Change patterns of oncomelanid snail burden in areas within the Yangtze River drainage after the three gorges dam operated

Table 2 Distribution of snail area burden (hm²) by environmental location in seven provinces in China, 2009–2017

Year	Total snail area	Marshlands and lakes				Plain regions		Hilly and mountainous regions
Year	Total snail area	Inner embankment		Outside embankment		Plain regions		Hilly and mountainous regions
	No.	No.	%	No.	%	No.	%	No.	%
2009	372 253	21 100	5.67	336 764	90.47	202	0.05	14 187	3.81
2010	373 516	21 138	5.66	337 679	90.41	195	0.05	14 504	3.88
2011	372 595	20 734	5.56	338 399	90.82	176	0.05	13 286	3.57
2012	368 633	20 382	5.53	335 507	91.01	209	0.06	12 535	3.40
2013	365 366	20 090	5.50	332 537	91.01	203	0.06	12 536	3.45
2014	364 245	22 345	6.13	329 658	90.50	145	0.04	12 096	3.32
2015	356 212	20 799	5.84	323 277	90.75	111	0.03	12 025	3.38
2016	356 752	21 291	5.97	317 884	89.11	133	0.04	17 444	4.89
2017	356 553	21 285	5.97	323 053	90.60	106	0.03	12 109	3.40

ISSN: 2049-9957