Observations on Chromosomes of Fourteen Moss Species from the Qinling Range,China

The chromosome numbers in fourteen moss species from the Qinling Range, and karyotype of Mnium lycopodioides are reported in this paper. Immature capsules were used as material. Bryum capillare L. ex Hedw was found. to have n = 10; Mnium lycopodioides Schwaegr. n = 6 with the karyotype formula n = 6 = 3m+3sm (1SAT); Plagiomnium maximoviczii (Lindl.)T. Kop. n=6; Bartramia halleriana var. elongate Turn. n=10+2m; Thuidium delicatulum (Hedw.) Mitt. n= 11; Thuidium philibertii Limpr. n= 10+m; Hygrohypnum ochraceum (Wils.) Loesk. n=10; Drepanocladus uncinatus (Hedw.) Warnst. n = 7+3m; Campylium chrysophyllus (Brid.) J. Lange. n = 10; Brachythecium starkei (Brid.) B. S. G. n=6; Brachythecium buchananii (Hook.) Jaeg. n=6; Brotherella yokohamae (Broth.)Broth. n= 9+2m; Gollamia neckerella (C. MÜll. )Broth. N=7; Pogonatum fastigiatum Mitt. n = 7. No report on the chromosome number of Brotherella yokohamae and Gollania neckerella has been found. The chromosome numbers in Brachythecium starkei andBrachythecium buchananii (Hook.) Jaeg. are different from previous reports, while the others are in accordance with the previous reports.     

Cytological Observation of 4 Chinese Moss Species

In this paper the chromosome countings of 4 moss species are reported for the first time in China. The materials used for investigation were taken from immature capsules. Meiosis in spore mother cells and also mitosis in the case of Plagiomnium cuspidatum were observed, with the result: Didymodon constrictus, n=14, Entodon schensianus, n=10+lm; Plagiomnium cuspidatum, n=6, Cratoncuron jilicinum, n=10. The chromosome numbers ofthe former two species are reported for the first time.     

Larval settlement can explain the adult distribution of Mytilus californianus Conrad but not of M. galloprovincialis Lamarck or M. trossulus Gould in Moss Landing, central California: Evidence from genetic identification of spat

We investigated the spatial distribution of adult and newly settled mussels (Mytilus galloprovincialis Lamarck, Mytilus trossulus Gould and Mytilus californianus Conrad) on the shore at Moss Landing, California to test the hypothesis that adult distributions are a result of settlement patterns. Adult M. californianus were most abundant on a wave-exposed rocky jetty and adults of Blue mussels (M. trossulus and M. galloprovincialis) were more abundant inside the protected Moss Landing harbor. Using taxon-specific polymerase chain reactions, we monitored recruitment during continuous 1-2 week intervals on fibrous scrubbing pads for 12 months in 2002-2003. All mussel species settled in greatest numbers on the exposed jetty, and Blue mussels settled in greater numbers there than did M. californianus. Because Blue mussels settled abundantly where their adults were rare, post-settlement mortality appeared to be the strongest influence on adult distribution. In contrast, M. californianus settled mostly in their adult habitat.     

Analysis of ent-kaurenoic acid by ultra-performance liquid chromatography-tandem mass spectrometry

ent-Kaurenoic acid (KA) is a key intermediate connected to a phytohormone gibberellin. To date, the general procedure for quantifying KA is by using traditional gas chromatography–mass spectrometry (GC–MS). In contrast, gibberellins, which are more hydrophilic than KA, can be easily quantified by liquid chromatography-tandem mass spectrometry (LC–MS/MS). In this study, we have established a new method to quantify KA by LC–MS/MS by taking advantage of a key feature of KA, namely the lack of fragmentation that occurs in MS/MS when electrospray ionization (ESI) is in the negative mode. Q1 and Q3 were adopted as identical channels for the multiple reaction monitoring of KA. The method was validated by comparing with the results obtained by selected ion monitoring in GC–MS. This new method could be applicable for the quantification of other hydrophobic compounds.     

