Micropropagation of common ash (Fraxinus excelsior)

Embryos extracted from dried seeds of common ash (Fraxinus excelsior), were germinated on growth regulator-free culture medium. Cotyledonary nodes from these seedlings were placed onto Murashige and Skoog, Woody Plant or Driver and Kuniyuki culture media with 22.2 or 44.4 M benzyladenine, on which they developed into shoot cultures following the outgrowth of axillary buds. With Murashige and Skoog medium, cultures often died. With Woody Plant Medium, survival of the cultures was considerably improved, but large amounts of callus were produced at the cut ends of the explants, and new axillary shoots had long internodes and small leaves. With Driver and Kuniyuki medium, both survival and callus formation were much improved, and the shoots produced were of high quality. Proliferation of axillary shoots was obtained from both shoot tip and nodal explants placed onto Driver and Kuniyuki medium with 22.2 M benzyladenine. Adventitious root formation was best with shoots inserted into half-strength Woody Plant Medium containing 2.45, 4.9 or 9.8 M indolebutyric acid. All of the rooted plantlets tested have successfully established in soil.     

Land use changes could modify future negative effects of climate change on old‐growth forest indicator species

Aim

Climate change is expected to have major impacts on terrestrial biodiversity at all ecosystem levels, including reductions in species‐level distribution and abundance. We aim to test the extent to which land use management, such as setting‐aside forest from production, could reduce climate‐induced biodiversity impacts for specialist species over large geographical gradients.

Location

Sweden.

Methods

We applied ensembles of species distribution models based on citizen science data for six species of red‐listed old‐forest indicator fungi confined to spruce dead wood. We tested the effect on species habitat suitabilities of alternative climate change scenarios and varying amounts of forest set‐aside from production over the coming century.

Results

With 3.6% of forest area set‐aside from production and assuming no climate change, overall habitat suitabilities for all six species were projected to increase in response to maturing spruce in set‐aside forest. However, overall habitat suitabilities for all six species were projected to decline under climate change scenario RCP4.5 (intermediate–low emissions), with even greater declines projected under RCP 8.5 (high emissions). Increasing the amount of forest set‐aside to 16% resulted in significant increases in overall habitat suitability, with one species showing an increase. A further increase to 32% forest set‐aside resulted in considerably more positive trends, with three of six species increasing.

Main conclusions

There is interspecific variation in the importance of future macroclimate and resource availability on species occurrence. However, large‐scale conservation measures, such as increasing resource availability through setting aside forest from production, could reduce future negative effects from climate change, and early investment in conservation is likely to reduce the future negative impacts of climate change on specialist species.     

北京浅山区香山特色小镇规划设计探索

香山小镇位于北京浅山区军庄镇,面对旅游、经济发展的压力和脆弱生态环境保育的课题,本案设计突出生态优先、绿色经济和文化共赢的可持续发展策略,把浅山区视为一个生命系统,从区域层面建立有指导性的生态保护导则,提升区域水资源管理、林相修复和栖息地复建的长远效益,推动有机果园和绿色旅游的发展;在设计过程中高度结合现状,设计结合自然,设计结合策划,修复基于保护。景观设计同步整合生态保护和策划、建设的要求,积极发掘民间工艺并创造性地应用于景观设计,发动当地居民的主动参与,塑造有温度、有记忆、有传承、亲切宜人的浅山特色生态小镇。     

Analysis of genetic relationships of Central American and Mexican pines using RAPD markers that distinguish species

Phylogenetic relationships were inferred for six Central American and Mexican pine species by analysing RAPD marker differences among pooled DNA samples. This population level pooling strategy discounts low-frequency allelic variation within taxa, thus obtaining a 'cumulative genotype' to compare among taxa. We used the morphologically based taxonomy of pines as the basis for inference concerning molecular marker divergence. Only RAPD polymorphisms that were repeatable and intensely amplified were used. The resulting data set was found to have strong hierarchical structure. Phylogenetic analyses were carried out using both neighbour-joining and maximum parsimony. The phylogenetic relationships indicated by analysis of the pine RAPD data provide new insights on pine taxonomy. The phylogenetic analyses of the RAPD marker data placed Pinus tecunumanii and P. patula clearly into two different subgroups, strongly supporting the classification of P. tecunumanii as a distinct species, and raise a new set of issues concerning the distinctions between Pinus tecunumanii and P. caribaea . Phylogenetically informative RAPD markers will be useful tools to address ex-situ conservation issues that involve taxonomic identification and species admixture.     

