Abstract:
Indigenous forests all over the world are suffering habitat alteration, loss of original
extensions, and increase of isolation levels, affecting their existence and
sustainability. In New Zealand about 70% of the original forest cover has been
destroyed since human settlement, converting them to a rare and threatened
resource. Part of the problem is because native forests are often immersed in a
landscape where other land uses are competing for the same space.
Effective conservation management of these indigenous forest remnants requires
information about their vulnerability to threats, in space and time. Few studies
provide an integrated assessment of the extent to which socio- economic effects are
responsible for native vegetation vulnerability and how these relationships change
through time. In this study socio-economic drivers at different scales are related to
land cover changes.
To analyse vulnerability of indigenous forests a temporal dataset was developed
from aerial photography for the years 1942, 1961, 1984, and satellite images for the
years 1999 and 2006. They were managed within a GIS, recording the extent and
distribution of these forests and other principal land covers in a study area of ca.
80,000 ha in the Northland region. Information about incentives to land production
and to conservation was compared to changes of composition, configuration and
conversion of land cover. Spatial conditioners of change, such as elevation, land use
capability and land legal protection, were also assessed as possible constrainers of
indigenous forest loss.
Results showed that the incentives to land production had changed their significance
for vulnerability of indigenous forests through time. These became conditioned by
other land covers and incentives to conservation, and besides, indigenous forest was
a quite stable cover where the physical characteristics of their location were
unsuitable for land production. I concluded that at scale of decades, changes in area
of indigenous forest were reversible; non- linear; driven by political, institutional
and economic changes but that, biophysical characteristics of the landscape can
preclude conversion. Such conclusions may help to set priorities for the long term
protection and management of indigenous forests.