The distribution of arthropod species on a 400 m elevational gradient (equivalent to a temperature decrease of 2.5°C) on Snowdon, North Wales, was examined and compared with the British distribution. Preferred temperature, an indication of optimal body temperature (Tb), and supercooling point (SCP), an indication of cold tolerance, of several species on the gradient were determined experimentally. The alpine beetle species Patrobus assimilis and Nebria rufescens had low preferred Tb, of 5.6 and 7.1°C respectively, whereas the more widespread upland species had higher preferred Tb, between 12.9 and 15.5°C. The SCP of both alpine and widespread beetles were similar, being between -6.9 and -5.8°C. The alpine species, which were smaller, were freeze intolerant, whereas the widespread species, which were larger, were freeze tolerant. On the national scale there was significant correlation between preferred Tb and species elevation, but no correlation with SCP. It is concluded that the alpine species survive on Snowdon because their optimal Tb is close to the ambient temperature at the time of day and year when they are active and because they are able to tolerate winter temperatures, by a combination of cold tolerance and shelter. Although a species' optimal niche will tend to shift upwards as mean temperatures rise with global climatic change, complex microclimatic and biotic factors make changes in distribution difficult to predict.
Parasitic infections of the South China tigers in the Meihua Mountains have not been explored previously. Faeces of 22 South China tigers from the China Tiger Park in the Meihua Mountains were examined. Eggs of ascaridoid nematodes and oocysts of coccidia were detected by Mini-FLOTAC assay. Morphological observation and molecular characterisation of the oocysts were carried out. The prevalence of Toxascaris leonina (von Linstow, 1902) was 18% (4/22), and the highest egg per gram (EPG) count in the faeces was 27,150. The prevalence of Cystoisospora sp. was 45% (1 0/22) and the highest oocysts per gram (OPG) in the faeces was 6,000. In addition, we found one ascaridoid nematode in the South China tiger's faeces and was molecularly and morphologically identified as T. leonina. The oocysts in the faeces were sporulated in vitro and identified as Cystoisospora sp. Amplification of full-length internal transcribed spacers (ITS) resulted in sequences 1,622 bp long. Using the sequences, Cystoisospora sp. of the South China tiger was closest to Isospora belli (Wenyon, 1923) and Cystoisospora suis (Biester, 1934).