红豆树天然古群落结构特征的研究

红豆树是国家Ⅱ级保护珍稀濒危植物,开展百年红豆树群落学特征研究,对于保护红豆树古树群具有重要的意义。在霞浦县崇儒乡,用群落学方法对百年天然红豆树群落特征进行了定量研究。结果表明：红豆树、刨花润楠和毛锥3个树种在乔木层中占据绝对优势,三者的重要值分别为84.1%、49.3%和29.5%。根据群落中各树种的重要值,可将其命名为“红豆树+刨花润楠+红楠”群落。红豆树古群落垂直结构丰富,乔木层、灌木层和草本层分层明显,上层木为红豆树和刨花润楠,中层木为红楠、毛锥、钩锥等,林下更新层主要为红豆树、刨花润楠、毛锥。红豆树群落红豆树种群呈增长型,天然更新良好,在无干扰状态下红豆树群落能够实现自然更新。     

气候变化背景下的中国林业建设

介绍了林业在应对气候变化国际进程中的重要地位,回顾了我国林业在应对气候变化背景下所取得的成就,提出了充分发挥森林碳汇潜力,科学应对气候变化的具体措施.     

浅谈如何在新农村中开展林果技术服务

目前,土地流转、技术服务、推广资金、人员素质等一系列问题,严重制约了新农村林果经济的生产与发展.在建设社会主义新农村的伟大历史时期,要增加农民收入,大力发展林果经济,重点加强科技推广,林业资源开发,林业技术人员培训等,努力提高林果技术服务的水平和效果.     

Effect of the particle size on the ammonia removal rate and the bacterial community composition of bioflocs

The total ammonia nitrogen (TAN) removal efficiency and bacterial community composition of bioflocs with <50-μm particle size, > 50-μm particle size and un-sieved bioflocs were investigated in the current study. The initial ratio of dissolved organic carbon to TAN (DOC/TAN) in the three groups were about 14:1. No significant difference was found in the removal rate of TAN, average concentrations of TAN and nitrite nitrogen among the three groups (P > 0.05). The C/N (w/w) ratio of the > 50-μm bioflocs was significantly higher than those of the other groups. No significant differences were found in the crude protein content in the bioflocs among the three groups. The development of the bacterial community compositions of the bioflocs was analyzed by Illumina MiSeq sequencing analyses. Most OTUs were shared among the three groups at all the sampled time points. With the increase in the relative abundance of phylum Firmicutes, that of phylum Proteobacteria, Chorolexi, and Bacteroidetes decreased in all the three groups. The phylum Firmicutes and genus Bacillus were predominant in all the sampled time points. At the end of the experiment, genus Bacillus accounted for 81% in the < 50-μm group, 82% in the > 50-μm group, and 75% in the un-sieved group.     

Changes to freshwater mussel assemblages after 25 years of impoundment and river habitat fragmentation

1. The Tennessee–Tombigbee Waterway is among the largest and most expensive environmental engineering projects of the 20^th century. The waterway accommodates barge navigation between the Tennessee River Drainage and Mobile River Basin through a series of locks, dams, canals, and dredged and diverted streams. These structures have altered riverine habitat and fragmented lotic habitats resulting in isolated freshwater mussel populations in patches of streams such as the East Fork Tombigbee River, where 42 species were known historically.
2. The first post‐waterway mussel surveys in 1987 and 1988 reported 31 taxa. During 2010 and 2011 surveys, 70 sites were sampled using both timed searches and quadrats and detected 29 extant mussel species. Between 1988 and 2010–2011 the relative abundance of nine mussel taxa decreased, whereas the abundance of 11 taxa increased. The populations of three federally listed species were detected at levels below the detection limits in 1988 as well as three non‐native unionids that appear to have colonized the East Fork Tombigbee River via the Tennessee–Tombigbee Waterway River.
3. Although mussel abundance and total species richness were relatively unchanged, assemblage composition shifted toward animals typical of smaller streams rather than large rivers. This shift suggests that present‐day East Fork Tombigbee River habitats favour smaller‐bodied, thinner shelled taxa that are laterally compressed and lack shell sculpture. These taxa are likely to be better adapted to hydrologically and hydraulically variable habitats than are thick‐shelled, large bodied, and sculptured mussels.
4. The results suggest that mussel assemblages are dynamic and may exhibit predictable responses to changes in hydrology, physical habitat conditions, and stream connectivity. However, examinations over broad (20+ yr) temporal scales are needed to observe these shifts. The data demonstrate the value of regular monitoring of diverse mussel assemblages and the importance of stream connectivity and flow modifications to this long‐lived group of benthic invertebrates.

     

Spatial disparities in neighborhood public tree coverage: Do modes of transportation matter?

