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Titel:Litter decomposition in the Atlantic Rainforest of Brazil
Autor:Gießelmann, Urs Christian
Weitere Beteiligte: Brandl, Roland (Prof. Dr.)
Veröffentlicht:2011
URI:https://archiv.ub.uni-marburg.de/diss/z2011/0654
DOI: https://doi.org/10.17192/z2011.0654
URN: urn:nbn:de:hebis:04-z2011-06543
DDC: Biowissenschaften, Biologie
Titel (trans.):Laubstreuzersetzung im Atlantischen Regenwald von Brasilien
Publikationsdatum:2011-12-19
Lizenz:https://rightsstatements.org/vocab/InC-NC/1.0/

Dokument

Schlagwörter:
Mata Atlantica, Regenwald, Mata Atlantica

Summary:
Primary tropical rainforests are increasingly replaced by secondary forests. Whether these secondary habitats are able to maintain the biodiversity and ecosystem functionality of the original forests is still a matter of debate. My dissertation aims to provide insights into the important ecosystem process of litter decomposition and its dynamics during secondary forest succession in the highly endangered Atlantic Rainforest of Brazil. I am intended to draw conclusions on the resilience of the decomposition process after disturbance. In the first part (Chapter 2) of my thesis I investigated the influence of plant litter species richness, litter mixture composition and macro- and meso-invertebrate activity on litter decomposition. Using a litter-mixing experiment I aimed to draw conclusions on the relationship between the decomposition subsystem and plant species diversity in the Atlantic Rainforest. The results of my experiment indicated that plant species identity and litter mixture composition, but not species richness per se, significantly influenced litter decomposition rates. However, litter decomposition rates were less variable between mixtures of high species richness suggesting a stabilising effect of species richness. Maybe this effect is due to interacting effects between component species as, in many cases, litter decomposition dynamics were non-additive, i.e. observed decomposition rates of litter mixtures differed from what would be expected from the decomposition rates of their component species. The exclusion of invertebrates also influenced litter decomposition, although this effect varied between species and mixtures. In summary, the relationship between the decomposition subsystem and species diversity in the Atlantic Rainforest appeared to be largely idiosyncratic. In the second part (Chapter 3) I analysed and compared species richness and community composition of litter dwelling fungi and of trees on forest sites of different successional age. I was intended to get insights into the successional dynamics of litter dwelling fungi communities and its relationship to tree succession, because litter dwelling fungi are known to have a substantial impact on litter decomposition. While tree species richness increased with increasing successional age, species richness of fungi showed no differences among successional stages. Fungi species composition, however, significantly differed between successional stages and was correlated with tree community composition. Beside a fast re-colonisation of fungi following plant succession the occurrence of so called latent species which act as a seed bank for fungal succession seems to be likely. Hence, litter dwelling fungal communities seem to adopt quickly to the respective tree communities. Thus, they appear to be highly resilient or resistant to disturbance. In the third part (Chapter 4) I set up a litter-transfer experiment along a successional chronosequence. I tested whether site specific litter decomposes faster on its home site than on other sites within and between successional stages indicating home-field advantage (HFA). I expected this experiment to provide insights into the successional dynamics of decomposers and the resilience of decomposer communities. Overall, my results did not support a home-field advantage of decomposability of site specific litter. Thus, the decomposer community is redundant or highly flexible in its ability to decompose different litter types. However, it should be noted that the effect of macro- and meso-invertebrates seemed to be reduced in my experiment, possibly due to climatic reasons. The high flexibility of the decomposer community could be due to the ability of microbial decomposers to quickly adjust to the decomposition of different substrates by shifting their community structure. Therefore, ecosystem functionality regarding litter decomposition at least partly appears to be highly resistant or able to recover quickly during secondary forest regeneration.


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