From the Cover: Form of an evolutionary tradeoff affects eco-evolutionary dynamics in a predator–prey system

Evolution on a time scale similar to ecological dynamics has been increasingly recognized for the last three decades. Selection mediated by ecological interactions can change heritable phenotypic variation (i.e., evolution), and evolution of traits, in turn, can affect ecological interactions. Hence, ecological and evolutionary dynamics can be tightly linked and important to predict future dynamics, but our understanding of eco-evolutionary dynamics is still in its infancy and there is a significant gap between theoretical predictions and empirical tests. Empirical studies have demonstrated that the presence of genetic variation can dramatically change ecological dynamics, whereas theoretical studies predict that eco-evolutionary dynamics depend on the details of the genetic variation, such as the form of a tradeoff among genotypes, which can be more important than the presence or absence of the genetic variation. Using a predator–prey (rotifer–algal) experimental system in laboratory microcosms, we studied how different forms of a tradeoff between prey defense and growth affect eco-evolutionary dynamics. Our experimental results show for the first time to our knowledge that different forms of the tradeoff produce remarkably divergent eco-evolutionary dynamics, including near fixation, near extinction, and coexistence of algal genotypes, with quantitatively different population dynamics. A mathematical model, parameterized from completely independent experiments, explains the observed dynamics. The results suggest that knowing the details of heritable trait variation and covariation within a population is essential for understanding how evolution and ecology will interact and what form of eco-evolutionary dynamics will result.Evolutionary dynamics, changes in intraspecific genotype frequency over generations, can have a time scale similar to that of ecological dynamics (1–3). Selection mediated by ecological interactions causes evolutionary dynamics, and evolution of traits, in turn, changes ecological interactions. Thus, understanding population dynamics needs to take account of the feedbacks between trait evolution and ecological interactions (i.e., eco-evolutionary feedbacks). These feedbacks have increasingly attracted ecologists’ attention since Pimentel (4) proposed genetic feedback as a mechanism regulating animal populations (e.g., refs. 5–11). This integration of evolutionary biology and ecology has important implications in both basic and applied problems in biology (12–17).Empirical studies have shown that rapid evolution can affect many ecological interactions, including predator–prey (18–20), host–parasite (21), herbivore–plant (22), competitive interactions (23), and interactions with abiotic environments (24–27). Previous empirical studies on eco-evolutionary feedbacks have usually compared the dynamics of populations with and without genetic variation, but recent theoretical models predicted that not only the presence or absence of genetic variation (28–30) but also the form of the evolutionary tradeoff among genotypes is important in generating qualitatively different dynamics (31–35). Indeed, the forms of evolutionary tradeoffs within populations are known to be remarkably variable in plants and microbes (36–38). Thus, there should be various eco-evolutionary dynamics depending on the form of evolutionary tradeoffs existing in wild populations. Nevertheless, to our knowledge, no empirical study has directly demonstrated the theoretically predicted effects of the evolutionary tradeoff on eco-evolutionary dynamics, and it is still unclear how different forms of an evolutionary tradeoff in real organisms can result in different eco-evolutionary dynamics.Here, using a predator–prey (rotifer–algal) system cultured in continuous flow-through microcosms (chemostats), we examined how different forms of an evolutionary tradeoff between defense and growth in algal prey (Chlorella vulgaris) affect the population dynamics of the predator–prey system and the evolutionary changes in the clonal frequency of the algal prey. Experimental studies using laboratory microcosms have been a powerful approach in exploring eco-evolutionary dynamics and testing theoretical predictions because of the constant environment and simple community structure (39–41). We used two different pairs of algal clones originally obtained from the University of Texas (UTEX) algal collection that showed different forms of a fitness tradeoff between antipredator defense and competitive ability to obtain the resource limiting population growth in the experimental system (inorganic nitrogen). Each pair of algal clones was cultured with an obligately asexual lineage of rotifer predators (Brachionus calyciflorus). Population dynamics of the predators and prey and clonal frequency changes in the algal pair were observed in long-term chemostat runs. We recorded evolutionary dynamics (genotype frequency change) by using an allele-specific quantitative PCR (AsQ-PCR) technique based on microsatellite DNA that allowed us to measure the relative abundance of algal clones (42). We also developed a mathematical model for the experimental system, based on a model of Jones and Ellner (43), parameterized the model using data from separate experiments, and compared the model’s predictions to the observed population and genotype dynamics.     