Urban green space has various environmental and ecological benefits, and uneven access to such amenities has drawn substantial attention from policy makers in developing sustainable community planning. In this study, we illustrate the spatial distribution of publicly owned and maintained trees in Edmonton, Canada and assess neighborhoods’ heterogeneous tree availability by using the container approach. Through spatial regression models, we further investigate the association of neighborhood public tree availability with socio-economic status (SES). We contribute to the existing literature by taking resident modes of transportation into consideration, in addition to many other commonly examined SES such as household income and ethnicity. Another unique contribution of this study is that we distinguish trees planted on different location types (i.e., boulevard, park, and buffer areas) when exploring the unequal coverage across neighborhoods and among different SES groups. Key results include: (1) a general examination without differentiating location types can lead to misleading results and thus provide inappropriate policy recommendations; (2) resident modes of transportation is a critical factor associated with a neighborhood’s public tree coverage; and (3) there exists evident spatial dependence on public tree availability between neighborhoods. The results from this study provide important information to better understand the issue and to allocate public resource (such as tree coverage) more efficiently and effectively to support sustainable community development.     

社群丰容对圈养小熊猫区域分配的影响

为探索社群丰容对重庆动物园圈养小熊猫行为区域分配的影响,2014年1月—2015年2月,用目标动物取样法对比观察春季、夏季、秋季、冬季社群丰容前后圈养小熊猫区域分配。结果表明:社群丰容增加了小熊猫对栖架、树上的利用,减少了内室和裸露地面和近游客区域的利用。树上利用的最大占比值在夏季,丰容增加了11.1%;栖架的利用最大占比值在春季,丰容增加了2.8%;冬季对内室的利用占比值最高,丰容后,其利用占比减少了8.4%,从而相应增加了小熊猫户外停留时间;丰容后,小熊猫对裸露地面的最大利用占比值减少了3.7%,近游客区域最大占比值减少了5.6%。小熊猫对六大区域的最高利用占比,丰容前后没有变化,最高为树上,最少为裸露地面。     

Conversion of cropland into agroforestry land versus naturally-restored grassland alters soil macro-faunal diversity and trophic structure in the semi-arid agro-pasture zone of northern China

Restoration of cropland(termed 'Farm') after abandonment including shrubs(termed 'Shrub'),trees(termed 'Tree') and natural grassland(termed 'Grass') has become a routine process aimed to improve land productivity and control desertification. During this restoration process, soil macro-faunal diversity, and trophic structure were investigated at four types of sites(Farm, Shrub, Tree, and Grass)during growing season in the semi-arid agro-pasture zone of northern China. Results indicated that the Staphylinidae family was found to dominate at the Grass, Shrub, and Tree sites, whiles larval Pyralidae individuals were found at the Grass site only. The density of the omnivores(i.e., Formicidae family) was significantly(P<0.05) greater at the Grass site than at the Tree and Farm sites. The total density and richness of predator and phytophages were found to be markedly(P<0.05) greater at the Grass site than at the Farm site. Meanwhile, we found the taxon richness of predators was significantly(P<0.05) higher at the Shrub site than at the Farm and Tree sites. Compared with the Farm and afforested Shrub/Tree sites,the Grass site had greater density, taxon richness, and Shannon index(P<0.05). In conclusion, natural restoration of abandoned croplands toward grassland was an effective strategy relative to artificial afforestation for improvement of soil biological diversity. Moreover, planting shrub is a preferable measure in abandoned croplands for land development in the semi-arid agro-pasture zone of northern China.     

Realizing the potential of trait‐based approaches to advance fisheries science

Analysing how fish populations and their ecological communities respond to perturbations such as fishing and environmental variation is crucial to fisheries science. Researchers often predict fish population dynamics using species‐level life‐history parameters that are treated as fixed over time, while ignoring the impact of intraspecific variation on ecosystem dynamics. However, there is increasing recognition of the need to include processes operating at ecosystem levels (changes in drivers of productivity) while also accounting for variation over space, time and among individuals. To address similar challenges, community ecologists studying plants, insects and other taxa increasingly measure phenotypic characteristics of individual animals that affect fitness or ecological function (termed “functional traits”). Here, we review the history of trait‐based methods in fish and other taxa, and argue that fisheries science could see benefits by integrating trait‐based approaches within existing fisheries analyses. We argue that measuring and modelling functional traits can improve estimates of population and community dynamics, and rapidly detect responses to fishing and environmental drivers. We support this claim using three concrete examples: how trait‐based approaches could account for time‐varying parameters in population models; improve fisheries management and harvest control rules; and inform size‐based models of marine communities. We then present a step‐by‐step primer for how trait‐based methods could be adapted to complement existing models and analyses in fisheries science. Finally, we call for the creation and expansion of publicly available trait databases to facilitate adapting trait‐based methods in fisheries science, to complement existing public databases of life‐history parameters for marine organisms.