Download Contribution of plantation forests to biodiversity conservation

International Congress on Cultivated Forests
Planted Forests and Sustainable Development, with a Scientific
Forum on Ecosystem Goods and Services from Planted
Forests.
Bilbao, Spain; October 3-7, 2006
The scientific conference on Ecosystem Goods and Services from Planted
Forests was organised by the NETFOP project (Networking Forest Plantations
in a Crowded World) through the Institute of Silviculture at the University of
Freiburg and the European Institute of Cultivated Forests (IEFC - project centre
of the European Forest Institute), and was supported by IUFRO, CIFOR and
IUCN.
Keynote
Contribution of plantation forests to biodiversity conservation: the
landscape perspective
1
H. Jactel , L. Barbaro1, and E.G. Brockerhoff2
1. Laboratory of Forest Entomology and Biodiversity, UMR BIOGECO, INRA,
Cedex, France
2. Ensis, PO Box 29237, Christchurch 8040, New Zealand.
email: [email protected]
Forests and most other natural ecosystems are faced with an unprecedented
loss of species, mainly due to human activities. Although a substantial area of
native forest is now protected, reserves are often too small or too isolated for
biodiversity protection, while at the same time, plantation forests are increasing
globally. In the controversial debate on relative threats and benefits of tree
plantations for biodiversity, the key arguments relate to native forest destruction
or complementation by plantation establishment. Other issues relate to
improved ecosystem functioning with high species diversity, and the proposition
that biodiversity maintenance become a standard for forest certification. For
both pragmatic and ecological reasons, greater attention is therefore given to
biodiversity conservation in plantation forestry.
Until recently, methods for biodiversity conservation mainly focussed on effects
at the stand-level, which disregard neighbouring native remnants and the fact
that large-scale species survival processes, such as meta-population dynamics,
may be more critical. The landscape is therefore arguably the most relevant
spatial scale to address forest biodiversity conservation. Fragmentation and
natural forest loss remain the main causes of biodiversity loss, and interactions
between indigenous fragments and adjacent plantations are a key issue in
biodiversity conservation programmes. Although the effects of habitat
fragmentation contribute to a higher risk of species extinction, when considered
independently, its effects are lower and less predictable than those of habitat
loss. A growing body of evidence on the “continuum model” suggests that
suitable food, shelter and/or climatic conditions may be found along gradients in
the matrix, allowing dispersal and survival of fragment-dwelling biota and thus
mitigating fragmentation effects. However, artificial habitats may act as
ecological traps or as sources of invasive species that can spread into
remnants. Therefore, besides the conservation of large patches of native forest,
another important biodiversity conservation objective should be the
management of matrix complexity. The mosaic concept suggests that landscape
complexity comprises habitat diversity and habitat heterogeneity. It offers a
useful conceptual framework for interpreting ecological processes that influence
landscape level biodiversity dynamics and provides simple recommendations for
biodiversity conservation in landscape planning.
Nevertheless three problems remain to be solved. Responses to landscape
features are often considered to be species-specific or dependent on life traits of
particular species. Biodiversity patterns in some forest landscapes have been
better correlated with past than with present landscape configurations
suggesting that landscape planning based on apparent effects of present
plantation forests could be misleading. Tensions also continue to exist between
the objectives of biodiversity conservation and plantation productivity. Higher
ecosystem complexity may disagree with current trends in forest management
for increased intensification and simplification. Biodiversity conservation may
also be seen as a luxury for people who struggle to cover their basic food and
fuel needs. Trade-offs between biodiversity conservation and human well-being
are probably easier to achieve on a landscape scale where a spatial partition of
forest objectives can be made. However many stakeholders are involved in
landscape management and planning, with a high diversity of means and goals.
For this reason, social scientists need to cooperate with foresters and ecologists
to develop a holistic approach to biodiversity conservation through long-term
and multi-scale plantation forest management.