| dc.description.abstract | In the present study, the temporal and spatial paleoecology of the Lower Silurian Rytteråker Formation in the Oslo region, is explored through multivariate gradient analysis of a novel dataset of stratigraphically collected acetate peels from two localities in the Oslo Region, as well as ordination-based reanalysis of two previously published datasets. By applying up to four different ecological ordination methods in parallel in a comparative, integrated approach – on both raw and abundance-scale weighted data, a single robust high-level faunal and environmental gradient associated with ordination axis one was identified in both the newly sampled and historical datasets. In both the novel acetate peel dataset and the historical dataset of bedding plane point-count data, the gradient appeared to be primarily structured by the abundances of pentamerid brachiopods, and secondarily by overall fossil diversity and richness. In-sample environmental proxy variables from the datasets, as well as newly gathered supplementary data in the form of elemental XRF measurements, magnetic susceptibility readings, brachiopod shell orientation measurements and field observations, seem to indicate storm frequency and/or high energy deposition as the most significant complex environmental variable structuring all three primary gradients. As such, the gradients are likely reflective both of real ecological change affecting species distribution, as well as a biases regarding preservation and taphonomy. As such, the results from this study partially challenge previous interpretations of the fauna of the Rytteråker Formation as being primarily controlled by depositional depth. Although depth would in some cases also be correlated with benthic storm frequency, the prospect of a barrier patch reef/shoal-lagoonal system in the area does not make this connection a necessity. It also provides a strong case for the multiple parallel ordination approach as a useful tool for discerning ecologically interpretable gradients both from new and historic datasets. However, as indicated disparities in diversity and richness, the novel acetate peel study design applied here seems to be more appropriate for discerning faunal gradients in localities that are generally more fossil rich (i.e. higher depositional energy), while larger-scale macrofossil surveys akin to some of the historical datasets, might be more appropriate for energetically quieter depositional environments. The link between periodic wave turbulence and faunal change also implies some interesting possible parallels between the underlying environmental factors influencing Paleozoic and modern benthic soft-substrate ecosystem gradients, which could provide a basis for future studies. | eng |