Recent shifts in emphasis to preservation of biological diversity and
establishment of large nature reserves have resulted in downgrading of
the perceived importance of data at the population level. These shift
s in emphasis, while laudable, should not result in loss of focus on t
he fundamental importance of population information. Suitable habitat,
although a prime necessity, is not sufficient for wildlife preservati
on. Species may not occupy otherwise suitable habitat because of inter
nal (predation, interspecific competition, disease) or external (adver
se climate, exploitation, disturbance, impact of exotic species, pollu
tion and toxicants) factors. Historical impacts may persist for many y
ears, and may require active restoration. Forest management plans must
consider population data on a metapopulation scale. Data for common s
pecies can be at the reconnaissance level whereas for threatened or se
nsitive species they need to be more detailed. To evaluate sustainabil
ity, population data must be integrated with forest stand data in proj
ection models to predict habitat-population mosaics at various times i
n the future. These models must be developed and improved over time in
an adaptive management approach.