Environmental Assessment
Volume C-4.4
Slurry Pipeline
Natural Habitats and Biodiversity
Ambatovy Project
151
January 2006
•
direct clearing of vegetation with right-of-way ground grading, new
access roads and improvements, construction camps, pipe storage areas;
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pipe hauling will be done with trucks, and pipe laying activities will
occur mainly during the dry season; and
•
during reclamation some parts of the pipeline could be taken out, but
most sections will be left in place.
Three major land use sub-areas were defined along the slurry pipeline LSA: the
western section, which is within the forest corridor (corridor zone); the central
section, which passes around primary forest fragments through an area defined
primarily by a tavy matrix (tavy zone), and the eastern section, containing
entirely secondary vegetation and a higher density of agricultural use
(agricultural zone) (Volume K; Appendix 3.1).
Development of the project will result in the loss or alteration of 940 ha of
habitat in the LSA (including associated buffers). Of all possible sources of
impacts from project construction and operation, habitat loss is among the most
important as it reduces the landscape’s capacity to support plant, wildlife and fish
species (Fahrig 1997; Andrén 1999; Fahrig 2003). Since the theory of island
biogeography was introduced by MacArthur and Wilson (1967), many studies
have demonstrated the negative relationship between loss of habitat area and
species richness and abundance (see review by Debinski and Holt 2000). Many
of the species are also endemic and/or have special conservation status
(Volume C, Section 4.4.3).
The removal and alteration of habitat during construction and operation also
results in the fragmentation (or breaking apart) of ecotypes on the landscape.
Fragmentation is typically associated with changes in patch size, number of
patches, habitat connectivity and edge effects (Fahrig 2003). The amount of
primary forest, wetlands, and degraded forest habitats will be influenced by
changes in mean patch size and number of patches. However, connectivity and
edge effects do not affect the area of these habitats that have the potential to
support flora and fauna species, so this potential impact pathway is invalid.
The greatest potential impact of fragmentation will be on the biota that inhabits
the landscape within the LSA, particularly the primary forest habitats within the
Mantadia-Zahamena corridor. The process of fragmentation often results in
disconnected habitat fragments with a high proportion of open perimeters.
Subsequently, fragmentation can increase the amount of habitat edge, decrease
the amount of habitat interior, and increase the distance between habitat patches
(Turner 1996; Fahrig 1997, 2003).
