Best Practices for Pollinators: Conserving Biodiversity in Open Spaces: by Dr. Vera Krischik, University of Minnesota, for Pollinator Conservation Biocontrol, LCCMR
In a world where habitats are being replaced by urban sprawl and commercial agriculture, creating habitat corridors for pollinators is increasingly more important to their survival. It's been calculated that two million acres of land in the U.S. are swallowed by urban sprawl each year. Urban and suburban communities often have open underutilized spaces that can be transformed into vital pollinator habitat. It's critical that land managers adopt pollinator-friendly practices to help protect native bees, butterflies, wasps, beetles and other pollinators.
- Community gardens
- Public lands such as abandoned lots, unmanaged land, or turf
- Public Utility Right of Ways (vegetation underneath power lines and on top of buried power lines and pipes)
- Roadsides, round-abouts and highway rest stops
- Strips of land in between lots or buildings
Thoughtful, well-planned best practices can create healthy environments for pollinators to live in and also help reduce maintenance needs, reduce erosion, improve water quality, provide water filtration, increase property values and offer ecological benefits to the surrounding landscapes. People want to live in communities with wildlife, clean water and land. Pollinator-friendly landscapes also give people a sense of community pride.
Rusty patch bumble bee on bergamot, endangered species (Heather Holm, 2017)
Pollinators are a "keystone" species for a healthy ecosystem. Over 200,000 plant species worldwide depend on pollination in forests, meadows, gardens, natural areas and agriculture.
The main threats facing pollinators include:
- Habitat loss: As native vegetation is replaced by roadways, manicured lawns, cropland, and infrastructure development. Pollinators are losing food and nesting areas critical for survival.
- Pesticides include insecticides, herbicides and fungicides.
- Degradation and fragmentation: When conditions decline due to factors such as pollution, invasive species and over-utilization of natural resources such as streams degraded by runoff of sediments and chemicals from cropland, or when large blocks of habitat are cut into small pieces by roads and housing too small to sustain a species.
- Climate change: Plant and animal species are out of sync. For example, flowering plants may occur farther north or at higher elevations as a response to warming temperatures and may become out of range for their pollinators.
- Restore or enhance existing habitat
- Replace areas of mown grasses/turf with prairies, meadows and gardens
- Adapt best practices for pollinators
- Use interpretative signage to raise awareness
- Create sheltered nesting and overwintering areas
- Reduce pesticides and therefore impacts on pollinators
A naturally diverse landscape discourages outbreaks of disease or insects. Such a landscape that also attracts beneficial insects that prey on unwanted pests like lacewings and lady beetles. Healthy soil supports plant health and resistance to disease.
Restore native vegetation
Consider using native vegetation in landscapes. When buying flowers, the more a plant is genetically manipulated, the less attractive it becomes to wildlife. The plant's natural evolutionary traits provide cues that entice pollinators to visit. For example, the native Echinacea purpurea has been cultivated into a floral frankenstein called "butterfly kisses". This cultivar's flower does not attract pollinators and the seedhead has virtually vanished.
Promote nutrient recycling through composting and soil health
Backyard and community composting is an ecologically sound way of disposing of yard wastes and is used to increase soil nutrients. Beetle banks, wood chip, dead wood and leaf piles or "untidy" areas only contribute to soil health, but also provide nesting areas for pollinators and beneficial insects.
Use integrated pest management (IPM) to control insects and diseases
- When choosing plants, pick naturally resistant plants.
- Inspect and monitor your plants' health on a regular basis, before problems are out of control.
- Instead of routinely spraying for insects, spot treat problems with soft pesticides such as insecticidal soaps, oils, and biorational products such as spinosad.
- Adopt biorational practices that use naturally occurring biological control agents, such as parasitoids and predatory insects.
Integrated Pest Management (IPM) is an approach to solving pest problems by applying knowledge about pests and plants to prevent plant damage early before it becomes a problem. IPM promotes multiple tactics to manage pests and suppress population size below threstholds that cause unacceptable levels of damage to plants or crops. IPM means responding to pest problems with the most effective and least-risk and least-toxic option. IPM is a science-based, decision-making process that includes monitoring and long range planning. By correcting conditions that lead to pest problems and using approved pesticides only when necessary, IPM provides more effective control while reducing pesticide use. The conservation of beneficial insects, that includes bees, insect predators, parasitic wasps, and butterflies, is an essential part of IPM.
It's important for land managers and gardeners to learn how to implement an IPM plan. Any individual or organization can adopt an IPM from backyards to public parks. IPM plans should be updated annually, and staff need to be trained on pesticide use and pollinator best practices.
Sticky trap at Carpenter Nature Center to monitor, identify and record insects present.
Inspection and monitoring: Regular and close examination of plants and landscaping to diagnose pest problems and their sources. Monitoring devices include traps, observation and record keeping.
Forecasting: Weather and plant growth cycles predict if and when pest outbreaks may occur. If properly timed, treatments or pesticides can be reduced or eliminated.
Thresholds: Before treating, wait until pest populations reach a determined level that could cause economic or irreversible plant damage.
Communication: Do regular updating of the IPM plan and pesticide/treatment list to remain effective. All staff should be educated and updated on IPM and best practices.
Recordkeeping: Keep records of pest traps, weather and treatments to determine thresholds, for comparison and use in pest management decisions.
