Although the importance of spatial scale in determining species status
(abundance and distribution) is widely recognized, most ecological in
vestigations have been conducted at local scales. Our goal was to inve
stigate the importance of spatial scale in assessing the status of the
green frog (Rana clamitans melanota) in the center of its range in ea
stern North America. Using repeated surveys at 160 ponds from 1992 to
1994, we investigated patterns of occupancy, abundance, and turnover a
t loca, sub-regional, regional, and geographic scales to determine the
status of the green frog in southwestern Ontario, Canada. Patterns of
pond occupancy were stable at the geographic scale. Occupancy was sta
ble in two regions and decreased in one. At the sub-regional scale, oc
cupancy was stable in six sub-regions, increased in one, and decreased
in two. Patterns of adult abundance were stable at the geographic sca
le. At the regional scale trends in adult abundance were increasing, d
ecreasing, or stable in each of three regions. At the sub-regional sca
le abundance was stable in three, increasing in one, decreasing in two
, and no trend occurred in three sub-regions. At the local scale abund
ance was stable at 20% of ponds, increased at 17.8%, decreased at 14.4
%, and no trend existed at 47.8%. Colonization and extinction rates ra
nged from 0 to 0.20 and 0 to 0.35 ponds/pond occupied/year, respective
ly, and differed among regions. Local extinctions took place at 25% of
ponds during the study, but no sub-regional or regional scale extinct
ions occurred. Small populations (<10 adults/pond) were prone to local
extinction. Determination of the status of the green frog is scale de
pendent. Although green frog populations are dynamic, it is common and
stable at the geographic scale, but its status varies among regions o
r sub-regions. Although processes that negatively affect a species may
operate at the local scale, a large-scale perspective is necessary to
determine status.