Restored and remnant Banksia woodlands elicit different foraging behavior in avian pollinators

Abstract

Pollinators and the pollination services they provide are critical for seed set and self‐sustainability of most flowering plants. Despite this, pollinators are rarely assessed in restored plant communities, where their services are largely assumed to re‐establish. Bird–pollinator richness, foraging, and interaction behavior were compared between natural and restored Banksia woodland sites in Western Australia to assess their re‐establishment in restored sites. These parameters were measured for natural communities of varying size and degree of fragmentation, and restored plant communities of high and low complexity for three years, in the summer and winter flowering of Banksia attenuata and B. menziesii, respectively. Bird visitor communities varied in composition, richness, foraging movement distances, and aggression among sites. Bird richness and abundance were lowest in fragmented remnants. Differences in the composition were associated with the size and degree of fragmentation in natural sites, but this did not differ between seasons. Restored sites and their adjacent natural sites had similar species composition, suggesting proximity supports pollinator re‐establishment. Pollinator foraging movements were influenced by the territorial behavior of different species. Using a network analysis approach, we found foraging behavior varied, with more frequent aggressive chases observed in restored sites, resulting in more movements out of the survey areas, than observed in natural sites. Aggressors were larger‐bodied Western Wattlebirds (Anthochaera chrysoptera) and New Holland Honeyeaters (Phylidonyris novaehollandiae) that dominated nectar resources, particularly in winter. Restored sites had re‐established pollination services, albeit with clear differences, as the degree of variability in the composition and behavior of bird pollinators for Banksias in the natural sites created a broad completion target against which restored sites were assessed. The abundance, diversity, and behavior of pollinator services to remnant and restored Banksia woodland sites were impacted by the size and degree of fragmentation, which in turn influenced bird–pollinator composition, and were further influenced by seasonal changes between summer and winter. Consideration of the spatial and temporal landscape context of restored sites, along with plant community diversity, is needed to ensure the maintenance of the effective movement of pollinators between natural remnant woodlands and restored sites.

Equivalent mating system parameters in post‐mining and undisturbed native plant populations confirms restitution of bird‐pollinator function

“…Proximity of restored populations to natural populations, hostility of intervening landscapes to pollinator movements, and the mobility of pollinators, will influence how critical pollinator limitation might be (Ritchie et al., 2019, 2021). In the current study, proximity to a large and relatively pristine nature reserve has apparently provided a source of pollinators for restored populations of L. multiflora , despite the disturbed mining landscape.…”

“…Parameters of plant populations such as size, density, shape and flowering intensity, presence and abundance of co-flowering species, and habitat fragmentation are also critical (Llorens et al, 2012;Ritchie et al, 2021). All of these ecological factors vary spatially and temporally.…”

“…For animal‐pollinated plants, pollinator limitation is a common cause of pollination failure (Larson & Barrett, 2000; Wilcock & Neiland, 2002). Barriers to successful restitution of pollinators in restoration sites include anthropogenic habitat fragmentation, spatial isolation of restored plant communities from undisturbed populations and their pollinators, unsuitability of restored habitats for attracting and keeping pollinators, and habitat heterogeneity effects on pollinator behaviour and foraging routes (Devoto et al., 2012; Menz et al., 2011; Ritchie et al., 2016, 2021; Winfree et al., 2011).…”

“…Extrinsic factors influencing the quality of pollen delivery include those relating to pollinators such as abundance, composition, mobility and foraging behaviour. Parameters of plant populations such as size, density, shape and flowering intensity, presence and abundance of co‐flowering species, and habitat fragmentation are also critical (Llorens et al., 2012; Ritchie et al., 2021). All of these ecological factors vary spatially and temporally.…”

Ten principles for restoring campo rupestre, a threatened tropical, megadiverse, nutrient‐impoverished montane grassland

“…Ecological interactions are key for supporting ecosystem multifunctionality and overcoming regeneration filters (Funk 2021). Restoring ecological interactions to achieve resilience is especially challenging in heterogeneous ecosystems with remarkable biodiversity (Menz et al 2011; Ritchie et al 2021). Similarly to the fynbos , campo rupestre is characterized by plant species with patchy populations, where small‐bodied pollinators access a range of species within a small area, have naturally small foraging ranges, and experience restricted dispersal, so that they remain in the relatively small, disjunct patches of suitable habitat.…”