ALBERT — All Library Books, journals and Electronic Records Telegrafenberg

1

Electronic Resource

Translocation of Herb-Rich Grassland from a Site in Wales Prior to Opencast Coal Extraction (1999)

Good, J. E. G. ; Wallace, H. L. ; Stevens, P. A. ; [et al.]

Boston, MA, USA : Blackwell Science Inc

Restoration ecology 7 (1999), S. 0

add to mindlist on the mindlist

Details

ISSN: 1526-100X

Source: Blackwell Publishing Journal Backfiles 1879-2005

Topics: Biology

Notes: Reinstatement of vegetation to a similar condition to that prior to disturbance is often required in industrial restoration schemes. Seeding with specially prepared seed mixes containing species suited to local soils is often the preferred option on grounds of practicality and cost. Turf translocation is more difficult and costly but, if successful, meets the reinstatement requirement more precisely. In a pilot study at a proposed opencast coal site in Wales, we compared the effectiveness of whole-turf translocation of herb-rich mesic grassland communities, with a less technically demanding and more cost-effective technique involving spreading turf over twice the area at the receiver site and rotovating it into the underlying soil. The translocated whole turf and rotovated turf plots were cut annually and the vegetation removed to simulate grazing that had occurred prior to translocation. Both the whole-turf and rotovated turf transplant techniques gave successful re-establishment of 50% or more of the species originally present. After three years, the cover and species composition were similar in “whole-turf” and “spread and rotovated” plots. This suggests that the “spread and rotovate” technique provides a satisfactory ecological alternative to whole-turf translocation. However, plant communities changed, in some cases substantially, after translocation using either technique. Altered soil hydrology and nutrition combined with the substitution of cutting for grazing are probably the main causes of these changes.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1046/j.1526-100X.1999.72028.x

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

2

Electronic Resource

The influence of soil variability on tree establishment at an experimental agroforestry site in North East Nigeria (1997)

Adderley, W. P. ; Jenkins, D. A. ; Sinclair, E. L. ; [et al.]

Oxford, UK : Blackwell Publishing Ltd

Soil use and management 13 (1997), S. 0

add to mindlist on the mindlist

Details

ISSN: 1475-2743

Source: Blackwell Publishing Journal Backfiles 1879-2005

Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Notes: Abstract. The characteristics and variability of soils within a 30 ha experimental site in N. E. Nigeria are analysed in relation to tree establishment. Profile description and analyses for some 480 surface samples of the sandy to clayey surface soils from Lake Chad lacustrine sediments provide baseline properties against which any subsequent modifications resulting from agroforestry practices can be assessed and to which initial tree performance can be related. This has been undertaken using principal component and spatial analyses. Inherited soil properties show spatial variations across the site which can be related to the soil textural parameters. The initial survival of trees planted for agroforestry experimentation shows strong correlations with the inherited characteristics of the soil rather than with acquired soil properties.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1111/j.1475-2743.1997.tb00549.x

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

3

Electronic Resource

Statistics of the largest geomagnetic storms per solar cycle (1844–1993) (1997)

Willis, D. M. ; Stevens, P. R. ; Crothers, S. R.

Springer

Annales geophysicae 15 (1997), S. 719-728

add to mindlist on the mindlist

Details

ISSN: 0992-7689

Source: Springer Online Journal Archives 1860-2000

Topics: Geosciences , Physics

Notes: Abstract A previous application of extreme-value statistics to the first, second and third largest geomagnetic storms per solar cycle for nine solar cycles is extended to fourteen solar cycles (1844–1993). The intensity of a geomagnetic storm is measured by the magnitude of the daily aa index, rather than the half-daily aa index used previously. Values of the conventional aa index (1868– 1993), supplemented by the Helsinki Ak index (1844–1880), provide an almost continuous, and largely homogeneous, daily measure of geomagnetic activity over an interval of 150 years. As in the earlier investigation, analytic expressions giving the probabilities of the three greatest storms (extreme values) per solar cycle, as continuous functions of storm magnitude (ad), are obtained by least-squares fitting of the observations to the appropriate theoretical extreme-value probability functions. These expressions are used to obtain the statistical characteristics of the extreme values; namely, the mode, median, mean, standard deviation and relative dispersion. Since the Ak index may not provide an entirely homogeneous extension of the aa index, the statistical analysis is performed separately for twelve solar cycles (1868–1993), as well as nine solar cycles (1868–1967). The results are utilized to determine the expected ranges of the extreme values as a function of the number of solar cycles. For fourteen solar cycles, the expected ranges of the daily aa index for the first, second and third largest geomagnetic storms per solar cycle decrease monotonically in magnitude, contrary to the situation for the half-daily aa index over nine solar cycles. The observed range of the first extreme daily aa index for fourteen solar cycles is 159–352 nT and for twelve solar cycles is 215–352 nT. In a group of 100 solar cycles the expected ranges are expanded to 137–539 and 177–511 nT, which represent increases of 108% and 144% in the respective ranges. Thus there is at least a 99% probability that the daily aa index will

