Can niche use in red and grey squirrels offer clues for their apparent coexistence

摘要: Summary 1. Introduced species are, world-wide, one of the most serious threats to biodiversity. Grey squirrels Sciurus carolinensis are many introduced have threatened a native congener; they thought replaced red vulgaris throughout much UK as result competition. The rate competitive replacement may be influenced by habitat composition, with some squirrel populations persisting for prolonged periods in presence greys predominantly coniferous forest. 2. Here similarity and grey squirrels’ pattern use was investigated Craigvinean forest Scotland, UK, site that has experienced apparent coexistence up 30 years. Overlap examined several dimensions: spatial overlap home ranges, dynamic association niche overlap. Habitat selection at three levels: core range areas, tree within range, characteristics patches used intensively each comparison random locations their range. 3. Although there between were clear differences macrohabitats utilized, selecting areas Norway spruce Picea abies riparian corridors mixed woodland ranges. Within individual similar, but again reds conifers broad-leaved trees. As no variables consistently affected microdistribution blocks or ‘stands’ trees, stands constitute good relatively homogeneous habitats either species. 4. There evidence suggest avoided using same time, potential considerable (0·77). However, partitioning reduced competition hence contributed persistence this site. 5. This work (i) reinforces earlier proposals management offers promising tool assist conservation squirrels; (ii) raises issue determining scale which operates; (iii) an illustration how invasive can mediated through manipulation availability.