Greater big-footed mouse (Macrotarsomys ingens)

Mohamed bin Zayed Species project number 13056001

Introduction
The greater big-footed mouse belongs to the subfamily of Nesomyinae, a group of 20 species of rodents that found only in Madagascar, in Ankarafantsika National Park (Garbutt 1999, Carleton and Schmidt , 1990). It is nocturnal, and is terrestrial and arboreal, spending all night time in the trees. It is classified as an endangered species (IUCN 2009) because its range is less than 5,000 km ², the extent and quality of habitat and number of mature individuals continues to decline. The cause may be the destruction of the habitat and the predation by wild and domestic dog ( Soarimalala & Goodman , 2011). It is very vulnerable to any threat because of its very restricted distribution. Dry forests of Madagascar are threatened by fire for agriculture and grazing, selective logging and the expansion of rural human populations (WWF 2007). Such destruction and habitat degradation will inevitably have serious consequences on the population of the greater big-footed mouse. So, our research has 3 objectives: to contribute to the reduction of habitat Macrotarsomys ingens, to encourage the efficient use of natural resources to improve the local quality of life, conserving biodiversity
Materials and Methods
At first, we need to have database of the target species. It is based on the census. One transect of 1 km has been establish. The census was carried out overnight in the transect, at 08 pm to 11 pm during 40 days. The method of capture-mark-recapture has been adopted. We can get the territory surface with this method by linking all capture point (site) for each individual.
For the habitat study or habitat description,
08 variables have been measured to determine if this species has a an habitat preference : Number of small trees , number of big trees, number of fallen trees , depth and coverage of the litter , ground cover, quantity of debris branches , average tree height. The measurement results will be tested by Kruskall-Wallis test. We need to test if there is a difference between sites with capture of Big Footed Mouse and site without capture.
The identification of threats and pressure consist to count domestic and wild dog (predator) walking and to count the number of fallen trees in the transect.
The sensitization of the local population is necessary in order to change the behavior of the local community. The method is based on the conference debate with local people for the protection of Macrotarsomys ingens because local population don't know the importance of the greater big-footed mouse, they think that it's is dangerous for their culture.

Results
- Density and population abundance:
11 individuals have been captured and marked during the present study.
d = N / S
d : Density of population ( individuals/m2 )
N: Number of individuals captured
S: surface ( m2)
d = 11/4000
d = 0.003 individuals/m2
We didn't get the surface of territory because the number of captured individuals was not enough for that. It means that we didn't had any recaptured individuals.

- The habitat preference of this species
The measurement results of 8 variables (annex 01) will be tested to determine the preference and requirement of the habitat. SPSS software has been used to know which variable is important for the greater big-footed mouse.
The Kruskal -Wallis test will be applied to the data to see if there is a difference between the items with no capture and without capture.
Chart 01 : Kruskall Wallis test for the litter depht
H (observed value) 5,346
H (critical value) 3,841
DF 1
One-tailed p-value 0,021
Alpha 0,05
The Kruskal-Wallis H is distributed as a Chi-square

The litter depth has a significant difference (p=0,021<0,05). It means that litter is very useful for Macrotarsomys ingens, may be for its nest and for its foods.

- Threats and pressures
The main threats for Macrotarsomys ingens is predation by domestic and wild dogs and habitat disturbance.
Average 2 domestic dogs per observation were seen during 40 days of work but we've never seen wild dog in the transect. We can say that the principal predator of this species is domestic dog walking in the forest. The cause can be their overeffectivness in the village and they walk in the forest for searching foods.

The habitat disturbance is caused by illicit entrance in the forest. Some people go to the forest for collecting some product like: medicinal plants, birds, common Tenrec,....

- Appropriate conservation strategy: this species needs forest to survive because no forest means no litter. So, the appropriate strategy consists to conserve the totality of the forest.

Discussion

The greater big-footed mouse is very difficult to catch by box traps; so, the method by using capture-mark-recapture is not very useful for its research. We used manual capture even if it was very difficult.
We didn't get the surface territory because, first, the greater big-footed mouse is difficult to catch by box traps, and second we didn't have recapture. The causes can be its large territory.
The greater big-footed mouse has an habitat preference, it needs a lot of litter to live. The litter can be used for the nest and also for food searching. We observed that almost of this species is terrestrial, but they climb tree to avoid predator.

Conclusion and recommendations
The greater big-footed mouse is rare in Ankarafantsika National Park. His protection is necessary to avoid the population decline. It needs forest to survive normally. We must control the entry of tourist and researcher and avoid the entry of domestic dogs in the forest.