Answers to Hone Your Problem-Solving Skills Questions
1. Four quadrats were used in each patch. Each treatment had 3 patches, so there was a total of 12 quadrats used in each treatment. The mean values for each treatment are:
| Treatment | Total no. taxa | Total no. individuals |
| Intact kelp beds | 68.1 | 434.4 |
| Recovered kelp beds | 73.8 | 580.8 |
| 12.1 | 63.5 |
580.8 individuals
0.25 m2
? 40 m2 = 92,928 individuals in the patch
Likewise, in areas where urchins were present, there was an average of
63.5 individuals per quadrat or 63.5 individuals per 0.25 m2. In the entire patch (which had an area of 40 m2), this suggests that we would have a total of 
3. Urchins had large impacts on species diversity and overall abundance. Compared to intact or recovered kelp beds, the presence of urchins had very large effects, reducing the total number of taxa by 6-7-fold and the total number of individuals in the patch by about 8-fold. The total number of taxa and the total number of individuals in recovered kelp beds were similar to the total number of taxa and the total number of individuals in intact kelp beds; this indicates that when protected from urchins, previously degraded patches can recover.