The effect of roadside mowing and road traffic on bumble bee abundance and pollinating insect habitat quality in New York highway rights-of-way.

Many insect pollinators, including native pollinators such as bumble bees (Bombus spp.), are facing population declines globally due to loss of natural habitats and other anthropogenic factors. The mandated grassy areas alongside roads, known as roadside rights-of-way (ROWs), are potential habitats for insect pollinators. Yet, roadsides ROWs are highly susceptible to disturbances including on-road traffic and roadside management practices, such as mowing, that may impede their performance as suitable habitat. My research objective was thus to examine if and how road traffic levels and roadside mowing interact to influence pollinating insect habitat quality and bumblebee abundance in highway roadside ROWs across New York State. I tested this using a variety of field survey methods in 2019 and 2020, along 30 highways (n=177 sampling locations) with Control Mowing- Low Traffic (n=33 sampling locations), Control Mowing - Medium Traffic (n=29), Control Mowing - High Traffic (n=27), Modified Mowing - Low Traffic (n=28), Modified Mowing - Medium Traffic (n=35), and Modified Mowing - High Traffic (n=25) treatments. Using generalized linear mixed models, I found no significant difference in habitat quality for pollinating insects between treatments. I was unable to quantitatively assess the treatment effect on bumble bee abundance, due to the extremely limited number of bumble bees observed (98% of n=916 observations across two methods and two years found 0 Bombus spp.). Further research is needed to know if and how roadside ROWs can support insect pollinators, including bumble bees