Habitat and landscape factors influence pollinators in a tropical megacity, Bangkok, Thailand

Abstract

BackgroundPollinators are well known for the ecosystem services they provide, and while urban areas are generally perceived as low-quality habitat for most wildlife, these cities often support a surprising degree of pollinator diversity. The current rapid growth of urban areas and concern over global pollinator declines have spurred numerous studies examining pollinator communities in temperate cities, but knowledge about tropical urban pollinators remains scarce.MethodsThis study investigated the effects of habitat and landscape factors on pollinator richness and abundance in a highly-populated, tropical city: Bangkok, Thailand. We conducted pollinator observations in 52 green areas throughout the city and collected data on patch size, floral abundance, plant richness, location type, and percent vegetation at five spatial scales.ResultsOf the 18,793 pollinators observed, over 98% were bees. Both patch size and floral abundance generally had positive effects on pollinators, although there was a significant interaction between the two factors; these findings were generally consistent across all focal taxa (Tetragonula stingless bees, Apis honey bees, Xylocopa carpenter bees, and butterflies).DiscussionOur results demonstrate the importance of maintaining large green areas in cities, since small green areas supported few pollinators, even when floral resources were abundant. Moreover, most pollinator taxa utilized a variety of location types (e.g., public parks, school campuses, temple grounds), with the exception of butterflies, which preferred parks. Our findings are generally consistent with those of temperate urban studies, but additional studies in the tropics are needed before global patterns can be assessed.

Conservation in post‐industrial cities: How does vacant land management and landscape configuration influence urban bees?

“…For instance, in the shrinking city of Poznań, Poland, greater bee richness occurred with increased proximity to a large patch of greenspace with direct connection to suburban land cover (Banaszak‐Cibicka et al., 2016). Likewise, larger patch sizes were associated with increased bee richness and abundances in the growing city of Bangkok, Thailand (Stewart et al., 2018). In part, patch sizes are likely influential because they affect nesting site availability (Stewart et al., 2018).…”

“…Likewise, larger patch sizes were associated with increased bee richness and abundances in the growing city of Bangkok, Thailand (Stewart et al., 2018). In part, patch sizes are likely influential because they affect nesting site availability (Stewart et al., 2018). Indeed, simultaneous work in Cleveland documented that native bees and wasps exhibit increased reproduction when a larger patch of greenspace was available within the urban landscape (KJ Turo, unpublished data), suggesting that habitat area may be a limiting factor for some urban bees.…”

Supporting Bees in Cities: How Bees Are Influenced by Local and Landscape Features

“…This correlation obviously largely depends on increasing the species of plants attractive to bees and lepidopterans rather than just generally increasing plant richness [ 83 ]. Floral abundance and frequency, however, may be more impactful than promoting richness itself [ 84 , 85 ]. Other factors including increased floral area (area occupied by blooming plants) have also been shown to influence butterfly and bee abundance [ 45 , 86 ].…”

Bacterial Communities in Three Parts of Intestinal Tracts of Carpenter Bees (Xylocopa tenuiscapa)

“…Hongjamrassilp et al (2014) analyzed the pollen composition on the body of X. nasalis in Ratcha Buri province, Thailand, and found that the pollens were mostly native to the region of Southeast Asia, suggesting that X. nasalis is highly valuable for crop pollination [ 3 ]. Furthermore, stingless bees, Apis honey bees and Xylocopa carpenter bees are major pollinators in highly populated, tropical cities such as Bangkok [ 4 ].…”