TITLE:
Expansion and Management Implications of Invasive Alien Spartina alterniflora in Yancheng Salt Marshes, China
AUTHORS:
Chunyue Liu, Hongxing Jiang, Shuqing Zhang, Chunrong Li, Xin Pan, Jun Lu, Yunqiu Hou
KEYWORDS:
Spartina alterniflora, SPOT-5, Remote Sensing, Fuzzy Set Assessment, Expansion Characteristics, Management Implications
JOURNAL NAME:
Open Journal of Ecology,
Vol.6 No.3,
February
18,
2016
ABSTRACT: Improved understanding of the spatial dynamics of invasive plant species
is critical for effective land management and control of future invasion. The
Yancheng National Nature Reserve (YNNR), an internationally important wetland,
has the largest distribution of alien Spartina
alterniflora in China. This alien plant was intentionally introduced for
erosion prevention and dike protection in China. However, it became an
aggressive competitor with native salt marsh plants in the coastal regions in
China. High resolution imagery, SPOT-5, was used to map plant communities
including invasive species in the south core zone of YNNR with the natural
ecosystem of salt marshes in 2003, 2005 and 2008. The fuzzy set assessment
method significantly improved the classification accuracies over the
conventional error matrix, i.e., from 73.8%,
73.5% and 81.4% to 91.5%, 91.6% and 93.4% in 2003, 2005 and 2008, respectively. It shows a great
potential for mapping invasive plant species. Phragmites australis and S.
alterniflora were the most accurately mapped classes, and sparse and denseSuaeda glauca were the least
accurately mapped. From 2003 to 2008, S.
alterniflora increased 28.8% from 1664.1 to 2142.6 ha in area size, and more
than 2.5 times from 742 to 2608 patches. The highest increase in patch number
occurred within the interval between 2001 and 3000 m from the eastern baseline.
This increase was dominated by small patches with area less than 200 m2.
During the study period, the mean spread width was 405 ± 80.7 m in the original
large patch of area over 200 ha. The eastward/seaward spread was distinctively
larger than the westward/landward. The results enhance the understanding of
alien plant’s invasion patterns and help improve conservation efforts.