Macroinvertebrate/environmental data and R script: Using taxa accumulation curves to evaluate macroinvertebrate sampling effectiveness of two handnet and a driftnet methods across water body types

These data files here contain the enviromental variables, fielddata, and the macroinvertebrate data for the standard, subsampling and driftnet method used in the paper. Also attached here is a script for calculating average models for taxa accumulation curves based onWeibull, Logarithmic, Negative Exponential, Asymptotic, and Monod models. We used the ‘vegan’ package (v2.6-8; Oksanen et al. 2024) under R Studio version 4.4.2 (R Core Team 2023).

Abstract:
Aquatic macroinvertebrates are key indicators of freshwater ecosystem health, yet effectively sampling their diversity remains challenging due to habitat heterogeneity and method limitations. This study evaluated three sampling approaches - standard handnet sampling, habitat-based subsampling, and driftnet collection - across various waterbody types. Using taxa accumulation curves (TACs), we compared the effectiveness of each method in capturing macroinvertebrate richness and examined whether richness estimates varied by waterbody.
Habitat-based subsampling consistently captured the highest richness (70–90% of estimated total), followed by standard handnet sampling (50–70%) and driftnets (60–70%), although driftnets showed greater variability due to lower organism counts. TACs proved useful for assessing sampling efficiency and richness capture across methods.
While less comprehensive, driftnets provided complementary data by detecting drifting taxa missed by handnet methods and offering insights into diel activity and potential recolonization processes. A combined sampling strategy therefore offers the most complete biodiversity assessment.
If standard methods are used alone, a preliminary habitat assessment is advised to ensure representative sampling. Subsampling strategies that distribute effort across multiple smaller samples were found effective in heterogeneous, but also visually homogeneous waterbodies. Relying on single large samples may misrepresent biodiversity, underscoring the need for tailored approaches to support water management and conservation.