Challenges to Introducing and Managing Disturbance Regimes for Holocarpha macradenia, an Endangered Annual Grassland Forb

Abstract:  Introducing rare plants to new sites for conservation to offset effects of habitat destruction requires detailed knowledge of habitat requirements, plant demography, and management needs. We conducted a factorial experiment replicated at three coastal prairie sites to test the effects of clipping frequency and litter accumulation on seed germination, seedling survival, reproduction, and seedling recruitment of introduced populations of the endangered, tall-stature, annual forb, Holocarpha macradenia (DC.) E. Greene. Clipping favored H. macradenia , primarily by enhancing seed germination and flower production. Litter accumulation had no effect on seed germination, even after 5 years of treatments. Seedling recruitment was highly site specific with large numbers of recruits recorded at only one of three sites. Although recruitment of seedlings was higher in clipped plots for 2–3 years, by 4–5 years after introduction very few seedlings survived to reproduction in any treatment. We attribute this result to a combination of poor habitat quality, small population size, and lack of a seed bank. We were unsuccessful in introducing this relatively well-studied species of concern to apparently suitable habitat at multiple sites in multiple years, which suggests that translocating rare plant populations to mitigate for habitat destruction is an expensive and highly uncertain endeavor.     

One-step formation of oligopeptide-like molecules from Glu and Asp in hydrothermal environments

Biopolymer accumulation in the absence of enzymes is an essential step for the chemical evolution of primitive life-like systems, and successful simulation experiments of prebiotic biopolymer formation have suggested that oligopeptides could have formed near submarine hydrothermal vent environments on primitive earth. However, the yield and length of oligopeptides -- typically limited to 6-mers -- seems to be inadequate. One reason is the rapid formation of diketopiperazines (DKPs) from dipeptides. In this study, using a hydrothermal microflow reactor, we show that the one-step synthesis of oligopeptide-like molecules of length up to 20-mers proceeds from Glu and Asp. Yields of up to 0.17-0.57% were obtained in an acidic solution within 183 s at 250-310 degrees C, as evaluated by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) analysis and different types of high-performance liquid chromatography (HPLC) analyses. The present study indicates that Glu and Asp may have played important roles in the chemical evolution of oligopeptide-like molecules in hydrothermal vent environments on primitive earth.     

稀有鮈鲫和日本青鳉肝细胞原代培养及其对2,3,7,8-TCDD的敏感性比较

利用胰酶消化和机械分散相结合的方法对稀有鮈鲫和日本青鳉的肝细胞进行分离和培养,测定了不同培养时间下两种原代培养肝细胞的活力,研究了两种原代培养肝细胞受到2,3,7,8-TCDD暴露后EROD活力变化的时间-和浓度-效应关系.结果表明,稀有鮈鲫和日本青鳉的肝细胞产率分别达到2.0×107cells.g-1和1.5×107cells.g-1,稀有鮈鲫原代肝细胞的活力可以稳定地保持5d,日本青鳉原代肝细胞的活力至少可以稳定地保持1周;不同浓度TCDD暴露后,两种鱼的原代肝细胞EROD活力变化均显示良好的时间-浓度-效应关系,TCDD诱导稀有鮈鲫和日本青鳉原代肝细胞EROD活力的最低可观察效应浓度(LOEC)分别为4pg.mL-1和1pg.mL-1;TCDD诱导日本青鳉原代肝细胞EROD活力的EC50值低于稀有鮈鲫.就原代肝细胞培养操作和对毒物胁迫的敏感性而言,日本青鳉优于稀有鮈鲫.     

土壤中La与P迁移的关联性初步研究

通过室内土柱淋溶试验和人工降雨模拟试验分别观察了元素P和La从土壤表层纵向和横向流失的特征,初步探讨了单一稀土元素La与土施畜禽肥料P随暴雨径流流失的关联性.淋溶试验结果表明,外源La和P在土壤中的纵向迁移都非常困难,La和P的迁移深度分别不超过土壤表层6 cm和8 cm;增加外源La可以降低土壤中水浸提P、NaHCO3浸提P和NaOH浸提P的量,提高HCl浸提P的量,增加残渣态P在TP中的比重;而人工降雨模拟试验结果表明,绝大部分La和总P都是通过径流沉积物相流失(占流失总量的95%以上),对于添加不同剂量的La系列,无论是从土壤表层的流失速率还是流失的总量,总P和La都存在良好的相关性.     

