毛竹及其变种叶片化学计量与养分重吸收效率

【目的】评价毛竹(Phyllostachys edulis)及其变种叶片养分重吸收效率,旨在揭示主要养分元素的生态适应机制,以期为毛竹及其变种的可持续经营提供科学依据。【方法】以毛竹及其变种[黄槽毛竹(P. edulis cv. Luteosulcata)、花毛竹(P. edulis cv. Tao Kiang)、厚壁毛竹(P. edulis cv. Pachyloen)、金丝毛竹(P. edulis cv. Gracilis)]为研究对象,分析不同竹龄(1、3、5 a)叶片化学计量特征与养分重吸收效率。【结果】毛竹及其变种C、N 含量差异较小,P含量波动性较大。不同竹种相同竹龄立竹间成熟叶和凋落叶C、N、P含量差异性较大,1年生竹种叶片养分含量较高,随着竹龄增加,竹种适应能力逐渐下降。毛竹及其变种相同年龄立竹间、同一变种不同年龄立竹间叶片化学计量比存在一定差异性。1、3、5年生花毛竹叶片N、P重吸收效率较高,年龄对除厚壁毛竹外的其他毛竹及其变种叶片N重吸收效率影响呈现先升后降趋势,而不同年龄毛竹及其变种叶片P重吸收效率波动性较大。【结论】研究区毛竹及其变种生长受P元素的限制,毛竹及其变种随竹龄的增加适应能力有所变化,花毛竹适应性较强,厚壁毛竹则对土壤的依赖性较大。     

谈“十四五”生态保护与绿色发展的生态关系

 从“十四五”保护与发展的生态关系角度，探讨了生态保护与绿色发展的十大生态关系，阐述了生态保护和绿色发展中的一系列有关生态关系的生态智慧及生态技术，并对长江、黄河等流域的生态保护和修复提出了相关建议。     

具有迁移效应和隔离措施的COVID-19传播模型分析

基于COVID-19传播过程中人口流动的必然性、无症状感染者的普遍性和隔离策略的有效性,该文提出了一类具有迁移效应、无症状感染者、自我防护意识和隔离策略的COVID-19传播动力学模型,利用下一代矩阵方法给出了各类子系统和全系统基本再生数的精确表达式.进一步地,通过采用线性近似理论,构造Lyapunov函数、比较原理等方法,得到了无病平衡点的全局渐近稳定性以及疾病的持久性.最后,数值模拟解释了主要的理论结果以及人口的迁移和隔离对疾病传播的影响.     

Breeding preferences in the treefrogs Dryophytes japonicus (Hylidae) in Mongolia

ABSTRACT

When a species occurs over a broad range of climates and landscapes, the breeding ecology of that species is expected to vary locally. Additionally, a basic knowledge of breeding ecology is required before other types of studies may be conducted, such as physiology or conservation. In North East Asia, Dryophytes japonicus is distributed from Japan to Mongolia, where its breeding ecology is unknown. The objectives of this study were to understand the breeding requirements of D. japonicus in this part of its range. We collected data for Dryophytes japonicus at 56 sites located within 23 independent localities in Northern Mongolia during the breeding season 2017. The data collected included habitat type and co-occurring amphibian, fishes and bird species. Our results show that the species prefers circa 70 m long oxbow lakes for breeding, while habitat characteristics, water quality and co-occurring species were not significantly associated with the occurrence of the species. We therefore conclude that D. japonicus is behaviourally plastic in Mongolia, as it is in other portions of its range, and that the species can use several types of environments and co-occur with different species at its breeding sites. Corvus dauuricus was the only bird species significant predicting the occurrence of D. japonicus, likely because of overlapping ecological preferences.     

生态农业规模化经营策略的系统动力学仿真分析

生态农业的规模化经营涉及规模化种植农地的获得、生态养种技术的采纳、生态农产品溢价的实现、环境的可持续性等诸多问题,是一个动态的复杂过程.以银河杜仲生猪规模养殖生态农业系统为例,构建生态农业规模化经营系统动力学模型.基于系统动力学仿真实验方法,对"扩大生态农业系统种植业生产规模、提高生态农业技术水平、完善生态农产品市场"三项生态农业规模化经营策略,设置相应策略参数,通过参数调控实施策略仿真实验.结果表明:扩大种植业生产规模能有效消除规模养殖环境污染,提高农产品竞争力;提高生态农业技术水平,对促进沼气资源的开发利用、降低沼液种植成本具有很好的作用;完善生态农产品市场,是实现生态农产品溢价、提高其社会效益的有效途径,影响着养殖主体开发与流转规模种植农地的决策.最后,基于策略仿真实验结果,针对银河杜仲生态农业系统实际,提出三项具体规模化经营对策.     

