Pasture intensification is insufficient to relieve pressure on conservation priority areas in open agricultural markets

Agricultural expansion is a leading driver of biodiversity loss across the world, but little is known on how future land‐use change may encroach on remaining natural vegetation. This uncertainty is, in part, due to unknown levels of future agricultural intensification and international trade. Using an economic land‐use model, we assessed potential future losses of natural vegetation with a focus on how these may threaten biodiversity hotspots and intact forest landscapes. We analysed agricultural expansion under proactive and reactive biodiversity protection scenarios, and for different rates of pasture intensification. We found growing food demand to lead to a significant expansion of cropland at the expense of pastures and natural vegetation. In our reference scenario, global cropland area increased by more than 400 Mha between 2015 and 2050, mostly in Africa and Latin America. Grazing intensification was a main determinant of future land‐use change. In Africa, higher rates of pasture intensification resulted in smaller losses of natural vegetation, and reduced pressure on biodiversity hotspots and intact forest landscapes. Investments into raising pasture productivity in conjunction with proactive land‐use planning appear essential in Africa to reduce further losses of areas with high conservation value. In Latin America, in contrast, higher pasture productivity resulted in increased livestock exports, highlighting that unchecked trade can reduce the land savings of pasture intensification. Reactive protection of sensitive areas significantly reduced the conversion of natural ecosystems in Latin America. We conclude that protection strategies need to adapt to region‐specific trade positions. In regions with a high involvement in international trade, area‐based conservation measures should be preferred over strategies aimed at increasing pasture productivity, which by themselves might not be sufficient to protect biodiversity effectively.     

Do nest boxes in restored woodlands promote the conservation of hollow‐dependent fauna?

Vegetation restoration is considered as an important strategy for reversing biodiversity decline in agricultural areas. However, revegetated areas often lack key vegetation attributes like large old hollow‐bearing trees. As these trees take a long time to develop, artificial cavities such as nest boxes are sometimes provided to address lag effects. We conducted a 3‐year experiment using 150 nest boxes with 4 designs to quantify patterns of occupancy within 16 replanted areas and 14 patches of remnant old‐growth eucalypt woodland. We quantified patterns of occupancy of nest boxes in physically connected versus isolated remnants and plantings, and multiple covariate effects on nest box occupancy at the nest box, tree, patch, and landscape levels. Our analyses revealed a lower probability of nest box occupancy within remnants (vs. plantings) for 2 of the 6 response variables examined: any species and the Feral Honeybee. Nest boxes in connected remnants and plantings were more likely to be occupied than those in isolated plantings and remnants by any mammal and the Common Brushtail Possum. Nest boxes in restored woodlands are used by some hollow‐dependent fauna but principally already common species and not taxa of conservation concern. Nest boxes were also used by pest species. A key management consideration must be to create connected habitat to facilitate colonization of nest boxes by mammals. Approximately 15% of the cavity‐dependent vertebrates within the study area used next boxes, possibly because the diverse requirements of the array of other species were not met by the range of nest boxes deployed.     

五台山旅游开发与植被景观相互影响的生态效应评价

研究旅游对植被的影响对于景区生态管理具有重要的实践意义。从景观重要值(LIV)、物种多样性(SD)、群落结构比(PCS)、阴生种比值(NSP)、伴人种比值(PS)和旅游影响系数(TII)6个方面,构建了一套涉及4个层次、27个具体指标的评价体系,并结合五台山景区进行了实证分析。结果表明:(1)在不同方向上,随着距离的增加,旅游活动越来越少,植被景观依次由居民区、商业区或人工植被区向草本区、灌草区和乔灌草区的方向演替。相应地,LIV、SD、PCS、NSP和生态效应值(EIV)越来越大,PS和TII越来越小。(2)不同的植被类型,其景观特征明显不同。对于LIV、SD、PCS、NSP和EIV5个特征值的表征,草本区灌草区乔灌草区;至于PS和TII,草本区灌草区乔灌草区。旅游干扰下不同种群有不同的生物生态学特性,其中,青杨种群相对独特。(3)就整个台怀镇而言,旅游开发程度的空间格局是景点分布和地形因素共同作用的结果,植被景观对此有着明显的生态响应。不同方向上样地的数量就是旅游开发程度强弱的表征。正南和东北方向开发程度最强,其次是正北、东南和西南、正东方向,西北和正西方向最弱。(4)根据EIV,将整个区域分为四类区:Ⅰ类区为寺庙区、居民区和商业区,Ⅱ类区为草本区,Ⅲ类区是乔、灌、草的混合区,Ⅳ类区是乔灌草区。     

