Comparative Analysis Of Pollinator Communities of Arenga Pinnata Under Different Vegetation Systems In South Tapanuli of Sumatera, Indonesia

Abstract

Pollinator communities play a crucial role in the reproductive success of the sugar palm (Arecaceae), an economically important species in tropical agroecosystems. This study examined how different vegetation systems influence pollinator diversity, composition, and daily activity patterns of sugar palm in South Tapanuli, North Sumatra, Indonesia. Field observations were conducted across three vegetation types: secondary forest, open land, and sugar palm monoculture, using six independent sites per vegetation type. Pollinator diversity was quantified using the Shannon–Wiener diversity index (H′), Simpson dominance index (D), and Pielou evenness index (E), while vegetation structure was characterized by plant species diversity, canopy cover, and distance from secondary forest. Differences among vegetation types were tested using one-way ANOVA followed by Tukey’s HSD, and relationships between pollinator diversity and vegetation variables were examined using multiple linear regression. Pollinator diversity was highest in secondary forest (H′ = 3.14; E = 0.82) and lowest in monoculture systems (H′ = 2.40; E = 0.65), which were characterized by higher dominance values (D = 0.29). Regression analyses revealed that higher vegetation diversity and denser canopy cover positively influenced H′ and E, whereas greater distance from secondary forest reduced pollinator diversity. Daily activity patterns exhibited a bimodal distribution, with peak visitation in the morning and late afternoon across all vegetation types. These findings demonstrate that vegetation complexity strongly shapes pollinator community structure and activity, highlighting the importance of maintaining structurally diverse habitats to support pollination services in sugar palm landscapes.