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/s00585-997-0719-5

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

4

Electronic Resource

Factors influencing nitrogen saturation in Sitka spruce stands in Wales, UK (1995)

Emmett, B. A. ; Stevens, P. A. ; Reynolds, B.

Springer

Water, air & soil pollution 85 (1995), S. 1629-1634

add to mindlist on the mindlist

Details

ISSN: 1573-2932

Source: Springer Online Journal Archives 1860-2000

Topics: Energy, Environment Protection, Nuclear Power Engineering

Notes: Abstract Preliminary empirical nitrogen critical load exceedance maps for the UK have identified large areas of Wales where nitrogen deposition exceeds the nitrogen critical load, indicating that some ecosystems are at risk from eutrophication. This paper synthesises the monitoring and experimental work which have been carried out to collect evidence for exceedance in spruce plantations in the uplands and to investigate the implications for acidity and eutrophication in these areas. The results have conclusively demonstrated that current nitrogen deposition to mature Sitka spruce stands, planted on freely draining acid soils, is in excess of ecosystem requirements and results in elevated nitrate leaching losses. In contrast, stands with large biological sinks such as aggrading stands or stands with high denitrification potential have low ntirate leaching losses. The controls on the magnitude of leaching losses in the mature stands on this soil type are discussed within the context of two categories: (i) “nitrate saturated” stands which exhibit no retention of incoming nitrate-N but retain incoming ammonium-N as demonstrated in the Welsh NITREX experimental site and (ii) more nitrogen-rich stands which are saturated for both nitrate-N and ammonium-N and respond directly to incoming ammonium-N with immediate increases in nitrate production and thus nitrate leaching losses. There is little evidence for any adverse effects on tree growth or health in response to excess nitrogen deposition, however, tree growth in the most mature stands is now limited by phosphorus and potassium deficiency. The risk of a reduction in soil and stream water quality in acid sensitive areas of Wales due to the link between nitrate leaching and aluminium concentrations has also been confirmed. The results are discussed within the framework proposed by Aber et al. 1989 for the sequence of changes in ecosystem function which occur following long-term chronic nitrogen deposition.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00477213

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

5

Electronic Resource

Stream chemistry impacts of conifer harvesting in welsh catchments (1995)

Reynolds, B. ; Stevens, P. A. ; Hughes, S. ; [et al.]

Springer

Water, air & soil pollution 79 (1995), S. 147-170

add to mindlist on the mindlist

Details

ISSN: 1573-2932

Source: Springer Online Journal Archives 1860-2000

Topics: Energy, Environment Protection, Nuclear Power Engineering

Notes: Abstract Hydrochemical data have been collected for between 6 and 9 years from forest harvesting experiments in small catchments (〉10 ha) at Plynlimon and Beddgelert, Wales, UK. Felling resulted in rapid increases in NO 3 − and K+ concentrations at both sites. A maximum of 3.2 mg N L−1 was observed at Plynlimon about one year after the start of felling. Concentrations declined to control stream values (0.5 mg N L−1) after 5 years. At Beddgelert, NO 3 − concentrations in the manipulated catchments remained above those in the unfelled control catchment for three years, before declining below control values. The NO 3 − pulse was related to increased rates of mineralization and nitrification in the soil after felling. The initial increase in K+ concentration after felling at Plynlimon was followed by a slow decline, but concentrations were still above those in the control stream after 5 years. From 4 to 8 years after felling at Beddgelert, K+ concentrations fell below and then generally remained lower than control values. The NO 3 − pulse after felling at Plynlimon sustained inorganic anion concentrations above those in the control stream for the first 18 months after felling. As the NO 3 − pulse declined, inorganic anion concentrations decreased to below those in the control stream about 4 years after felling. At Beddgelert, the smaller increase in NO 3 − concentrations had less of an effect on inorganic anion concentrations which decreased after felling relative to values in the control stream. The increase in NO 3 − was associated with temporary streamwater acidification in the felled catchments due to the increased rates of nitrification and nitrate leaching. At Plynlimon, streamwater filterable Al concentrations declined after felling, but controls on Al behaviour are complex and not explained by simple equilibrium relationships with Al(OH)3 or by variations in inorganic anion concentrations. At Beddgelert, felling had no effect on stream water filterable Al concentrations. Felling at Plynlimon led to a large reduction in streamwater Cl−, Na+ and SO 4 2− concentrations. At Beddgelert reductions in SO 4 2− and ‘sea salt’ ion concentrations were less clear, reflecting the smaller proportions of the catchments which were harvested. Felling had no deleterious effects on water quality, apart from a temporary slight further decline in stream pH at Beddgelert. Increases in NO 3 − concentrations were short-lived and concentrations were well below drinking water standards. Filterable Al concentrations were already higher than statutory standards, but were not increased or decreased through felling.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF01100435

