Macroinvertebrate Community Composition in Three Low-Order Neotropical Cloud Forest Streams in Mindo, Ecuador

PURPOSE: Tropical cloud forest streams are highly threatened ecosystems. A gap in knowledge exists on how these ecosystems function, information that is crucial for effective conservation. In this study, macroinvertebrate community composition, functional feeding group (FFG) analysis, ecosystem attributes and physicochemical parameters were used to evaluate biophysical stream conditions of three low-order neotropical cloud forest streams in Mindo, Ecuador. SUBJECTS: Macroinvertebrate communities of three low-order neotropical streams were sampled, identified, and categorized into FFG. METHODS AND MATERIALS: Three modified Surber net samples were taken at each site to collect macroinvertebrates. A YSI probe was used to measure physicochemical parameters. ANALYSES: One-Way ANOVA or Kruskal-Wallis (post-hoc = TukeyHSD) were used to measure differences in FFG densities among streams. A canonical correspondence analysis was used to determine which environmental variables drive the differences. RESULTS: As stream size increased from 1st to 3rd order, the macroinvertebrate communities shift from being collector-gatherer dominated (65.2 to 29.8%, respectively) to being scraper dominated (17.9 to 56.3%, respectively). Shredders are poorly represented in all streams (2.7, 3.3, and 2.0% for 1st, 2nd, and 3rd order stream, respectively) similar to reports from other tropical systems. Variables driving differences among site include substrate, width, and dissolved oxygen (mg/L). CONCLUSIONS: Temperate-based analyses and conservation approaches may not be suitable for tropical streams. Until tropical-based theories are established, however, temperate conservation efforts should be implemented. Results from this study provide base-line physical, chemical, and biological data on these streams that can be effectively used to track environmental changes in land-us