Table 3. Results of forward selection and Monte Carlo permutation tests from the redundancy analysis (RDA) of all 94 sampling sites.
| Variables | Lambda-1 | P | Lambda A | P |
|---|---|---|---|---|
| TN | 0.05 | 0.002** | 0.05 | 0.002** |
| Latitude | 0.03 | 0.008** | 0.02 | 0.010* |
| T | 0.03 | 0.026* | 0.03 | 0.020* |
| NO3-N | 0.02 | 0.176 | 0.02 | 0.152 |
| Distance | 0.01 | 0.556 | 0.01 | 0.370 |
| Crustacea | 0.01 | 0.888 | 0.00 | 0.500 |
| NH4-N | 0.03 | 0.034* | 0.01 | 0.624 |
| Longtitude | 0.02 | 0.120 | 0.01 | 0.818 |
| Protozoa | 0.00 | 0.802 | 0.00 | 0.706 |
| SD | 0.01 | 0.546 | 0.01 | 0.784 |
| TP | 0.03 | 0.010** | 0.00 | 0.992 |
| SRP | 0.03 | 0.018* | 0.01 | 0.610 |
| Altitude | 0.01 | 0.178 | 0.00 | 1.000 |
Environmental variables were listed by the order of their inclusion in the RDA model. Lambda-1 represents the independent effect of each environmental variable when the variable was treated separately. Lambda A represents the effect that each variable brings in addition to the all variables already selected and the most important variable included first. The P-value indicates the significance of each variable either when considered independently or dependently (*P < 0.05, **P < 0.01). TN = total nitrogen; T = water temperature; NO3-N = nitrate nitrogen; NH4-N = ammonia nitrogen; distance = average geographical distance of a given sampling site from the other sampling sites; Crustacea = total abundance of all crustacean species; Protozoa = total abundance of all protozoa species; SD = Secchi disk depth; TP = total phosphorus; SRP = soluble reactive phosphorus.