A (area) = area of vegetation in square-cm 



I (inflorescences) = number of inflorescences 



Thus, a plants with an area of 6 1/4-squares and 3 inflorescences 

 is coded, A24-I3. 



Statistical Analysis 



For the purpose of analysis, each plant is treated as an 

 independent observation. Two dependent variables may be derived 

 from the data: (1) plant size, a measure of plant vigor, and (2) 

 number of inflorescences, a measure of fecundity. Both variables 

 can be analyzed with a mixed-model analysis of variance (ANOVA) 

 (Sokal and Rohlf 1981) with year as the fixed factor and plant as 

 the random factor. If only two years are being analyzed, the 

 ANOVA reduces to a paired-samples t-test. If more than two years 

 are analyzed, the ANOVA is followed by a contrast or multiple 

 range test to determine which pairs of years are significantly 

 different . 



There are three sources of variation for these dependent 

 variables in a long-term study: (1) experimental error, resulting 

 from counting or measuring inaccuracies, (2) short-term changes 

 resulting from year-to-year climatic fluctuations, and (3) long- 

 term changes - positive or negative trends resulting from habitat 



11 