Long‐term outcomes of forest restoration in an urban park

Creating, restoring, and sustaining forests in urban areas are complicated by habitat fragmentation, invasive species, and degraded soils. Although there is some research on the outcomes of urban reforestation plantings during the first 5 years, there is little research on longer term outcomes. Here, we compare the successional trajectories of restored and unrestored forest sites 20 years after initiating restoration. The sites are located within the Rodman's Neck area of Pelham Bay Park, in the northeast corner of the Bronx in New York City (NYC), U.S.A. Compared with unrestored sites, we saw improvements in species diversity, greater forest structure complexity, and evidence of the regeneration and retention of native tree species in restored sites. In addition, we found differences in restoration outcomes depending on the level of intervention: clearing exotic shrubs and vines and planting native trees and shrubs improved tree diversity and canopy closure to a greater extent than clearing exotics alone, and the mechanical removal of invasive plants after the native plantings further improved some measures of restoration, such as tree species diversity and native tree regeneration. The results of this study suggest that the goal of a sustainable forest ecosystem dominated by native trees and other plant species may not be achievable without continued human intervention on site. In addition, these results indicate that the restoration approach adopted by NYC's reforestation practitioners is moving the site toward a more desirable vegetative community dominated by native species.     

Selection for commercial forestry determines global patterns of alien conifer invasions

Question Are the patterns of alien conifer (Pinaceae, Cupressaceae) invasions different between continents, and how is invasion success influenced by commercial forestry practices? Location Temperate and subtropical countries and regions (n = 60) from five continents spanning both hemispheres. Methods We used generalized linear mixed models to test how continent identity, region area and use in commercial forestry affect probabilities of Pinaceae and Cupressaceae species to escape following introduction and cumulative logit regression models to assess how these predictors affect the likelihood that a species becomes naturalized or invasive. Results Sixty Pinaceae of a global total of 232 and 26 Cupressaceae of a total of 142 species have escaped from cultivation across the study regions examined. Average numbers of both alien Pinaceae and Cupressaceae species per region were highest in Oceania, followed by Africa. Moreover, the probability of alien Cupressaceae and Pinaceae becoming naturalized or invasive was particularly high in these two continents. For both families, species used in commercial forestry have a significantly higher probability of escape than those which are only introduced for ornamental or other purposes. In the case of Pinaceae, forestry species also become naturalized or invasive more frequently than non‐forestry species, while no such effect was detectable for Cupressaceae. Conclusions We found that non‐native conifers are more likely to escape from cultivation, naturalize and turn into invasive weeds on the continents of the Southern Hemisphere. In addition to this biogeographic signal, introduction effort strongly determines the behaviour of introduced Pinaceae, and less so, Cupressaceae. A clear conflict exists between the economic benefits of conifer forestry and the risks to the environment from invasions. Future expansion of commercial forestry should address spatial planning to ecosystems vulnerable to invasion and adopt comprehensive risk assessment procedures.     

Predicting invasions by woody species in a temperate zone: a test of three risk assessment schemes in the Czech Republic (Central Europe)

To assess the validity of previously developed risk assessment schemes in the conditions of Central Europe, we tested (1) Australian weed risk assessment scheme (WRA; Pheloung et al . 1999); (2) WRA with additional analysis by Daehler et al . (2004); and (3) decision tree scheme of Reichard and Hamilton (1997) developed in North America, on a data set of 180 alien woody species commonly planted in the Czech Republic. This list included 17 invasive species, 9 naturalized but non-invasive, 31 casual aliens, and 123 species not reported to escape from cultivation. The WRA model with additional analysis provided best results, rejecting 100% of invasive species, accepting 83.8% of non-invasive, and recommending further 13.0% for additional analysis. Overall accuracy of the WRA model with additional analysis was 85.5%, higher than that of the basic WRA scheme (67.9%) and the Reichard–Hamilton model (61.6%). Only the Reichard–Hamilton scheme accepted some invaders. The probability that an accepted species will become an invader was zero for both WRA models and 3.2% for the Reichard–Hamilton model. The probability that a rejected species would have been an invader was 77.3% for both WRA models and 24.0% for the Reichard–Hamilton model. It is concluded that the WRA model, especially with additional analysis, appears to be a promising template for building a widely applicable system for screening out invasive plant introductions.     

