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Mid-Late Holocene environmental change in northern Sweden : an investigation using fossil insect remainsKhorasani, Sara January 2013 (has links)
For the first time, Mid-Late Holocene insect fossil assemblages were studied from inland northern Sweden, producing new evidence relating to both natural environmental changes and human impacts. The insect fossil assemblages from natural deposits indicated extensive woodland with old and dead wood and a deep litter layer of decaying matter. Human impacts became apparent from the 1st millennium AD, when the landscape around many sites became more open, with elements of heath. It is difficult to determine whether these changes were driven purely by human activity, indicating subtle landscape change as a result of periodic exploitation, or if natural influences were significant in creating this landscape structure. If connected with human use, then the impacts of periodic exploitation can be seen to be subtle and localised, but notable enough to leave tell-tale signs in the insect fossil record. These relatively subtle changes in the environment can be compared with the more severe effects found during periods of historically known permanent settlement, where extensively open and disturbed habitats are suggested in the insect fossil record. Species associated with arable and pasture land are restricted to the last few hundred years, in association with settled occupation. The climate signal in the insect fossil record has been weak, and use of the Mutual Climatic Range method (MCR) has not revealed evidence of climatic fluctuations during the Late Holocene period.
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Interakce rostlin a hmyzu ve spodním miocénu střední Evropy v paleoklimatologických a paleoekologických souvislostech / Plant - insect interactions in lower Miocene of Central Europe: palaeoclimatological and palaeoecological implicationsKnor, Stanislav January 2015 (has links)
The paleoecology of plant - arthropod herbivory associations constitute very important source of knowledge about the phylogeny and co-evolution of both groups. The traces of herbivory interactions between plants and arthropods on the fossil leaves are preserved as so called damaged types (DTs) clustered into distinct functional feeding groups (FFGs). The diversity and frequency of these damage traces also seem to have been strongly influenced by environmental and climatic conditions. This research has been focused on rich fossil plant assemblages from the area of the Most Basin in the north-western Bohemia. The undergoing work has comprised the diagnosis of the individual damages on the basis of their specific morphological traits as their number, size, shape and distributional pattern on the leaf surface. The next issue has involved the statistical analyses concerning the differences in the frequency and diversity of the types of damage and functional feeding groups between two separate fossiliferous layers, namely those of the stratigraphically older Bílina Delta and younger Břešťany Clay. Significant differences were confirmed in this regard, especially in connection with achieved frequency and proportional occurrences of distinct functional feeding groups in the Bílina Delta. The galls were the...
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