Urbanization affects plant flowering phenology and pollinator community: effects of water availability and land cover

Kaesha Neil,Christofer Bang,Jianguo Wu,Stanley Faeth

doi:10.1186/s13717-014-0017-6

Kaesha Neil, Christofer Bang + Show 2 more

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https://doi.org/10.1186/s13717-014-0017-6

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Abstract

Abstract Introduction Climate change and urbanization have been shown to alter plant phenology. However, a mechanistic understanding of these changes in flowering phenology and associated pollinator communities is lacking. Thus, this study was designed to examine finer scale flowering phenological patterns and driving processes in an arid urban ecosystem. Specifically, we tested the effect of water availability and land cover type on the flowering phenology of brittlebush (Encelia farinosa) and investigated the arthropod pollinator community associated with brittlebush. Methods The fieldwork was carried out as part of a larger community ecology experiment following a factorial nested design. We chose three land cover types, each of which had three replicates, resulting in a total of nine sites. For water availability manipulations, 60 genetically different 5-gallon potted plants were placed on the ground within each site. Pan-trapping was used to collect potential pollinators. Results Our results showed that water availability did not produce significant differences in flowering phenology. However, brittlebush planted in mesiscaped urban sites bloomed later, longer, and at a higher percentage than those planted in desert remnant sites and desert fringe sites. Furthermore, desert remnant sites were significantly lower in pollinator abundance than desert fringe sites. Pollinator richness varied over time in all land cover types. Conclusions This study provides empirical evidence that land cover type, which is strongly correlated to temperature, is the primary cause for altered flowering phenology of brittlebush in the Phoenix area, although water availability may also be important. Moreover, land cover affects total abundance of bee pollinators.

Highlights

Climate change and urbanization have been shown to alter plant phenology
Our results showed that water availability did not produce significant differences in flowering phenology
Pollinator richness varied over time in all land cover types

Summary

Introduction

Climate change and urbanization have been shown to alter plant phenology. a mechanistic understanding of these changes in flowering phenology and associated pollinator communities is lacking. Phenological changes (the timing of environment-influenced developmental events) associated with urbanization and global climate change have been observed worldwide for bird migration, amphibian reproduction, plant leafing and flowering, and arthropod appearance and development (Buyantuyev and Wu 2009; Grimm et al 2008; Neil et al 2010; Neil and Wu 2006; Walther et al 2002). Earlier and, to a lesser extent, later blooming of plants over time and within urban areas compared to Abundance and richness of bees have been studied extensively across the world (Cane et al 2006; Eremeeva and Sushchev 2005; Matteson et al 2008; McFrederick and LeBuhn 2006; McIntyre and Hostetler 2001; Pauw 2007; Tommasi et al 2004) to understand the effects of global climate change and urbanization on pollinators. Models (Memmott et al 2007) and studies of synchronized phenology (Gordo and Sanz 2005; Parmesan 2006; Walther et al 2002) have found a general trend towards less synchrony between historically interdependent species

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