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Mühlenberg, Eva ; Stadler, Bernhard:
Effects of altitude on aphid-mediated processes in the canopy of Norway spruce.
In: Agricultural and Forest Entomology.
Bd. 7
(2005)
Heft 2
.
- S. 133-143.
ISSN 1461-9563
DOI: https://doi.org/10.1111/j.1461-9555.2005.00253.x
Abstract
1 The abundance of aphids and their honeydew are important in shaping theecology of food web interactions and nutrient cycling in forests of Norwayspruce. Here, the effects of the different environmental conditions at two studysites located at different altitudes (500 m, 765 m a.s.l.), in the Fichtelgebirge,north-eastern Bavaria, Germany, on the abundance of Cinara pilicornis andtheir influence on epiphytic microorganisms on shoots of Picea abies werecompared. Subsequent changes in throughfall fluxes were measured over aperiod of 12 weeks beneath infested and reference trees. In a laboratoryexperiment, the effects of ultraviolet (UV) radiation on microbial mortalityand C and N concentrations in leachates were determined.2 The warmer and drier conditions at the low altitude site favoured an earlyonset to aphid multiplication in spring compared with the high altitude site,where aphid numbers peaked 3 weeks later.3 The presence of honeydew was associated with a significant increase in the totalnumber of cultured epiphytic filamentous fungi, yeasts and bacteria in 12 of the 18sample units, indicating better culturability or growth, whereas altitude had nosignificant effect on cultured cell numbers. By contrast to the reference trees, thehigh dissolved organic carbon (DOC) and hexose-C fluxes beneath infested trees atthe peak in aphid abundance, in June and July, resulted in a concomitant decrease inthe fluxes of total inorganic nitrogen beneath infested trees (low altitude: 19.7%;high altitude:52.3%). Fluxes of organic nitrogen were significantly higher beneathinfested trees at the time of infestation. Similarly, potassium fluxes in throughfallincreased 1.6–2.0-fold in response to aphid infestation.4 The exposure of infested and uninfested shoots of Norway spruce to UV-A andUV-B radiation only weakly affected epiphytic microbial mortality and did notaffect the concentrations of the different nitrogen compound in leachates.However, bacteria, tended to be more active in the leachates collected frominfested shoots, which resulted in the higher concentrations of aminosugar-N.The aphids had a more pronounced effect on the concentrations of DOC inleachates, with average DOC concentrations being 4.2-fold higher than inleachates from uninfested shoots.5 It is suggested that, even at very low densities, aphids exert a strong influencevia honeydew on the performance of microorganisms, and nutrient and energyflow, in spruce forests.Neue Seite 1(pdf)
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| Publikationsform: | Artikel in einer Zeitschrift |
|---|---|
| Begutachteter Beitrag: | Ja |
| Zusätzliche Informationen: | BAYCEER28586 |
| Institutionen der Universität: | Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften > Fachgruppe Biologie Forschungseinrichtungen > Forschungszentren > Bayreuther Zentrum für Ökologie und Umweltforschung - BayCEER Fakultäten Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften Forschungseinrichtungen Forschungseinrichtungen > Forschungszentren |
| Titel an der UBT entstanden: | Ja |
| Themengebiete aus DDC: | 500 Naturwissenschaften und Mathematik |
| Eingestellt am: | 21 Aug 2015 06:49 |
| Letzte Änderung: | 21 Aug 2015 06:49 |
| URI: | https://eref.uni-bayreuth.de/id/eprint/18465 |