泾河沿岸景观格局梯度变化及驱动力分析

以MODIS影像数据为基础,利用Fragstats为工具,对泾河主干沿岸做10 km缓冲区(Buffer) ,从景观水平和类型水平上,分析河岸带景观格局的梯度变化,同时对产生这种梯度变化的驱动力进行分析。结果表明泾河自上游而下,景观水平上的景观指数有3种不同的变化类型:(1)上升型(2 )下降型(3)无明显趋势,表现出斑块数量、丰富度、连接度的递增,形状指数、分维数和斑块大小的递减;类型水平上以农田、草地和农草交错类为主,这3种类型的景观指数表现突出,具有明显的峰值。景观格局的梯度变化受到温度、降水、土壤等影响,同时,人为干扰也是不可忽视的重要因素,经济发展,人口增加使景观类型及其分布格局发生巨大的变化。景观格局的数量化对生态系统评估、监测起重要的作用。     

The Role of Solvent in Protein Folding and in Aggregation

We discuss features of the effect of solvent on protein folding andaggregation, highlighting the physics related to the particulate nature and the peculiar structure of the aqueous solvent, and the biological significance of interactions between solvent and proteins. To this purpose we use a generalized energy landscape of extended dimensionality. A closer look at the properties of solvent induced interactions and forces proves useful for understanding the physical grounds of `ad hoc' interactions and for devising realistic ways of accounting for solvent effects. The solvent has long been known to be a crucially important part of biological systems, and times appear mature for it to be adequately accounted for in the protein folding problem. Use of the extended dimensionality energy landscape helpseliciting the possibility of coupling among conformational changes and aggregation, such as proved by experimental data in the literature.     

不同区域的人口密集农村地区土壤有机碳的分布

基于IKONOS高分辨率（1m）卫星遥感图,根据Ellis提出的村级景观分类体系,研究我国5个不同宏观生态区域（高邑、宜兴、金堂、益阳和电白）的村级景观细微尺度上土地利用、土地覆盖、生态立地各层次上土壤表层（0～30cm）有机碳的密度和储量,结果表明：高邑、宜兴、金堂、益阳和电白5个地区的土壤有机碳密度分别为：2．62、3．47、2．24、2．86kg／m^2和2．70kg／m^2,平均土壤有机碳密度为2．78kg／m^2。土地利用景观中,高邑地区的水浇地和其它地区的水田和林地的土壤有机碳密度较高,高邑、宜兴、金堂、益阳和电白5个地区土壤有机碳储量最高的土地利用景观分别为水浇地、水田、旱地、水田和林地、林地;土地覆盖景观中,1年生和多年生植被覆盖景观的土壤有机碳密度最高。在由高邑至宜兴,最后至电白的纬度逐渐降低过程中,1年生植被覆盖景观的土壤有机碳储量逐渐减少,而多年生土地覆盖景观呈相反趋势。     

天然片断生境中山姜(Alpinia japonica)种群遗传结构

理论和实验研究表明片断化是导致生物多样性丧失的主要因素之一,但有关研究基本上集中在人类活动引发的片断化生境体系中.由于长期气候变化以及地形等因素的影响,一些物种的种群之间天然情况下就存在隔离,对这些种群进行研究可以弥补人类活动引起的片断化体系经历时间较短的不足.山姜是一个喜湿耐荫的多年生植物,分布在热带亚热带地区,由于气候和地形原因,该物种在浙江东部呈现天然片断化状态,如在浙江天童森林公园及其周边地区,仅分布在少数几个沟谷中.以这些种群为对象,采用RAPD标记分析经历长期天然片断化山姜种群遗传多样性程度和遗传分化格局.7条RAPD引物获得了69个位点,其中多态位点68个.种群水平遗传多样性较高,多态位点百分比、期望杂合度和Shannon多样性指数分别为78.81%～85.51%、0.3170～0.3430、0.4560～0.4914,这与其异交的繁殖方式有关,同时与山姜克隆生长,每个世代维持的时间长,种群更新降低也有关系.遗传变异大多分配在种群内,但种群间遗传分化达到显著程度,ΦST为0.297,计算的基因流中等,为0.592,不足以克服长期遗传漂变导致的种群分化,Mantel检验表明遗传距离与空间距离不存在相关关系,显示了长期片断化状态下遗传漂变的作用.     

