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Title: Taxonomy, biogeography and ecology of Andean tardigrades at different spatial scales
Author: Ramsay, Balbina
ISNI:       0000 0004 7430 8411
Awarding Body: University of Plymouth
Current Institution: University of Plymouth
Date of Award: 2018
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Micrometazoans are animals smaller than 2 mm. Their biogeography is poorly understood, and tardigrades provide a tractable phylum for exploring distribution patterns at a variety of scales. Polylepis forest habitat offers considerable advantages for making tardigrade comparisons across a wide range of scales in the Andes. This thesis aims to improve identifications of tardigrades with a character matrix approach, to assess the relative importance of habitat and bryophyte host on tardigrades, to describe the fine-scale spatial structure of tardigrade assemblages, and to estimate the sampling effort required for a reliable estimate of tardigrade diversity within Polylepis forest. Samples of bryophytes and lichens were collected from Polylepis forest and neighbouring habitats, and the tardigrades extracted and identified, mostly to operational taxonomic units. Some new species were discovered during the course of this work; one is described here. Abundance, diversity and composition of tardigrade samples were compared quantitatively. The thesis presents the first example of a character matrix for a tardigrade genus, bringing together information for the genus Isohypsibius from many different sources and describing suites of characters for each species. It will facilitate identification within the genus in future. Tardigrade assemblage data were highly variable within the samples, with empty samples dominating one study. Analysis of one forest site indicated that at least 50 samples would be needed to characterise the tardigrade diversity there. Although both were important, habitat-scale effects were more influential on tardigrade abundance, diversity and composition than host-scale effects. In both cases, microenvironmental and resource filters are the likely mechanisms driving these differences. Based on the results, recommendations are made for expanding such research into broader geographical scales: standardising sample volume, replicate sampling across hosts on the forest floor, recognising the importance of habitat-scale effects when selecting study sites, and the development of character matrices for tardigrade genera.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: tardigrades ; ecology ; spatial scales ; taxonomy