Comparing the effectiveness of pitfall traps and active sampling methods for ants and spiders in a Chromolaena odorata invaded site

Abstract

Background: Active and passive arthropod sampling techniques have their specific limitations. Pitfall trapping is a commonly used passive sampling method, and bush beating, aerial hand collection above the knee, aerial hand collection below the knee cryptic and non-cryptic are widely used active sampling techniques. Objective and method: Pitfall traps and four active sampling techniques were used in a Chromolaena odorata invaded site to compare the methods used in sampling arthropods in Buffelsdraai Conservancy outside the city of Durban, South Africa. Results: Pitfall traps were the most efficient and the most effective sampling technique with high species richness for both the ant (78%) and spider (76%) samples. One explanation for these differences could be the longer sampling time for passive sampling compared to active sampling. Conclusion: Compared to the subjective identification of species by collectors in active techniques, the non-selective capturing of species by pitfall traps improves its efficiency. The fewest taxa and individuals were collected by aerial hand collection techniques but these techniques are recommended to supplement pitfall traps. The combination of methods allows for the adequate sampling of the various strata found in vegetatively complex sites. An investigation into the possible use of canopy techniques in C. odorata sites would be beneficial, as it considers the various vegetation strata when sampling for biodiversity.