Pollen–vegetation relationships along steep climatic gradients in western Amazonia

Question: How accurately do Amazonian montane forest pollen spectra reflect the vegetation? Can compositional changes observed in the vegetation along environmental gradients be identified in the pollen spectra? How well do herbarium collection data and bioclimatic envelopes represent abundance changes along elevation gradients? Location: Amazonian montane forests, Peru. Methods: Moss polsters collected along five altitudinal transects spanning over 3000 m a.s.l. were used to characterize pollen spectra. Vegetation plot data from a network of 15 1‐ha permanent plots were used to correlate pollen spectra with present‐day vegetation. Probability density functions (PDFs) fitted to pollen and plot data allowed comparisons using Spearman correlation coefficients. Ordination analyses were used to summarize changes in pollen spectra. Correlations between pollen‐based PDFs and previously‐published herbarium collection PDFs were also evaluated. Results: Pollen spectra closely reflected changes in species composition along elevation gradients. A mid‐elevation shift in pollen spectra was identified using ordination analyses. Pollen spectra from the driest forest in our data set were statistically different from those of wet forests. Pollen abundance PDFs along the altitudinal gradient were significantly correlated (P<0.01) with PDFs fitted to plot abundance, basal area and herbarium collection data for ten out of 11 taxa analysed. Conclusions: Pollen spectra closely reflected the vegetation composition of Amazonian montane forests. The differentiation of pollen spectra from dry localities showed the potential of genus‐level pollen data to reflect precipitation gradients. Pollen spectra also reflected mid‐elevation compositional changes well along the lower elevation limit of ground cloud formation. Despite collection biases, herbarium‐based bioclimatic envelope PDFs also represented well forest compositional changes along elevation gradients.     

Surprisingly fast recovery of biological soil crusts following livestock removal in southern Australia

Question: Biological soil crusts (BSCs) exist in arid and semi‐arid ecosystems worldwide, and their recovery following the removal of a disturbance agent is integral to the rehabilitation of degraded landscapes. We asked: what is the likelihood of success and time frame of BSC recovery in vegetation remnants of southeast Australia, following livestock exclusion by fencing. Location: Dryland agricultural region of northwest Victoria, Australia. Methods: We conducted a “space for time” study of BSC recovery across 21 sites where livestock have been excluded by fencing between 1 and >50 years ago, and used boosted regression tree models to explore the response of BSCs to livestock exclusion while controlling for the influence of environmental variables on BSC abundance. Results: Our results show a relatively rapid, passive recovery of BSCs following livestock exclusion, with cover stabilizing after 20 years. Sites heavily disturbed by livestock grazing at the time of fencing stabilized at a lower cover. In contrast to studies from other countries, our results suggest mosses, not cyanobacteria, are the important colonizers in our study region. Conclusions: Ecosystem function in degraded remnants of southern Australia can be improved in a relatively short time frame through passive recovery alone. This knowledge will benefit land managers choosing between restoration options in disturbed and fragmented arid‐landscapes.     

福建戴云山国家级自然保护区藓类植物区系研究

通过3次野外实地考察采得藓类植物标本2198份,经室内鉴定,戴云山国家级自然保护区藓类植物共计47科、130属、302种(含种下单位),其中福建省新纪录3科、11属、74种.经区系成分分析,戴云山以东亚成分为主,占总种数的33.33％;其次是热带亚洲成分和北温带成分,分别占总种数的22.22％和16.67％,具亚热带性质.将戴云山与台湾玉山、江西阳际峰、浙江大盘山、广西猫儿山、广西九万山、福建鹫峰山东麓、云南大围山和四川峨眉山的藓类植物区系成分比较发现,戴云山的藓类植物区系成分更具岭南区特色.聚类分析结果也表明,戴云山与岭南区的猫儿山、九万山、大围山和毗邻区——云贵区的峨眉山聚在一起,因此,建议将岭南区与华东区在福建省内的界限略向北移.     

