Evaluation of Natural Enemy Abundance Based on Riparian Vegetation at Rice Field in Slamet Village, East Java, Indonesia

Abstract

Riparian vegetation habitats in irrigation canals provide various ecosystem regulatory services for human life, one of them was providing natural enemies for agricultural pests. This study aims to analyze the abundance of natural enemies at the paddy field, then to figure out the interaction between the riparian vegetation and natural enemies based on four different locations of tertiary irrigation canals at Slamet Village. Arthropods were observed by visual control and yellow pan trap methods. Whereas, riparian vegetation sampling points were determined by purposive sampling. The measured riparian vegetation and natural enemies were described by the important value index (INP), abundance, Shannon-Wiener diversity index (H'), evenness (E), dominance index (Id), and taxa richness (TR). The interaction between the riparian vegetation and natural enemies was analyzed by the PAST 3.20 program. The results showed that the first location of irrigation canals had the highest Shannon-Wiener Index value, taxa richness, evenness, and the lowest dominance value of riparian vegetation with respectively 4.97; 37 species; 0.93; and 0.02. Moreover, it was following with the highest value of natural enemies taxa richness (16 species), total abundance (4450 individuals), H' index (2.37), evenness (0.59), and low dominance index (0.27). Arthropods that act as natural enemies that were commonly found in this location came from the Formicidae, Coenagrionidae, and Coccinelidae families, while the most common pests found are from the Acrididae families. The opposite of that, the fourth location had the highest value of dominance index of riparian vegetation and pest arthropods (0.15; 0.84), H’ index of pest (2.31), taxa richness of pest (0.77), and the total abundance of pest arthropod (942 individuals). Pests that inhabit this location came from the Acrididae, Drosophilidae, Tephritidae, and Aphididae families