Global Short Term Trend: Relatively stable to decline of 30%
Comments: In some parts of its range, this species appears to be declining due to habitat conversion and drainage. In other areas, available habitat appears to be increasing. For example, in Arkansas, the Arkansas River was converted to series of lakes in the 1950s, creating slow waters with alligator weed mats that are colonized by this species (T. Witsell pers. comm. 2010); floating mats of vegetation seem to be generally increasing in Arkansas, and perhaps elsewhere. In some states, population trends are mixed; for example, in Kentucky, some populations are stable and some are declining with changes in hydrology (D. White pers. comm. 2010).
Global Long Term Trend: Decline of 50-70%
Comments: Range seems to have retreated within the last century, particularly in the north and east; this species is now possibly extirpated in New York, Maryland, and Michigan. The wetland habitats preferred by C. decomposita have declined significantly from their historical extent due to extensive wetland drainage.