Revue internationale d'écologie méditerranéenne International ...

FAITS DE CONSERVATION EN MÉDITERRANÉE / MEDITERRANEAN CONSERVATION NEWS ◆
adjusted with detection probability and extrapolated to the entire
surface area of preferred habitat in the Camargue estimated from
a GIS to obtain abundance estimates of the brood population.
A minimum estimate of 559 breeding pairs was obtained (95%
confidence interval: 436-855). This estimate is much higher than
previous ones (80-100 pairs for the Camargue, 250 pairs for
France), and indicates strong underestimation of the population
size when not taking into account detectability.
Our results suggest that the Red-crested Pochard may require
a reassessment of its conservation status for France and Europe.
In particular, Red-crested Pochard may not qualify any more to
an Endangered status in the French Red List of threatened birds,
which might contribute to focus stronger conservation efforts
on a narrower list of Endangered species, or to switch these
conservation efforts to another species of higher conservation
concern. Nevertheless, the Red-crested Pochard can be classified
as Vulnerable in France: its conservation thus still requires protection
of its wetland habitat and sound population and harvest
monitoring.
Contact : Pierre Defos du Rau
ONCFS, Délégation régionale, 10bis route d’Ax, 31120 Portet/
Garonne, France, e-mail: p.defosdurau@oncfs.gouv.fr,
tél. : 335 62 20 75 55 – fax : 335 62 20 75 56
For more information, read :
— DEFOS DU RAU, P., BARBRAUD, C. & MONDAIN-MONVAL, J.Y.,
2003. Estimating breeding population size of the Red-Crested
Pochard (Netta Rufina) in the Camargue (Southern France) taking
into account detection probability: implications for conservation.
Animal Conservation, 6 : 379-385.
Number of rabbits hunted
600
500
400
300
200
100
0
J F M A M J J A S O N D
Figure 1. A. Number of adult rabbits (white circles) and juveniles (black circles)
that can be hunted in a simulated population.
ecologia mediterranea, tome 29, fascicule 2, p. 249-258
Months of the year
A
When is the best time to hunt
if we want to have a lot of rabbits?
Modelling an answer
The wild rabbit as a pest: hunting as a control measure
In the 10th century BC the Phoenicians referred to Spain
as the ‘Land of the Rabbits’, such was the abundance of this
lagomorph: rabbits were so common and such prolific breeders
that they were considered as pests that needed controlling. Since
then, the most traditional and frequent control method used was
hunting and rabbits came to constitute one of the main natural
and economic resources in rural areas in Spain and most of the
rest of southwest Europe.
Rabbit abundance varies with the seasons. The reproductive
period begins in autumn when food supplies allow females to
reach adequate physical condition, although activity may be interrupted
during winter. Activity continues with renewed vigour in
spring, until food scarcities in summer cause a gradual decrease
in breeding behaviour (fig. 1). As a result, rabbit abundances
show a seasonal pattern, with an increase after reproduction and
a decline towards the beginning of autumn and the start of the
next reproductive period.
So, given this yearly pattern of rabbit abundance, when is the
best time to hunt if the aim is to control rabbit populations? The
answer is, logically, when rabbit abundance is at its lowest. Hunting
when fewest rabbits are alive, most of which will be adults, will
reduce overall reproductive capacity for the next season. And so
it comes as no surprise that hunting was traditionally practised
from October to December and that this pattern continued in
Spain throughout the last century.
Percentage of reproductive females
100
80
60
40
20
0
J F M A M J J A S O N D
B. Percentage of reproductive females in a Spanish population (black bars)
and the possible percentage increase under favourable conditions (grey bars). .
B
253