@booklet {Gallucci:2008ph,
	title = {Effects of megafauna exclusion on nematode assemblages at a deep-sea site},
	volume = {55},
	year = {2008},
	note = {Deep-Sea Research Part I-Oceanographic Research Papers},
	pages = {332-349},
	publisher = {PERGAMON-ELSEVIER SCIENCE LTD},
	address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND},
	abstract = {Caging experiments were performed at the Arctic deep-sea long-term observatory HAUSGARTEN to investigate the effects of megafauna exclusion on nematode assemblages. Six experimental cages were deployed at 2500 m water depth and sampled after 4 years for meiofauna and a series of sediment parameters. With the exception of chlorophyll a and phaeopigments, which were significantly higher inside the cages, sediment parameters did not differ between inside and outside the cages. Yet multivariate analysis of the sedimentary environment showed a higher variability outside the cages, indicating higher environmental heterogeneity in the presence of megafauna. Nematode densities (aver. 1516 ind 10 cm(-2)) were significantly higher in sediments from inside the cages, whereas total number of species (aver. 70 sp.), Shannon-Wiener diversity (aver. 3.4) and Pielou evenness (aver. 0.8) did not differ between the two treatments. Also differences in faunal multivariate structure between cage and control samples were not significant. Nevertheless, Fisher{\textquoteright}s alpha diversity, the number of nematode genera and taxonomic distinctness showed significantly higher values outside the cages. Since univariate measures are often insensitive to changes in community structure.. and interpretation of the multivariate analysis was confounded by the large number of rare species, we further analysed our data by dividing the species into three groups of frequency (frequent, intermediate and occasional) and into three groups of abundance (dominant, sub-dominant and scarce). Results from this analysis revealed that the higher nematode abundances inside the cages were mainly due to an increase in density of scarce species that were either frequent or intermediate in frequency. In contrast, occasional species were adversely affected. These results lead us to believe that it is mainly the frequent species occurring in low densities that take advantage of favourable conditions (i.e. lack of disturbance or increased phytodetritus) in the deep sea. The higher taxonomic distinctness, Fisher{\textquoteright}s diversity, and number of genera at the control sites, together with the fact that they were environmentally more heterogeneous, suggest that megafaunal organisms play an important role in creating microhabitats in the sediment and significantly influence deep-sea nematode assemblages. However, the lack of any changes in species richness inside the cages after 4 years suggests that they cannot fully account for the maintenance of the remarkable high levels of species coexistence in the deep sea. The key is more likely to be found in evolutionary history than actual ecology. (c) 2007 Elsevier Ltd. All rights reserved.},
	keywords = {Biodiversity, biological disturbance, caging experiment, sediment heterogeneity},
	doi = {DOI 10.1016/j.dsr.2007.12.001},
	author = {Gallucci, Fabiane and Fonseca, Gustavo and Soltwedel, Thomas}
}
@article {Gallucci:2008la,
	title = {Active colonisation of disturbed sediments by deep-sea nematodes: evidence for the patch mosaic model},
	journal = {Marine Ecology-Progress Series},
	volume = {367},
	year = {2008},
	pages = {173-183},
	publisher = {INTER-RESEARCH},
	address = {NORDBUNTE 23, D-21385 OLDENDORF LUHE, GERMANY},
	abstract = {An on-board experiment was performed during a research cruise to investigate the ability of deep-sea nematode species to actively colonise defaunated sediments. Small cylinders of 500 pm wire mesh filled with defaunated sediment were inserted into microcosms containing sediment with indigenous meiofauna collected from 1300 m depth in the Arctic Ocean. The defaunated sediments were either enriched with the diatom Thalassiosira weissflogii, or remained unenriched. Samples from the defaunated sediment were taken after 9 and 17 d. As controls, microcosms with sediment containing the indigenous meiofauna but without an internal cylinder were also sampled at each time interval. Nematodes colonised both enriched and unenriched sediments with abundances of up to 20\% of the controls. Irrespective of the time of sampling, abundance and number of species were significantly higher in the enriched treatment, suggesting that the presence of food enhances colonisation and resilience. Nematode assemblages in the defaunated sediments were species-rich and differed from the controls. The majority of colonising species were rare or undetectable in the controls, suggesting that episodic disturbances may be necessary for their persistence in deep sea sediments. Colonisation was in part determined by species characteristics such as size and motility. At the same time, a large number of different species colonised the empty cylinders, resulting in poor similarity in community composition between replicates, particularly between samples enriched with diatoms. Our results indicate a poor predictability of community composition of recently disturbed sediments despite highly reproducible abundance and diversity patterns and lends experimental support to the existence of a spatio-temporal mosaic that emerges from highly localised colonisation patterns.},
	keywords = {Deep-sea, disturbance, Infauna migration, Microcosm experiments, nematodes, Patch dynamics, sediment},
	doi = {DOI 10.3354/meps07537},
	author = {Gallucci, Fabiane and Moens, Tom and Vanreusel, Ann and Fonseca, Gustavo}
}