啄木鸟科内谱系生物地理学新探

啄木鸟群体共包含254种,但早期对啄木鸟的分类学研究局限于形态学、行为学和鸣唱法等方向,分子研究结果又彼此存在差异,因此啄木鸟分类系统目前还有争议。分子数据的大量累积为啄木鸟系统发育的研究提供了条件。利用从GenBank获取的ND2基因序列,对啄木鸟科179种啄木鸟采用NJ法、MP法以及ML法分别进行了分子进化树构建,同时用NJ法重建了Picumnus属分子进化树。此外又利用cytb基因序列采用NJ法对Dryobates属和Picoides属进行分子进化树重建。我们的结果显示,姬啄木亚科Picumnus属新大陆物种彼此的进化关系仍需进一步研究,而该属唯一一种旧大陆种P.innominatus,种内遗传差异在种间水平依然显著,这说明其种内遗传差异一直被低估了。在啄木鸟亚科内,Hemicircus属和Nesoctites属为姐妹关系,而Geocolaptes olivaceus插入了Campethera属支系中,并非与其构成姐妹群体。此外,一些姐妹群在新旧大陆上的分布,推测这种分布可能与第四纪冰川有关。啄木鸟从旧大陆向新大陆迁移,在第四纪冰川作用下不断发生分布范围的扩张与收缩,最终形成现存的分布格局。     

Invasive autumn olive performance varies in different reclamation conditions: implications for restoration

Surface mining has caused significant disturbance globally, and is responsible for the loss of more than 600,000 ha of the world's largest temperate deciduous forest in the Appalachian region of the United States alone. Due to the heavy disturbance on mine lands, invasive plants have become dominant on many former coalfields, some of which were intentionally planted with exotic species. The establishment of invasive plants on these disturbed lands has often led to reductions in establishment of desirable native species. Autumn olive (Elaeagnus umbellata), an exotic nitrogen‐fixing shrub, is a problematic invasive species on reclaimed sites in Appalachia. To better understand how reclamation conditions affect autumn olive, we assessed the effects of the mine‐soil substrate and vegetation seeding on autumn olive establishment and growth. In each experiment, we also manipulated the herbaceous plant community to further examine effects on autumn olive establishment and growth. In spring 2015, we transplanted 480 1‐year‐old autumn olive seedlings across both experiments. After 2 years of growth, autumn olive performed better in weathered‐rock than in unweathered‐rock substrates; in bare‐ground plots than in vegetated plots; and in tree‐compatible (low‐competition) seeding than in more‐competitive conventional seeding. No treatment precluded autumn olive establishment. However, our results show that strategic use of beginning substrates and planting mixes can have strong inhibitory effects on invasive plants, but also that substrate and herbaceous‐plant community conditions favorable to establishment of native trees are also favorable to autumn olive.     

Environmental analysis of producing biochar and energy recovery from pulp and paper mill biosludge

Sweden is one of the largest exporters of pulp and paper products in the world. It follows that huge quantities of sludge rich in carbonaceous organic material and containing heavy metals are generated. This paper carried out a comparative environmental analysis of three different technologies, which can be adopted to produce biochar and recover energy from the biosludge, using landfilling as the reference case. These three thermochemical biosludge management systems—using incineration, pyrolysis, and hydrothermal carbonization (HTC)—were modeled using life cycle assessment (LCA). Heat generated in the incineration process (System A) was considered to be for captive consumption within the kraft pulp mills. It was assumed that the biochars—pyrochar and hydrochar—produced from pyrolysis (System B) and HTC (System C), respectively, were added to the forest soils. The LCA results show that all the alternative systems considerably improve the environmental performance of biosludge management, relative to landfilling. For all systems, there are net reductions in greenhouse gas emissions (–0.89, –1.43, and –1.13 tonnes CO₂‐equivalent per tonne dry matter biosludge in Systems A, B, and C, respectively). System B resulted in the lowest potential eutrophication and terrestrial ecotoxicity impacts, whereas System C had the least acidification potential. The results of this analysis show that, from an environmental point of view, biochar soil amendment as an alternative method for handling pulp and paper mill biosludge is preferable to energy recovery. However, an optimal biochar system needs to factor in the social and economic contexts as well.