Implications of Interspecific and Intraspecific Abundance-Occupancy Relationships

Abstract

Positive interspecific and intraspecific relationships between local abundance and regional occupancy have been widely documented. The former are essentially pervasive. These patterns have some potentially significant applied implications: (1) Biodiversity inventorying there can be no simple and effective trade-off between the intensity and spatial extent of biodiversity inventorying, (2) Population monitoring intraspecific, and to a more limited extent interspecific. population monitoring may be based on measures of occupancy, particularly where only crude indications of marked shifts in abundance are required, (3) Harvesting - harvesting of local populations may often result in a reduction in wider occupancy, but if local extinctions are caused by over-exploitation this may not generally result in a reduction in local abundance elsewhere in the range of a species, (4) Conservation species of conservation concern may face the double jeopardy of low abundance and small range size, but depending on the extent of a causal link between levels of abundance and occupancy it may be possible to cheat the abundance-occupancy relationship and maintain species at relatively high local densities for their range sizes, and (5) Invasions - pest species may become more of a problem in those areas in which they already occur, because their local densities will increase, as they spread,.