January 1986-September 1990, for stations at Bigfork (Figure 1 

 and 2), and Seeley Lake (Figure 3 and 4), Montana, are provided 

 on pp. 10-11 and 12-13, respectively (U.S. Department of Commerce 

 1982) . Data indicate that total precipitation at Bigfork and 

 Seeley Lake was below normal in 1988, but above normal in 1989 

 (Figure 1 and 3, pp. 10 and 12, respectively). The average 

 yearly temperature was also below normal for both stations in 

 1989 (Figure 2 and 4, pp. 11 and 13, respectively), although not 

 from January through August of 1990. More specifically, for 

 August and September of 1989 (when germination might begin) 

 temperatures were below normal for both stations. Finally, for 

 the five monitoring ponds from 1988 to 1989 (Table 4, p. 8) pond 

 depths were 10, 30, 40, and 55 percent deeper (ponds 008, 009, 

 013, 020, and 027 respectively) in 1989. In 1990, monitoring 

 ponds were slightly deeper. Although this latter measurement is 

 approximate (depth was measured with a meter stick each time and 

 the stick may have been pushed deeper into the pond substrate 

 from one year to the next) , it still reflects a significant 

 increase in water depth between 1988 and 1989. In combination, 

 these factors could have resulted in less than optimal 

 germination conditions for H. aguatilis in the fall of 1989, the 

 outcome of which was the observed decrease in population size in 

 1990. Every pond is probably different with respect to drying 

 regime, and therefore trend in population size. This may explain 

 the anomalous results reported for ponds 12 and 26 over the past 

 three years. If seed germination is enhanced when ponds are dry, 

 then for most of the ponds, suboptimal drying regimes were 

 present between 1989 and 1990. 



Climate data are currently only available through September of 

 1990; however, for both the Bigfork and Seeley Lake stations, 

 precipitation appears to have been below normal and temperatures 

 above normal. Low H. aguatilis population counts might persist 

 through 1991, since the latter half of 1990 was mostly above 

 normal with respect to precipitation (Figure 1 and 3) , and the 

 depth measurements were similar to 1989 levels. However, if a 

 warmer and dryer trend occurs through summer of 1991, population 

 counts in 1992 would be predicted to be higher for most ponds. 



Also of interest in the 1990 surveys was the number of ponds that 

 were deep yellow-red in color, and had what appeared to be an 

 oily slick on the surface of the water. It is postulated that if 

 water levels remained high through the fall, more leaf material 

 would remain in the water which would not decompose, but would 

 instead leach into the water. The oil slick may also be an end 

 product of leaching. In any case, a reduction in incoming light 

 due to discoloration might also limit survival of H. aguatilis 

 seedlings, resulting in smaller populations as observed in 1990. 

 Heavy algal growth present may be the result of higher water 

 temperatures. Algal growth could also limit establishment of H. 

 aguatilis seedlings. 



