservations (IRs) are effective protecting forests in the Colombian Guyana shield. We analyse whether these territories have successfully halted deforestation and agricultural frontier expansion by comparing deforestation occurring within these areas with their surroundings from 1985 to 2002. We also evaluate the impact of roads, illicit crops, and the size of PAs and IRs on deforestation rates. The results indicate that deforestation levels along the outside borders of both management figures were almost four times higher than inside declared PAs and 1.5 times higher than in IRs. However, within IRs, the loss of forested ecosystems was approximately six times greater than inside national parks. As a whole, roads were a significant factor associated with the changes in the region, as well as the influential expansion of coca cultivation particularly outside the national parks. The size of the PAs and indigenous lands also determined their positive impact as barrier against deforestation. Our results suggest strong pressure on areas surrounding PAs, driven by economic forces such as illegal crop expansion, particularly in the last decade. Indigenous lands with small territories have suffered intensive deforestation processes since the 1980s, but changes have been less dramatic in larger areas. Today, PAs are an effective barrier to deforestation, especially given their large extension, but are still under high risk. Future management plans should consider a designed infrastructure development paired with the establishment of new indigenous reservations with minimum viable sizes in order to control accessibility, natural resources extraction, and deforestation.