An easier method to identify the individual genomic composition of allopolyploid complexes

A new method for the fast identification of the genomic composition of the cyprinid Squalius alburnoides is presented. The method is based on a length polymorphism detected in the β‐actin gene, which serves as the basis for the development of a semi‐quantitative PCR.     

Semi‐continuous in situ magnetic separation for enhanced extracellular protease production—modeling and experimental validation

In modern biotechnology proteases play a major role as detergent ingredients. Especially the production of extracellular protease by Bacillus species facilitates downstream processing because the protease can be directly harvested from the biosuspension. In situ magnetic separation (ISMS) constitutes an excellent adsorptive method for efficient extracellular protease removal during cultivation. In this work, the impact of semi‐continuous ISMS on the overall protease yield has been investigated. Results reveal significant removal of the protease from Bacillus licheniformis cultivations. Bacitracin‐functionalized magnetic particles were successfully applied, regenerated and reused up to 30 times. Immediate reproduction of the protease after ISMS proved the biocompatibility of this integrated approach. Six subsequent ISMS steps significantly increased the overall protease yield up to 98% because proteolytic degradation and potential inhibition of the protease in the medium could be minimized. Furthermore, integration of semi‐continuous ISMS increased the overall process efficiency due to reduction of the medium consumption. Process simulation revealed a deeper insight into protease production, and was used to optimize ISMS steps to obtain the maximum overall protease yield. Biotechnol. Bioeng. 2013; 110: 2161–2172. © 2013 Wiley Periodicals, Inc.     

Quantifying habitat impacts of natural gas infrastructure to facilitate biodiversity offsetting

Habitat degradation through anthropogenic development is a key driver of biodiversity loss. One way to compensate losses is “biodiversity offsetting” (wherein biodiversity impacted is “replaced” through restoration elsewhere). A challenge in implementing offsets, which has received scant attention in the literature, is the accurate determination of residual biodiversity losses. We explore this challenge for offsetting gas extraction in the Ustyurt Plateau, Uzbekistan. Our goal was to determine the landscape extent of habitat impacts, particularly how the footprint of “linear” infrastructure (i.e. roads, pipelines), often disregarded in compensation calculations, compares with “hub” infrastructure (i.e. extraction facilities). We measured vegetation cover and plant species richness using the line‐intercept method, along transects running from infrastructure/control sites outward for 500 m, accounting for wind direction to identify dust deposition impacts. Findings from 24 transects were extrapolated to the broader plateau by mapping total landscape infrastructure network using GPS data and satellite imagery. Vegetation cover and species richness were significantly lower at development sites than controls. These differences disappeared within 25 m of the edge of the area physically occupied by infrastructure. The current habitat footprint of gas infrastructure is 220 ± 19 km² across the Ustyurt (total ~ 100,000 km²), 37 ± 6% of which is linear infrastructure. Vegetation impacts diminish rapidly with increasing distance from infrastructure, and localized dust deposition does not conspicuously extend the disturbance footprint. Habitat losses from gas extraction infrastructure cover 0.2% of the study area, but this reflects directly eliminated vegetation only. Impacts upon fauna pose a more difficult determination, as these require accounting for behavioral and demographic responses to disturbance by elusive mammals, including threatened species. This study demonstrates that impacts of linear infrastructure in regions such as the Ustyurt should be accounted for not just with respect to development sites but also associated transportation and delivery routes.     

A regional‐scale consideration of the effects of species richness on above‐ground biomass in temperate natural grasslands of China

Question: Can species richness be a predictor for above‐ground biomass in natural grasslands at a regional scale? Location: A total of 647 sites across temperate natural grasslands of northern China. Methods: Structural equation modelling (SEM) was used to examine the effect of species richness on above‐ground biomass. Asymptotically distribution‐free estimation was selected for parameter estimation. The SEM process was performed at five sample sizes (n=50, 100, 200, 300 and 647). Spatial structure in the original data was examined by calculating Moran's I. Results: SEM run at n=647 revealed a positive effect of species richness on above‐ground biomass after controlling for the influences of bioclimatic factors and grazing. At the four reduced sample size levels, the positive effect held true for most cases in 400 observations (>92%). Conclusions: Contrary to observations in previous studies in natural grasslands, our data showed a positive effect of species richness on above‐ground biomass. This suggests that, as a short‐term effect of diversity on productivity, niche complementarity among coexisting species tends to be an important process in arid and semi‐arid natural grasslands. We hold that biodiversity conservation is among the fundamental approaches required to maintain productivity of grasslands in arid and semi‐arid areas.     

Experimental changes in disturbance type do not induce short‐term shifts in plant community structure in three semi‐arid grasslands of the Victorian Riverine Plain managed for nature conservation

Summary Since the mid 1990s, there has been a significant increase in the area of semi‐arid grasslands included in the National Reserve Systems in the Victorian Riverine Plain. This expansion has not been matched by an improved understanding of the alternate disturbance regimes that might produce better outcomes for native ecosystem conservation. Over the past 150 years, stock grazing has completely replaced fire in these grasslands. As a result, the impact of fire on native (and exotic) plant biodiversity is little understood. This study compared the current grazing regime (i.e. ‘status quo’) with burning and the removal of grazing (‘deferred’ management) across three grasslands in the Victorian Riverine Plain to determine the effects of short‐term exposure to alternate disturbances on community structure. Our results showed little change in species density, composition or abundance under the three disturbance treatments. A long exposure to stock grazing may have reduced the abundance of species likely to respond positively to burning. The cover of the biological soil crust responded positively to fire; such changes are known to significantly influence establishment and the functional composition of communities. As such, further investigation of the functional attributes of these communities may broaden our understanding of short‐term responses to alternate disturbance events. To better understand the utility of fire as a management tool, a long‐term commitment to expanding the implementation of this regime from its current extent will greatly increase the understanding of alternate disturbances in this landscape.     

