Vol. 15 - Deutsches Primatenzentrum

Lemur News Vol. 15, 2010 Page 65
espèces allochtones de Ankoba) et dans six portions de
forêt épineuse qui sont inclues dans le domaine privé de
Berenty. Nous avons relevé l’état du pelage des animaux
selon trois conditions: fourrure intègre (niveau 1), fourrure
faiblement endommagée (ponctuée par des petites zones,
sans pelage, couvrant moins de 30 % du corps; niveau 2),
fourrure fortement endommagée (pelage manquant sur une
surface supérieure à 30 %;niveau 3).Nous avons aperçu seulement
quatre sifaka au niveau de pelage 3 et, par conséquence,
nous avons pu évaluer statistiquement les différences
seulement entre les niveaux de pelage 1 et 2, en comparant
forêt épineuse et les forêts riveraines, soi au niveau
des groups d’animaux (n= 41) soi au niveau des zones recensée
(n= 9). Même si avons détecté un nombre significativement
plus haut de sifaka avec la fourrure faiblement
endommagée dans le domaine épineuse,la nature et surtout
l’entité du dommage indiquent que les conditions du pelage
n’arrivent pas vraiment à différentier des segments distincts
dans la population de sifaka de Berenty.
Introduction
An index of coat condition can be a non-invasive tool for
tracking health and stress at the population level (Jolly,
2009a). In fact, pelage growth can be directly influenced by
the proximate stimulus of light (acting through neuro-endocrine
pathways), by the nutritional status, and indirectly by
temperature and behavior (Ling, 1970). Two main functions
of fur are a) insulation, which allows conservation of body
heat, thus reducing energy expenditure and food requirements;
and b) shielding, which protects day-active mammals
from excessive heat load from solar radiation (Scott et al.,
2001; Kenagy and Pearson, 2000).
Here, we considered coat condition of Propithecus verreauxi
(Verreaux’s sifaka) as a possible indicator of the "health status"
of animals in different habitats and investigated whether
it could provide information on possible population stress in
the poorly investigated spiny forest of south Madagascar.
The dry spiny forest of southern Madagascar is a thorny environment,both
metaphorically and literally speaking.Listed as
one of the 200 most important ecological regions in the
world,it harbors the highest level of plant endemism in Madagascar
(Elmqvist et al., 2007). In spite of its importance, the
spiny forest is underrepresented in terms of protection and
conservation programs (Fenn, 2003; Ganzhorn et al., 2003;
Seddon et al.,2000).To fill,at least in part,this gap,we investigated
sifaka fur condition in different spiny forest parcels
inside the Berenty Estate (Androy region,south Madagascar)
and compared it with sifaka inhabiting the riverine forest
areas inside the Berenty Reserve, a habitat much richer in
staple food for lemurs.
Methods
Study site, survey technique, and fur condition evaluation
In March-April 2008, a comprehensive sifaka survey was conducted
in the Berenty Estate, covering 134 ha of spiny forest
and 60 ha of non-spiny forest areas. The Berenty Estate is located
in the semi-arid Androy Region (rainfall averages less
than 500 mm per year). The spiny forest is usually 3 to 6 m in
height with dwarf and xerophyte plants,and emerging trees of
the Family Didieraceae that may reach more than 10 m in
height,such as the keystone species Allouadia procera (Elmqvist
et al., 2007). We performed the survey in all accessible spiny
forest parcels (sacred areas, used as a cemetery, cannot be
accessed by anyone except for local family clans) and in three
riverine areas of the Berenty Reserve (on the Mandrare river),
comprising a northern section (occupied by the 40 ha secondary
forest of Ankoba dominated by the exotic legume species
Pithecellobium dulce;S 24.99°;E 46.29°) and a southern section
(Malaza: S 25.01°; E 46,31°) (Fig. 1 shows study locations). Inside
Malaza we considered the 7 ha gallery forest (dominated
by tamarinds;Tamarindus indica) and the front-transitional forest
(13 ha) (Jolly et al.,2006).In all the areas considered in this
study,logging and hunting are prohibited,and the fossa (Cryptoprocta
ferox) isabsent.
Fig.1:Study site location:Berenty reserve (solid outline;white
area:scrub;diagonal lines:Ankoba and Malaza riverine forests)
and spiny forest fragments (black areas): 1 = Spiny Malaza; 2 =
Spiny Reserve 1;3 = Spiny Reserve 2;4 = West Rapily;5 = Fragment
X; 6 = Anjapolo, about 13 km north-west of Berenty.
Dashed outlines include degraded spiny and/or scrub areas.
The rest of the territory (white) is covered by pasture and
sisal fields. (Map based on Google Earth satellite view).
We performed the survey via walking, at a speed of about 1
km/h,along preexisting trails and through forest paths chosen
ad hoc to have visibility of at least 50 m to the right and left (to
avoid pseudoreplication we followed Norscia and Palagi,
2008).
During the census we evaluated the fur condition of each individual
lemur.We scored coat condition on a 3-point scale:coat
undamaged, with fur fully covering the body (level 1); ruffled
coat,with fur punctuated by small areas of reduced/missing fur
(on less than 30 % of the body, especially on elbows and/or
knees;level 2);patchy coat,usually with black skin areas clearly
visible due to reduced/missing fur (on more than 30 % of the
body, especially on elbows/knees, external sides of forearms
and thighs, fingers and toes; level 3) (Fig. 3).
Statistics
We performed the analyses at group or at forest site level.
Owing to the small sample size (n