Assessing the health of a river ecosystem is often monitored by assessing stream invertebrate populations (PDF) and emporal comparisons of invertebrate assemblages reveal positive or negative trends to shape water management policy (Barbour et al 1999).
Table 12 (JPEG) lists the orders that are least tolerant to pollution. The current total number of taxa is 105, which is double the number of taxa found in local reference stream data from Bayer et al (1992).
Figure 27 (JPEG) shows the relative abundance of macroinvertibrates collected in three sections of the Blanco River. This indicates substantial levels of invertebrate biodiversity. High levels of invertebrate biodiversity are usually associated with high habitat heterogeneity (Vinson and Hawkins 1998). Habitats impacted by increased urbanization often exhibit invertebrate homogenization (Ebersole 1997, Paul and Meyer 2001).
The Blanco River’s highly diverse invertebrate composition is likely due to minimal impacts from recent and current land use changes and development.
Future management activities critical to maintaining this biodiversity and resulting ecosystem functioning must include land use management strategies that minimize instream water quality degradation.