Q. Paynter et al., Factors affecting the establishment of Cytisus scoparius in southern France: implications for managing both native and exotic populations, J APPL ECOL, 35(4), 1998, pp. 582-595
1. The ecology of the woody shrub Cytisus scoparius was studied for 4 years
in its native range in southern France to investigate how it call become a
n invasive weed.
2. The proportion of the seed bank that germinated each year was highest in
disturbed plots and was correlated with the March rainfall. The seed bank
declined at a rate of c. 50% per year when fresh seed rain was excluded,
3. The fate of 2863 seedlings was followed for a variety of treatments.
4. Seedling survival depended on disturbance: none survived their first sum
mer in undisturbed plots; more than 40% survived their first summer and c.
14% survived to flowering age in plots that were initially cultivated.
5. Seedlings flowered first in their fourth year, although only c, 10% set
seed.
6. Neither inter- nor intraspecific competition was found to affect signifi
cantly seedling survival on cultivated plots. However, some seedlings grown
in the absence of interspecific competitors flowered and set seed in their
third year.
7. Applications of insecticide, molluscicide or fungicide did not affect si
gnificantly seedling survival, growth or minimum age of reproduction on cul
tivated plots.
8. It is concluded that management strategies should minimize disturbance t
o competing vegetation, which can inhibit germination and smother emerging
seedlings. In many circumstances strategies that target the seed bank, such
as burning, are not expected to work.
9. Herbivores and pathogens may prevent stand re-establishment indirectly,
by reducing the size, vigour and density of broom plants so that competing
vegetation can persist and smother emergent seedlings following the death o
f the parent stand.