Answers to Hone Your Problem-Solving Skills Questions

1. Yes, the data follow the species-area relationship.

2. The percentage loss of species per year can be calculated using the t₅₀ scaling factor.

1 hectare: 50%∕5 years = 10% species loss per year

10 ha: 50%∕8 years = 6.25% species loss per year

100 ha: 50%∕12 years = 4.17% species loss per year

The 1 ha fragments have the greatest species loss, and the 100 ha fragments have the least.

3. The number of species in the fragments 9 years after the start of the experiment can be calculated using the following equation: initial species number - (initial number of species ? percentage species loss per year ? 9 years). Thus,

1 ha: 83 species - (83 species ? 10% loss per year ? 9 years) = 8 species

10 ha: 92 species - (92 species ? 6.25% loss per year ? 9 years) = 40 species

100 ha: 113 species - (113 species ? 4.17% loss per year ? 9 years) = 71 species

4. The fragments that had 9 years of isolation would have the steepest species-area slope. Once fragmentation occurs, the fragments act more like islands. Thus, the smallest fragments had greater species loss than the largest fragments because they had higher extinction rates and lower immigration rates. In addition, the smaller the fragment, the greater percentage of edge habitat, which is more hazardous for species, and thus extinction risk increases even more.