The relationship between pattern and scale in parasite communities: a stranger in a strange land.

摘要: Problems of pattern and scale are considered in relation to helminth communities freshwater fish by examining them at different hierarchical taxonomic spatial scales, with a view seeking generalizations heuristic value, assessing the importance phylogenetic ecological determinants community structure improving understanding unpredictable communities. Initially, were analysed level salmonid genera, focusing on Oncorhynchus, its heartland Canada: then O. mykiss throughout global range finally individual localities which it has been introduced Britain. In heartland, dominated specialist helminths, forming element: minority element comprises broad generalists non-salmonid specialists. Most species except generic specialists shared between host genera. As distance was translocated from increases, so disappear first decline. The is thus increasingly composed also becomes poor. Helminths may be acquired native salmonids and/or unrelated hosts, depending availability. This same paralleled restricted region: reflects present presence other genera fish; i.e., supply-side situation. change analysis enabled recognition patterns value improved interpreting local variation as 'noise' that often obscures fundamental patterns. this taxa fish, elements dominate heartlands, but stranger strange land.