半干旱黄土高原地区地膜覆盖和底墒对春小麦生长及产量的影响

在年均降水量为415mm的半干旱地区黄绵土旱地上,以春小麦为供试作物进行大田实验,研究不同底墒(包括低底墒、中底墒和高底墒)下．地膜覆盖(包括不覆膜、播种后覆膜30d、覆膜60d和覆膜120d即全程覆膜)进程对作物生产的影响。结果表明．增加底墒和合理的覆膜进程均会显著增加作物的生长和产量,但底墒不同,其最佳覆膜进程不同：在低底墒时,覆膜处理反而使产量低于不覆膜处理;在中底墒时．覆膜30d产量最高,随着覆膜时间延长．产量呈下降趋势,甚至全程覆膜产量低于不覆膜处理;高底墒以覆膜60d产量最高。综合作物生长和产量,全程覆膜并没有多少实际意义。在同种覆膜处理下,随着底墒的增加,根生物量、地上干物质、叶面积及产量也增加显著,高底墒覆膜60d处理的产量在所有处理中为最高。     

Methodological bias in the seed bank flora holds significant implications for understanding seed bank community functions

• Persistent seed banks are a key plant regeneration strategy, buffering environmental variation to allow population and species persistence. Understanding seed bank functioning within herb layer dynamics is therefore important. However, rather than assessing emergence from the seed bank in herb layer gaps, most studies evaluate the seed bank functioning via a greenhouse census. We hypothesise that greenhouse data may not reflect seed bank‐driven emergence in disturbance gaps due to methodological differences. Failure in detecting (specialist) species may then introduce methodological bias into the ecological interpretation of seed bank functions using greenhouse data.
• The persistent seed bank was surveyed in 40 semi‐natural grassland plots across a fragmented landscape, quantifying seedling emergence in both the greenhouse and in disturbance gaps. Given the suspected interpretational bias, we tested whether each census uncovers similar seed bank responses to fragmentation.
• Seed bank characteristics were similar between censuses. Census type affected seed bank composition, with >25% of species retrieved better by either census type, dependent on functional traits including seed longevity, production and size. Habitat specialists emerged more in disturbance gaps than in the greenhouse, while the opposite was true for ruderal species. Both censuses uncovered fragmentation‐induced seed bank patterns.
• Low surface area sampling, larger depth of sampling and germination conditions cause underrepresentation of the habitat‐specialised part of the persistent seed bank flora during greenhouse censuses. Methodological bias introduced in the recorded seed bank data may consequently have significant implications for the ecological interpretation of seed bank community functions based on greenhouse data.

     

Fire and the demography of camelthorn (Acacia erioloba Meyer) in the southern Kalahari – evidence for a bonfire effect?

Fires in arid environments are rare, so are not deemed as important as in mesic savannas. We investigated mortality and resprouting amongst camelthorn (Acacia erioloba) after two fires (at Vaalbos National Park and Susanna farm) in semi‐arid savanna near Kimberley, South Africa. Resprouting response 18 months after a fire was the greatest amongst <6.5 m high trees; extent of foliage damage by fire and bark thickness were the next best predictors of resprouting vigour amongst that size class. The largest size class (8–12 m height) of A. erioloba suffered the greatest mortality rates (40% and 83% at Vaalbos and Susanna respectively), with damage either severe or minor. We hypothesize that large tree mortality rates are partly attributable to well‐developed assemblages of flammable subcanopy plants producing a bonfire beneath trees. These mortality rates indicate that fire reduces both tree abundance and relative representation of large trees, and although able to resprout, A. erioloba is fire‐sensitive, which may explain its restriction to Kalahari sands where rainfall is less than 900 mm year^?1. Therefore, although relatively infrequent, fires shape Kalahari woodland structure, particularly as A. erioloba is long lived and slow growing. Large trees have been shown to be important to biodiversity in the southern Kalahari, so frequent fires could impact biodiversity.     

Rapid identification of acylated flavonol tetraglycosides in oolong teas using HPLC-MSn

A method was developed to separate and identify acylated flavonol tetraglycosides (AFTGs) by combining isocratic HPLC with electrospray ionisation tandem mass spectrometry. Better separation was obtained for oolong tea infusion using a manually packed Sephadex LH-20 mini-column than with an ACCUBOND ODS solid-phase column. Seven unknown and one known AFTGs were found in oolong teas prepared by various semi-fermentation processes and their structures were identified by mass spectrometry. According to the analyses of diverse oolong teas including Dongding Oolong, Tieguanyin, Wuyi Oolong, Fenghuang Oolong, Gaoshan Shibi, Laocong Shuixian and Baihao Oolong, AFTGs seemed to be universally present, and each oolong tea could be classified into one of three groups (Dongding Oolong, Tieguanyin and Wuyi Oolong) on the basis of its AFTGs profile. The results suggest that the developed method is rapid and sensitive for identifying natural compounds.