Progressive bias in species status is symptomatic of fine-grained mapping units subject to repeated sampling

摘要: Atlas maps of butterflies invariably fail to distinguish the status records, that is, whether they are observations breeding populations or vagrant individuals. Yet, for conservation purposes, it is clearly important know records relate in suitable habitats not. The high mobility butterfly adults carries two expectations. First, vagrants will frequently be recorded within grid squares, particularly when mapping fine grained. Second, frequency likely higher units comprising biotopes with few habitats, than those rich if only because there a greater regional pool potential depleted habitats. It follows repeated sampling squares differences species cumulative between and poor In this paper, these predictions have been tested using data from 30, 1 ha on Alderley Edge Site Special Scientific Interest (SSSI) (UK), half which woodland (few habitats) open (non-woodland; habitats). Butterflies during 38 visits over 4 years. Within distinguished basis presence larval hostplants other resources seasonal maintenance. Owing occurrence vagrants, number was found significantly fewer total units. Vagrants were more abundant contain hostplants, dominated by many hostplants. Repeated resulted increase species. Furthermore, relative increased at rate compared non-woodland squares. Suggestions made as how recording atlases may improved.