‘Dieback’ (chronic decline) of Eucalyptus viminalis on the Monaro is not new,unique or difficult to explain

Ross and Brack (2015) reported a widespread decline over the past decade in the health of Eucalyptus viminalis on the Monaro Tablelands in southern New South Wales. They were unable to attribute this to changes in management, lack of fire, or ‘declining levels of structural diversity’. They noted consistent infestation of trees by a native weevil and recommended further work on the role of climate and rainfall in ‘Monaro dieback’. However, chronic decline involving a wide range of arbivores has affected a wide range of eucalypts across Australia since European settlement, and is currently rampant in many areas of forest and woodland. Pasture improvement and/or exclusion of fire and grazing are the major causes of chronically declining health of eucalypts. The data presented by Ross and Brack (2015) provide some support for this conclusion and no contrary evidence.     

Adapting agriculture to climate change

The strong trends in climate change already evident, the likelihood of further changes occurring, and the increasing scale of potential climate impacts give urgency to addressing agricultural adaptation more coherently. There are many potential adaptation options available for marginal change of existing agricultural systems, often variations of existing climate risk management. We show that implementation of these options is likely to have substantial benefits under moderate climate change for some cropping systems. However, there are limits to their effectiveness under more severe climate changes. Hence, more systemic changes in resource allocation need to be considered, such as targeted diversification of production systems and livelihoods. We argue that achieving increased adaptation action will necessitate integration of climate change-related issues with other risk factors, such as climate variability and market risk, and with other policy domains, such as sustainable development. Dealing with the many barriers to effective adaptation will require a comprehensive and dynamic policy approach covering a range of scales and issues, for example, from the understanding by farmers of change in risk profiles to the establishment of efficient markets that facilitate response strategies. Science, too, has to adapt. Multidisciplinary problems require multidisciplinary solutions, i.e., a focus on integrated rather than disciplinary science and a strengthening of the interface with decision makers. A crucial component of this approach is the implementation of adaptation assessment frameworks that are relevant, robust, and easily operated by all stakeholders, practitioners, policymakers, and scientists.     

Depth Profiling of Compression-Induced Disorders and Polymorphic Transition on Tablet Surfaces with Grazing Incidence X-ray Diffraction

Purpose The importance of induced crystal disorders like crystallite size, crystal defects, and amorphicity with respect to the dissolution rate of the drug has been discussed in many cases. Thus, the characterization of these properties is of great importance in the pharmaceutical formulation development, although the exact correlation between disorders and dissolution rate is still unclear. The aim of this study was to analyze pharmaceutical tablets with grazing incidence X-ray diffraction, which enables the depth profiling of the crystallographic properties of the tablets. To study and clarify the potential of grazing incidence diffraction in the analysis of pharmaceutical materials, the effect of the compaction process on the surface of tablets was examined. Methods Carbamazepine, tolbutamide, and chlorpropamide tablets, compacted using different compression pressures, were studied using grazing incidence angle X-ray diffraction. The effects of compression on the crystallographic properties were investigated as a function of the distance from the tablet surface. Results The surfaces of the tolbutamide and chlorpropamide tablets were disordered due to the compression. The manifestation of the disorder was deduced to be due to amorphicity, small crystallite size, and amount of crystal defects. The changes were mainly on the surface and diminished strongly as a function of the distance from the surface of the tablet. Moreover, the changes were dependent on the compression pressure used. The changes on the surface of the carbamazepine tablets were also due to the compression but these changes were not clearly dependent on the depth nor the compression pressure. The partial phase transition took place in the chlorpropamide tablets due to the compression. The magnitude of the transition was not highest on the surface because amorphization and texturization also took place on the tablet surface during the compression. Conclusions The present study proved that grazing incidence X-ray diffraction is a potential novel research tool to reveal crystallographic transformations taking place on the surfaces of the tablets induced, for example, by compression pressure.     

