Implications of interspecific and intraspecific abundance-occupancy relationships

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 extant 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.