The biodiversity of larval Chironomidae within limestone springs

This thesis examines the crenobiology of part of English Peak District known as the White Peak. The study is centred on the biodiversity of Chironomidae larvae and the physical and chemical characteristics that influence their distribution. Fifteen limestone springs were examined encompassing three spatial scales over a 12-month period. At the macro-scale, springs were examined in relation to the dominant abiotic characteristics (e.g. thermal vs coldwater, perennial vs intermittent springs). Most springs had relatively similar physical and ionic compositions and appeared to have relatively stable characteristics through time (meso-scale level). Thermal springs were characterised by low dissolved oxygen concentrations and high water temperature, conductivity, sulphate and calcium concentration compared to the coldwater springs. Perennial coldwater springs only differed from intermittent springs on the basis of physical characteristics dissolved oxygen concentration and conductivity. At the scale of single springbrook (micro-scale level), water characteristics were relatively stable with little variation longitudinally. Chironomidae biodiversity within the White Peak was relatively high with a total of 79 taxa being recorded from 15 springs. The most common subfamily was Orthocladiinae, which represented 83.1% of the total chironomid larvae recorded. Examination of individual springs indicated that faunal communities were dominated by a variety of taxa. However a small number of ubiquitous taxa were dominant at most springs. Analyses indicated that the Chironomidae community within the springs was primarily controlled by physical habitat characteristics (mineral substrates, submerged vegetation and mean flow velocity) rather than chemical characteristics. Thermal springs supported lower larval Chironomidae abundance and diversity compared to coldwater springs. Perennial springs supported higher Chironomidae abundances and diversities compared to intermittent springs. Chironomidae larval were more diverse and abundant in perennial springs with coarse substrates. Alga supported more greater diversities and abundances than mosses or macrophytes. Examination of heavy metal contamination at a single spring source (Tricket Sough) indicated that elevated zinc concentrations in water, sediments and chironomid larval resulted in increased rates of mentum deformities (e.g. missing median teeth, extra lateral teeth, asymmetrical teeth structure) compared to the reference site (Otter Hole).