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

6

Electronic Resource

Cyclic Traction Machine for Long-Term Culture of Fibroblast-Populated Collagen Gels (1999)

Langelier, E. ; Rancourt, D. ; Bouchard, S. ; [et al.]

Springer

Annals of biomedical engineering 27 (1999), S. 67-72

add to mindlist on the mindlist

Details

ISSN: 1573-9686

Keywords: Tissue engineering ; Collagen gels ; Fibroblasts ; Cyclic traction ; Traction machine ; Collagen fibers orientation

Source: Springer Online Journal Archives 1860-2000

Topics: Medicine , Technology

Notes: Abstract Our research group has been investigating the effect of cyclic deformations on the evolution of fibroblast populated collagen gels (FPCG). Since existing traction machines are not designed for such an application, we had to design a cyclic traction machine adapted to tissue culture inside an incubator over an extended period of time. Biocompatible materials were used for fabrication to allow for easy sterilization and to prevent any adverse reaction from the tissue. The traction machine is based on a computer-controlled stepping motor system for easy adjustment of the deformation amplitude and frequency. The maximum stretching speed achieved is around 1mm/s. The traction machine can measure FPCG mechanical properties and perform rupture tests to determine its ultimate strength. Several FPCGs have been successfully cultured with the machine for up to four weeks without any adverse reaction. © 1999 Biomedical Engineering Society. PAC99: 8270Gg, 8380Lz

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1114/1.166

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

7

Electronic Resource

Host preferences ofTrichogrammatoidea bactrae fumata (Hym.: Trichogrammatidae) an egg parasitoid of leafrollers (Lep.: Tortricidae) (1995)

Stevens, P. S.

Springer

BioControl 40 (1995), S. 379-385

add to mindlist on the mindlist

Details

ISSN: 1573-8248

Keywords: Epiphyas postvittana ; Planotortrix octo ; Ctenopseustis obliquana ; kiwifruit ; host selection

Source: Springer Online Journal Archives 1860-2000

Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Description / Table of Contents: Résumé Trichogrammatoidea bactrae fumata Nagaraja est un parasitoïde spontané des œufs de quelques tordeuses dans les vergers de kiwis en Nouvelle-Zélande. Le parasitoïde a montré une préférence marquée pour les jeunes oeufs-hôtes d'Epiphyas postvittana qui augmentent les chances de réussite de son développement. Une telle préférence est moins nette avecCtenopseustis obliquana. Des expériences de préférence des espèces-hôtes ont révélé que le parasitoïde attaquait rarementPlanotortrix octo et que la réussite du développement dans cet hôte était peu élevée. Après un élevage surE. postvittana, cet hôte a été préféré. Par contre, après un élevage duC. obliquana, le parasitoïde n'a montré aucune préférence pourE. postivittana ouC. obliquana.

Notes: Abstract Trichogrammatoidea bactrae fumata Nagaraja is a naturally occurring egg parasitoid of some leafrollers in New Zealand kiwifruit orchards. The parasitoid showed a distinct preference for younger host-eggs ofEpiphyas postvittana, in which it achieved a higher rate of successful development. Such a preference is not as apparent withCtenopseustis obliquana. Host-species preference experiments found that the parasitoid rarely attackedPlanotortrix octo, and successful wasp emergence from parasitised eggs of this host was low.Epiphyas postvittana was the preferred host whenT. bactrae fumata was reared on this species. When reared onC. obliquana, the parasitoid showed no preference forE. postvittana orC. obliquana.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF02373726

Permalink