The role of cattle in maintaining plant species diversity in wet dune valleys

The succession of species-rich wetland vegetation in dune valleys into species-poor dwarf shrub vegetation was followed by means of permanent vegetation plots, in which the cover of vascular plant, moss and lichen species were recorded over a period of up to 33 years. Low density cattle grazing is an effective substitute for rabbits in stalling this succession, thus preserving the local plant species diversity. The influence of direct rabbit grazing pressure on the vegetation was studied in exclosures. The differences were significant, but not long-lasting after the exclosures had been opened again to the rabbits. Cladina lichen-rich Empetrum-heathland in the dunes is a stage in a probably cyclic succession that might be triggered by grazing. The total vascular plant, moss and lichen diversity of the dune ecosystem can be maintained by a combination of extensive cattle grazing and a regular but limited re-creation of pioneer situations.     

Harvesting surface vegetation does not impede self‐recovery of Sphagnum peatlands

Ecosystem restoration frequently involves the reintroduction of plant material in the degraded ecosystem. When there are no plant nurseries or seeds available on the market, the plant material has to be harvested in the wild, in a “donor ecosystem.” A comprehensive assessment of donor ecosystem recovery is lacking, especially for Sphagnum‐dominated donor peatlands, where all top vegetation is harvested mechanically with different practices. We aimed to evaluate (1) the regeneration of vegetation, especially of Sphagnum mosses, to determine which harvesting practices are best to enhance recovery and (2) the influence of the site hydrological conditions and meteorological variables of the first complete growing season postharvesting on peat moss regeneration. Twenty‐five donor sites covering a 17‐year chronosequence (harvested 1–17 years ago) were inventoried along with 15 associated natural reference sites located in Quebec, New Brunswick, and Alberta, Canada. All donor sites aged 10 years or more were dominated by Sphagnum mosses, though plant composition varied between donor and their associated reference sites because of the wetter conditions at harvested donor sites. Harvesting practices strongly influenced donor site recovery, showing that the skills of the practitioner are an essential ingredient. Harvesting practices minimizing donor site disturbances are recommended, such as the choice of the adequate donor site (localization, hydrologic conditions, vegetation), the use of less disruptive methods, and harvesting when the soil is deeply frozen. This study demonstrated that harvesting surface plant material for peatland restoration is not detrimental towards the recovery of near‐natural peatland ecosystems.     

Species richness, abundance, rarity and environmental gradients in coastal barren vegetation

Coastal barrens in Nova Scotia are heathlands characterised by short, predominantly ericaceous vegetation, sparse tree cover, exposed bedrock, pockets of Sphagnum bog, and stressful climatic conditions. Although coastal barrens are prominent in the physical and cultural landscape, they are largely unprotected. We selected six barrens along the Atlantic coast, and surveyed 20 1-m² plots at each barren for vascular plants, macrolichens, mosses and environmental factors. We recorded 173 species (105 vascular, 41 macrolichen, 27 moss), including six provincially rare vascular species found predominantly in nearshore areas with high levels of substrate salt and nutrients, variable substrate depth, and short vegetation. Although vascular plant and moss richness were similarly correlated with vegetation height, substrate depth, organic matter content, and rock exposure, there were no clear correlations between vascular plant, macrolichen and moss richness across all sites. Vascular plant rarity and species richness were not correlated, but had inverse relationships with key environmental gradients. Tailoring conservation efforts to protect areas of high richness may thus mean that rare species are missed, and vice versa. Ordination and ANOSIM show that barrens vegetation differs widely among sites; therefore, protecting any singular coastal barren will not protect the entire range of vegetation communities and species in this heathland type. Conservation planning should emphasize protecting environmental gradients correlated with richness, rarity and plant community structure, including substrate depth and moisture, and vegetation height. Additionally, protected areas should include a coastal-inland gradient and a diversity of substrate types, including exposed rock and trees.