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The coexistence of species is fundamentally important in maintaining high species diversity in a defined area, and is partly responsible for the remarkable diversity of the Cape Floristic Region. The ecological attributes that determine the community assembly processes of competitive interactions and ecological sorting are subject to phylogenetic constraint and niche conservatism, suggesting that patterns of coexistence should be phylogenetically structured. This study compares patterns of coexistence against phylogenetic and ecological divergence in the genus Tetraria (Cyperaceae), and related sedges in the tribe Schoeneae, at different spatial and phylogenetic scales in multiple communities across the Cape Fynbos Biome. The investigation is based on coexistence data inferred from plot data from 13 phytosociological studies, ecological distances based on plant functional traits, and phylogenetic distances based on a molecular phylogeny of the species in question. Species coexisting in plots are significantly less related than expected on the basis of chance, and plots of phylogenetic distance against coexistence show triangular relationships, implying coexistence between closely related species is restricted, but that coexistence levels between more distantly related species may vary greatly. Quantification of these triangular relationships was problematic due to the small sample sizes and the low power of the nonparametric tests used. The pattern is more pronounced when a closely related subset of the species was used in a separate analysis, suggesting that phylogenetic scale is important. Coexisting species are significantly more closely related at the study than at the plot scale, implying relaxation of the effects of competitive interactions at coarser spatial scales. Significant positive correlation between ecological and phylogenetic divergence implies that phylogenetic constraint and niche conservatism has a strong effect on the ecological attributes of the study species. These results provide support for the hypothesis that the patterns of coexistence among species' in the genus Tetraria, and related sedges in the tribe Schoeneae, are influenced by phylogenetic constraint and niche conservatism on ecological attributes.

Palearctic migrants, including barn swallows Hirundo rustica, responded to climate change in Europe from the mid to late 1900s with phenological changes, mostly showing earlier arrival and start of breeding. During this period, barn swallows in the Palearctic exhibited variable patterns of change in the timing of their arrival, breeding and departure from the breeding grounds. At the South African non-breeding grounds, the timing of migration shifted between the 1980s and 2000s, again with geographic variability. To explain these changes further, I examined geographic and temporal variability in the timing of flight feather ('primary') moult, and trends in body weight, in barn swallows ringed in South Africa between 1986 and 2012. Citizen science bird ringing, started in South Africa in 1948, generated all the data used in this project. All data were obtained from the South African Bird Ringing Unit (SAFRING).

Morphometrics was used to study variation in Schizeae pectinata as previous study showed that material originating from the summer rainfall area of South Africa differ in several aspects from that originating from the winter rainfall area. The plant has a simple structure and consequently spore, stoma and sporangia sizes, as well as the number per lamina was studied to determine if the species can be subdivided into two groups, e summer and e winter rainfall group, as was previously hypothesised. Univariate and bivariate methods were used to display the extent of variation within the species. Univariate analysis reflect variability of spore and stomata size, and the number of pinna pairs per lamina. Statistical analyses showed that interpopulation variation for these characters are often highly significant. Phonetic methods were used in the analyses of the data set and shows continuous variation in this species. This continuous variation in Schizaea pectinata could be linked to a phenotypic response to environmental differences between the two regions.

Supervisor: P Linder. / All members of Cunonia, excluding C. capensis, occur on the island of New Caledonia. Dickison has repeatedly noted (1973, 1975, 1980, and 1984,) that evolutionary patterns may have led to incorrect systematic conclusions among many cunoniaceous genera, which are likely to generate incorrect systematic conclusions. For this reason, a study into the morphological characters defining C. capensis was undertaken. Although the possibility that the disjunct biogeographical pattern of C. capensis might be explained on the basis of taxonomic error was appealing, it was not conclusively supported from this investigation. Instead it was found that of the six characters supposed to distinguish Cunonia from Weinmannia, three agreed with the present position of C. capensis with Cunonia, whilst the other three placed C. capensis with Weinmannia. This study also served to highlight the need for further investigation and identification of characters which separate Cunonia and Weinmannia at the species level.

The Cape Floristic Region, South Africa, has high numbers of rare and endemic plants. Many, including Pauridia Harv., are geophytes in the Hypoxidaceae. The two species of Pauridia differ in morphology and range, with P. minuta occupying a wide range across lowland CFR and P. longituba being restricted to granite outcrops on the West coast. Genetic structure correlated to geography has been described for the haploid chloroplast genome. Here the diploid nuclear genome is investigated using inter-simple sequence repeat amplification. Eleven populations were sampled from DNA collected for a previous study. Analysis of molecular variance was done. Ordination based on similarity and covariance was done to detect structure. Most of the variance was found to be within populations (65.54%) and between populations within groups (35.69%). Some variance (10.10%) was found between P. minuta geographic groups. Principal Component Analysis revealed a little structure, grouping some similar haplotypes together. Cluster analysis placed P. longituba within P. minuta, reflecting the haplotypic structure. Differences in structure revealed between the chloroplast and nuclear genome may be explained by differences in gene flow resulting from the different modes of inheritance - chloroplast via seed and nuclear via pollen and seed. Further analysis of genetic distance correlations between the chloroplast and nuclear data would provide a useful quantitative measure of difference in structure.