基于机器学习方法的景观斑块属性对物种丰富度的影响研究

景观破碎化对物种的影响依赖于斑块属性,斑块属性体现了斑块的类型、面积、形状及其与周围斑块间关系。然而,在破碎化农业景观中这些斑块属性对关键物种的联合影响仍知之甚少。选取中国海南地区的典型农业破碎化景观,实测了180个斑块中三类关键物种,分别为害虫-橡胶材小蠹虫(Xyleborus affinis)、传粉昆虫-中华蜜蜂(Apis cerana)和天敌物种-玉米螟赤眼蜂(Trichogrammatid ostriniae Pang et Chen),刻画了各斑块属性,包括斑块类型、斑块面积、形状指数、距天然林距离、是否与橡胶接触、景观中天然林所占比例、是否有林下植物,并使用3种机器学习模型(神经网络、随机森林、支持向量机)拟合斑块属性与三类物种丰富度关系,解析斑块属性的相对重要性。结果表明,与支持向量机和神经网络相比,随机森林模型对三个物种的丰富度预测效果均最好,其R²在橡胶材小蠹虫、中华蜜蜂和赤眼蜂中分别达到0.785、0.845和0.798;基于随机森林模型的结果表明,斑块类型对橡胶材小蠹虫和中华蜜蜂丰富度相对重要性高于其他斑块属性;斑块面积对赤眼蜂丰富度影响高于其他斑块属性,且与斑块类型存在交互作用;橡胶林中橡胶材小蠹虫与中华蜜蜂丰富度高于天然林和其他斑块类型,玉米螟赤眼蜂丰富度则在天然林与农田中最高。研究揭示了斑块属性对不同物种丰富度的相对影响,阐明了斑块类型在不同物种中的重要作用,并证实了机器学习是推导斑块属性对物种影响的有效方法。     

Effects of pasture and forest microclimatic conditions on the foraging activity of leaf-cutting ants

The fragmentation and transformation of land cover modify the microclimate of ecosystems. These changes have the potential to modify the foraging activity of animals, but few studies have examined this topic. In this study, we investigated whether and how the foraging activity of the leaf-cutter ant Atta cephalotes is modified by microclimatic variations due to land cover change from forest to pasture. We characterized the microclimate of each habitat and identified alterations in foraging behavior in response to relative humidity (RH), air temperature, and surface temperature along ant foraging trails by synchronously assessing foraging activity (number of ants per 5 min including incoming laden and unladen and outgoing ants) and microclimatic variables (air temperature, RH, and maximum and minimum surface temperature along the foraging trail). There were climatic differences between habitats during the day but not throughout the night, and A. cephalotes was found to have a high tolerance for foraging under severe microclimatic changes. This species can forage at surface temperatures between 17 and 45°C, air temperatures between 20 and 36°C, and an RH between 40% and 100%. We found a positive effect of temperature on the foraging activity of A. cephalotes in the pasture, where the species displayed thermophilic behavior and the ability to forage across a wide range of temperatures and RH. These results provide a mechanism to partially explain why A. cephalotes becomes highly prolific as anthropogenic disturbances increase and why it has turned into a key player of human-modified neotropical landscapes.     

Associations between wasp communities and forest structure: Do strong local patterns hold across landscapes?

Abstract Forest structure and habitat complexity have been used extensively to predict the distribution and abundance of insect assemblages in forest ecosystems. We tested empirically derived predictions of strong, consistent relationships between wasp assemblages and habitat complexity, using both field assessments and vegetation indices from remote sensing as measures of habitat complexity. Wasp samples from 26 paired ‘high and low’ complexity sites in two forests approximately 70 km apart, were compared with normalized difference vegetation indices (NDVIs) derived from multispectral videography of the survey sites. We describe a strong unequivocal link between habitat complexity and wasp communities, the patterns holding over coarse and fine landscape scales. NDVIs were also excellent predictors of habitat complexity and hence wasp community patterns. Sites with greater NDVIs consistently supported a greater abundance and species richness, and a different composition of wasps to sites with low NDVIs. Using vegetation indices from remote sensing to gauge habitat complexity has significant potential for ecosystem modelling and rapid biodiversity assessment.