湖南某地采铀试验工程废水处理工艺设计

通过分析湖南境内某铀矿原地爆破浸出、地表堆浸采铀试验工程工艺流程以及该工程产生的废水源强及性质,介绍了BaCl2-Ca(OH)2中和沉淀法对该股废水处理的可行性及达到的效果。     

云南镇雄县珙桐新分布区及保护对策

报道了云南镇雄国家I级保护植物珙桐新分布区的面积、数量及生态环境,提出了相应的保护措施。     

金尾矿综合利用技术研究与应用进展

黄金矿石的品位低,经选冶后产生比其他金属矿石更多的尾矿。黄金矿山每天尾矿的大量排放,造成了黄金及其他有价金属的流失,同时大量的尾矿堆积,对环境带来极大的危害。为了进一步回收有价金属,保护矿区的生态环境,本文介绍了尾矿的综合利用技术,其中重点介绍了尾矿中有价元素的综合回收技术,进一步变废为宝,开发宝贵的二次资源。     

A new method for broad-scale modeling and projection of plant assemblages under climatic,biotic, and environmental cofiltering

There is increasing interestin broad-scale analysis, modeling, and prediction of the distribution and composition of plant species assemblages under climatic, environmental, and biotic change, particularly for conservation purposes. We devised a method to reliably predict the impact of climate change on large assemblages of plant communities, while also considering competing biotic and environmental factors. To this purpose, we first used multilabel algorithms in order to convert the task of explaining a large assemblage of plant communities into a classification framework able to capture with high cross-validated accuracy the pattern of species distributions under a composite set of biotic and abiotic factors. We applied our model to a large set of plant communities in the Swiss Alps. Our model explained presences and absences of 175 plant species in 608 plots with >87% cross-validated accuracy, predicted decreases in α, β, and γ diversity by 2040 under both moderate and extreme climate scenarios, and identified likely advantaged and disadvantaged plant species under climate change. Multilabel variable selection revealed the overriding importance of topography, soils, and temperature extremes (rather than averages) in determining the distribution of plant species in the study area and their response to climate change. Our method addressed a number of challenging research problems, such as scaling to large numbers of species, considering species relationships and rarity, and addressing an overwhelming proportion of absences in presence–absence matrices. By handling hundreds to thousands of plants and plots simultaneously over large areas, our method can inform broad-scale conservation of plant species under climate change because it allows species that require urgent conservation action (assisted migration, seed conservation, and ex situ conservation) to be detected and prioritized. Our method also increases the practicality of assisted colonization of plant species by helping to prevent ill-advised introduction of plant species with limited future survival probability.     

稀土对植物抗逆作用的自由基机制

通过研究及收集的资料，提出在植物生长期中，稀土元素能增加植物的抗逆性，当植物受到酸雨、重金属及盐胁迫时，稀土表现出抗氧化性质，而且稀土对植物的抗逆作用是由于其具有清除含氧自由基的作用。     

自然保护区人类活动天地一体化监管与评价技术体系

基于遥感监测与实地核查相结合的技术,构建了集目标、内容、指标、流程为一体的自然保护区人类活动天地一体化监管与评价的技术体系,在此基础上提出了自然保护区人类活动影响评价方法和模型.最后,为了验证方法体系的可靠性,以河南董寨国家级自然保护区为例进行了示范研究,结果表明：该自然保护区有工矿用地、旅游用地、采石场、农业用地、居民点、其他人工设施和道路7种人类活动类型,人类活动总面积占保护区总面积的16.60%,以农业用地为主,占自然保护区人类活动总面积的89.41%.人类活动主要分布在实验区,实验区人类活动总面积5554.9hm²、总数量231处,分别占人类活动总面积和总数量的68.65%和58.93%.该自然保护区人类活动影响指数为0.000697,人类活动影响较明显,不利于物种和生态系统的保护.