Figure 1
A native-planted hedgerow in Yolo County, California. Photograph courtesy H.M.White.
Source publication
Background/Question/Methods
Hedgerows provide valuable ecosystem services including air and water quality protection, soil erosion control, promotion of pollinators and other beneficial insects, and biodiversity. Planting hedgerows at field margins is an increasingly common conservation measure in heavily transformed agricultural regions of Calif...
Context in source publication
Context 1
... selected four hedgerow sites in Yolo County that were similar in age and structure and that were already being used in UC Cooperative Extension research (Fig. 1). Nearby unenhanced field margins served as control sites, and both hedgerow and control sites were standardized by adjacent crop type. Six 20-min avian search censuses were conducted at 2-week intervals along 0.25-mi stretches of hedgerow and control habitat in both winter (Nov. 2011-Jan 2012) and breeding (Apr-June 2012) seasons. ...
Citations
... Despite the goal of providing habitat for birds, research on woody field margin habitats in California has focused on evaluating their benefits for pollinators and other agriculturally-beneficial insects (Morandin et al., 2014;Morandin and Kremen, 2013). Studies detailing the effects of hedgerows and other field margin habitats on birds in California have been preliminary (White et al., 2013), or have focused on single crop-types or seasons (Jedlicka et al., 2014;Kross et al., 2016). To inform and improve state and national policies and incentive programs, we evaluated the effects of different field margin habitat features on both breeding and winter season avian community structure in the context of several local and landscape scale habitat characteristics. ...
Considerable funding has been allocated to conservation management of non-crop habitat in agricultural landscapes, particularly field margin habitat such as hedgerows. Evaluation of the biodiversity benefits of non-crop habitat has lagged behind implementation, however, especially in the United States where this habitat has the potential to supply important resources for both common and rare species of birds. We examined the effects of woody field margin vegetation on winter and breeding season avian communities at 103 fields, row crops, and orchards in California's Central Valley, one of the most intensively-farmed landscapes on Earth. We found that margins with hedgerows, treelines or remnant riparian habitat harbored 2–3 times as many bird species, significantly greater species evenness, and 3–6 times higher maximum total abundances of birds than bare or weedy margins. The effect of margin type on richness was modulated by water year, whereas the effect of margin type on maximum total abundance was modulated by adjacent crop type. At the landscape scale, hedgerow and riparian margins that were further from woodland harbored greater species richness; a result that supports our recommendation for targeted development of hedgerows in simplified agricultural landscapes. These results demonstrate that non-crop woody habitats, both planted and remnant native patches, increase the biodiversity value of farms, providing support for policies to preserve remaining habitat and incentivize installation of woody hedgerows.
