Conservation and Sustainable Use of the Biosphere - WBGU

Biological-ecological basic research J 3.1
373
J 3.1.2
Population biology and population genetics
Alongside research in the area of taxonomy and systematics,
a second focus should be placed on population
biology. Processes that lead to the evolution,
genesis, maintenance and endangering of species
begin in individuals or populations (cf core programme
element 2 of Diversitas, 1998).
Therefore, deeper knowledge of population biology
and genetics is a basic prerequisite for understanding
the spatial and temporal dynamics of
ecosystems and their species composition.The different
populations of one species can also demonstrate
specific local adaptations to certain environmental
conditions which can be of great economic importance
for the development of resistances in crops.The
Council sees an urgent need for research in the following
areas:
• The genetic variability within and between populations
of endangered species – but also of wild
related species of crops – merits more study. Thus,
the potential consequences of genetic erosion for
the survival of species with small populations can
be made clearer.The impact of demographic, environment-related
and genetic chance occurrences,
as well as natural disasters on the population
dynamic is highly relevant in this context.
• The sources-sinks dynamic and genetic transfer
within and between populations should be studied
more closely with the approach of meta population
biology in the context of long-term projects.
That way a basis for the management of endangered
species would be established in the light of
increasing habitat fragmentation. In this context,
the MVP concept (Minimum Viable Population)
should be carried forward and tested on various
experimental model systems.
J 3.1.3
Functional ecology
The third focus of biological basic research the Council
recommends is support for functionally oriented
ecology and ecosystem research (cf core programme
element 1 of Diversitas). It is the precondition
amongst other things for responding to the following
core question: ‘Are there ecosystem thresholds of
diversity, above or below which abrupt changes in the
structure and functioning of ecosystems result and in
particular: are there minimum limits below which the
system collapses?’
Our understanding of the diverse interactions and
connections within ecosystems is extremely rudimentary,
but is the precondition for both evaluating
human interventions in the biosphere and for the
development of sustainable use systems. For the
implementation of many of the research recommendations
enumerated here, the fundamentals of taxonomy
and population biology are in turn required;
interdisciplinary approaches are therefore what will
lead to success.
• The biodiversity of an ecosystem is strongly determined
by site factors. A tighter approach to the
effects of the various site factors should be
recorded and combined to form an overall complex.
• The reciprocal relations between diversity, structure
and function of ecosystems call for intensive
research initiatives. Grassland, climatic chamber
and laboratory experiments are not sufficient for
that purpose. Experiments relating to the connection
between biodiversity and ecosystem
processes must also urgently be conducted in
other terrestrial, limnic and marine ecosystems
and on several levels (not just at species level). In
parallel, findings from experiments with model
ecosystems in the field should also be verified. In
this context the connections between biological
diversity and soil processes, herbivore activity and
pollination are of particular importance.
• Ecosystems seem in many cases to demonstrate a
higher diversity than is necessary for their functioning
under stable environmental conditions. If
this assumption is correct, then even extensive
interventions by mankind might prove insignificant
– however only if stable environmental conditions
can be guaranteed. This hypothesis is in
urgent need of clarification. The impact of
extreme climatic events (in simulated scenarios of
global climate change) and other anthropogenic
disturbances on the relationship between species
diversity and ecosystem processes and the stability
or resilience of ecosystems (Box D 2.4-2) must
therefore also be studied. In this way the ability to
indicate early on the potential consequences of
human interventions in the biosphere could be
enhanced and corresponding countermeasures
could be developed and taken.
• In this connection not just the question of the
influence of species diversity per se, but also the
influence of the respective species composition on
ecosystem processes need to be pursued. How are
two systems that have the same number of species
but a different composition of species types (eg
beech forest versus spruce forest) functionally different?
• The possibilities of identifying what are termed
keystone species (Section D 2.4) in ecosystems and
using them as indicators for the structure and