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USGS Western Ecological Research Center

Spring Surveys, 1983-2007

Spring Surveys, 1983-2007

YEAR INDEP % CHANGE PUPS % CHANGE PUP/INDEP RATIO TOTAL % CHANGE
1983 1156 - 121 - 10.5 : 100 1277 -
1984 1180 2.1 123 1.6 10.4 : 100 1303 2.0
1985 1119 -5.2 242 96.8 21.6 : 100 1361 4.5
1986 1358 21.4 228 -5.8 16.8 : 100 1586 14.2
1987 1435 5.7 226 -0.9 15.7 : 100 1661 4.7
1988 1504 4.8 221 -2.2 14.7 : 100 1725 3.9
1989 1571 4.4 285 29.0 18.1 : 100 1856 7.6
1990 1466 -6.7 214 -24.9 14.6 : 100 1680 -9.5
1991 1700 16.0 241 12.6 14.2 : 100 1941 15.5
1992 1810 6.5 291 20.8 16.1 : 100 2101 8.2
1993 2022 11.7 217 -25.4 10.7 : 100 2239 6.6
1994 2076 2.7 283 30.4 13.6 : 100 2359 5.4
1995 2095 0.9 282 -0.4 13.5 : 100 2377 0.8
1996 1963 -6.3 315 11.7 16.0 : 100 2278 -4.2
1997 1919 -2.2 310 -1.6 16.2 : 100 2229 -2.2
1998 1955 1.9 159 -48.7 8.1 : 100 2114 -5.2
1999 1858 -5.0 232 45.9 12.5 : 100 2090 -1.1
2000 2053 10.5 264 13.8 12.9:100 2317 10.9
2001 1863 -9.3 298 12.9 16.0:100 2161 -6.7
2002 1846 -0.9 293 -1.7 15.9:100 2139 -1.0
2003 2270 23.0 235 -19.8 10.4:100 2505 17.1
2004 2495 9.9 330 40.4 13.2:100 2825 12.8
2005 2417 -3.1 318 -3.6 13.2:100 2735 -3.2
2006 2369 -2.0 323 1.6 13.6:100 2692 -1.6
2007 2637 11.3 389 20.4 14.8:100 3026 12.4


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