The Population Ecology of Agroecosystems - Agroecology: The Ecology of Sustainable Food Systems - page 182

and researchers need to build on population ecology con-
cepts such as safe site, r - and K -strategies, and ecological
niche to further develop techniques and principles for
effective and sustainable management of crop and noncrop
organisms.

A site that facilitates interactions among
researchers in plant population biology.

Centre for Population Biology
www.cpb.bio.ic.ac.uk/
This site has information on the centre's basic
research in population biology and related
disciplines, dedicated to understand and
predict the functioning of ecological systems,
from populations to ecosystems.

FOOD FOR THOUGHT

1. What might permit coexistence of two very

similar crop species that would otherwise be
thought to competitively exclude each other if
allowed to grow in the same resource space?

Aberdeen Population Ecology Research Unit
www.abdn.ac.uk/aperu/aperu.shtml
The APERU is a collaborative group of statis-
ticians and population ecologists in England.
This site contains information on their
approaches and projects on population
ecology.

2. How might the concept of niche diversity be

used to design an alternative management
strategy for a particular herbivorous pest in a
cropping system?

3. Identify several particularly sensitive steps in the

life cycle of a weed species, and describe how
this knowledge might be of value in managing
populations of the weed in a sustainable fashion.

RECOMMENDED READING

Grime, J.R. 2002. Plant Strategies, Vegetative Processes, and
Ecosystem Properties. 2nd ed. John Wiley and Sons:
New York. A review of the relevance of the plant strategy
concept in ecological and evolutionary theory.
Harper, J.L. 1977. Population Biology of Plants. Academic
Press: London. Considered to be the key reference in
modern plant population biology, this topic
thoroughly reviews plant demography and life history
strategies.
Radosevich, S.R., J.S. Holt, and C. Ghersa. 1997. We e d E c o l o g y :
Implications for Vegetation Management . 2nd ed. John
Wiley and Sons: New York. A thorough review of how
ecological knowledge of weeds and weed populations
forms an essential basis for successful weed
management.
Silvertown, J.W. and D. Charlesworth. 2001. Introduction to
Plant Population Ecology . 4th ed. Blackwell Science:
Oxford, London, Vermont. An up-to-date introduction
to the field of plant population ecology, with many ref-
erences to studies of agricultural populations.
Van der Pijl, L. 1972. Principles of Dispersal in Higher Plants .
2nd ed. Springer-Verlag: Berlin. A review of the ecology
of dispersal mechanisms in plants and their role in deter-
mining the success of different plant species in the
environment.

4. What aspect of plant demographics have agron-

omists been able to use successfully in their
quest for improved crop yields, but which has
sacrificed overall agroecosystem sustainability?
What changes would you make in the research
agenda of agronomists in order to correct this
problem?

5. What is your definition of a “good” weed?

6. Tropical environments seem to have more

specialists, whereas temperate environments have
more generalists. Where do agroecosystems fall
in this spectrum?

INTERNET RESOURCES

The Land Institute
www.landinstitute.org
The Land Institute is leading the effort to
develop a perennial grain crop.

Plant Population Ecology section of the Ecological
Society of America
pltecol.cas.usf.edu/index.pl