Table 1.
Species richness estimates using Chao2 (frogs) and the Michaelis–Menten equation (small mammals) and Jaccard's community similarity indices for paired sites within each sampled region along the Juruá River in Amazonia
| Region | Predicted asymptote left-bank site | Predicted asymptote right-bank site | Jaccard's similarity index | ||
|---|---|---|---|---|---|
| Frogs | |||||
| Terra firme | |||||
| Headwaters | 39.5 | 30.1 | 0.356 | ||
| Upper central | 87.3 | 49.1 | 0.429 | ||
| Lower central | 60.7 | 43.6 | 0.533 | ||
| Mouth | 49.2 | 48.4 | 0.474 | ||
| Mean (SD) | 59.2 (20.7) | 42.8 (8.8) | |||
| Várzea | |||||
| Headwaters | 22.2 | 27.8 | 0.316 | ||
| Upper central | 26.3 | 28.3 | 0.278 | ||
| Lower central | 27.4 | 20.1 | 0.552 | ||
| Mouth | 25.0 | 21.0 | 0.182 | ||
| Mean (SD) | 25.2 (2.2) | 24.3 (4.3) | |||
| Small mammals* | |||||
| Terra firme | |||||
| Headwaters | 14.1 | —† | 14.2 | — | 0.611 |
| Upper central | 14.8 | 5.7 | 14.7 | 9.1 | 0.571 |
| Lower central | — | 3.5 | 13.9 | 2.2 | 0.316 |
| Mouth | 7.9 | 9.7 | 8.9 | — | 0.500 |
| Mean (SD) | 12.3 (3.8) | 6.3 (3.1) | 12.9 (2.7) | 5.6 (4.9) | |
| Várzea | |||||
| Headwaters | 11.2 | — | 18.4 | 5.4 | 0.591 |
| Upper central | 8.1 | 8.8 | 6.7 | 7.8 | 0.643 |
| Lower central | 6.5 | 6.2 | 6.7 | 3.8 | 0.357 |
| Mouth | 7.6 | 4.6 | 5.9 | 6.4 | 0.429 |
| Mean (SD) | 8.4 (2.0) | 6.5 (2.2) | 9.4 (6.0) | 5.9 (1.7) | |
*
Predicted asymptote, terrestrial canopy.
†
Dashes indicate that richness estimates were not obtained because the nonlinear regressions failed to converge or because, relative to other regressions, residual sums of squares were inordinately large.