Asynchrony among insect pollinator groups and flowering plants with elevation

Abstract

Mountains influence species distribution through differing climate variables associated with increasing elevation. These factors determine species niche ranges and phenology. Although the distribution patterns of some specific insect groups relative to elevation have been determined, how differing environmental conditions across elevation zones differentially influence the phenology of various insect groups is largely unknown. This is important in this era of rapid climate change. We assess here how species composition and seasonal peaks in abundance among different insect pollinator groups and flowering plants differ across four floristically distinct elevation zones up a sentinel mountain subject to strong weather events. We sampled insect pollinators in four major groups (bees, wasps, beetles and flies) over two spring seasons. Pollinator species composition across all elevation zones tracks flowering plant species composition. In terms of abundance, beetles were the dominant group across the three lower zones, but declined greatly in the summit zone, where flies and bees were more abundant. Bee abundance peaked earlier than the other groups across all four elevation zones, where there were significant peaks in abundance. Bee abundance peaked earlier than flowering plants at the middle zone and slightly later than flowering plants at the base zone, suggesting a mismatch. We conclude that, while elevation shapes species distribution, it also differentially influences species phenology. This may be of great significance in long-term assessment of species distribution in sensitive mountain ecosystems.

Changes in the structure and composition of the ‘Mexical’ scrubland bee community along an elevational gradient

“…Regarding community composition, we found significant and consistent differences along our elevation gradient, as we expected, in agreement with previous works [45,46,48,49]. Community composition changes along elevation are mainly due to temperature and flower density, and to some extent, also to geographic distance.…”

“…Based on previous studies [35][36][37][38][39][40][41][42][43][44][45][46][47], one would expect bee abundance and richness to decrease along the altitudinal gradient. We also expect changes in community composition along our elevational gradient [45,46,48,49]. Regarding the drivers behind these patterns, we expect that decreasing trends of bee richness and abundance would be associated to decreasing temperatures along the elevational gradient [42,44,47,50].…”

Plant phylogeny as a major predictor of flower visitation by nitidulid beetles, a lineage of ancestral angiosperm pollinators

“…Relationships between the frequency of beetle visitation to flowers and ecological (habitat type, altitude; Adedoja et al 2018Adedoja et al , 2020Herrera 2020) and floral features (size, color; Johnson & Midgley 2001;Teixido et al 2011;Streinzer et al 2019) have been often reported. In the present study, however, none of the environmental (habitat type, elevation) or macroscopic floral features (perianth type and color, flower mass) considered predicted nitidulid visitation rates when plant phylogeny was statistically taken into account.…”

Age class of alien tree stands retained for mammal protection have differential effects on flower‐visiting insect assemblages

“…Most of the plants flower in spring season, with the exception of some Proteaceae species that flower in winter. Plant–pollinator interactions in this biome are highly specialised (Pauw & Stanwey, 2015); however, biodiversity in this region is highly threatened by climate change (Altwegg et al ., 2014; Adedoja et al ., 2020), land use change (Rouget et al ., 2014; Topp & Loos, 2019), and biological invasion (Geerts & Pauw, 2009; Mangachena & Geerts, 2017), among other drivers of global change. Invasive alien trees are highly successful in the CFR and are among the greatest significant threat to biodiversity and water distribution in this region (Le Maitre et al ., 2000; Gaertner et al ., 2012).…”