Cultural, biological and chemical controls: The pest's environment can be disrupted by turning under gardens, mowing prairies, sterilizing tools and harvesting early. Land managers can conserve by attracting and/or using the many beneficial natural enemies already at work. Use chemicals or pesticides only as a last resort, follow the label, and only when weather conditions permit.
- Hand weeding
- Biocontrols, beneficial insects, nematods
- Building soil health, composting, mulching (wood chip, leaf, or pine needles)
- Insecticidal soaps, diatomaceous earth, corn gluten, white vinegar
- Goats, sheep or cattle for vegetation management
Pollinator friendly habitat provides:
- diverse and abundant pollinator food sources including blooms from spring through fall with nectar and pollen;
- clean water source;
- "untidy" areas for nesting and overwintering
Housing (nest areas or bee houses): Native bees and butterflies share the same basic life cycle - egg, larva, pupa, and adult - and also the same basic habitat needs: place to lay eggs, flowers on which to forage for nectar and pollen. Butterflies lay eggs on plants suitable for their caterpillars to eat, whereas bees create a nest in a secure location and stock it with food for their offspring. Nest areas include:
- underneath tree bark or siding,
- mulch or compost piles,
- dead or laying wood and wood piles
- open soil for underground nests
- brush or shrubs, prairie grasses
- bee or butterfly house
- abandoned mouse holes or bird nests,
Raising young: Some butterflies are very particular about which host-plants to lay eggs such as Monarch caterpillars with milkweeds. Although a butterfly may carefully choose a host plant, her parental responsibility ends when she lays her eggs. However a female bee needs to create a secure nest area, stock the nest with nectar and pollen for the larvae/young to eat. Some solitary bee offspring stay with the nest for about 11 months, passing through egg, larva, and pupa stages before emerging as an adult. Some social bees like bumble bees nest as a colony in small cavities such as an old mouse nest.
Beetle banks (mulch piles): Years ago, farmers used beetle banks as standard practice to attract beneficial insects for pest control. Farmers made beetle banks by tilling a row alongside their crop rows, leaving the soil disturbed, and then seeding it with tall grasses. Today, beetle banks are more of a bump/pile rather than a bank. Nevertheless, these beneficial insect habitats serve the same purpose. Beetle bumps are comprised of a pile of wood chips or compost. This creates a protected environment for pollinators and beneficial insects to nest and over winter.
Bees forage for themselves and to supply their colony and/or nests. Butterflies and solitary bees will drink nectar from any flower they can reach with their tongue (probiscus). Some pollinators are particular about their food flowers, where some are generalists and gather pollen from many different flower species. Specialists rely on a single plant species. The lifecycles of specialist are closely tied to the host plant. It's important to provide a variety of plants as host or "nursery" plants and others to provide nectar and pollen from spring through fall.
Pollinator Friendly habitat benefits:
- Other species of wildlife benefit too, such as birds that eat flower seed and caterpillars
- Visual interest and relaxation
- Interpretative signage provides awareness
- Supports biodiversity
- Sense of community pride and engagement
- Increased property values
- Clean water and healthy environment
- Select a sunny site, open and well-ventilated with low unwanted weed densities.
- Select plants that will prosper in the soil and growing conditions. Prairie meadow are low maintenance if you choose the correct seed and plant mix. Include a wide variety of plants and grasses to ensure year-round interest.
- Site preparation includes removing all weed plants (site prep methods):
- Remove weed plants using organic site prep (smothering, solarization)
- Plant a cover crop of buckwheat or winter wheat to out compete weed plants (smother cropping)
- Repeated deep soil tillage every three weeks for a full growing season.
- Sod removal or turf cutter on turf lawns with minimal weeds.
- Choose the best planting time, either spring (spring thaw - June 15) or fall (Sept. 15 - soil freeze). Some plants remain dormant or need to overwinter, and come up the following spring. Watering the first two months encourages higher seed germination and survival. Fall planted prairies do not require watering, the seed will germinate the next spring. A nurse crop that germinates in fall such as annual rye is recommended for fall plantings. Prairie seed can be: 1) no-till seeder such as a seed drill which minimizes soil disturbance and has less weeds, 2) broadcast seeder, or 3) hand broadcast. Seed quality is important. Choose a quality supplier.
- Management: Prairies, gardens and other habitat require timed mowing, burning, weeding and watering when needed. The first year will require extra care, and especially the first several weeks to remove the unwanted weeds that emerge from the seed bed (hand pull or selectively weed wack). A native prairie generally takes 3 years to fully establish.
Community native flower garden installation, Stillwater, Minnesota
Underutilized lot in Stillwater, Minnesota by Pollinator Friendly Alliance
Native prairie trail through county park land, by Prairie Restorations
NATIVE SEED SOURCES:
Board of Water & Soil Resources: https://bwsr.state.mn.us/seed-mixes
Xerces Society pollinator conservation seed mixes: https://xerces.org/pollinator-conservation/pollinator-conservation-seed-mixes
Minnesota Native Landscapes seed: https://mnnativelandscapes.com/products/seed/
Prairie Restorations seed: http://www.prairieresto.com/pollinator-package.shtml
Prairie Moon seed: https://www.prairiemoon.com/seed-mixes/
Johnston Seed Company seed: https://www.johnstonseed.com/products/wildflowers/