Pollinating animals in the urban environment

Abstract

Urban environments contain habitats for flowering plants and their pollinating animal species. It is, however, unclear how the urban matrix influences plant-pollinator processes. We recorded plant diversity, floral abundance, flower visitor diversity and plot visits at 89 plant patches within the city of Zürich. The urban matrix surrounding each site was analyzed for the landscape metrics edge density and the extent of green area up to 200 m radius. The correlation between edge density and bee diversity and visitation frequency varied over the entire spatial range, while the correlation for syrphid diversity and visitation frequency levelled off at 80 m radius. In contrast, the correlations with green area were more consistent, with bee diversity levelling off after 100 m, while syrphid diversity and visits continued to increase. The variation in the correlation of bee visits was partly accounted for by the large contribution of honeybees. Plant diversity significantly affected bee diversity and visits, and syrphid visits. Floral abundance had a positive effect on bee visits and bee diversity. Syrphid diversity had a negative interaction with floral abundance and green area. The extent of green area increased bee diversity and visits, and syrphid visits, while edge density reduced visitation by bees. This study showed that plant diversity and floral abundance in urban environments promote pollinating flower visitors. The extent of green area and edge density are important urban mosaic attributes that affect pollinator abundance and visitation frequency at multiple scales.

Flower-visitor and pollen transport networks in a large city: structure and properties

“…ER/CE are zero models used for generation of random matrices for comparisons with actual results (see Materials and methods), where p stands for the probability that the modelgenerated matrix is equally or more nested than is the actual one. Boldface indicates statistically significant results when both zero models were significantly less nested at p \ 0.05 important insect pollinator groups, e.g., bees (Bates et al 2011;Hennig and Ghazoul 2012;Tonietto et al 2011), hoverflies (Bates et al 2011), sarcophagid flies (Mulieri et al 2011) or butterflies (Dallimer et al 2012;Soga and Koike 2013), all recorded also in our study. Their response, however, may be highly variable and depend on many factors.…”

“…Their response, however, may be highly variable and depend on many factors. For instance, the abundance of bee species in urban conditions is positively correlated with floral abundance and diversity (Wojcik 2011), as well as resource distribution (e.g., nesting or egg-laying sites; Hennig and Ghazoul 2012). As shown by the latter authors, diversity and visitation by syrphids in urban conditions can also be related to the presence of a green area.…”

Buzzing on top: Linking wild bee diversity, abundance and traits with green roof qualities

“…The availability of pollen and nectar as well as nesting sites within speciesspecific flying distances is important for wild bees to colonize habitats successfully (Westrich 1996;Gathmann and Tscharntke 2002;Zurbuchen et al 2010;Wojcik and McBride 2012). Bees are ectothermic and thermophile organisms, thus the warmer (micro-) climate of cities enables favourable habitat conditions for many wild bee species (Cane 2005;Hennig and Ghazoul 2012). Research on urban sites likely to be populated by wild bees, provides important information for urban planning to enhance wild bee diversity ).…”

Diversity and abundance of solitary and primitively eusocial bees in an urban centre: a case study from Northampton (England)

“…In a review, Hernandez et al (2009) found only 59 research publications worldwide on urban bee ecology and concluded that we are only beginning to document urban bee communities and their dynamics. The interest in urban bee ecology has surged in recent years (Everaars et al 2011;Winfree et al 2011;Hennig and Ghazoul 2012;Banaszak-Cibicka and Zmihorski 2012;Hinners et al 2012;Matteson et al 2013;Verboven et al 2014;Lowenstein et al 2014;Baldock et al 2015). However urbanisation is predicted to increase dramatically, with the number of people living in urban areas reaching 5 billion by 2030 (UN 2011).…”