Breeding biology of the Pale-bellied Tyrant-manakin Neopelma pallescens (Aves: Pipridae) in south-eastern Brazil

The Pale-bellied Tyrant-manakin (Neopelma pallescens) inhabits semi-deciduous and riparian forests in central-north South America. Contrary to most manakins, there is no evident sexual dichromatism in the species and little is known about its breeding biology. We studied the breeding biology of a colour-banded population of the species from August to December 2016 and from August to October 2017 in the Campus Florestal of the Universidade Federal de Viçosa, south-eastern Brazil. The breeding season extended from early September to late November. The species is promiscuous, with males exhibiting simple courtship displays (exploded leks) in individual arenas. The nest (n = 13) is a cup attached by its top lip between forked branches and is very simple, with a structural layer made with dry grass stems and heads, attached to the branch with spider silk. The outer and lining layers are absent. The mean clutch size was 1.8 eggs (n = 11), which are oval and pale coloured, covered with spots of different shades of brown, often concentrated in the larger pole. Mean egg length and width (± SD) were 21.0 ± 0.9 × 15.8 ± 0.7 mm (n = 14) and the mean weight was 2.8 ± 0.4 g (n = 10). The incubation period could not be estimated, but the nestling period was 15 days (n = 2). The simple percentage of successful nests was 15.4%, with 76.9% of the nests depredated and 7.7% abandoned. This is the first detailed study about the breeding biology of any Neopelma species, providing relevant data for the study of the evolution of life history strategies not only for the genus, but for the whole family Pipridae.     

Comparison of breeding biology aspects of Fluvicola nengeta (Aves: Tyrannidae) between two nesting sites

Fluvicola nengeta is an insectivorous bird that belongs to the Tyrannidae family, which lives close to bodies of water and can occur in urban areas as well. It makes use of natural and man-made substrates to build its nests. This study aims at describing the reproductive biology of F. nengeta by comparing nests built on vegetation and man-made structures as to their shapes, nest dimensions, building materials, distance from bodies of water and reproductive success. Forty-four nests were found, where 30 were located in vegetation and 14 on man-made structures. Nests did not exhibit any single pattern and were divided into three distinct shapes: closed/globular/base; closed/ovoid/base (45.5%; n = 5 for both) and low cup/base (9%; n = 1). Nests built on man-made structures exhibited a larger amount of anthropic material, such as plastic and paper, instead of plant-derived materials. Nests on man-made structures were found to be higher up from the ground (459.8 ± 46.9 m) and farther from water (232.9 ± 54.8 m) in comparison to those on vegetation (92.2 ± 28.6 m and 7.3 ± 4.7 m, respectively), aside from exhibiting a higher Mayfield reproductive success (37%) when compared to nests built on vegetation (34%). The estimated values of the daily survival rate (DSR) for vegetation nests were 0.997 for the incubation period and 0.928 for the nestling period. In man-made structure nests, DSRs were 0.968 and 0.964, respectively, during the incubation and nestling periods. The period survival rate (PSR) of nests in vegetation was significantly higher than the PSRs of nests in man-made structures during the incubation period. DSRs did not differ between incubation and nestling periods for either nesting sites.     

基于养生理念的小区生态园林植物群落配置设计——以池州和泰星城小区为例

首先论述了小区生态园林植物配置的原则,提出养生保健理念配置具体手法,具体调查了池州市和泰星城小区绿化树种的选择以及群落配置,进行了系统分析评价,借以探讨池州养生宜居小区的建设。     

基于PSR框架的甘肃省环县耕地生态安全评价

以生态退化区甘肃环县为研究区,通过构建"压力-状态-响应"(PSR)模型,从自然、经济和社会3个方面选取20个评价指标,建立耕地生态安全评价指标体系,计算耕地生态安全指数并划分安全等级,对2005-2016年环县耕地生态安全变化状况进行定量分析.结果表明:①基于PSR模型的评价指标体系能够较好地反映耕地生态系统各个要素之间的关联,适用于区域耕地生态安全的综合评价.②2005-2016年期间,环县耕地生态安全水平逐渐提高,生态功能有所改善,耕地生态安全经历了"恶化-敏感-安全"的演变过程.③单项指标的变化表明环县2005-2016年间人口密度、人均耕地面积、土地垦殖率、单位面积耕地化肥施用量、年降水量以及工业废水排放达标率变化明显,是影响区域耕地生态安全状况的关键因素.今后在加强对耕地数量保护的同时,应采取休耕等耕地休养方式加强耕地质量和耕地生态建设与维护,致力于耕地生态系统的恢复和重建,促进区域耕地可持续利用.