Pollinator species play an important role in Nevada’s ecosystems and agriculture production. Populations of pollinator species have been in decline due to a variety of factors, but disease, parasites, pesticide exposure and habitat loss are some of the major causes. Roadsides and rights-of-ways have the potential to provide critical habitat for many pollinator species. These areas/sites/lands not only provide shelter and a variety of food sources, but can provide habitat links, also known as movement corridors. These corridors help decrease habitat fragmentation for pollinator species.
- Nevada is home to over 800 native bee species. Most of these species are solitary creatures that create nests underground. One advantage of native bees is that they are more likely to be actively pollinate flowers in cold and cloudy weather when non-native honey bees are seeking shelter in their hives.
- A variety of other insects are also pollinators such as moths and butterflies. For example, monarch butterflies overwinter in California then return to Nevada to complete their lifecycle and breed on native milkweeds such as the showy or narrowleaf milkweed, but they also depend on various nectar species for food and help pollinate a wide variety of native plant species, not just milkweed.
Native plants vs. Noxious weed species
- Species like dandelions, or clover may be considered weedy to some landowners but can benefit pollinators as sources for food. It is important that weed control meets management objectives. Removal of all weedy species in an area may negatively impact pollinators by removing a potential food source. Additionally, plants that many consider weeds are in fact native species in their natural habitat.
- Native plants provide a food source for pollinators in the form of pollen and nectar. Some pollinators are considered specialist and require certain plant species to feed and complete their lifecycle. Ecosystems with native plants tend to have greater biodiversity. This helps ensure that pollinators have access to different food sources throughout the year. Native species are also well adapted to the Nevada climate and can withstand drought and excess heat.
- Noxious weed species can quickly invade disturbed sites and roadsides to displace native plant species. Plants like perennial pepperweed form dense infestations have a significant impact to plant diversity which limits the variety of food sources pollinators require throughout the growing season. Landowners are required to control noxious species when the occur on their property per 555.150. The list of Nevada’s noxious species can be found on the Nevada department of agriculture’s website.
- Proper plant identification is important to determine which plants are beneficial and which should be removed. For example, thistles can be an important food source for many pollinators. Native thistles are often desired in a landscape setting, but invasive thistles and species listed as noxious can quickly invade and crowd out native plant species. The Nevada Department of Agriculture’s noxious weed program can help identify invasive and noxious species.
Pollinator plant selection
- Native plants are preferred over other species, as these plants have adapted with native pollinators to survive in Nevada’s unique climate. Species diversity is important to provide pollinators with a variety of flower shapes and sizes. Bloom periods should overlap throughout the growing season to provide a constant food source. Early and late blooming species may provide a critical food source when nothing else is available.
- Consult your local cooperative extension or master gardener’s program to learn more about native wildflowers in your area. The Nevada native plant society and pollinator partnership also have good information on plant species beneficial to pollinators.
Mowing practices to reduce harm to pollinator species
- Reducing the frequency of mowing can increase the amount of flowering plants available to pollinators throughout the growing season. A single mowing activity in late fall can reduce negative impacts mowing might have on pollinator species.
- Timing should be considered when developing a mowing plan. Early spring mowing may increase the number of wildflowers present at a site. When possible avoid mowing when plants are blooming.
- Adjust mowing practices if providing pollinator habitat is a management goal. Avoid mowing areas unless it meets a specific management objective. When possible avoid mowing an entire site at one time, dividing an area into portions, and mowing at different times can help ensure pollinators have access to a food source. Increasing height of mowing to 10 in. or greater will allow plants to recover quickly. It may be beneficial to spot mow areas where control is needed and avoid areas with beneficial plant species. Using a flush bar and reducing speed to 8 mph can allow pollinators time to escape.
- Mow the areas with the least amount of weeds first this will help reduce the risk of spreading those species. Always clean equipment before moving to another site.
Herbicide application practices to reduce exposure to pollinator species
- Reduce exposure of pollinators to herbicide applications by limiting use near pollinator habitat. Treating invasive and noxious species before a plant flowers is effective for controlling annual species and will help reduce the risk that pollinators will be exposed to herbicides. When possible make herbicide applications in the early morning or after dusk when pollinators are less active.
- Selective herbicide applications help target weeds and avoid impacts on desirable plant species. Spot applications are preferred over broadcast applications but if broadcast applications are needed consider the timing of those applications. It may be possible to schedule applications when weeds are emerging, and desirable species are dormant.
Avoid conditions where herbicides may drift to non-target plant species. Conditions that help prevent drift are when wind speeds are within 3-10 mph, and temperatures are under 80° F. Be sure to use appropriate pressure and nozzles for the application. Always follow pesticide label requirements.
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