云南省高原山区血吸虫病流行区居民放牧和野便行为研究

目的 目的 了解云南省高原山区血吸虫病流行区居民野外自由放牧和野外大便 （野便） 行为情况。 方法 方法 选择鹤庆县西甸、 磨光2个行政村作为研究试区。随机抽取30%的6～65岁居民, 以询问式问卷调查的形式, 调查其野外自由放牧和野便的行为情况, 并对调查对象进行血清学检查, 了解其血吸虫病感染情况。 结果 结果 共调查居民412人。居民对家畜饲养回答圈养、 自由放牧、 不知道和没有回答的人数所占的比例分别为55.34%、 4.85%、 26.94%和12.86%。居民无放牧行为、 每周放牧< 5次、 每周放牧≥ 5次人数占调查人数的比例分别为75.49%、 16.02%和8.50%。居民无野便行为、 每周野便< 5次、 每周野便≥ 5次和没有回答的人数占调查人数的比例分别为68.45%、 27.67%、 2.91%和0.97%。 结论 结论 鹤庆县血吸虫病流行区居民野外自由放牧和野便行为较普遍, 对当地血吸虫病防治工作影响较大, 在今后的防治工作中仍应突出人畜粪便管理和禁牧措施, 巩固血吸虫病防治成果, 以实现传播阻断目标。     

Crystalline Monolayer Ordering at Substrate/Polymer Interfaces in Poly(3‐hexylthiophene) Ultrathin Films

The nanocrystalline structure of thermally annealed P3HT ultrathin films was studied as a function of the substrate properties using AFM, GIXRD, and static contact angle measurements which showed that an edge‐on structure is formed on both types of substrate. Substrate‐induced ordering is observed at the interface with air only when the film matches the average lamellae thickness, ≈30 nm in the present case, while, when the film thickness is higher than a single lamella size, i.e., ≈60 nm the substrate nature does not affect the lamellar ordering at the film/air interface. In other words, the substrate properties seem able to induce the ordering of the only first crystalline layer. These results are discussed in terms of simple relationships between interface free energy and chain mobility.

     

新疆塔城地区草原放牧公犊生产性能的研究

选取12月龄的新疆褐牛公犊10头和美新褐F1公犊9头（美国褐牛×新疆褐牛杂种F1）在新疆塔城天然草原放牧150d,研究在天然草原放牧条件下新疆褐牛及美新褐F,公犊的生产性能。结果表明：美新褐F1体重比新疆褐牛提高了13．01％（P〈0．05）,体高比新疆褐牛提高了5．36％（P〈0．01）：宰前活重、胴体重分别比新疆褐牛提高了13．01％、15．17％（P〈0．05）,相关性分析得出新疆褐牛各体尺、胴体重之间均存在显著或极显著相关,而美新褐F。只有胸围、体重、胴体重之间存在显著或极显著相关。美新褐F1生长发育好于新疆褐牛,使其总体品质有所提高,达到了选育提高的目的。     

新疆精河县草原生态保护奖补政策实施的效果分析

新疆精河县草场植被类型复杂多样,全县冬夏冷热悬殊、干燥少雨,草原生态极其脆弱。近年来,由于人为和自然的因素,草原退化较严重,自2011年起,国家和自治区不断地加大对草原生态保护的补奖力度。本文从草原禁牧、草畜平衡政策实施及生态补偿资金发放情况等方面着手,通过项目实施前后在草场生产力、牲畜存栏数、生态和社会效益及牧民收入等方面的数据对比,对新疆精河县草原生态保护奖补政策实施情况及实施效果进行评估,对项目运行过程中存在的问题进行分析,并提出了相应对策。     

Reducing the impact of summer cattle grazing on water quality in the Sierra Nevada Mountains of California: a proposal

The Sierra Nevada Mountain range serves as an important source of drinking water for the State of California. However, summer cattle grazing on federal lands affects the overall water quality yield from this essential watershed as cattle manure is washed into the lakes and streams or directly deposited into these bodies of water. This organic pollution introduces harmful microorganisms and also provides nutrients such as nitrogen and phosphorus which increase algae growth causing eutrophication of otherwise naturally oligotrophic mountain lakes and streams. Disinfection and filtration of this water by municipal water districts after it flows downstream will become increasingly costly. This will be compounded by increasing surface water temperatures and the potential for toxins release by cyanobacteria blooms. With increasing demands for clean water for a state population approaching 40 million, steps need to be implemented to mitigate the impact of cattle on the Sierra Nevada watershed. Compared to lower elevations, high elevation grazing has the greatest impact on the watershed because of fragile unforgiving ecosystems. The societal costs from non-point pollution exceed the benefit achieved through grazing of relatively few cattle at the higher elevations. We propose limiting summer cattle grazing on public lands to lower elevations, with a final goal of allowing summer grazing on public lands only below 1,500 m elevation in the Central and Northern Sierra and 2,000 m elevation in the Southern Sierra.