FRESH WATER - Taranaki Regional Council

Table 4.28: Wetland numbers.
In 2008, aerial photos taken in 2007 were used to evaluate changes
in the extent of wetland coverage in the region from 1996. The grid
references listed in the 1996 inventory were examined on the 2007
aerial photos and the area of each wetland was calculated. Table 4.28
sets out the number of wetlands found through the 1996 survey, the
number that were found to have disappeared and the number found in
2008, according to ecological district. The number of wetlands found
in 2008 differed from that found in 1996 because: some had clearly
disappeared (and this was verifi ed by checking aerial photos taken in
2001), some areas originally classifi ed as estuaries were not counted
(as they were not really estuaries), some errors in grid references
were found, some areas had been double-counted in 1996 and some
additional wetlands were located.
Table 4.28 shows that of the original 717 natural wetlands identifi ed in
the 1996 inventory 63 (8.8%) were confi rmed to have disappeared. The
majority of wetlands that had disappeared were from the Egmont and
Foxton ecological districts, areas where there is greatest pressure for
land development from agriculture. The majority of these wetlands were
estimated as being less than 5 ha.
Ecological District TOTAL
Egmont Nth Taranaki Matemate _ aonga Manawatu Plains Foxton
Number of wetlands reported in the 1996 survey 289 125 187 56 50 717
Number found to have disappeared by 2008 23 16 1 8 15 63
Total number of wetlands found in 2008 272 107 174 45 41 639
Area of wetlands found in 2008 (ha) 1,762.5 659.3 977.3 275.7 372.9 4,048
Figure 4.38. Wetland extent and regionally signifi cant wetlands.
The total number of wetlands, as identifi ed through aerial photographs,
now sits at 639, covering an area of 4,048 ha. This estimation of the
total area of wetlands in Taranaki differs from that estimated through a
national analysis of satellite imagery, which concluded that 3,045 ha of
wetland remains 70 . It is likely that the analysis of the aerial photographs
is more accurate. The extent of wetlands, as well as those identifi ed as
regionally signifi cant, is illustrated in Figure 4.38.
A systematic study is proposed to compare the area of wetland between
aerial photos fl own in 2001 with those fl own in 2007. This will produce
a more comprehensive baseline from which to evaluate future wetland
monitoring and a better assessment of the extent (in terms of area) of
wetland loss.
Small gully wetland (red dot) in South Taranaki, 2001.
Wetland replaced by contoured paddock, 2007.
Taranaki Regional Council
Taranaki Regional Council
State of the Environment Report 2009
131