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Landscapes Forest and Global Change - ESA - Escola Superior ...

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F.M. Rabenilalana et al. 2010. Multi-temporal analysis of forest l<strong>and</strong>scape fragmentation in the North East of Madagascar<br />

94<br />

3.2 Fragmentation forest area<br />

In terms of forest area, a decrease (occurred during the period under review) was observed<br />

between the two periods. A deforestation rate of 5.25 % per year was calculated. Figure 1<br />

explains that 46% of low fragmented forest was changed into the other l<strong>and</strong> use classes in 2009.<br />

Approximately, most of the forested area lost has been converted into cropl<strong>and</strong> <strong>and</strong> only 36% in<br />

highly fragmented forest. In fact, there has been a tendency of highlighting small-scale<br />

migratory farmers <strong>and</strong> "poverty" as the major cause of l<strong>and</strong>scape change.<br />

In spite of increased fragmentation, the “gains <strong>and</strong> losses’ analysis showed that some fragments<br />

persisted. In reality, more or less 35% of the total forest area resists change. These values<br />

illustrate l<strong>and</strong>scape changes at a very high rate. And if there is no action taken soon, large<br />

amounts of habitat <strong>and</strong> biodiversity values will be lost.<br />

Area (Ha)<br />

35 000,00<br />

30 000,00<br />

25 000,00<br />

20 000,00<br />

15 000,00<br />

10 000,00<br />

5 000,00<br />

0,00<br />

2004 2009<br />

Year<br />

Low fragmented Fragmented<br />

Figure 1: <strong>Forest</strong> area change from 2004 to 2009<br />

3.2 <strong>Change</strong> analysis<br />

The impact of distance variables (distance to streams, rivers, paths, villages <strong>and</strong> topographic<br />

parameters) on l<strong>and</strong>scape changes was calculated. Cramer’s V test revealed that a) the selected<br />

distance variables did not influence low fragmented forest patches because V equal 0; b)<br />

distance to path <strong>and</strong> topographic parameters did, however, impact high fragmented forest<br />

patches (see figure 2).<br />

V*<br />

0,45<br />

0,4<br />

0,35<br />

0,3<br />

0,25<br />

0,2<br />

0,15<br />

0,1<br />

0,05<br />

0<br />

Village distance to<br />

fragmented forest<br />

Path distance to<br />

fragmented forest<br />

Stream & river distance<br />

to fragmented forest<br />

Topography to<br />

fragmented forest<br />

Variables distance<br />

Cramer's V* ( V significant)<br />

Figure 2: Test of driver variables<br />

<strong>Forest</strong> <strong>L<strong>and</strong>scapes</strong> <strong>and</strong> <strong>Global</strong> <strong>Change</strong>-New Frontiers in Management, Conservation <strong>and</strong> Restoration. Proceedings of the IUFRO L<strong>and</strong>scape Ecology<br />

Working Group International Conference, September 21-27, 2010, Bragança, Portugal. J.C. Azevedo, M. Feliciano, J. Castro & M.A. Pinto (eds.)<br />

2010, Instituto Politécnico de Bragança, Bragança, Portugal.

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