Changes in a population of an endangered rattlesnake Sistrurus catenatus following a severe flood

We studied changes in the abundance, population structure, and reproductive traits of an endangered rattlesnake Sistrurus catenatus between 1979-1983 and 1993-1995. This population was subjected to an extensive flood during the summer of 1993, the most severe flood in northern Missouri in at least 100 years. The abundance of rattlesnakes had not changed substantially since the initial studies in the 1980s, but sex ratio, population structure, and body condition differed significantly. Most of these changes can be attributed to the 1993 flood, which severely damaged the habitat for the snakes and may have reduced prey availability. Data collected in 1995-1996 suggest that both the habitat and the massasauga population are recovering from the 1993 flood Monitoring programs for endangered species should collect data not just on changes in abundance, but changes in underlying population characteristics as well. (C) 1998 Elsevier Science Ltd