24
2 Genetic Resources: Status, Development, Losses, and Conservation
2.2.2
Determinants for the Loss of PGRFA
The level of PGRF A diversity maintained in farmers' fields is determined by the
decisions made on the farm level, depending on the individual or farm-specific
objectives. The practice of cultivating different varieties or crop species and
thereby maintaining a specific level of PGRF A diversity, is mostly a positive
externality of the farm sector. The decisions made at the farm level concern the
degree of change of the existing agricultural system on the farm level. The
changes in the agricultural system determines the level of land-use development,
which has the most severe impact on the future level of PGRF A diversity in
farmers' fields. Furthermore, the maintenance-level of PGRF A in farmers' fields
is not determined by the land-use development and farmers' decisions only, but
also by related factors; among others, the socio-economic factors, the
development of a relevant market, as well as policies and institutions. These
factors influence the decision making process at the farm level and are
summarized as the factors at the framework level, which directly or indirectly
influence the present and future level of PGRF A in farmers' fields. Consequently,
the decision-making process on the farm level is the key element of the factors
determining the diversity level of PGRFA in farmers' fields. depicts the three
levels: the framework level, the decision-making process on farm- evel, and the
level of the land-use development, whereby the main factors on the framework
level are specified. The site- and time-specific factors of the different levels and
their inter- and intra-linkages determine whether the quantity of PGRF A diversity
in farmers' fields may be maintained, increased or reduced. In the following
section, the different factors of the different levels shown in are discussed in
more detail.
The farmers, being the main contributors to diversity of PGRF A in the past, are
at present those who influence the state of diversity of PGRF A the most with their
day-to-day activities. The decisions at the farm level may result in changes of the
agricultural production system. These changes will influence the land-use
development. The major change in the agricultural system is its intensification
through the application of new technology, which may lead to variety
replacement, over-exploitation of genetic resources, and habitat destruction (see
Fig. 2.4). As a side-effect, the changes in the agricultural systems may lead to the
introduction of new pests, diseases or weeds; or, in an extreme case, these
changes may lead to the abandonment of agricultural production and the
development of non-agricultural land-use systems.
All the different kinds of land-use conversion described above are determined
mainly by the decision-making process at the farm level. These decisions are
influenced by the farmer's constraints and possibilities of land-use activities on
the one hand, and by economic, political, and social factors on the other. This
broadens the concept and integrates factors at the framework level, which
influence the extent of PGRF A in farmers' fields. The factors are summarized in
the following section (see Fig. 2.4).
2 Genetic Resources: Status, Development, Losses, and Conservation
2.2.2
Determinants for the Loss of PGRFA
The level of PGRF A diversity maintained in farmers' fields is determined by the
decisions made on the farm level, depending on the individual or farm-specific
objectives. The practice of cultivating different varieties or crop species and
thereby maintaining a specific level of PGRF A diversity, is mostly a positive
externality of the farm sector. The decisions made at the farm level concern the
degree of change of the existing agricultural system on the farm level. The
changes in the agricultural system determines the level of land-use development,
which has the most severe impact on the future level of PGRF A diversity in
farmers' fields. Furthermore, the maintenance-level of PGRF A in farmers' fields
is not determined by the land-use development and farmers' decisions only, but
also by related factors; among others, the socio-economic factors, the
development of a relevant market, as well as policies and institutions. These
factors influence the decision making process at the farm level and are
summarized as the factors at the framework level, which directly or indirectly
influence the present and future level of PGRF A in farmers' fields. Consequently,
the decision-making process on the farm level is the key element of the factors
determining the diversity level of PGRFA in farmers' fields. depicts the three
levels: the framework level, the decision-making process on farm- evel, and the
level of the land-use development, whereby the main factors on the framework
level are specified. The site- and time-specific factors of the different levels and
their inter- and intra-linkages determine whether the quantity of PGRF A diversity
in farmers' fields may be maintained, increased or reduced. In the following
section, the different factors of the different levels shown in are discussed in
more detail.
The farmers, being the main contributors to diversity of PGRF A in the past, are
at present those who influence the state of diversity of PGRF A the most with their
day-to-day activities. The decisions at the farm level may result in changes of the
agricultural production system. These changes will influence the land-use
development. The major change in the agricultural system is its intensification
through the application of new technology, which may lead to variety
replacement, over-exploitation of genetic resources, and habitat destruction (see
Fig. 2.4). As a side-effect, the changes in the agricultural systems may lead to the
introduction of new pests, diseases or weeds; or, in an extreme case, these
changes may lead to the abandonment of agricultural production and the
development of non-agricultural land-use systems.
All the different kinds of land-use conversion described above are determined
mainly by the decision-making process at the farm level. These decisions are
influenced by the farmer's constraints and possibilities of land-use activities on
the one hand, and by economic, political, and social factors on the other. This
broadens the concept and integrates factors at the framework level, which
influence the extent of PGRF A in farmers' fields. The factors are summarized in
the following section (see Fig. 2.4).