Vol. 15 - Deutsches Primatenzentrum

Lemur News Vol. 15, 2010 Page 31
Discussion
The parcel of Ivontaka Nord is considered to be an example
of disturbed primary forest.Anthropogenic effects are much
stronger in Ivontaka Nord than in other parcels,because it is
the smallest of the three, and the closest to the town of
Mananara. Before the creation of the national park, the area
of Ivontaka Nord was frequently used as a place to grow
crops through tavy,harvest wood for construction and cooking,and
hunt lemurs.For these reasons,the lemur population
of the parcel was at one time diminished to the point of localized
extinction of the critically endangered Varecia v.variegata,
in addition to the localized extinctions of Indri indri and Hapalemur
griseus (J. Betsiahilika, personal communication). Yet,
because it is connected through a corridor of community
managed forest to the less disturbed parcel of Ivontaka Sud
(Fig.1),in 2002,V.v.variegata migrated into the GCF corridor
between Ivontaka Sud and Ivontaka Nord, and in 2005 these
lemurs could again be found within the parcel. However, the
species of Indri indri and Hapalemur griseus are not believed to
currently inhabit the parcel, though they can be found in the
other two parcels within the biosphere (J. Betsiahilika, personal
communication).
Within the parcel, there was convincing evidence to suggest
that the lemurs might be recovering even more than previously
known. During the two weeks of transects, Eulemur
rubriventer was observed within the parcel, even though its
recorded range ends west of the biosphere reserve. In addition,traces
of the distinct eating habits (shredding the stems
of tall plants whilst stripping off foliage) of Hapalemur griseus
were found within the savoka. Additionally, there were reports
of Indri indri spending time in the corridor between
Ivontaka Sud and Ivontaka Nord (J. Betsiahilika, personal
communication).
Through field observations, E. albifrons was found to have a
population twice that found in other areas such as Masoala
(Mittermeier et al.,2006).They frequent both the parcel and
community forest. During the season in which this study
took place,when most of the fruit within the parcel is not yet
ripe, many Eulemur albifrons were reported by local villagers
to be exiting the parcel in search of other cultivated fruits
like lychee and banana. V. v. variegata on the other hand
appeared to not leave the protected parcel.It is possible that
they adapt their feeding habits based on the season and thus
do not eat cultivated fruits (Ratsimbazafy, 2002).
The observed density of V. v. variegata was not congruent
with the report of the local guide (F.Frejes,personal communication).
This species, like Eulemur rubriventer, was observed
on only one occasion. Because of time constraints, surveys
had to be conducted over a two week period and with only
the use of one field team. For more complete and definitive
findings, a survey needs to be done over a longer period of
time, possibly across different seasons. Also, it would be
beneficial to conduct the same type of study after dark.
Finally, it would be helpful to determine lemur densities in
the other two parcels, and the community managed forests
in-between.
Conclusion
It is currently of the utmost importance to make sure that
the integrity of forested sections outside the realm of the
parcel remains protected.These areas represent a buffer between
the fragile low altitude rainforest and an ever expanding
human population. The corridor formed by these community-managed
forests, between the three national park
parcels, is a priority area. It has already been shown to provide
a bridge to facilitate migration between the three parcels,which
is critical in a country where forest fragmentation
is proving detrimental to the gene flow of lemurs (Louis et al.,
2006).
Through the work of the biosphere reserve,significant steps
have already been taken to encourage conservation. Both
government officials and villagers appear to be working together
to promote a healthy ecosystem. Already with the
promotion of crops such as vanilla,cloves,and coffee,as an alternative
to other more environmentally negative livelihoods,
villagers say they have seen an improvement both in
their lives and the forest health (Desana and Berger,personal
communication). However, people have needs; the agricultural
inhabitants of these rural areas need both to grow their
food and to have wood and other materials for performing
everyday tasks. It is possible to improve both the lives of the
people in the area and decrease their negative impact on
their environment through simple strategies such as rice intensification
and promoting more efficient cooking methods.
Maybe then populations of Indri indri, Hapalemur griseus, and
Propithecus diadema,all species that at one time inhabited the
area, will return to the parcel of Ivontaka Nord.
Acknowledgements
This study was carried out under a Memorandum of Understanding
between SIT and ANGAP Mananara for an internship
for the author in November 2008.SIT thanks the Ministry
of Higher Education and Scientific Research and the University
of Antananarivo for the ongoing collaboration under
which SIT Study abroad operates. This study could not have
been possible without the help of Barry Ferguson and Jim
Hansen of SIT in addition to the staff in the ANGAP office of
Mananara, including Willy Mora, Jocelyn Bezara, Justin Besiahilika,
and Jean Cristophe Josoa.
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