Conservation and Sustainable Use of the Biosphere - WBGU

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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

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