I conducted a series of research programmes on various aspects of Tardigrada biology. The published results of which are hereby presented as part fulfilment of my submission for a PhD by publications at Plymouth University. In this thesis my research publications are grouped into four chapters: Ecology & Faunistics, Alpha Taxonomy, Freshwater Fauna – a taxonomic challenge, and Superfamilies. In the first, I highlight my early papers which dealt with the faunistic surveys as I trained in systematics and taxonomy of the phylum. Amongst the key findings reported were the protozoan symphoriant, Pyxidium tardigradum van der Land, 1966, Marley and Wright (1994); a new addition to the reported fauna of the United Kingdom, Greaves & Marley(1996); and my first work on international samples from Arctic Canada, Sutcliffe et al.(2000). In the second chapter, Alpha Taxonomy, I have included five papers. The first, Marley and Wright (1996), illustrates my work with one of the Royal Museums of Scotland’s collections, where I updated the diagnoses of their specimens and described a new addition to the Icelandic fauna. The second paper, Russell, Marley & Hockings (2001), demonstrates how I was searching for new research methods to apply to tardigrades. It was because of similar exploration, with methods of SEM preparation, that I was invited to join the Australian-Anglo team working on sediment core samples from Antarctic freshwater lakes, Gibson et al. 2009. The remaining two papers in the chapter describe species new to science, Echiniscus ollantaytamboensis Nickel, Miller and Marley, 2001, and my first sole authored paper describing a species new to science, Platicrista ramsayi Marley, 2006. The third chapter, Freshwater Fauna – a taxonomic challenge, deals with a programme of research based initially on my findings at the Royal Museums of Scotland, Edinburgh. This then required subsequent visits the USA and Italy to work on the taxonomic issues with original authors on their more recently described genera. I prepared the original Case for the ICZN, but this was then held by the commission for several years pending their amendments to the Code. I then rewrote the Case into the final paper, Marley, Bertolani & Nelson (2008). The final chapter consists of two papers in which I worked on combining my expertise on the morphological characters of the buccal apparatus and claws, and combining this with new molecular dataset derived from sequencing individual specimens. My colleagues on these papers were Dr S.J. McInnes and Mr C.J. Sands, both from the British Antarctic Survey. Overall I am including 14 published papers and 5 published conference abstracts and three online articles. The following taxa were erected during this work: Pseudobiotus kathmanae, Echiniscus ollantaytamboensis, Platicrista ramsayi, Ramazzottidae, Isohypsibiidae, Macrobiotoidea, Eohypsibioidea, Hypsibioidea, and Isohypsibioidea. Plus the following taxa were re-described, Pseudobiotus, Thulinius, Thulinius augusti, Thulinius ruffoi, and Thulinius stephanae.

<p>Dragonflies (Odonata) are one of the ancestral groups of extant insects. They represent one of the three most basal branches in the phylogeny of winged insects. The other two groups are the Ephemeroptera, mayflies, and Neoptera, the latter which covers the remaining winged insects. The first paper is about the phylogenetic position of Odonata in relation to the other basal insect clades using 18S and 28S rDNA sequences. It was demonstrated that there are under certain parameters a strong statistical support for a sister-group relationship between Odonata and Neoptera forming the group Palaeoptera. The second paper is about the phylogeny of the Holarctic dragonfly <i>Leucorrhinia</i>. Dragonfly larvae are frequently equipped with spines on the abdomen, with great variation in spinyness between species. From an analysis of sequences of ITS and 5.8S rDNA it was found that spines have been lost at least twice in <i>Leucorrhinia,</i> in the European<i> L. rubicunda</i> and again in a clade of North American species. The third paper is on the subfamily Ischnurinae (Odonata: Coenagrionidae), a group dominated by the two larger genera Ischnura and Enallagma along with several mono- or oligotypic genera. From the presented molecular study, using mitochondrial 16S rDNA and COII sequences, it is demonstrated that Ischnurinae, and Ischnura are monophyletic. Enallagma is not monophyletic, and the genus name Enallagma should be restricted to the <i>E. cyathigerum </i>clade. he fourth paper is a catalog of the genus Coenagrion, with full information on synonymy, type material and bibliographical data. The fifth paper is an appeal to the International Commission on Zoological Nomenclature to suppress the genus group name Agrion. The letter of appeal elucidates the priority of Agrion, and demonstrates why it has fallen out of use. A case if made for why Agrion should be placed on the list of unavailable names, and Calopteryx given full validity.</p>

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There is currently considerable controversy within philosophy over how a natural kind term's extension is determined. Adherents to traditional theories of meaning argue that extension is determined by intensional properties which usually consist of identifying descriptions. Recently a new, essentialist alternative to these traditional accounts has been advocated; proponents of this view maintain that a term's extension includes all objects which are essentially the same as a given paradigm instance of the term's use. In the present thesis it is argued that both description theories and essentalism describe not how classification must proceed but rather two alternative strategies for how a classification of natural kinds might be attempted. A term's extension is not determined in advance by either identifying descriptions or hidden essential properties since stress on either of these is itself a choice. This claim is exemplified by using empirical material drawn from the recent (post 1900) history of a classifictory science, botanical systematics. By means of this evidence it is shown that both "descriptionist" and "essentialist" strategies of concept application have been (and still are) pursued by different groups of taxonomists. One consequence of the position outlined above is that classifications are conventions and that they are evaluated instrumentally. The force of this argument is best illustrated by conceiving of classifications as part of a wider network of beliefs which are socially transmitted and sustained. Changes in networks are designed to further the interests to which a network is being put. It is argued here that the main kinds of interests which have been important in twentieth century systematics are 1) interests in technical prediction and control and 2) professional vested interests. An important aspect of both these kinds of interests is that they are normally considered to be "internal" to science. It follows that to understand scientific knowledge from a sociological perspective does not, of necessity, entail commitment to "external" explanations of scientific change.