Assessing changes in stream macroinvertebrate communities across ecological gradients using morphological versus DNA...

Area of Science:

• Ecology
• Environmental Science
• Molecular Biology

Background:

• Freshwater macroinvertebrates are key bioindicators for assessing ecosystem health.
• Traditional morphotaxonomy is widely used but can be labor-intensive.
• DNA metabarcoding offers a potentially more efficient alternative for biomonitoring.

Purpose of the Study:

• To compare the effectiveness of DNA metabarcoding and morphotaxonomy in biomonitoring.
• To test if both methods detect similar ecological gradients and drivers of community change.
• To assess the potential for intercalibration between metabarcoding and morphotaxonomy.

Main Methods:

• Compared morphotaxonomic identification (family level) with DNA metabarcoding (single/multiple markers).
• Analyzed macroinvertebrates from 80 streams in Portugal under a biomonitoring program.
• Assessed community sensitivity to disturbance using the IASPT index and correlated spatial variations.

Main Results:

• Metabarcoding identified fewer families but showed comparable community sensitivities to disturbance (IASPT index).
• Spatial patterns in community metrics and influencing factors were significantly correlated between methods.
• A consistent dominant gradient of community change was detected, with similar anthropogenic stressors identified by both approaches.

Conclusions:

• Morphotaxonomy and DNA metabarcoding can yield consistent spatial patterns of community variation and drivers.
• Results support the hypothesis that both methods can detect similar ecological gradients.
• DNA metabarcoding is a promising tool for freshwater biomonitoring, with potential for intercalibration with traditional methods.