Comparative vegetation analyses of two transects crossing a characteristic glacier valley in the Central Alps

Raffl, Corinna; Erschbamer, Brigitta

doi:10.1127/0340-269x/2004/0034-0225

Cited by 42 publications

(65 citation statements)

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“…Since 1858, the Rotmoosferner glacier has been retreating and has left a mainly level valley 2 km in length, ascending only in the younger parts of the foreland (Ͻ50 years) (9). The well-preserved chronosequence has been described in detail regarding soil formation, vegetational gradient, invertebrate succession, and total soil microbial communities (4,9,18,25). The parent material of the soils is mainly neoglacial moraine till and fluvioglacial sands (25).…”

Section: Methodsmentioning

confidence: 99%

Abundance of narG , nirS , nirK , and nosZ Genes of Denitrifying Bacteria during Primary Successions of a Glacier Foreland

Kandeler

Deiglmayr

Tscherko

et al. 2006

Appl Environ Microbiol

552

214

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Quantitative PCR of denitrification genes encoding the nitrate, nitrite, and nitrous oxide reductases was used to study denitrifiers across a glacier foreland. Environmental samples collected at different distances from a receding glacier contained amounts of 16S rRNA target molecules ranging from 4.9 ؋ 10 5 to 8.9 ؋ 10 5 copies per nanogram of DNA but smaller amounts of narG, nirK, and nosZ target molecules. Thus, numbers of narG, nirK, nirS, and nosZ copies per nanogram of DNA ranged from 2.1 ؋ 10 3 to 2.6 ؋ 10 4 , 7.4 ؋ 10 2 to 1.4 ؋ 10 3 , 2.5 ؋ 10 2 to 6.4 ؋ 10 3 , and 1.2 ؋ 10 3 to 5.5 ؋ 10 3 , respectively. The densities of 16S rRNA genes per gram of soil increased with progressing soil development. The densities as well as relative abundances of different denitrification genes provide evidence that different denitrifier communities develop under primary succession: higher percentages of narG and nirS versus 16S rRNA genes were observed in the early stage of primary succession, while the percentages of nirK and nosZ genes showed no significant increase or decrease with soil age. Statistical analyses revealed that the amount of organic substances was the most important factor in the abundance of eubacteria as well as of nirK and nosZ communities, and copy numbers of these two genes were the most important drivers changing the denitrifying community along the chronosequence. This study yields an initial insight into the ecology of bacteria carrying genes for the denitrification pathway in a newly developing alpine environment.Primary successional ecosystems, such as glacier forelands and volcanoes, present an ideal opportunity to study the biological colonization of substrates. Since the ice covers of many glaciers have receded over the past century, glacier forelands have released substrates for soil development. Autotrophic colonizers are expected to be important in the initial stages of primary community assembly. Organic substrates for microbial growth, however, might also come from allochthonous dead organic matter and living invertebrates in these environments. Hodkinson et al. (8) therefore recently proposed a previously unrecognized heterotrophic phase which should allow the initial establishment of functional communities. Accordingly, future studies in microbial ecology must account for both autotrophic and heterotrophic colonization along primary successional gradients such as glacier forelands, land lifts, floodplains, landslides, and volcanoes. In the past few years, studies have focused mainly on the composition and activities of the soil microbiota in primary succession of receding glaciers (19,21,24,25). Only a few studies have employed molecular tools to understand the diversity of archaeal and bacterial community structures along the forefields of receding glaciers (2,13,20). Analyses of activity and genetic structures of the nitrate reducer community at the Rotmoosferner glacier have shown that N cycling processes as well as microbial community composition depend on the successional age (...

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Section: Methodsmentioning

confidence: 99%

Abundance of narG , nirS , nirK , and nosZ Genes of Denitrifying Bacteria during Primary Successions of a Glacier Foreland

Kandeler

Deiglmayr

Tscherko

et al. 2006

Appl Environ Microbiol

552

214

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“…The pioneer stage is characterized by pioneer assemblages mainly composed of Saxifraga aizoides, S. oppositifolia, Linaria alpina, and Artemisia genipi (Raffl and Erschbamer, 2004;Raffl et al, 2006). The pioneers are then replaced by early successional species such as Trifolium pallescens and Poa alpina.…”

Section: Research Areamentioning

confidence: 99%

“…alpinus, and T. pratense ssp. nivale (Raffl and Erschbamer, 2004). The nomenclature follows Fischer et al (2005).…”

Section: Research Areamentioning

confidence: 99%

Colonization processes on a central Alpine glacier foreland

Erschbamer

Schlag²,

Winkler

2008

J Vegetation Science

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Questions: What are the colonization trends in vegetated vs. bare‐ground plots over a 10‐year period in a central Alpine glacier foreland? What are the long‐term effects of artificial seed addition to these plots? Location: Glacier foreland of the Rotmoosferner in the Central Alps, Obergurgl, Tyrol, Austria, 2380 – 2400 m a.s.l. Methods: A total of 40 permanent plots were established on moraines ice‐free for 35 and 50 years on vegetated and bare‐ground areas. Half of them were treated with a seed mixture in 1996 and 1997. Number and cover of the species were recorded in 1996 and from 2002/2003 to 2006. Results: Species richness doubled in the control plots and tripled in seeded plots on the 35‐year‐ice‐free moraine. On the 50‐year‐ice‐free moraine the increase in species number was more modest. Significant site, seeding and time effects were found. Seed addition had no effects in the bare‐ground plots on the older moraine and low effects in those on the younger moraine. All plots showed significant changes in cover of single species. The pioneer species decreased significantly in both moraines, in the control as well as in the seeded plots. A disappearance during the next years is predicted. Conclusions: Colonization in bare‐ground plots is limited by a lack of safe sites, whereas vegetated plots facilitate recruitment and establishment. Colonization on the glacier foreland is also dispersal limited. Seed addition enhanced the presence of already established species, and late successional species were newly introduced.

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“…All functional groups were increasing more or less equally, showing the high dynamic of this initial grassland at the glacier foreland. The grassland has mean cover values of 67% (Raffl & Erschbamer 2004;Raffl et al 2006). Obviously, the open patches within this site allow new colonization in grazed as well as in ungrazed plots.…”

Section: Discussionmentioning

confidence: 99%

Ongoing changes at the long-term monitoring sites of Gurgler Kamm Biosphere Reserve, Tyrol, Austria

Mayer¹,

Erschbamer²

2014

ecomont

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Grazing exclusion led to decreases in species numbers. Significant positive grazing effects were detected for dwarf shrubs and legumes in the subalpine zone and for herbs in the upper alpine zone. Within the untreated sites, species numbers and frequencies changed significantly with time, involving almost all functional groups. The lichen heath was the most stable community. Here, only graminoids showed an increasing trend. All in all, the intermediate disturbance hypothesis was found to be valid also for high altitudes. A continuation of the traditional grazing regime is therefore suggested for the entire Gurgler Kamm Biosphere Reserve.

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Comparative vegetation analyses of two transects crossing a characteristic glacier valley in the Central Alps

Cited by 42 publications

References 0 publications

Abundance of narG , nirS , nirK , and nosZ Genes of Denitrifying Bacteria during Primary Successions of a Glacier Foreland

Abundance of narG , nirS , nirK , and nosZ Genes of Denitrifying Bacteria during Primary Successions of a Glacier Foreland

Colonization processes on a central Alpine glacier foreland

Ongoing changes at the long-term monitoring sites of Gurgler Kamm Biosphere Reserve, Tyrol, Austria

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