The VBHA do not represent a short-term response to habitat degradation, it represents the long-term visual degradation process, such as was proposed by Allan (2004).
However, the excellent water quality (indicated by FBI) and the suboptimal habitat quality (VBHA), despite local organic contamination from tourism activities and mismanagement of wastewater, are evidence that the watershed area degradation is moderate, where the anthropic changes have not been enough to decrease their function and resilience, habitat structure and essential environmental services to people.
In another hand, the weak and no significant association between the IIBAMA, water temperature, and the VBHA indicates that in the headwaters of the two studied basins the water temperature, the habitat structure and stability by themselves, do not represent a determinant variable for biotic integrity.
However, we suggest using IIBAMA together with indexes to estimate the habitat and water quality, such as VBHA and FBI to assess the environmental quality of streams and rivers accurately, even in other regions with similar conditions.
The letters represent the environmental variable of correlation: a) Family biotic index (FBI), b) Visual based habitat assessment (VBHA), c) pH, d) Total dissolved solids (TDS), e) Dissolved oxygen (DO), f) Temperature.
FBI: Family biotic index, VBHA: Visual based habitat assessment, TDS: Total dissolved solids (ppm), DO: Dissolved oxygen (mg [L.sup.-1]); Temp: Temperature ([degrees]C), ES: El Salto, PC: Presa del Carmen, PR: Presa de Rayas, Com: Comonfort, LQ: La Quemada, LG: Los Galvanes, Xo: El Xote, RG: Rio Grande, Cal: Calvillo, SS: El salto de los salados, FS: Fraccion Sanchez, PH: La planta-La Hacienda, PP: Puente la Plazuela, Pin: Pinihuan, Can: Canoas, QM: Quinta Matilde, ER: El Realito, Qui: Quiotillos, EO: El Oasis, Chu: Chuveje, Car: Carpintero, Ras: Rascon, Tam: Tamasopo, Jal: Jalpan, Ayu: Ayutla, SM: Santa Maria, EC: El Carrizal, Tan: Tancuilin, SMT: Santa Maria (Tancoyol), RM: Rio Moctezuma, Con: Conca, Ex: Extoraz, RB: Rio Blanco.